[feature] media: add webp support (#1155)

* media: add webp support

Signed-off-by: Sigrid Solveig Haflínudóttir <sigrid@ftrv.se>

* bump exif-terminator to v0.5.0

Signed-off-by: Sigrid Solveig Haflínudóttir <sigrid@ftrv.se>

Signed-off-by: Sigrid Solveig Haflínudóttir <sigrid@ftrv.se>
This commit is contained in:
Sigrid Solveig Haflínudóttir 2022-12-06 14:15:25 +01:00 committed by GitHub
parent f9e5ec99bd
commit 1a3f26fb5c
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
26 changed files with 4348 additions and 19 deletions

4
go.mod
View file

@ -40,7 +40,7 @@ require (
github.com/spf13/viper v1.14.0
github.com/stretchr/testify v1.8.1
github.com/superseriousbusiness/activity v1.2.1-gts
github.com/superseriousbusiness/exif-terminator v0.4.0
github.com/superseriousbusiness/exif-terminator v0.5.0
github.com/superseriousbusiness/oauth2/v4 v4.3.2-SSB
github.com/tdewolff/minify/v2 v2.12.4
github.com/ulule/limiter/v3 v3.10.0
@ -50,6 +50,7 @@ require (
github.com/wagslane/go-password-validator v0.3.0
golang.org/x/crypto v0.0.0-20220829220503-c86fa9a7ed90
golang.org/x/exp v0.0.0-20220613132600-b0d781184e0d
golang.org/x/image v0.1.0
golang.org/x/net v0.0.0-20221014081412-f15817d10f9b
golang.org/x/oauth2 v0.0.0-20221014153046-6fdb5e3db783
golang.org/x/text v0.4.0
@ -134,7 +135,6 @@ require (
github.com/ugorji/go/codec v1.2.7 // indirect
github.com/vmihailenco/msgpack/v5 v5.3.5 // indirect
github.com/vmihailenco/tagparser/v2 v2.0.0 // indirect
golang.org/x/image v0.0.0-20220902085622-e7cb96979f69 // indirect
golang.org/x/mod v0.6.0-dev.0.20220907135952-02c991387e35 // indirect
golang.org/x/sys v0.2.0 // indirect
golang.org/x/tools v0.1.12 // indirect

14
go.sum
View file

@ -571,8 +571,8 @@ github.com/subosito/gotenv v1.4.1 h1:jyEFiXpy21Wm81FBN71l9VoMMV8H8jG+qIK3GCpY6Qs
github.com/subosito/gotenv v1.4.1/go.mod h1:ayKnFf/c6rvx/2iiLrJUk1e6plDbT3edrFNGqEflhK0=
github.com/superseriousbusiness/activity v1.2.1-gts h1:wh7v0zYa1mJmqB35PSfvgl4cs51Dh5PyfKvcZLSxMQU=
github.com/superseriousbusiness/activity v1.2.1-gts/go.mod h1:AZw0Xb4Oju8rmaJCZ21gc5CPg47MmNgyac+Hx5jo8VM=
github.com/superseriousbusiness/exif-terminator v0.4.0 h1:pzAg7luCi8oc2LVDwgTLvTinh/+/2UuWgJZrM8MMaT4=
github.com/superseriousbusiness/exif-terminator v0.4.0/go.mod h1:OPfOSEDWjXaW3BILJBN89j0VLD8bglmHwHHwwwSLb5A=
github.com/superseriousbusiness/exif-terminator v0.5.0 h1:57SO/geyaOl2v/lJSQLVcQbdghpyFuK8ZTtaHL81fUQ=
github.com/superseriousbusiness/exif-terminator v0.5.0/go.mod h1:d5IkskXco/3XRXzOrI73uGYn+wahJEqPlQSSqn6jxSw=
github.com/superseriousbusiness/go-jpeg-image-structure/v2 v2.0.0-20220321154430-d89a106fdabe h1:ksl2oCx/Qo8sNDc3Grb8WGKBM9nkvhCm25uvlT86azE=
github.com/superseriousbusiness/go-jpeg-image-structure/v2 v2.0.0-20220321154430-d89a106fdabe/go.mod h1:gH4P6gN1V+wmIw5o97KGaa1RgXB/tVpC2UNzijhg3E4=
github.com/superseriousbusiness/oauth2/v4 v4.3.2-SSB h1:PtW2w6budTvRV2J5QAoSvThTHBuvh8t/+BXIZFAaBSc=
@ -644,6 +644,7 @@ github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9de
github.com/yuin/goldmark v1.1.32/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
github.com/yuin/goldmark v1.3.5/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
github.com/zeebo/assert v1.1.0/go.mod h1:Pq9JiuJQpG8JLJdtkwrJESF0Foym2/D9XMU5ciN/wJ0=
github.com/zeebo/blake3 v0.2.1/go.mod h1:TSQ0KjMH+pht+bRyvVooJ1rBpvvngSGaPISafq9MxJk=
github.com/zeebo/pcg v1.0.1/go.mod h1:09F0S9iiKrwn9rlI5yjLkmrug154/YRW6KnnXVDM/l4=
@ -678,6 +679,7 @@ golang.org/x/crypto v0.0.0-20201203163018-be400aefbc4c/go.mod h1:jdWPYTVW3xRLrWP
golang.org/x/crypto v0.0.0-20210421170649-83a5a9bb288b/go.mod h1:T9bdIzuCu7OtxOm1hfPfRQxPLYneinmdGuTeoZ9dtd4=
golang.org/x/crypto v0.0.0-20210616213533-5ff15b29337e/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
golang.org/x/crypto v0.0.0-20210711020723-a769d52b0f97/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
golang.org/x/crypto v0.0.0-20211108221036-ceb1ce70b4fa/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
golang.org/x/crypto v0.0.0-20211215153901-e495a2d5b3d3/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
golang.org/x/crypto v0.0.0-20220722155217-630584e8d5aa/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
@ -698,8 +700,8 @@ golang.org/x/exp v0.0.0-20220613132600-b0d781184e0d/go.mod h1:Kr81I6Kryrl9sr8s2F
golang.org/x/image v0.0.0-20190227222117-0694c2d4d067/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
golang.org/x/image v0.0.0-20190802002840-cff245a6509b/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
golang.org/x/image v0.0.0-20220902085622-e7cb96979f69 h1:Lj6HJGCSn5AjxRAH2+r35Mir4icalbqku+CLUtjnvXY=
golang.org/x/image v0.0.0-20220902085622-e7cb96979f69/go.mod h1:doUCurBvlfPMKfmIpRIywoHmhN3VyhnoFDbvIEWF4hY=
golang.org/x/image v0.1.0 h1:r8Oj8ZA2Xy12/b5KZYj3tuv7NG/fBz3TwQVvpJ9l8Rk=
golang.org/x/image v0.1.0/go.mod h1:iyPr49SD/G/TBxYVB/9RRtGUT5eNbo2u4NamWeQcD5c=
golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=
golang.org/x/lint v0.0.0-20190301231843-5614ed5bae6f/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
@ -723,6 +725,7 @@ golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
golang.org/x/mod v0.4.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
golang.org/x/mod v0.4.1/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
golang.org/x/mod v0.6.0-dev.0.20220907135952-02c991387e35 h1:CZP0Rbk/s1EIiUMx5DS2MhK2ct52xpQxqddVD0FmF+o=
golang.org/x/mod v0.6.0-dev.0.20220907135952-02c991387e35/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
@ -774,6 +777,7 @@ golang.org/x/net v0.0.0-20220412020605-290c469a71a5/go.mod h1:CfG3xpIq0wQ8r1q4Su
golang.org/x/net v0.0.0-20220425223048-2871e0cb64e4/go.mod h1:CfG3xpIq0wQ8r1q4Su4UZFWDARRcnwPjda9FqA0JpMk=
golang.org/x/net v0.0.0-20220607020251-c690dde0001d/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
golang.org/x/net v0.0.0-20220624214902-1bab6f366d9e/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
golang.org/x/net v0.0.0-20220826154423-83b083e8dc8b/go.mod h1:YDH+HFinaLZZlnHAfSS6ZXJJ9M9t4Dl22yv3iI2vPwk=
golang.org/x/net v0.0.0-20221014081412-f15817d10f9b h1:tvrvnPFcdzp294diPnrdZZZ8XUt2Tyj7svb7X52iDuU=
golang.org/x/net v0.0.0-20221014081412-f15817d10f9b/go.mod h1:YDH+HFinaLZZlnHAfSS6ZXJJ9M9t4Dl22yv3iI2vPwk=
@ -812,6 +816,7 @@ golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJ
golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sync v0.0.0-20220601150217-0de741cfad7f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sync v0.1.0 h1:wsuoTGHzEhffawBOhz5CYhcrV4IdKZbEyZjBMuTp12o=
golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
@ -888,6 +893,7 @@ golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBc
golang.org/x/sys v0.0.0-20220610221304-9f5ed59c137d/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20220704084225-05e143d24a9e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.0.0-20220908164124-27713097b956/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

View file

@ -65,7 +65,7 @@ func (suite *InstancePatchTestSuite) TestInstancePatch1() {
b, err := io.ReadAll(result.Body)
suite.NoError(err)
suite.Equal(`{"uri":"http://localhost:8080","account_domain":"localhost:8080","title":"Example Instance","description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","short_description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","email":"someone@example.org","version":"0.0.0-testrig","registrations":true,"approval_required":true,"invites_enabled":false,"configuration":{"statuses":{"max_characters":5000,"max_media_attachments":6,"characters_reserved_per_url":25},"media_attachments":{"supported_mime_types":["image/jpeg","image/gif","image/png"],"image_size_limit":10485760,"image_matrix_limit":16777216,"video_size_limit":41943040,"video_frame_rate_limit":60,"video_matrix_limit":16777216},"polls":{"max_options":6,"max_characters_per_option":50,"min_expiration":300,"max_expiration":2629746},"accounts":{"allow_custom_css":true},"emojis":{"emoji_size_limit":51200}},"urls":{"streaming_api":"wss://localhost:8080"},"stats":{"domain_count":2,"status_count":16,"user_count":4},"thumbnail":"http://localhost:8080/assets/logo.png","contact_account":{"id":"01F8MH17FWEB39HZJ76B6VXSKF","username":"admin","acct":"admin","display_name":"","locked":false,"bot":false,"created_at":"2022-05-17T13:10:59.000Z","note":"","url":"http://localhost:8080/@admin","avatar":"","avatar_static":"","header":"http://localhost:8080/assets/default_header.png","header_static":"http://localhost:8080/assets/default_header.png","followers_count":1,"following_count":1,"statuses_count":4,"last_status_at":"2021-10-20T10:41:37.000Z","emojis":[],"fields":[],"enable_rss":true,"role":"admin"},"max_toot_chars":5000}`, string(b))
suite.Equal(`{"uri":"http://localhost:8080","account_domain":"localhost:8080","title":"Example Instance","description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","short_description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","email":"someone@example.org","version":"0.0.0-testrig","registrations":true,"approval_required":true,"invites_enabled":false,"configuration":{"statuses":{"max_characters":5000,"max_media_attachments":6,"characters_reserved_per_url":25},"media_attachments":{"supported_mime_types":["image/jpeg","image/gif","image/png","image/webp"],"image_size_limit":10485760,"image_matrix_limit":16777216,"video_size_limit":41943040,"video_frame_rate_limit":60,"video_matrix_limit":16777216},"polls":{"max_options":6,"max_characters_per_option":50,"min_expiration":300,"max_expiration":2629746},"accounts":{"allow_custom_css":true},"emojis":{"emoji_size_limit":51200}},"urls":{"streaming_api":"wss://localhost:8080"},"stats":{"domain_count":2,"status_count":16,"user_count":4},"thumbnail":"http://localhost:8080/assets/logo.png","contact_account":{"id":"01F8MH17FWEB39HZJ76B6VXSKF","username":"admin","acct":"admin","display_name":"","locked":false,"bot":false,"created_at":"2022-05-17T13:10:59.000Z","note":"","url":"http://localhost:8080/@admin","avatar":"","avatar_static":"","header":"http://localhost:8080/assets/default_header.png","header_static":"http://localhost:8080/assets/default_header.png","followers_count":1,"following_count":1,"statuses_count":4,"last_status_at":"2021-10-20T10:41:37.000Z","emojis":[],"fields":[],"enable_rss":true,"role":"admin"},"max_toot_chars":5000}`, string(b))
}
func (suite *InstancePatchTestSuite) TestInstancePatch2() {
@ -95,7 +95,7 @@ func (suite *InstancePatchTestSuite) TestInstancePatch2() {
b, err := io.ReadAll(result.Body)
suite.NoError(err)
suite.Equal(`{"uri":"http://localhost:8080","account_domain":"localhost:8080","title":"Geoff's Instance","description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","short_description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","email":"admin@example.org","version":"0.0.0-testrig","registrations":true,"approval_required":true,"invites_enabled":false,"configuration":{"statuses":{"max_characters":5000,"max_media_attachments":6,"characters_reserved_per_url":25},"media_attachments":{"supported_mime_types":["image/jpeg","image/gif","image/png"],"image_size_limit":10485760,"image_matrix_limit":16777216,"video_size_limit":41943040,"video_frame_rate_limit":60,"video_matrix_limit":16777216},"polls":{"max_options":6,"max_characters_per_option":50,"min_expiration":300,"max_expiration":2629746},"accounts":{"allow_custom_css":true},"emojis":{"emoji_size_limit":51200}},"urls":{"streaming_api":"wss://localhost:8080"},"stats":{"domain_count":2,"status_count":16,"user_count":4},"thumbnail":"http://localhost:8080/assets/logo.png","contact_account":{"id":"01F8MH17FWEB39HZJ76B6VXSKF","username":"admin","acct":"admin","display_name":"","locked":false,"bot":false,"created_at":"2022-05-17T13:10:59.000Z","note":"","url":"http://localhost:8080/@admin","avatar":"","avatar_static":"","header":"http://localhost:8080/assets/default_header.png","header_static":"http://localhost:8080/assets/default_header.png","followers_count":1,"following_count":1,"statuses_count":4,"last_status_at":"2021-10-20T10:41:37.000Z","emojis":[],"fields":[],"enable_rss":true,"role":"admin"},"max_toot_chars":5000}`, string(b))
suite.Equal(`{"uri":"http://localhost:8080","account_domain":"localhost:8080","title":"Geoff's Instance","description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","short_description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","email":"admin@example.org","version":"0.0.0-testrig","registrations":true,"approval_required":true,"invites_enabled":false,"configuration":{"statuses":{"max_characters":5000,"max_media_attachments":6,"characters_reserved_per_url":25},"media_attachments":{"supported_mime_types":["image/jpeg","image/gif","image/png","image/webp"],"image_size_limit":10485760,"image_matrix_limit":16777216,"video_size_limit":41943040,"video_frame_rate_limit":60,"video_matrix_limit":16777216},"polls":{"max_options":6,"max_characters_per_option":50,"min_expiration":300,"max_expiration":2629746},"accounts":{"allow_custom_css":true},"emojis":{"emoji_size_limit":51200}},"urls":{"streaming_api":"wss://localhost:8080"},"stats":{"domain_count":2,"status_count":16,"user_count":4},"thumbnail":"http://localhost:8080/assets/logo.png","contact_account":{"id":"01F8MH17FWEB39HZJ76B6VXSKF","username":"admin","acct":"admin","display_name":"","locked":false,"bot":false,"created_at":"2022-05-17T13:10:59.000Z","note":"","url":"http://localhost:8080/@admin","avatar":"","avatar_static":"","header":"http://localhost:8080/assets/default_header.png","header_static":"http://localhost:8080/assets/default_header.png","followers_count":1,"following_count":1,"statuses_count":4,"last_status_at":"2021-10-20T10:41:37.000Z","emojis":[],"fields":[],"enable_rss":true,"role":"admin"},"max_toot_chars":5000}`, string(b))
}
func (suite *InstancePatchTestSuite) TestInstancePatch3() {
@ -125,7 +125,7 @@ func (suite *InstancePatchTestSuite) TestInstancePatch3() {
b, err := io.ReadAll(result.Body)
suite.NoError(err)
suite.Equal(`{"uri":"http://localhost:8080","account_domain":"localhost:8080","title":"GoToSocial Testrig Instance","description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","short_description":"\u003cp\u003eThis is some html, which is \u003cem\u003eallowed\u003c/em\u003e in short descriptions.\u003c/p\u003e","email":"admin@example.org","version":"0.0.0-testrig","registrations":true,"approval_required":true,"invites_enabled":false,"configuration":{"statuses":{"max_characters":5000,"max_media_attachments":6,"characters_reserved_per_url":25},"media_attachments":{"supported_mime_types":["image/jpeg","image/gif","image/png"],"image_size_limit":10485760,"image_matrix_limit":16777216,"video_size_limit":41943040,"video_frame_rate_limit":60,"video_matrix_limit":16777216},"polls":{"max_options":6,"max_characters_per_option":50,"min_expiration":300,"max_expiration":2629746},"accounts":{"allow_custom_css":true},"emojis":{"emoji_size_limit":51200}},"urls":{"streaming_api":"wss://localhost:8080"},"stats":{"domain_count":2,"status_count":16,"user_count":4},"thumbnail":"http://localhost:8080/assets/logo.png","contact_account":{"id":"01F8MH17FWEB39HZJ76B6VXSKF","username":"admin","acct":"admin","display_name":"","locked":false,"bot":false,"created_at":"2022-05-17T13:10:59.000Z","note":"","url":"http://localhost:8080/@admin","avatar":"","avatar_static":"","header":"http://localhost:8080/assets/default_header.png","header_static":"http://localhost:8080/assets/default_header.png","followers_count":1,"following_count":1,"statuses_count":4,"last_status_at":"2021-10-20T10:41:37.000Z","emojis":[],"fields":[],"enable_rss":true,"role":"admin"},"max_toot_chars":5000}`, string(b))
suite.Equal(`{"uri":"http://localhost:8080","account_domain":"localhost:8080","title":"GoToSocial Testrig Instance","description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","short_description":"\u003cp\u003eThis is some html, which is \u003cem\u003eallowed\u003c/em\u003e in short descriptions.\u003c/p\u003e","email":"admin@example.org","version":"0.0.0-testrig","registrations":true,"approval_required":true,"invites_enabled":false,"configuration":{"statuses":{"max_characters":5000,"max_media_attachments":6,"characters_reserved_per_url":25},"media_attachments":{"supported_mime_types":["image/jpeg","image/gif","image/png","image/webp"],"image_size_limit":10485760,"image_matrix_limit":16777216,"video_size_limit":41943040,"video_frame_rate_limit":60,"video_matrix_limit":16777216},"polls":{"max_options":6,"max_characters_per_option":50,"min_expiration":300,"max_expiration":2629746},"accounts":{"allow_custom_css":true},"emojis":{"emoji_size_limit":51200}},"urls":{"streaming_api":"wss://localhost:8080"},"stats":{"domain_count":2,"status_count":16,"user_count":4},"thumbnail":"http://localhost:8080/assets/logo.png","contact_account":{"id":"01F8MH17FWEB39HZJ76B6VXSKF","username":"admin","acct":"admin","display_name":"","locked":false,"bot":false,"created_at":"2022-05-17T13:10:59.000Z","note":"","url":"http://localhost:8080/@admin","avatar":"","avatar_static":"","header":"http://localhost:8080/assets/default_header.png","header_static":"http://localhost:8080/assets/default_header.png","followers_count":1,"following_count":1,"statuses_count":4,"last_status_at":"2021-10-20T10:41:37.000Z","emojis":[],"fields":[],"enable_rss":true,"role":"admin"},"max_toot_chars":5000}`, string(b))
}
func (suite *InstancePatchTestSuite) TestInstancePatch4() {
@ -216,7 +216,7 @@ func (suite *InstancePatchTestSuite) TestInstancePatch6() {
b, err := io.ReadAll(result.Body)
suite.NoError(err)
suite.Equal(`{"uri":"http://localhost:8080","account_domain":"localhost:8080","title":"GoToSocial Testrig Instance","description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","short_description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","email":"","version":"0.0.0-testrig","registrations":true,"approval_required":true,"invites_enabled":false,"configuration":{"statuses":{"max_characters":5000,"max_media_attachments":6,"characters_reserved_per_url":25},"media_attachments":{"supported_mime_types":["image/jpeg","image/gif","image/png"],"image_size_limit":10485760,"image_matrix_limit":16777216,"video_size_limit":41943040,"video_frame_rate_limit":60,"video_matrix_limit":16777216},"polls":{"max_options":6,"max_characters_per_option":50,"min_expiration":300,"max_expiration":2629746},"accounts":{"allow_custom_css":true},"emojis":{"emoji_size_limit":51200}},"urls":{"streaming_api":"wss://localhost:8080"},"stats":{"domain_count":2,"status_count":16,"user_count":4},"thumbnail":"http://localhost:8080/assets/logo.png","contact_account":{"id":"01F8MH17FWEB39HZJ76B6VXSKF","username":"admin","acct":"admin","display_name":"","locked":false,"bot":false,"created_at":"2022-05-17T13:10:59.000Z","note":"","url":"http://localhost:8080/@admin","avatar":"","avatar_static":"","header":"http://localhost:8080/assets/default_header.png","header_static":"http://localhost:8080/assets/default_header.png","followers_count":1,"following_count":1,"statuses_count":4,"last_status_at":"2021-10-20T10:41:37.000Z","emojis":[],"fields":[],"enable_rss":true,"role":"admin"},"max_toot_chars":5000}`, string(b))
suite.Equal(`{"uri":"http://localhost:8080","account_domain":"localhost:8080","title":"GoToSocial Testrig Instance","description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","short_description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","email":"","version":"0.0.0-testrig","registrations":true,"approval_required":true,"invites_enabled":false,"configuration":{"statuses":{"max_characters":5000,"max_media_attachments":6,"characters_reserved_per_url":25},"media_attachments":{"supported_mime_types":["image/jpeg","image/gif","image/png","image/webp"],"image_size_limit":10485760,"image_matrix_limit":16777216,"video_size_limit":41943040,"video_frame_rate_limit":60,"video_matrix_limit":16777216},"polls":{"max_options":6,"max_characters_per_option":50,"min_expiration":300,"max_expiration":2629746},"accounts":{"allow_custom_css":true},"emojis":{"emoji_size_limit":51200}},"urls":{"streaming_api":"wss://localhost:8080"},"stats":{"domain_count":2,"status_count":16,"user_count":4},"thumbnail":"http://localhost:8080/assets/logo.png","contact_account":{"id":"01F8MH17FWEB39HZJ76B6VXSKF","username":"admin","acct":"admin","display_name":"","locked":false,"bot":false,"created_at":"2022-05-17T13:10:59.000Z","note":"","url":"http://localhost:8080/@admin","avatar":"","avatar_static":"","header":"http://localhost:8080/assets/default_header.png","header_static":"http://localhost:8080/assets/default_header.png","followers_count":1,"following_count":1,"statuses_count":4,"last_status_at":"2021-10-20T10:41:37.000Z","emojis":[],"fields":[],"enable_rss":true,"role":"admin"},"max_toot_chars":5000}`, string(b))
}
func (suite *InstancePatchTestSuite) TestInstancePatch7() {
@ -279,7 +279,7 @@ func (suite *InstancePatchTestSuite) TestInstancePatch8() {
}
suite.NotEmpty(instanceAccount.AvatarMediaAttachmentID)
expectedInstanceResponse := fmt.Sprintf(`{"uri":"http://localhost:8080","account_domain":"localhost:8080","title":"GoToSocial Testrig Instance","description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","short_description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","email":"admin@example.org","version":"0.0.0-testrig","registrations":true,"approval_required":true,"invites_enabled":false,"configuration":{"statuses":{"max_characters":5000,"max_media_attachments":6,"characters_reserved_per_url":25},"media_attachments":{"supported_mime_types":["image/jpeg","image/gif","image/png"],"image_size_limit":10485760,"image_matrix_limit":16777216,"video_size_limit":41943040,"video_frame_rate_limit":60,"video_matrix_limit":16777216},"polls":{"max_options":6,"max_characters_per_option":50,"min_expiration":300,"max_expiration":2629746},"accounts":{"allow_custom_css":true},"emojis":{"emoji_size_limit":51200}},"urls":{"streaming_api":"wss://localhost:8080"},"stats":{"domain_count":2,"status_count":16,"user_count":4},"thumbnail":"http://localhost:8080/fileserver/%s/attachment/original/%s.gif","thumbnail_type":"image/gif","thumbnail_description":"A bouncing little green peglin.","contact_account":{"id":"01F8MH17FWEB39HZJ76B6VXSKF","username":"admin","acct":"admin","display_name":"","locked":false,"bot":false,"created_at":"2022-05-17T13:10:59.000Z","note":"","url":"http://localhost:8080/@admin","avatar":"","avatar_static":"","header":"http://localhost:8080/assets/default_header.png","header_static":"http://localhost:8080/assets/default_header.png","followers_count":1,"following_count":1,"statuses_count":4,"last_status_at":"2021-10-20T10:41:37.000Z","emojis":[],"fields":[],"enable_rss":true,"role":"admin"},"max_toot_chars":5000}`, instanceAccount.ID, instanceAccount.AvatarMediaAttachmentID)
expectedInstanceResponse := fmt.Sprintf(`{"uri":"http://localhost:8080","account_domain":"localhost:8080","title":"GoToSocial Testrig Instance","description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","short_description":"\u003cp\u003eThis is the GoToSocial testrig. It doesn't federate or anything.\u003c/p\u003e\u003cp\u003eWhen the testrig is shut down, all data on it will be deleted.\u003c/p\u003e\u003cp\u003eDon't use this in production!\u003c/p\u003e","email":"admin@example.org","version":"0.0.0-testrig","registrations":true,"approval_required":true,"invites_enabled":false,"configuration":{"statuses":{"max_characters":5000,"max_media_attachments":6,"characters_reserved_per_url":25},"media_attachments":{"supported_mime_types":["image/jpeg","image/gif","image/png","image/webp"],"image_size_limit":10485760,"image_matrix_limit":16777216,"video_size_limit":41943040,"video_frame_rate_limit":60,"video_matrix_limit":16777216},"polls":{"max_options":6,"max_characters_per_option":50,"min_expiration":300,"max_expiration":2629746},"accounts":{"allow_custom_css":true},"emojis":{"emoji_size_limit":51200}},"urls":{"streaming_api":"wss://localhost:8080"},"stats":{"domain_count":2,"status_count":16,"user_count":4},"thumbnail":"http://localhost:8080/fileserver/%s/attachment/original/%s.gif","thumbnail_type":"image/gif","thumbnail_description":"A bouncing little green peglin.","contact_account":{"id":"01F8MH17FWEB39HZJ76B6VXSKF","username":"admin","acct":"admin","display_name":"","locked":false,"bot":false,"created_at":"2022-05-17T13:10:59.000Z","note":"","url":"http://localhost:8080/@admin","avatar":"","avatar_static":"","header":"http://localhost:8080/assets/default_header.png","header_static":"http://localhost:8080/assets/default_header.png","followers_count":1,"following_count":1,"statuses_count":4,"last_status_at":"2021-10-20T10:41:37.000Z","emojis":[],"fields":[],"enable_rss":true,"role":"admin"},"max_toot_chars":5000}`, instanceAccount.ID, instanceAccount.AvatarMediaAttachmentID)
suite.Equal(expectedInstanceResponse, string(b))
}

View file

@ -30,6 +30,7 @@
"github.com/buckket/go-blurhash"
"github.com/disintegration/imaging"
_ "golang.org/x/image/webp" // blank import to support WebP decoding
)
const (
@ -71,7 +72,7 @@ func decodeImage(r io.Reader, contentType string) (*imageMeta, error) {
var err error
switch contentType {
case mimeImageJpeg:
case mimeImageJpeg, mimeImageWebp:
i, err = imaging.Decode(r, imaging.AutoOrientation(true))
case mimeImagePng:
strippedPngReader := io.Reader(&PNGAncillaryChunkStripper{
@ -104,7 +105,7 @@ func decodeImage(r io.Reader, contentType string) (*imageMeta, error) {
}
// deriveThumbnail returns a byte slice and metadata for a thumbnail
// of a given jpeg, png, or gif, or an error if something goes wrong.
// of a given jpeg, png, gif or webp, or an error if something goes wrong.
//
// If createBlurhash is true, then a blurhash will also be generated from a tiny
// version of the image. This costs precious CPU cycles, so only use it if you
@ -117,7 +118,7 @@ func deriveThumbnail(r io.Reader, contentType string, createBlurhash bool) (*ima
var err error
switch contentType {
case mimeImageJpeg, mimeImageGif:
case mimeImageJpeg, mimeImageGif, mimeImageWebp:
i, err = imaging.Decode(r, imaging.AutoOrientation(true))
case mimeImagePng:
strippedPngReader := io.Reader(&PNGAncillaryChunkStripper{

View file

@ -215,7 +215,7 @@ func (p *ProcessingMedia) loadFullSize(ctx context.Context) error {
// decode the image
ct := p.attachment.File.ContentType
switch ct {
case mimeImageJpeg, mimeImagePng:
case mimeImageJpeg, mimeImagePng, mimeImageWebp:
decoded, err = decodeImage(stored, ct)
case mimeImageGif:
decoded, err = decodeGif(stored)
@ -319,7 +319,7 @@ func (p *ProcessingMedia) store(ctx context.Context) error {
p.attachment.Type = gtsmodel.FileTypeImage
// nothing to terminate, we can just store the multireader
readerToStore = multiReader
case mimeJpeg, mimePng:
case mimeJpeg, mimePng, mimeWebp:
p.attachment.Type = gtsmodel.FileTypeImage
if fileSize > 0 {
terminated, err := terminator.Terminate(multiReader, int(fileSize), extension)

View file

@ -43,6 +43,9 @@
mimePng = "png"
mimeImagePng = mimeImage + "/" + mimePng
mimeWebp = "webp"
mimeImageWebp = mimeImage + "/" + mimeWebp
)
type processState int32

View file

@ -37,6 +37,7 @@ func AllSupportedMIMETypes() []string {
mimeImageJpeg,
mimeImageGif,
mimeImagePng,
mimeImageWebp,
}
}
@ -68,6 +69,7 @@ func supportedImage(mimeType string) bool {
mimeImageJpeg,
mimeImageGif,
mimeImagePng,
mimeImageWebp,
}
for _, accepted := range acceptedImageTypes {
if mimeType == accepted {

View file

@ -91,7 +91,7 @@ func (v *jpegVisitor) HandleSegment(segmentMarker byte, _ string, _ int, _ bool)
if segmentMarker == jpegstructure.MARKER_EOI {
// take account of the last 2 bytes taken up by the EOI
eoiLength := 2
// this is the total file size we will
// have written including the EOI
willHaveWritten := v.writtenTotalBytes + eoiLength

View file

@ -43,6 +43,8 @@ func Terminate(in io.Reader, fileSize int, mediaType string) (io.Reader, error)
switch mediaType {
case "image/jpeg", "jpeg", "jpg":
err = terminateJpeg(scanner, pipeWriter, fileSize)
case "image/webp", "webp":
err = terminateWebp(scanner, pipeWriter)
case "image/png", "png":
// for pngs we need to skip the header bytes, so read them in
// and check we're really dealing with a png here
@ -86,6 +88,18 @@ func terminateJpeg(scanner *bufio.Scanner, writer io.WriteCloser, expectedFileSi
return nil
}
func terminateWebp(scanner *bufio.Scanner, writer io.WriteCloser) error {
v := &webpVisitor{
writer: writer,
}
// use the webp visitor's 'split' function, which satisfies the bufio.SplitFunc interface
scanner.Split(v.split)
scanAndClose(scanner, writer)
return nil
}
func terminatePng(scanner *bufio.Scanner, writer io.WriteCloser) error {
ps := pngstructure.NewPngSplitter()

View file

@ -0,0 +1,101 @@
/*
exif-terminator
Copyright (C) 2022 SuperSeriousBusiness admin@gotosocial.org
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package terminator
import (
"encoding/binary"
"errors"
"io"
)
const (
riffHeaderSize = 4 * 3
)
var (
riffHeader = [4]byte{'R', 'I', 'F', 'F'}
webpHeader = [4]byte{'W', 'E', 'B', 'P'}
exifFourcc = [4]byte{'E', 'X', 'I', 'F'}
xmpFourcc = [4]byte{'X', 'M', 'P', ' '}
errNoRiffHeader = errors.New("no RIFF header")
errNoWebpHeader = errors.New("not a WEBP file")
)
type webpVisitor struct {
writer io.Writer
doneHeader bool
}
func fourCC(b []byte) [4]byte {
return [4]byte{b[0], b[1], b[2], b[3]}
}
func (v *webpVisitor) split(data []byte, atEOF bool) (advance int, token []byte, err error) {
// parse/write the header first
if !v.doneHeader {
if len(data) < riffHeaderSize {
// need the full header
return
}
if fourCC(data) != riffHeader {
err = errNoRiffHeader
return
}
if fourCC(data[8:]) != webpHeader {
err = errNoWebpHeader
return
}
if _, err = v.writer.Write(data[:riffHeaderSize]); err != nil {
return
}
advance += riffHeaderSize
data = data[riffHeaderSize:]
v.doneHeader = true
}
// need enough for fourcc and size
if len(data) < 8 {
return
}
size := int64(binary.LittleEndian.Uint32(data[4:]))
if (size & 1) != 0 {
// odd chunk size - extra padding byte
size++
}
// wait until there is enough
if int64(len(data)-8) < size {
return
}
fourcc := fourCC(data)
rawChunkData := data[8 : 8+size]
if fourcc == exifFourcc || fourcc == xmpFourcc {
// replace exif/xmp with blank
rawChunkData = make([]byte, size)
}
if _, err = v.writer.Write(data[:8]); err == nil {
if _, err = v.writer.Write(rawChunkData); err == nil {
advance += 8 + int(size)
}
}
return
}

193
vendor/golang.org/x/image/riff/riff.go generated vendored Normal file
View file

@ -0,0 +1,193 @@
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package riff implements the Resource Interchange File Format, used by media
// formats such as AVI, WAVE and WEBP.
//
// A RIFF stream contains a sequence of chunks. Each chunk consists of an 8-byte
// header (containing a 4-byte chunk type and a 4-byte chunk length), the chunk
// data (presented as an io.Reader), and some padding bytes.
//
// A detailed description of the format is at
// http://www.tactilemedia.com/info/MCI_Control_Info.html
package riff // import "golang.org/x/image/riff"
import (
"errors"
"io"
"io/ioutil"
"math"
)
var (
errMissingPaddingByte = errors.New("riff: missing padding byte")
errMissingRIFFChunkHeader = errors.New("riff: missing RIFF chunk header")
errListSubchunkTooLong = errors.New("riff: list subchunk too long")
errShortChunkData = errors.New("riff: short chunk data")
errShortChunkHeader = errors.New("riff: short chunk header")
errStaleReader = errors.New("riff: stale reader")
)
// u32 decodes the first four bytes of b as a little-endian integer.
func u32(b []byte) uint32 {
return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
}
const chunkHeaderSize = 8
// FourCC is a four character code.
type FourCC [4]byte
// LIST is the "LIST" FourCC.
var LIST = FourCC{'L', 'I', 'S', 'T'}
// NewReader returns the RIFF stream's form type, such as "AVI " or "WAVE", and
// its chunks as a *Reader.
func NewReader(r io.Reader) (formType FourCC, data *Reader, err error) {
var buf [chunkHeaderSize]byte
if _, err := io.ReadFull(r, buf[:]); err != nil {
if err == io.EOF || err == io.ErrUnexpectedEOF {
err = errMissingRIFFChunkHeader
}
return FourCC{}, nil, err
}
if buf[0] != 'R' || buf[1] != 'I' || buf[2] != 'F' || buf[3] != 'F' {
return FourCC{}, nil, errMissingRIFFChunkHeader
}
return NewListReader(u32(buf[4:]), r)
}
// NewListReader returns a LIST chunk's list type, such as "movi" or "wavl",
// and its chunks as a *Reader.
func NewListReader(chunkLen uint32, chunkData io.Reader) (listType FourCC, data *Reader, err error) {
if chunkLen < 4 {
return FourCC{}, nil, errShortChunkData
}
z := &Reader{r: chunkData}
if _, err := io.ReadFull(chunkData, z.buf[:4]); err != nil {
if err == io.EOF || err == io.ErrUnexpectedEOF {
err = errShortChunkData
}
return FourCC{}, nil, err
}
z.totalLen = chunkLen - 4
return FourCC{z.buf[0], z.buf[1], z.buf[2], z.buf[3]}, z, nil
}
// Reader reads chunks from an underlying io.Reader.
type Reader struct {
r io.Reader
err error
totalLen uint32
chunkLen uint32
chunkReader *chunkReader
buf [chunkHeaderSize]byte
padded bool
}
// Next returns the next chunk's ID, length and data. It returns io.EOF if there
// are no more chunks. The io.Reader returned becomes stale after the next Next
// call, and should no longer be used.
//
// It is valid to call Next even if all of the previous chunk's data has not
// been read.
func (z *Reader) Next() (chunkID FourCC, chunkLen uint32, chunkData io.Reader, err error) {
if z.err != nil {
return FourCC{}, 0, nil, z.err
}
// Drain the rest of the previous chunk.
if z.chunkLen != 0 {
want := z.chunkLen
var got int64
got, z.err = io.Copy(ioutil.Discard, z.chunkReader)
if z.err == nil && uint32(got) != want {
z.err = errShortChunkData
}
if z.err != nil {
return FourCC{}, 0, nil, z.err
}
}
z.chunkReader = nil
if z.padded {
if z.totalLen == 0 {
z.err = errListSubchunkTooLong
return FourCC{}, 0, nil, z.err
}
z.totalLen--
_, z.err = io.ReadFull(z.r, z.buf[:1])
if z.err != nil {
if z.err == io.EOF {
z.err = errMissingPaddingByte
}
return FourCC{}, 0, nil, z.err
}
}
// We are done if we have no more data.
if z.totalLen == 0 {
z.err = io.EOF
return FourCC{}, 0, nil, z.err
}
// Read the next chunk header.
if z.totalLen < chunkHeaderSize {
z.err = errShortChunkHeader
return FourCC{}, 0, nil, z.err
}
z.totalLen -= chunkHeaderSize
if _, z.err = io.ReadFull(z.r, z.buf[:chunkHeaderSize]); z.err != nil {
if z.err == io.EOF || z.err == io.ErrUnexpectedEOF {
z.err = errShortChunkHeader
}
return FourCC{}, 0, nil, z.err
}
chunkID = FourCC{z.buf[0], z.buf[1], z.buf[2], z.buf[3]}
z.chunkLen = u32(z.buf[4:])
if z.chunkLen > z.totalLen {
z.err = errListSubchunkTooLong
return FourCC{}, 0, nil, z.err
}
z.padded = z.chunkLen&1 == 1
z.chunkReader = &chunkReader{z}
return chunkID, z.chunkLen, z.chunkReader, nil
}
type chunkReader struct {
z *Reader
}
func (c *chunkReader) Read(p []byte) (int, error) {
if c != c.z.chunkReader {
return 0, errStaleReader
}
z := c.z
if z.err != nil {
if z.err == io.EOF {
return 0, errStaleReader
}
return 0, z.err
}
n := int(z.chunkLen)
if n == 0 {
return 0, io.EOF
}
if n < 0 {
// Converting uint32 to int overflowed.
n = math.MaxInt32
}
if n > len(p) {
n = len(p)
}
n, err := z.r.Read(p[:n])
z.totalLen -= uint32(n)
z.chunkLen -= uint32(n)
if err != io.EOF {
z.err = err
}
return n, err
}

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package vp8 implements a decoder for the VP8 lossy image format.
//
// The VP8 specification is RFC 6386.
package vp8 // import "golang.org/x/image/vp8"
// This file implements the top-level decoding algorithm.
import (
"errors"
"image"
"io"
)
// limitReader wraps an io.Reader to read at most n bytes from it.
type limitReader struct {
r io.Reader
n int
}
// ReadFull reads exactly len(p) bytes into p.
func (r *limitReader) ReadFull(p []byte) error {
if len(p) > r.n {
return io.ErrUnexpectedEOF
}
n, err := io.ReadFull(r.r, p)
r.n -= n
return err
}
// FrameHeader is a frame header, as specified in section 9.1.
type FrameHeader struct {
KeyFrame bool
VersionNumber uint8
ShowFrame bool
FirstPartitionLen uint32
Width int
Height int
XScale uint8
YScale uint8
}
const (
nSegment = 4
nSegmentProb = 3
)
// segmentHeader holds segment-related header information.
type segmentHeader struct {
useSegment bool
updateMap bool
relativeDelta bool
quantizer [nSegment]int8
filterStrength [nSegment]int8
prob [nSegmentProb]uint8
}
const (
nRefLFDelta = 4
nModeLFDelta = 4
)
// filterHeader holds filter-related header information.
type filterHeader struct {
simple bool
level int8
sharpness uint8
useLFDelta bool
refLFDelta [nRefLFDelta]int8
modeLFDelta [nModeLFDelta]int8
perSegmentLevel [nSegment]int8
}
// mb is the per-macroblock decode state. A decoder maintains mbw+1 of these
// as it is decoding macroblocks left-to-right and top-to-bottom: mbw for the
// macroblocks in the row above, and one for the macroblock to the left.
type mb struct {
// pred is the predictor mode for the 4 bottom or right 4x4 luma regions.
pred [4]uint8
// nzMask is a mask of 8 bits: 4 for the bottom or right 4x4 luma regions,
// and 2 + 2 for the bottom or right 4x4 chroma regions. A 1 bit indicates
// that region has non-zero coefficients.
nzMask uint8
// nzY16 is a 0/1 value that is 1 if the macroblock used Y16 prediction and
// had non-zero coefficients.
nzY16 uint8
}
// Decoder decodes VP8 bitstreams into frames. Decoding one frame consists of
// calling Init, DecodeFrameHeader and then DecodeFrame in that order.
// A Decoder can be re-used to decode multiple frames.
type Decoder struct {
// r is the input bitsream.
r limitReader
// scratch is a scratch buffer.
scratch [8]byte
// img is the YCbCr image to decode into.
img *image.YCbCr
// mbw and mbh are the number of 16x16 macroblocks wide and high the image is.
mbw, mbh int
// frameHeader is the frame header. When decoding multiple frames,
// frames that aren't key frames will inherit the Width, Height,
// XScale and YScale of the most recent key frame.
frameHeader FrameHeader
// Other headers.
segmentHeader segmentHeader
filterHeader filterHeader
// The image data is divided into a number of independent partitions.
// There is 1 "first partition" and between 1 and 8 "other partitions"
// for coefficient data.
fp partition
op [8]partition
nOP int
// Quantization factors.
quant [nSegment]quant
// DCT/WHT coefficient decoding probabilities.
tokenProb [nPlane][nBand][nContext][nProb]uint8
useSkipProb bool
skipProb uint8
// Loop filter parameters.
filterParams [nSegment][2]filterParam
perMBFilterParams []filterParam
// The eight fields below relate to the current macroblock being decoded.
//
// Segment-based adjustments.
segment int
// Per-macroblock state for the macroblock immediately left of and those
// macroblocks immediately above the current macroblock.
leftMB mb
upMB []mb
// Bitmasks for which 4x4 regions of coeff contain non-zero coefficients.
nzDCMask, nzACMask uint32
// Predictor modes.
usePredY16 bool // The libwebp C code calls this !is_i4x4_.
predY16 uint8
predC8 uint8
predY4 [4][4]uint8
// The two fields below form a workspace for reconstructing a macroblock.
// Their specific sizes are documented in reconstruct.go.
coeff [1*16*16 + 2*8*8 + 1*4*4]int16
ybr [1 + 16 + 1 + 8][32]uint8
}
// NewDecoder returns a new Decoder.
func NewDecoder() *Decoder {
return &Decoder{}
}
// Init initializes the decoder to read at most n bytes from r.
func (d *Decoder) Init(r io.Reader, n int) {
d.r = limitReader{r, n}
}
// DecodeFrameHeader decodes the frame header.
func (d *Decoder) DecodeFrameHeader() (fh FrameHeader, err error) {
// All frame headers are at least 3 bytes long.
b := d.scratch[:3]
if err = d.r.ReadFull(b); err != nil {
return
}
d.frameHeader.KeyFrame = (b[0] & 1) == 0
d.frameHeader.VersionNumber = (b[0] >> 1) & 7
d.frameHeader.ShowFrame = (b[0]>>4)&1 == 1
d.frameHeader.FirstPartitionLen = uint32(b[0])>>5 | uint32(b[1])<<3 | uint32(b[2])<<11
if !d.frameHeader.KeyFrame {
return d.frameHeader, nil
}
// Frame headers for key frames are an additional 7 bytes long.
b = d.scratch[:7]
if err = d.r.ReadFull(b); err != nil {
return
}
// Check the magic sync code.
if b[0] != 0x9d || b[1] != 0x01 || b[2] != 0x2a {
err = errors.New("vp8: invalid format")
return
}
d.frameHeader.Width = int(b[4]&0x3f)<<8 | int(b[3])
d.frameHeader.Height = int(b[6]&0x3f)<<8 | int(b[5])
d.frameHeader.XScale = b[4] >> 6
d.frameHeader.YScale = b[6] >> 6
d.mbw = (d.frameHeader.Width + 0x0f) >> 4
d.mbh = (d.frameHeader.Height + 0x0f) >> 4
d.segmentHeader = segmentHeader{
prob: [3]uint8{0xff, 0xff, 0xff},
}
d.tokenProb = defaultTokenProb
d.segment = 0
return d.frameHeader, nil
}
// ensureImg ensures that d.img is large enough to hold the decoded frame.
func (d *Decoder) ensureImg() {
if d.img != nil {
p0, p1 := d.img.Rect.Min, d.img.Rect.Max
if p0.X == 0 && p0.Y == 0 && p1.X >= 16*d.mbw && p1.Y >= 16*d.mbh {
return
}
}
m := image.NewYCbCr(image.Rect(0, 0, 16*d.mbw, 16*d.mbh), image.YCbCrSubsampleRatio420)
d.img = m.SubImage(image.Rect(0, 0, d.frameHeader.Width, d.frameHeader.Height)).(*image.YCbCr)
d.perMBFilterParams = make([]filterParam, d.mbw*d.mbh)
d.upMB = make([]mb, d.mbw)
}
// parseSegmentHeader parses the segment header, as specified in section 9.3.
func (d *Decoder) parseSegmentHeader() {
d.segmentHeader.useSegment = d.fp.readBit(uniformProb)
if !d.segmentHeader.useSegment {
d.segmentHeader.updateMap = false
return
}
d.segmentHeader.updateMap = d.fp.readBit(uniformProb)
if d.fp.readBit(uniformProb) {
d.segmentHeader.relativeDelta = !d.fp.readBit(uniformProb)
for i := range d.segmentHeader.quantizer {
d.segmentHeader.quantizer[i] = int8(d.fp.readOptionalInt(uniformProb, 7))
}
for i := range d.segmentHeader.filterStrength {
d.segmentHeader.filterStrength[i] = int8(d.fp.readOptionalInt(uniformProb, 6))
}
}
if !d.segmentHeader.updateMap {
return
}
for i := range d.segmentHeader.prob {
if d.fp.readBit(uniformProb) {
d.segmentHeader.prob[i] = uint8(d.fp.readUint(uniformProb, 8))
} else {
d.segmentHeader.prob[i] = 0xff
}
}
}
// parseFilterHeader parses the filter header, as specified in section 9.4.
func (d *Decoder) parseFilterHeader() {
d.filterHeader.simple = d.fp.readBit(uniformProb)
d.filterHeader.level = int8(d.fp.readUint(uniformProb, 6))
d.filterHeader.sharpness = uint8(d.fp.readUint(uniformProb, 3))
d.filterHeader.useLFDelta = d.fp.readBit(uniformProb)
if d.filterHeader.useLFDelta && d.fp.readBit(uniformProb) {
for i := range d.filterHeader.refLFDelta {
d.filterHeader.refLFDelta[i] = int8(d.fp.readOptionalInt(uniformProb, 6))
}
for i := range d.filterHeader.modeLFDelta {
d.filterHeader.modeLFDelta[i] = int8(d.fp.readOptionalInt(uniformProb, 6))
}
}
if d.filterHeader.level == 0 {
return
}
if d.segmentHeader.useSegment {
for i := range d.filterHeader.perSegmentLevel {
strength := d.segmentHeader.filterStrength[i]
if d.segmentHeader.relativeDelta {
strength += d.filterHeader.level
}
d.filterHeader.perSegmentLevel[i] = strength
}
} else {
d.filterHeader.perSegmentLevel[0] = d.filterHeader.level
}
d.computeFilterParams()
}
// parseOtherPartitions parses the other partitions, as specified in section 9.5.
func (d *Decoder) parseOtherPartitions() error {
const maxNOP = 1 << 3
var partLens [maxNOP]int
d.nOP = 1 << d.fp.readUint(uniformProb, 2)
// The final partition length is implied by the remaining chunk data
// (d.r.n) and the other d.nOP-1 partition lengths. Those d.nOP-1 partition
// lengths are stored as 24-bit uints, i.e. up to 16 MiB per partition.
n := 3 * (d.nOP - 1)
partLens[d.nOP-1] = d.r.n - n
if partLens[d.nOP-1] < 0 {
return io.ErrUnexpectedEOF
}
if n > 0 {
buf := make([]byte, n)
if err := d.r.ReadFull(buf); err != nil {
return err
}
for i := 0; i < d.nOP-1; i++ {
pl := int(buf[3*i+0]) | int(buf[3*i+1])<<8 | int(buf[3*i+2])<<16
if pl > partLens[d.nOP-1] {
return io.ErrUnexpectedEOF
}
partLens[i] = pl
partLens[d.nOP-1] -= pl
}
}
// We check if the final partition length can also fit into a 24-bit uint.
// Strictly speaking, this isn't part of the spec, but it guards against a
// malicious WEBP image that is too large to ReadFull the encoded DCT
// coefficients into memory, whether that's because the actual WEBP file is
// too large, or whether its RIFF metadata lists too large a chunk.
if 1<<24 <= partLens[d.nOP-1] {
return errors.New("vp8: too much data to decode")
}
buf := make([]byte, d.r.n)
if err := d.r.ReadFull(buf); err != nil {
return err
}
for i, pl := range partLens {
if i == d.nOP {
break
}
d.op[i].init(buf[:pl])
buf = buf[pl:]
}
return nil
}
// parseOtherHeaders parses header information other than the frame header.
func (d *Decoder) parseOtherHeaders() error {
// Initialize and parse the first partition.
firstPartition := make([]byte, d.frameHeader.FirstPartitionLen)
if err := d.r.ReadFull(firstPartition); err != nil {
return err
}
d.fp.init(firstPartition)
if d.frameHeader.KeyFrame {
// Read and ignore the color space and pixel clamp values. They are
// specified in section 9.2, but are unimplemented.
d.fp.readBit(uniformProb)
d.fp.readBit(uniformProb)
}
d.parseSegmentHeader()
d.parseFilterHeader()
if err := d.parseOtherPartitions(); err != nil {
return err
}
d.parseQuant()
if !d.frameHeader.KeyFrame {
// Golden and AltRef frames are specified in section 9.7.
// TODO(nigeltao): implement. Note that they are only used for video, not still images.
return errors.New("vp8: Golden / AltRef frames are not implemented")
}
// Read and ignore the refreshLastFrameBuffer bit, specified in section 9.8.
// It applies only to video, and not still images.
d.fp.readBit(uniformProb)
d.parseTokenProb()
d.useSkipProb = d.fp.readBit(uniformProb)
if d.useSkipProb {
d.skipProb = uint8(d.fp.readUint(uniformProb, 8))
}
if d.fp.unexpectedEOF {
return io.ErrUnexpectedEOF
}
return nil
}
// DecodeFrame decodes the frame and returns it as an YCbCr image.
// The image's contents are valid up until the next call to Decoder.Init.
func (d *Decoder) DecodeFrame() (*image.YCbCr, error) {
d.ensureImg()
if err := d.parseOtherHeaders(); err != nil {
return nil, err
}
// Reconstruct the rows.
for mbx := 0; mbx < d.mbw; mbx++ {
d.upMB[mbx] = mb{}
}
for mby := 0; mby < d.mbh; mby++ {
d.leftMB = mb{}
for mbx := 0; mbx < d.mbw; mbx++ {
skip := d.reconstruct(mbx, mby)
fs := d.filterParams[d.segment][btou(!d.usePredY16)]
fs.inner = fs.inner || !skip
d.perMBFilterParams[d.mbw*mby+mbx] = fs
}
}
if d.fp.unexpectedEOF {
return nil, io.ErrUnexpectedEOF
}
for i := 0; i < d.nOP; i++ {
if d.op[i].unexpectedEOF {
return nil, io.ErrUnexpectedEOF
}
}
// Apply the loop filter.
//
// Even if we are using per-segment levels, section 15 says that "loop
// filtering must be skipped entirely if loop_filter_level at either the
// frame header level or macroblock override level is 0".
if d.filterHeader.level != 0 {
if d.filterHeader.simple {
d.simpleFilter()
} else {
d.normalFilter()
}
}
return d.img, nil
}

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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// filter2 modifies a 2-pixel wide or 2-pixel high band along an edge.
func filter2(pix []byte, level, index, iStep, jStep int) {
for n := 16; n > 0; n, index = n-1, index+iStep {
p1 := int(pix[index-2*jStep])
p0 := int(pix[index-1*jStep])
q0 := int(pix[index+0*jStep])
q1 := int(pix[index+1*jStep])
if abs(p0-q0)<<1+abs(p1-q1)>>1 > level {
continue
}
a := 3*(q0-p0) + clamp127(p1-q1)
a1 := clamp15((a + 4) >> 3)
a2 := clamp15((a + 3) >> 3)
pix[index-1*jStep] = clamp255(p0 + a2)
pix[index+0*jStep] = clamp255(q0 - a1)
}
}
// filter246 modifies a 2-, 4- or 6-pixel wide or high band along an edge.
func filter246(pix []byte, n, level, ilevel, hlevel, index, iStep, jStep int, fourNotSix bool) {
for ; n > 0; n, index = n-1, index+iStep {
p3 := int(pix[index-4*jStep])
p2 := int(pix[index-3*jStep])
p1 := int(pix[index-2*jStep])
p0 := int(pix[index-1*jStep])
q0 := int(pix[index+0*jStep])
q1 := int(pix[index+1*jStep])
q2 := int(pix[index+2*jStep])
q3 := int(pix[index+3*jStep])
if abs(p0-q0)<<1+abs(p1-q1)>>1 > level {
continue
}
if abs(p3-p2) > ilevel ||
abs(p2-p1) > ilevel ||
abs(p1-p0) > ilevel ||
abs(q1-q0) > ilevel ||
abs(q2-q1) > ilevel ||
abs(q3-q2) > ilevel {
continue
}
if abs(p1-p0) > hlevel || abs(q1-q0) > hlevel {
// Filter 2 pixels.
a := 3*(q0-p0) + clamp127(p1-q1)
a1 := clamp15((a + 4) >> 3)
a2 := clamp15((a + 3) >> 3)
pix[index-1*jStep] = clamp255(p0 + a2)
pix[index+0*jStep] = clamp255(q0 - a1)
} else if fourNotSix {
// Filter 4 pixels.
a := 3 * (q0 - p0)
a1 := clamp15((a + 4) >> 3)
a2 := clamp15((a + 3) >> 3)
a3 := (a1 + 1) >> 1
pix[index-2*jStep] = clamp255(p1 + a3)
pix[index-1*jStep] = clamp255(p0 + a2)
pix[index+0*jStep] = clamp255(q0 - a1)
pix[index+1*jStep] = clamp255(q1 - a3)
} else {
// Filter 6 pixels.
a := clamp127(3*(q0-p0) + clamp127(p1-q1))
a1 := (27*a + 63) >> 7
a2 := (18*a + 63) >> 7
a3 := (9*a + 63) >> 7
pix[index-3*jStep] = clamp255(p2 + a3)
pix[index-2*jStep] = clamp255(p1 + a2)
pix[index-1*jStep] = clamp255(p0 + a1)
pix[index+0*jStep] = clamp255(q0 - a1)
pix[index+1*jStep] = clamp255(q1 - a2)
pix[index+2*jStep] = clamp255(q2 - a3)
}
}
}
// simpleFilter implements the simple filter, as specified in section 15.2.
func (d *Decoder) simpleFilter() {
for mby := 0; mby < d.mbh; mby++ {
for mbx := 0; mbx < d.mbw; mbx++ {
f := d.perMBFilterParams[d.mbw*mby+mbx]
if f.level == 0 {
continue
}
l := int(f.level)
yIndex := (mby*d.img.YStride + mbx) * 16
if mbx > 0 {
filter2(d.img.Y, l+4, yIndex, d.img.YStride, 1)
}
if f.inner {
filter2(d.img.Y, l, yIndex+0x4, d.img.YStride, 1)
filter2(d.img.Y, l, yIndex+0x8, d.img.YStride, 1)
filter2(d.img.Y, l, yIndex+0xc, d.img.YStride, 1)
}
if mby > 0 {
filter2(d.img.Y, l+4, yIndex, 1, d.img.YStride)
}
if f.inner {
filter2(d.img.Y, l, yIndex+d.img.YStride*0x4, 1, d.img.YStride)
filter2(d.img.Y, l, yIndex+d.img.YStride*0x8, 1, d.img.YStride)
filter2(d.img.Y, l, yIndex+d.img.YStride*0xc, 1, d.img.YStride)
}
}
}
}
// normalFilter implements the normal filter, as specified in section 15.3.
func (d *Decoder) normalFilter() {
for mby := 0; mby < d.mbh; mby++ {
for mbx := 0; mbx < d.mbw; mbx++ {
f := d.perMBFilterParams[d.mbw*mby+mbx]
if f.level == 0 {
continue
}
l, il, hl := int(f.level), int(f.ilevel), int(f.hlevel)
yIndex := (mby*d.img.YStride + mbx) * 16
cIndex := (mby*d.img.CStride + mbx) * 8
if mbx > 0 {
filter246(d.img.Y, 16, l+4, il, hl, yIndex, d.img.YStride, 1, false)
filter246(d.img.Cb, 8, l+4, il, hl, cIndex, d.img.CStride, 1, false)
filter246(d.img.Cr, 8, l+4, il, hl, cIndex, d.img.CStride, 1, false)
}
if f.inner {
filter246(d.img.Y, 16, l, il, hl, yIndex+0x4, d.img.YStride, 1, true)
filter246(d.img.Y, 16, l, il, hl, yIndex+0x8, d.img.YStride, 1, true)
filter246(d.img.Y, 16, l, il, hl, yIndex+0xc, d.img.YStride, 1, true)
filter246(d.img.Cb, 8, l, il, hl, cIndex+0x4, d.img.CStride, 1, true)
filter246(d.img.Cr, 8, l, il, hl, cIndex+0x4, d.img.CStride, 1, true)
}
if mby > 0 {
filter246(d.img.Y, 16, l+4, il, hl, yIndex, 1, d.img.YStride, false)
filter246(d.img.Cb, 8, l+4, il, hl, cIndex, 1, d.img.CStride, false)
filter246(d.img.Cr, 8, l+4, il, hl, cIndex, 1, d.img.CStride, false)
}
if f.inner {
filter246(d.img.Y, 16, l, il, hl, yIndex+d.img.YStride*0x4, 1, d.img.YStride, true)
filter246(d.img.Y, 16, l, il, hl, yIndex+d.img.YStride*0x8, 1, d.img.YStride, true)
filter246(d.img.Y, 16, l, il, hl, yIndex+d.img.YStride*0xc, 1, d.img.YStride, true)
filter246(d.img.Cb, 8, l, il, hl, cIndex+d.img.CStride*0x4, 1, d.img.CStride, true)
filter246(d.img.Cr, 8, l, il, hl, cIndex+d.img.CStride*0x4, 1, d.img.CStride, true)
}
}
}
}
// filterParam holds the loop filter parameters for a macroblock.
type filterParam struct {
// The first three fields are thresholds used by the loop filter to smooth
// over the edges and interior of a macroblock. level is used by both the
// simple and normal filters. The inner level and high edge variance level
// are only used by the normal filter.
level, ilevel, hlevel uint8
// inner is whether the inner loop filter cannot be optimized out as a
// no-op for this particular macroblock.
inner bool
}
// computeFilterParams computes the loop filter parameters, as specified in
// section 15.4.
func (d *Decoder) computeFilterParams() {
for i := range d.filterParams {
baseLevel := d.filterHeader.level
if d.segmentHeader.useSegment {
baseLevel = d.segmentHeader.filterStrength[i]
if d.segmentHeader.relativeDelta {
baseLevel += d.filterHeader.level
}
}
for j := range d.filterParams[i] {
p := &d.filterParams[i][j]
p.inner = j != 0
level := baseLevel
if d.filterHeader.useLFDelta {
// The libwebp C code has a "TODO: only CURRENT is handled for now."
level += d.filterHeader.refLFDelta[0]
if j != 0 {
level += d.filterHeader.modeLFDelta[0]
}
}
if level <= 0 {
p.level = 0
continue
}
if level > 63 {
level = 63
}
ilevel := level
if d.filterHeader.sharpness > 0 {
if d.filterHeader.sharpness > 4 {
ilevel >>= 2
} else {
ilevel >>= 1
}
if x := int8(9 - d.filterHeader.sharpness); ilevel > x {
ilevel = x
}
}
if ilevel < 1 {
ilevel = 1
}
p.ilevel = uint8(ilevel)
p.level = uint8(2*level + ilevel)
if d.frameHeader.KeyFrame {
if level < 15 {
p.hlevel = 0
} else if level < 40 {
p.hlevel = 1
} else {
p.hlevel = 2
}
} else {
if level < 15 {
p.hlevel = 0
} else if level < 20 {
p.hlevel = 1
} else if level < 40 {
p.hlevel = 2
} else {
p.hlevel = 3
}
}
}
}
}
// intSize is either 32 or 64.
const intSize = 32 << (^uint(0) >> 63)
func abs(x int) int {
// m := -1 if x < 0. m := 0 otherwise.
m := x >> (intSize - 1)
// In two's complement representation, the negative number
// of any number (except the smallest one) can be computed
// by flipping all the bits and add 1. This is faster than
// code with a branch.
// See Hacker's Delight, section 2-4.
return (x ^ m) - m
}
func clamp15(x int) int {
if x < -16 {
return -16
}
if x > 15 {
return 15
}
return x
}
func clamp127(x int) int {
if x < -128 {
return -128
}
if x > 127 {
return 127
}
return x
}
func clamp255(x int) uint8 {
if x < 0 {
return 0
}
if x > 255 {
return 255
}
return uint8(x)
}

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// This file implements the inverse Discrete Cosine Transform and the inverse
// Walsh Hadamard Transform (WHT), as specified in sections 14.3 and 14.4.
func clip8(i int32) uint8 {
if i < 0 {
return 0
}
if i > 255 {
return 255
}
return uint8(i)
}
func (z *Decoder) inverseDCT4(y, x, coeffBase int) {
const (
c1 = 85627 // 65536 * cos(pi/8) * sqrt(2).
c2 = 35468 // 65536 * sin(pi/8) * sqrt(2).
)
var m [4][4]int32
for i := 0; i < 4; i++ {
a := int32(z.coeff[coeffBase+0]) + int32(z.coeff[coeffBase+8])
b := int32(z.coeff[coeffBase+0]) - int32(z.coeff[coeffBase+8])
c := (int32(z.coeff[coeffBase+4])*c2)>>16 - (int32(z.coeff[coeffBase+12])*c1)>>16
d := (int32(z.coeff[coeffBase+4])*c1)>>16 + (int32(z.coeff[coeffBase+12])*c2)>>16
m[i][0] = a + d
m[i][1] = b + c
m[i][2] = b - c
m[i][3] = a - d
coeffBase++
}
for j := 0; j < 4; j++ {
dc := m[0][j] + 4
a := dc + m[2][j]
b := dc - m[2][j]
c := (m[1][j]*c2)>>16 - (m[3][j]*c1)>>16
d := (m[1][j]*c1)>>16 + (m[3][j]*c2)>>16
z.ybr[y+j][x+0] = clip8(int32(z.ybr[y+j][x+0]) + (a+d)>>3)
z.ybr[y+j][x+1] = clip8(int32(z.ybr[y+j][x+1]) + (b+c)>>3)
z.ybr[y+j][x+2] = clip8(int32(z.ybr[y+j][x+2]) + (b-c)>>3)
z.ybr[y+j][x+3] = clip8(int32(z.ybr[y+j][x+3]) + (a-d)>>3)
}
}
func (z *Decoder) inverseDCT4DCOnly(y, x, coeffBase int) {
dc := (int32(z.coeff[coeffBase+0]) + 4) >> 3
for j := 0; j < 4; j++ {
for i := 0; i < 4; i++ {
z.ybr[y+j][x+i] = clip8(int32(z.ybr[y+j][x+i]) + dc)
}
}
}
func (z *Decoder) inverseDCT8(y, x, coeffBase int) {
z.inverseDCT4(y+0, x+0, coeffBase+0*16)
z.inverseDCT4(y+0, x+4, coeffBase+1*16)
z.inverseDCT4(y+4, x+0, coeffBase+2*16)
z.inverseDCT4(y+4, x+4, coeffBase+3*16)
}
func (z *Decoder) inverseDCT8DCOnly(y, x, coeffBase int) {
z.inverseDCT4DCOnly(y+0, x+0, coeffBase+0*16)
z.inverseDCT4DCOnly(y+0, x+4, coeffBase+1*16)
z.inverseDCT4DCOnly(y+4, x+0, coeffBase+2*16)
z.inverseDCT4DCOnly(y+4, x+4, coeffBase+3*16)
}
func (d *Decoder) inverseWHT16() {
var m [16]int32
for i := 0; i < 4; i++ {
a0 := int32(d.coeff[384+0+i]) + int32(d.coeff[384+12+i])
a1 := int32(d.coeff[384+4+i]) + int32(d.coeff[384+8+i])
a2 := int32(d.coeff[384+4+i]) - int32(d.coeff[384+8+i])
a3 := int32(d.coeff[384+0+i]) - int32(d.coeff[384+12+i])
m[0+i] = a0 + a1
m[8+i] = a0 - a1
m[4+i] = a3 + a2
m[12+i] = a3 - a2
}
out := 0
for i := 0; i < 4; i++ {
dc := m[0+i*4] + 3
a0 := dc + m[3+i*4]
a1 := m[1+i*4] + m[2+i*4]
a2 := m[1+i*4] - m[2+i*4]
a3 := dc - m[3+i*4]
d.coeff[out+0] = int16((a0 + a1) >> 3)
d.coeff[out+16] = int16((a3 + a2) >> 3)
d.coeff[out+32] = int16((a0 - a1) >> 3)
d.coeff[out+48] = int16((a3 - a2) >> 3)
out += 64
}
}

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// Each VP8 frame consists of between 2 and 9 bitstream partitions.
// Each partition is byte-aligned and is independently arithmetic-encoded.
//
// This file implements decoding a partition's bitstream, as specified in
// chapter 7. The implementation follows libwebp's approach instead of the
// specification's reference C implementation. For example, we use a look-up
// table instead of a for loop to recalibrate the encoded range.
var (
lutShift = [127]uint8{
7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
}
lutRangeM1 = [127]uint8{
127,
127, 191,
127, 159, 191, 223,
127, 143, 159, 175, 191, 207, 223, 239,
127, 135, 143, 151, 159, 167, 175, 183, 191, 199, 207, 215, 223, 231, 239, 247,
127, 131, 135, 139, 143, 147, 151, 155, 159, 163, 167, 171, 175, 179, 183, 187,
191, 195, 199, 203, 207, 211, 215, 219, 223, 227, 231, 235, 239, 243, 247, 251,
127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 153, 155, 157,
159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 187, 189,
191, 193, 195, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 219, 221,
223, 225, 227, 229, 231, 233, 235, 237, 239, 241, 243, 245, 247, 249, 251, 253,
}
)
// uniformProb represents a 50% probability that the next bit is 0.
const uniformProb = 128
// partition holds arithmetic-coded bits.
type partition struct {
// buf is the input bytes.
buf []byte
// r is how many of buf's bytes have been consumed.
r int
// rangeM1 is range minus 1, where range is in the arithmetic coding sense,
// not the Go language sense.
rangeM1 uint32
// bits and nBits hold those bits shifted out of buf but not yet consumed.
bits uint32
nBits uint8
// unexpectedEOF tells whether we tried to read past buf.
unexpectedEOF bool
}
// init initializes the partition.
func (p *partition) init(buf []byte) {
p.buf = buf
p.r = 0
p.rangeM1 = 254
p.bits = 0
p.nBits = 0
p.unexpectedEOF = false
}
// readBit returns the next bit.
func (p *partition) readBit(prob uint8) bool {
if p.nBits < 8 {
if p.r >= len(p.buf) {
p.unexpectedEOF = true
return false
}
// Expression split for 386 compiler.
x := uint32(p.buf[p.r])
p.bits |= x << (8 - p.nBits)
p.r++
p.nBits += 8
}
split := (p.rangeM1*uint32(prob))>>8 + 1
bit := p.bits >= split<<8
if bit {
p.rangeM1 -= split
p.bits -= split << 8
} else {
p.rangeM1 = split - 1
}
if p.rangeM1 < 127 {
shift := lutShift[p.rangeM1]
p.rangeM1 = uint32(lutRangeM1[p.rangeM1])
p.bits <<= shift
p.nBits -= shift
}
return bit
}
// readUint returns the next n-bit unsigned integer.
func (p *partition) readUint(prob, n uint8) uint32 {
var u uint32
for n > 0 {
n--
if p.readBit(prob) {
u |= 1 << n
}
}
return u
}
// readInt returns the next n-bit signed integer.
func (p *partition) readInt(prob, n uint8) int32 {
u := p.readUint(prob, n)
b := p.readBit(prob)
if b {
return -int32(u)
}
return int32(u)
}
// readOptionalInt returns the next n-bit signed integer in an encoding
// where the likely result is zero.
func (p *partition) readOptionalInt(prob, n uint8) int32 {
if !p.readBit(prob) {
return 0
}
return p.readInt(prob, n)
}

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// This file implements parsing the predictor modes, as specified in chapter
// 11.
func (d *Decoder) parsePredModeY16(mbx int) {
var p uint8
if !d.fp.readBit(156) {
if !d.fp.readBit(163) {
p = predDC
} else {
p = predVE
}
} else if !d.fp.readBit(128) {
p = predHE
} else {
p = predTM
}
for i := 0; i < 4; i++ {
d.upMB[mbx].pred[i] = p
d.leftMB.pred[i] = p
}
d.predY16 = p
}
func (d *Decoder) parsePredModeC8() {
if !d.fp.readBit(142) {
d.predC8 = predDC
} else if !d.fp.readBit(114) {
d.predC8 = predVE
} else if !d.fp.readBit(183) {
d.predC8 = predHE
} else {
d.predC8 = predTM
}
}
func (d *Decoder) parsePredModeY4(mbx int) {
for j := 0; j < 4; j++ {
p := d.leftMB.pred[j]
for i := 0; i < 4; i++ {
prob := &predProb[d.upMB[mbx].pred[i]][p]
if !d.fp.readBit(prob[0]) {
p = predDC
} else if !d.fp.readBit(prob[1]) {
p = predTM
} else if !d.fp.readBit(prob[2]) {
p = predVE
} else if !d.fp.readBit(prob[3]) {
if !d.fp.readBit(prob[4]) {
p = predHE
} else if !d.fp.readBit(prob[5]) {
p = predRD
} else {
p = predVR
}
} else if !d.fp.readBit(prob[6]) {
p = predLD
} else if !d.fp.readBit(prob[7]) {
p = predVL
} else if !d.fp.readBit(prob[8]) {
p = predHD
} else {
p = predHU
}
d.predY4[j][i] = p
d.upMB[mbx].pred[i] = p
}
d.leftMB.pred[j] = p
}
}
// predProb are the probabilities to decode a 4x4 region's predictor mode given
// the predictor modes of the regions above and left of it.
// These values are specified in section 11.5.
var predProb = [nPred][nPred][9]uint8{
{
{231, 120, 48, 89, 115, 113, 120, 152, 112},
{152, 179, 64, 126, 170, 118, 46, 70, 95},
{175, 69, 143, 80, 85, 82, 72, 155, 103},
{56, 58, 10, 171, 218, 189, 17, 13, 152},
{114, 26, 17, 163, 44, 195, 21, 10, 173},
{121, 24, 80, 195, 26, 62, 44, 64, 85},
{144, 71, 10, 38, 171, 213, 144, 34, 26},
{170, 46, 55, 19, 136, 160, 33, 206, 71},
{63, 20, 8, 114, 114, 208, 12, 9, 226},
{81, 40, 11, 96, 182, 84, 29, 16, 36},
},
{
{134, 183, 89, 137, 98, 101, 106, 165, 148},
{72, 187, 100, 130, 157, 111, 32, 75, 80},
{66, 102, 167, 99, 74, 62, 40, 234, 128},
{41, 53, 9, 178, 241, 141, 26, 8, 107},
{74, 43, 26, 146, 73, 166, 49, 23, 157},
{65, 38, 105, 160, 51, 52, 31, 115, 128},
{104, 79, 12, 27, 217, 255, 87, 17, 7},
{87, 68, 71, 44, 114, 51, 15, 186, 23},
{47, 41, 14, 110, 182, 183, 21, 17, 194},
{66, 45, 25, 102, 197, 189, 23, 18, 22},
},
{
{88, 88, 147, 150, 42, 46, 45, 196, 205},
{43, 97, 183, 117, 85, 38, 35, 179, 61},
{39, 53, 200, 87, 26, 21, 43, 232, 171},
{56, 34, 51, 104, 114, 102, 29, 93, 77},
{39, 28, 85, 171, 58, 165, 90, 98, 64},
{34, 22, 116, 206, 23, 34, 43, 166, 73},
{107, 54, 32, 26, 51, 1, 81, 43, 31},
{68, 25, 106, 22, 64, 171, 36, 225, 114},
{34, 19, 21, 102, 132, 188, 16, 76, 124},
{62, 18, 78, 95, 85, 57, 50, 48, 51},
},
{
{193, 101, 35, 159, 215, 111, 89, 46, 111},
{60, 148, 31, 172, 219, 228, 21, 18, 111},
{112, 113, 77, 85, 179, 255, 38, 120, 114},
{40, 42, 1, 196, 245, 209, 10, 25, 109},
{88, 43, 29, 140, 166, 213, 37, 43, 154},
{61, 63, 30, 155, 67, 45, 68, 1, 209},
{100, 80, 8, 43, 154, 1, 51, 26, 71},
{142, 78, 78, 16, 255, 128, 34, 197, 171},
{41, 40, 5, 102, 211, 183, 4, 1, 221},
{51, 50, 17, 168, 209, 192, 23, 25, 82},
},
{
{138, 31, 36, 171, 27, 166, 38, 44, 229},
{67, 87, 58, 169, 82, 115, 26, 59, 179},
{63, 59, 90, 180, 59, 166, 93, 73, 154},
{40, 40, 21, 116, 143, 209, 34, 39, 175},
{47, 15, 16, 183, 34, 223, 49, 45, 183},
{46, 17, 33, 183, 6, 98, 15, 32, 183},
{57, 46, 22, 24, 128, 1, 54, 17, 37},
{65, 32, 73, 115, 28, 128, 23, 128, 205},
{40, 3, 9, 115, 51, 192, 18, 6, 223},
{87, 37, 9, 115, 59, 77, 64, 21, 47},
},
{
{104, 55, 44, 218, 9, 54, 53, 130, 226},
{64, 90, 70, 205, 40, 41, 23, 26, 57},
{54, 57, 112, 184, 5, 41, 38, 166, 213},
{30, 34, 26, 133, 152, 116, 10, 32, 134},
{39, 19, 53, 221, 26, 114, 32, 73, 255},
{31, 9, 65, 234, 2, 15, 1, 118, 73},
{75, 32, 12, 51, 192, 255, 160, 43, 51},
{88, 31, 35, 67, 102, 85, 55, 186, 85},
{56, 21, 23, 111, 59, 205, 45, 37, 192},
{55, 38, 70, 124, 73, 102, 1, 34, 98},
},
{
{125, 98, 42, 88, 104, 85, 117, 175, 82},
{95, 84, 53, 89, 128, 100, 113, 101, 45},
{75, 79, 123, 47, 51, 128, 81, 171, 1},
{57, 17, 5, 71, 102, 57, 53, 41, 49},
{38, 33, 13, 121, 57, 73, 26, 1, 85},
{41, 10, 67, 138, 77, 110, 90, 47, 114},
{115, 21, 2, 10, 102, 255, 166, 23, 6},
{101, 29, 16, 10, 85, 128, 101, 196, 26},
{57, 18, 10, 102, 102, 213, 34, 20, 43},
{117, 20, 15, 36, 163, 128, 68, 1, 26},
},
{
{102, 61, 71, 37, 34, 53, 31, 243, 192},
{69, 60, 71, 38, 73, 119, 28, 222, 37},
{68, 45, 128, 34, 1, 47, 11, 245, 171},
{62, 17, 19, 70, 146, 85, 55, 62, 70},
{37, 43, 37, 154, 100, 163, 85, 160, 1},
{63, 9, 92, 136, 28, 64, 32, 201, 85},
{75, 15, 9, 9, 64, 255, 184, 119, 16},
{86, 6, 28, 5, 64, 255, 25, 248, 1},
{56, 8, 17, 132, 137, 255, 55, 116, 128},
{58, 15, 20, 82, 135, 57, 26, 121, 40},
},
{
{164, 50, 31, 137, 154, 133, 25, 35, 218},
{51, 103, 44, 131, 131, 123, 31, 6, 158},
{86, 40, 64, 135, 148, 224, 45, 183, 128},
{22, 26, 17, 131, 240, 154, 14, 1, 209},
{45, 16, 21, 91, 64, 222, 7, 1, 197},
{56, 21, 39, 155, 60, 138, 23, 102, 213},
{83, 12, 13, 54, 192, 255, 68, 47, 28},
{85, 26, 85, 85, 128, 128, 32, 146, 171},
{18, 11, 7, 63, 144, 171, 4, 4, 246},
{35, 27, 10, 146, 174, 171, 12, 26, 128},
},
{
{190, 80, 35, 99, 180, 80, 126, 54, 45},
{85, 126, 47, 87, 176, 51, 41, 20, 32},
{101, 75, 128, 139, 118, 146, 116, 128, 85},
{56, 41, 15, 176, 236, 85, 37, 9, 62},
{71, 30, 17, 119, 118, 255, 17, 18, 138},
{101, 38, 60, 138, 55, 70, 43, 26, 142},
{146, 36, 19, 30, 171, 255, 97, 27, 20},
{138, 45, 61, 62, 219, 1, 81, 188, 64},
{32, 41, 20, 117, 151, 142, 20, 21, 163},
{112, 19, 12, 61, 195, 128, 48, 4, 24},
},
}

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// This file implements the predicition functions, as specified in chapter 12.
//
// For each macroblock (of 1x16x16 luma and 2x8x8 chroma coefficients), the
// luma values are either predicted as one large 16x16 region or 16 separate
// 4x4 regions. The chroma values are always predicted as one 8x8 region.
//
// For 4x4 regions, the target block's predicted values (Xs) are a function of
// its previously-decoded top and left border values, as well as a number of
// pixels from the top-right:
//
// a b c d e f g h
// p X X X X
// q X X X X
// r X X X X
// s X X X X
//
// The predictor modes are:
// - DC: all Xs = (b + c + d + e + p + q + r + s + 4) / 8.
// - TM: the first X = (b + p - a), the second X = (c + p - a), and so on.
// - VE: each X = the weighted average of its column's top value and that
// value's neighbors, i.e. averages of abc, bcd, cde or def.
// - HE: similar to VE except rows instead of columns, and the final row is
// an average of r, s and s.
// - RD, VR, LD, VL, HD, HU: these diagonal modes ("Right Down", "Vertical
// Right", etc) are more complicated and are described in section 12.3.
// All Xs are clipped to the range [0, 255].
//
// For 8x8 and 16x16 regions, the target block's predicted values are a
// function of the top and left border values without the top-right overhang,
// i.e. without the 8x8 or 16x16 equivalent of f, g and h. Furthermore:
// - There are no diagonal predictor modes, only DC, TM, VE and HE.
// - The DC mode has variants for macroblocks in the top row and/or left
// column, i.e. for macroblocks with mby == 0 || mbx == 0.
// - The VE and HE modes take only the column top or row left values; they do
// not smooth that top/left value with its neighbors.
// nPred is the number of predictor modes, not including the Top/Left versions
// of the DC predictor mode.
const nPred = 10
const (
predDC = iota
predTM
predVE
predHE
predRD
predVR
predLD
predVL
predHD
predHU
predDCTop
predDCLeft
predDCTopLeft
)
func checkTopLeftPred(mbx, mby int, p uint8) uint8 {
if p != predDC {
return p
}
if mbx == 0 {
if mby == 0 {
return predDCTopLeft
}
return predDCLeft
}
if mby == 0 {
return predDCTop
}
return predDC
}
var predFunc4 = [...]func(*Decoder, int, int){
predFunc4DC,
predFunc4TM,
predFunc4VE,
predFunc4HE,
predFunc4RD,
predFunc4VR,
predFunc4LD,
predFunc4VL,
predFunc4HD,
predFunc4HU,
nil,
nil,
nil,
}
var predFunc8 = [...]func(*Decoder, int, int){
predFunc8DC,
predFunc8TM,
predFunc8VE,
predFunc8HE,
nil,
nil,
nil,
nil,
nil,
nil,
predFunc8DCTop,
predFunc8DCLeft,
predFunc8DCTopLeft,
}
var predFunc16 = [...]func(*Decoder, int, int){
predFunc16DC,
predFunc16TM,
predFunc16VE,
predFunc16HE,
nil,
nil,
nil,
nil,
nil,
nil,
predFunc16DCTop,
predFunc16DCLeft,
predFunc16DCTopLeft,
}
func predFunc4DC(z *Decoder, y, x int) {
sum := uint32(4)
for i := 0; i < 4; i++ {
sum += uint32(z.ybr[y-1][x+i])
}
for j := 0; j < 4; j++ {
sum += uint32(z.ybr[y+j][x-1])
}
avg := uint8(sum / 8)
for j := 0; j < 4; j++ {
for i := 0; i < 4; i++ {
z.ybr[y+j][x+i] = avg
}
}
}
func predFunc4TM(z *Decoder, y, x int) {
delta0 := -int32(z.ybr[y-1][x-1])
for j := 0; j < 4; j++ {
delta1 := delta0 + int32(z.ybr[y+j][x-1])
for i := 0; i < 4; i++ {
delta2 := delta1 + int32(z.ybr[y-1][x+i])
z.ybr[y+j][x+i] = uint8(clip(delta2, 0, 255))
}
}
}
func predFunc4VE(z *Decoder, y, x int) {
a := int32(z.ybr[y-1][x-1])
b := int32(z.ybr[y-1][x+0])
c := int32(z.ybr[y-1][x+1])
d := int32(z.ybr[y-1][x+2])
e := int32(z.ybr[y-1][x+3])
f := int32(z.ybr[y-1][x+4])
abc := uint8((a + 2*b + c + 2) / 4)
bcd := uint8((b + 2*c + d + 2) / 4)
cde := uint8((c + 2*d + e + 2) / 4)
def := uint8((d + 2*e + f + 2) / 4)
for j := 0; j < 4; j++ {
z.ybr[y+j][x+0] = abc
z.ybr[y+j][x+1] = bcd
z.ybr[y+j][x+2] = cde
z.ybr[y+j][x+3] = def
}
}
func predFunc4HE(z *Decoder, y, x int) {
s := int32(z.ybr[y+3][x-1])
r := int32(z.ybr[y+2][x-1])
q := int32(z.ybr[y+1][x-1])
p := int32(z.ybr[y+0][x-1])
a := int32(z.ybr[y-1][x-1])
ssr := uint8((s + 2*s + r + 2) / 4)
srq := uint8((s + 2*r + q + 2) / 4)
rqp := uint8((r + 2*q + p + 2) / 4)
apq := uint8((a + 2*p + q + 2) / 4)
for i := 0; i < 4; i++ {
z.ybr[y+0][x+i] = apq
z.ybr[y+1][x+i] = rqp
z.ybr[y+2][x+i] = srq
z.ybr[y+3][x+i] = ssr
}
}
func predFunc4RD(z *Decoder, y, x int) {
s := int32(z.ybr[y+3][x-1])
r := int32(z.ybr[y+2][x-1])
q := int32(z.ybr[y+1][x-1])
p := int32(z.ybr[y+0][x-1])
a := int32(z.ybr[y-1][x-1])
b := int32(z.ybr[y-1][x+0])
c := int32(z.ybr[y-1][x+1])
d := int32(z.ybr[y-1][x+2])
e := int32(z.ybr[y-1][x+3])
srq := uint8((s + 2*r + q + 2) / 4)
rqp := uint8((r + 2*q + p + 2) / 4)
qpa := uint8((q + 2*p + a + 2) / 4)
pab := uint8((p + 2*a + b + 2) / 4)
abc := uint8((a + 2*b + c + 2) / 4)
bcd := uint8((b + 2*c + d + 2) / 4)
cde := uint8((c + 2*d + e + 2) / 4)
z.ybr[y+0][x+0] = pab
z.ybr[y+0][x+1] = abc
z.ybr[y+0][x+2] = bcd
z.ybr[y+0][x+3] = cde
z.ybr[y+1][x+0] = qpa
z.ybr[y+1][x+1] = pab
z.ybr[y+1][x+2] = abc
z.ybr[y+1][x+3] = bcd
z.ybr[y+2][x+0] = rqp
z.ybr[y+2][x+1] = qpa
z.ybr[y+2][x+2] = pab
z.ybr[y+2][x+3] = abc
z.ybr[y+3][x+0] = srq
z.ybr[y+3][x+1] = rqp
z.ybr[y+3][x+2] = qpa
z.ybr[y+3][x+3] = pab
}
func predFunc4VR(z *Decoder, y, x int) {
r := int32(z.ybr[y+2][x-1])
q := int32(z.ybr[y+1][x-1])
p := int32(z.ybr[y+0][x-1])
a := int32(z.ybr[y-1][x-1])
b := int32(z.ybr[y-1][x+0])
c := int32(z.ybr[y-1][x+1])
d := int32(z.ybr[y-1][x+2])
e := int32(z.ybr[y-1][x+3])
ab := uint8((a + b + 1) / 2)
bc := uint8((b + c + 1) / 2)
cd := uint8((c + d + 1) / 2)
de := uint8((d + e + 1) / 2)
rqp := uint8((r + 2*q + p + 2) / 4)
qpa := uint8((q + 2*p + a + 2) / 4)
pab := uint8((p + 2*a + b + 2) / 4)
abc := uint8((a + 2*b + c + 2) / 4)
bcd := uint8((b + 2*c + d + 2) / 4)
cde := uint8((c + 2*d + e + 2) / 4)
z.ybr[y+0][x+0] = ab
z.ybr[y+0][x+1] = bc
z.ybr[y+0][x+2] = cd
z.ybr[y+0][x+3] = de
z.ybr[y+1][x+0] = pab
z.ybr[y+1][x+1] = abc
z.ybr[y+1][x+2] = bcd
z.ybr[y+1][x+3] = cde
z.ybr[y+2][x+0] = qpa
z.ybr[y+2][x+1] = ab
z.ybr[y+2][x+2] = bc
z.ybr[y+2][x+3] = cd
z.ybr[y+3][x+0] = rqp
z.ybr[y+3][x+1] = pab
z.ybr[y+3][x+2] = abc
z.ybr[y+3][x+3] = bcd
}
func predFunc4LD(z *Decoder, y, x int) {
a := int32(z.ybr[y-1][x+0])
b := int32(z.ybr[y-1][x+1])
c := int32(z.ybr[y-1][x+2])
d := int32(z.ybr[y-1][x+3])
e := int32(z.ybr[y-1][x+4])
f := int32(z.ybr[y-1][x+5])
g := int32(z.ybr[y-1][x+6])
h := int32(z.ybr[y-1][x+7])
abc := uint8((a + 2*b + c + 2) / 4)
bcd := uint8((b + 2*c + d + 2) / 4)
cde := uint8((c + 2*d + e + 2) / 4)
def := uint8((d + 2*e + f + 2) / 4)
efg := uint8((e + 2*f + g + 2) / 4)
fgh := uint8((f + 2*g + h + 2) / 4)
ghh := uint8((g + 2*h + h + 2) / 4)
z.ybr[y+0][x+0] = abc
z.ybr[y+0][x+1] = bcd
z.ybr[y+0][x+2] = cde
z.ybr[y+0][x+3] = def
z.ybr[y+1][x+0] = bcd
z.ybr[y+1][x+1] = cde
z.ybr[y+1][x+2] = def
z.ybr[y+1][x+3] = efg
z.ybr[y+2][x+0] = cde
z.ybr[y+2][x+1] = def
z.ybr[y+2][x+2] = efg
z.ybr[y+2][x+3] = fgh
z.ybr[y+3][x+0] = def
z.ybr[y+3][x+1] = efg
z.ybr[y+3][x+2] = fgh
z.ybr[y+3][x+3] = ghh
}
func predFunc4VL(z *Decoder, y, x int) {
a := int32(z.ybr[y-1][x+0])
b := int32(z.ybr[y-1][x+1])
c := int32(z.ybr[y-1][x+2])
d := int32(z.ybr[y-1][x+3])
e := int32(z.ybr[y-1][x+4])
f := int32(z.ybr[y-1][x+5])
g := int32(z.ybr[y-1][x+6])
h := int32(z.ybr[y-1][x+7])
ab := uint8((a + b + 1) / 2)
bc := uint8((b + c + 1) / 2)
cd := uint8((c + d + 1) / 2)
de := uint8((d + e + 1) / 2)
abc := uint8((a + 2*b + c + 2) / 4)
bcd := uint8((b + 2*c + d + 2) / 4)
cde := uint8((c + 2*d + e + 2) / 4)
def := uint8((d + 2*e + f + 2) / 4)
efg := uint8((e + 2*f + g + 2) / 4)
fgh := uint8((f + 2*g + h + 2) / 4)
z.ybr[y+0][x+0] = ab
z.ybr[y+0][x+1] = bc
z.ybr[y+0][x+2] = cd
z.ybr[y+0][x+3] = de
z.ybr[y+1][x+0] = abc
z.ybr[y+1][x+1] = bcd
z.ybr[y+1][x+2] = cde
z.ybr[y+1][x+3] = def
z.ybr[y+2][x+0] = bc
z.ybr[y+2][x+1] = cd
z.ybr[y+2][x+2] = de
z.ybr[y+2][x+3] = efg
z.ybr[y+3][x+0] = bcd
z.ybr[y+3][x+1] = cde
z.ybr[y+3][x+2] = def
z.ybr[y+3][x+3] = fgh
}
func predFunc4HD(z *Decoder, y, x int) {
s := int32(z.ybr[y+3][x-1])
r := int32(z.ybr[y+2][x-1])
q := int32(z.ybr[y+1][x-1])
p := int32(z.ybr[y+0][x-1])
a := int32(z.ybr[y-1][x-1])
b := int32(z.ybr[y-1][x+0])
c := int32(z.ybr[y-1][x+1])
d := int32(z.ybr[y-1][x+2])
sr := uint8((s + r + 1) / 2)
rq := uint8((r + q + 1) / 2)
qp := uint8((q + p + 1) / 2)
pa := uint8((p + a + 1) / 2)
srq := uint8((s + 2*r + q + 2) / 4)
rqp := uint8((r + 2*q + p + 2) / 4)
qpa := uint8((q + 2*p + a + 2) / 4)
pab := uint8((p + 2*a + b + 2) / 4)
abc := uint8((a + 2*b + c + 2) / 4)
bcd := uint8((b + 2*c + d + 2) / 4)
z.ybr[y+0][x+0] = pa
z.ybr[y+0][x+1] = pab
z.ybr[y+0][x+2] = abc
z.ybr[y+0][x+3] = bcd
z.ybr[y+1][x+0] = qp
z.ybr[y+1][x+1] = qpa
z.ybr[y+1][x+2] = pa
z.ybr[y+1][x+3] = pab
z.ybr[y+2][x+0] = rq
z.ybr[y+2][x+1] = rqp
z.ybr[y+2][x+2] = qp
z.ybr[y+2][x+3] = qpa
z.ybr[y+3][x+0] = sr
z.ybr[y+3][x+1] = srq
z.ybr[y+3][x+2] = rq
z.ybr[y+3][x+3] = rqp
}
func predFunc4HU(z *Decoder, y, x int) {
s := int32(z.ybr[y+3][x-1])
r := int32(z.ybr[y+2][x-1])
q := int32(z.ybr[y+1][x-1])
p := int32(z.ybr[y+0][x-1])
pq := uint8((p + q + 1) / 2)
qr := uint8((q + r + 1) / 2)
rs := uint8((r + s + 1) / 2)
pqr := uint8((p + 2*q + r + 2) / 4)
qrs := uint8((q + 2*r + s + 2) / 4)
rss := uint8((r + 2*s + s + 2) / 4)
sss := uint8(s)
z.ybr[y+0][x+0] = pq
z.ybr[y+0][x+1] = pqr
z.ybr[y+0][x+2] = qr
z.ybr[y+0][x+3] = qrs
z.ybr[y+1][x+0] = qr
z.ybr[y+1][x+1] = qrs
z.ybr[y+1][x+2] = rs
z.ybr[y+1][x+3] = rss
z.ybr[y+2][x+0] = rs
z.ybr[y+2][x+1] = rss
z.ybr[y+2][x+2] = sss
z.ybr[y+2][x+3] = sss
z.ybr[y+3][x+0] = sss
z.ybr[y+3][x+1] = sss
z.ybr[y+3][x+2] = sss
z.ybr[y+3][x+3] = sss
}
func predFunc8DC(z *Decoder, y, x int) {
sum := uint32(8)
for i := 0; i < 8; i++ {
sum += uint32(z.ybr[y-1][x+i])
}
for j := 0; j < 8; j++ {
sum += uint32(z.ybr[y+j][x-1])
}
avg := uint8(sum / 16)
for j := 0; j < 8; j++ {
for i := 0; i < 8; i++ {
z.ybr[y+j][x+i] = avg
}
}
}
func predFunc8TM(z *Decoder, y, x int) {
delta0 := -int32(z.ybr[y-1][x-1])
for j := 0; j < 8; j++ {
delta1 := delta0 + int32(z.ybr[y+j][x-1])
for i := 0; i < 8; i++ {
delta2 := delta1 + int32(z.ybr[y-1][x+i])
z.ybr[y+j][x+i] = uint8(clip(delta2, 0, 255))
}
}
}
func predFunc8VE(z *Decoder, y, x int) {
for j := 0; j < 8; j++ {
for i := 0; i < 8; i++ {
z.ybr[y+j][x+i] = z.ybr[y-1][x+i]
}
}
}
func predFunc8HE(z *Decoder, y, x int) {
for j := 0; j < 8; j++ {
for i := 0; i < 8; i++ {
z.ybr[y+j][x+i] = z.ybr[y+j][x-1]
}
}
}
func predFunc8DCTop(z *Decoder, y, x int) {
sum := uint32(4)
for j := 0; j < 8; j++ {
sum += uint32(z.ybr[y+j][x-1])
}
avg := uint8(sum / 8)
for j := 0; j < 8; j++ {
for i := 0; i < 8; i++ {
z.ybr[y+j][x+i] = avg
}
}
}
func predFunc8DCLeft(z *Decoder, y, x int) {
sum := uint32(4)
for i := 0; i < 8; i++ {
sum += uint32(z.ybr[y-1][x+i])
}
avg := uint8(sum / 8)
for j := 0; j < 8; j++ {
for i := 0; i < 8; i++ {
z.ybr[y+j][x+i] = avg
}
}
}
func predFunc8DCTopLeft(z *Decoder, y, x int) {
for j := 0; j < 8; j++ {
for i := 0; i < 8; i++ {
z.ybr[y+j][x+i] = 0x80
}
}
}
func predFunc16DC(z *Decoder, y, x int) {
sum := uint32(16)
for i := 0; i < 16; i++ {
sum += uint32(z.ybr[y-1][x+i])
}
for j := 0; j < 16; j++ {
sum += uint32(z.ybr[y+j][x-1])
}
avg := uint8(sum / 32)
for j := 0; j < 16; j++ {
for i := 0; i < 16; i++ {
z.ybr[y+j][x+i] = avg
}
}
}
func predFunc16TM(z *Decoder, y, x int) {
delta0 := -int32(z.ybr[y-1][x-1])
for j := 0; j < 16; j++ {
delta1 := delta0 + int32(z.ybr[y+j][x-1])
for i := 0; i < 16; i++ {
delta2 := delta1 + int32(z.ybr[y-1][x+i])
z.ybr[y+j][x+i] = uint8(clip(delta2, 0, 255))
}
}
}
func predFunc16VE(z *Decoder, y, x int) {
for j := 0; j < 16; j++ {
for i := 0; i < 16; i++ {
z.ybr[y+j][x+i] = z.ybr[y-1][x+i]
}
}
}
func predFunc16HE(z *Decoder, y, x int) {
for j := 0; j < 16; j++ {
for i := 0; i < 16; i++ {
z.ybr[y+j][x+i] = z.ybr[y+j][x-1]
}
}
}
func predFunc16DCTop(z *Decoder, y, x int) {
sum := uint32(8)
for j := 0; j < 16; j++ {
sum += uint32(z.ybr[y+j][x-1])
}
avg := uint8(sum / 16)
for j := 0; j < 16; j++ {
for i := 0; i < 16; i++ {
z.ybr[y+j][x+i] = avg
}
}
}
func predFunc16DCLeft(z *Decoder, y, x int) {
sum := uint32(8)
for i := 0; i < 16; i++ {
sum += uint32(z.ybr[y-1][x+i])
}
avg := uint8(sum / 16)
for j := 0; j < 16; j++ {
for i := 0; i < 16; i++ {
z.ybr[y+j][x+i] = avg
}
}
}
func predFunc16DCTopLeft(z *Decoder, y, x int) {
for j := 0; j < 16; j++ {
for i := 0; i < 16; i++ {
z.ybr[y+j][x+i] = 0x80
}
}
}

98
vendor/golang.org/x/image/vp8/quant.go generated vendored Normal file
View file

@ -0,0 +1,98 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// This file implements parsing the quantization factors.
// quant are DC/AC quantization factors.
type quant struct {
y1 [2]uint16
y2 [2]uint16
uv [2]uint16
}
// clip clips x to the range [min, max] inclusive.
func clip(x, min, max int32) int32 {
if x < min {
return min
}
if x > max {
return max
}
return x
}
// parseQuant parses the quantization factors, as specified in section 9.6.
func (d *Decoder) parseQuant() {
baseQ0 := d.fp.readUint(uniformProb, 7)
dqy1DC := d.fp.readOptionalInt(uniformProb, 4)
const dqy1AC = 0
dqy2DC := d.fp.readOptionalInt(uniformProb, 4)
dqy2AC := d.fp.readOptionalInt(uniformProb, 4)
dquvDC := d.fp.readOptionalInt(uniformProb, 4)
dquvAC := d.fp.readOptionalInt(uniformProb, 4)
for i := 0; i < nSegment; i++ {
q := int32(baseQ0)
if d.segmentHeader.useSegment {
if d.segmentHeader.relativeDelta {
q += int32(d.segmentHeader.quantizer[i])
} else {
q = int32(d.segmentHeader.quantizer[i])
}
}
d.quant[i].y1[0] = dequantTableDC[clip(q+dqy1DC, 0, 127)]
d.quant[i].y1[1] = dequantTableAC[clip(q+dqy1AC, 0, 127)]
d.quant[i].y2[0] = dequantTableDC[clip(q+dqy2DC, 0, 127)] * 2
d.quant[i].y2[1] = dequantTableAC[clip(q+dqy2AC, 0, 127)] * 155 / 100
if d.quant[i].y2[1] < 8 {
d.quant[i].y2[1] = 8
}
// The 117 is not a typo. The dequant_init function in the spec's Reference
// Decoder Source Code (http://tools.ietf.org/html/rfc6386#section-9.6 Page 145)
// says to clamp the LHS value at 132, which is equal to dequantTableDC[117].
d.quant[i].uv[0] = dequantTableDC[clip(q+dquvDC, 0, 117)]
d.quant[i].uv[1] = dequantTableAC[clip(q+dquvAC, 0, 127)]
}
}
// The dequantization tables are specified in section 14.1.
var (
dequantTableDC = [128]uint16{
4, 5, 6, 7, 8, 9, 10, 10,
11, 12, 13, 14, 15, 16, 17, 17,
18, 19, 20, 20, 21, 21, 22, 22,
23, 23, 24, 25, 25, 26, 27, 28,
29, 30, 31, 32, 33, 34, 35, 36,
37, 37, 38, 39, 40, 41, 42, 43,
44, 45, 46, 46, 47, 48, 49, 50,
51, 52, 53, 54, 55, 56, 57, 58,
59, 60, 61, 62, 63, 64, 65, 66,
67, 68, 69, 70, 71, 72, 73, 74,
75, 76, 76, 77, 78, 79, 80, 81,
82, 83, 84, 85, 86, 87, 88, 89,
91, 93, 95, 96, 98, 100, 101, 102,
104, 106, 108, 110, 112, 114, 116, 118,
122, 124, 126, 128, 130, 132, 134, 136,
138, 140, 143, 145, 148, 151, 154, 157,
}
dequantTableAC = [128]uint16{
4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16, 17, 18, 19,
20, 21, 22, 23, 24, 25, 26, 27,
28, 29, 30, 31, 32, 33, 34, 35,
36, 37, 38, 39, 40, 41, 42, 43,
44, 45, 46, 47, 48, 49, 50, 51,
52, 53, 54, 55, 56, 57, 58, 60,
62, 64, 66, 68, 70, 72, 74, 76,
78, 80, 82, 84, 86, 88, 90, 92,
94, 96, 98, 100, 102, 104, 106, 108,
110, 112, 114, 116, 119, 122, 125, 128,
131, 134, 137, 140, 143, 146, 149, 152,
155, 158, 161, 164, 167, 170, 173, 177,
181, 185, 189, 193, 197, 201, 205, 209,
213, 217, 221, 225, 229, 234, 239, 245,
249, 254, 259, 264, 269, 274, 279, 284,
}
)

442
vendor/golang.org/x/image/vp8/reconstruct.go generated vendored Normal file
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// This file implements decoding DCT/WHT residual coefficients and
// reconstructing YCbCr data equal to predicted values plus residuals.
//
// There are 1*16*16 + 2*8*8 + 1*4*4 coefficients per macroblock:
// - 1*16*16 luma DCT coefficients,
// - 2*8*8 chroma DCT coefficients, and
// - 1*4*4 luma WHT coefficients.
// Coefficients are read in lots of 16, and the later coefficients in each lot
// are often zero.
//
// The YCbCr data consists of 1*16*16 luma values and 2*8*8 chroma values,
// plus previously decoded values along the top and left borders. The combined
// values are laid out as a [1+16+1+8][32]uint8 so that vertically adjacent
// samples are 32 bytes apart. In detail, the layout is:
//
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
// . . . . . . . a b b b b b b b b b b b b b b b b c c c c . . . . 0
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 1
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 2
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 3
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y c c c c . . . . 4
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 5
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 6
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 7
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y c c c c . . . . 8
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 9
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 10
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 11
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y c c c c . . . . 12
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 13
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 14
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 15
// . . . . . . . d Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y . . . . . . . . 16
// . . . . . . . e f f f f f f f f . . . . . . . g h h h h h h h h 17
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 18
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 19
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 20
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 21
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 22
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 23
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 24
// . . . . . . . i B B B B B B B B . . . . . . . j R R R R R R R R 25
//
// Y, B and R are the reconstructed luma (Y) and chroma (B, R) values.
// The Y values are predicted (either as one 16x16 region or 16 4x4 regions)
// based on the row above's Y values (some combination of {abc} or {dYC}) and
// the column left's Y values (either {ad} or {bY}). Similarly, B and R values
// are predicted on the row above and column left of their respective 8x8
// region: {efi} for B, {ghj} for R.
//
// For uppermost macroblocks (i.e. those with mby == 0), the {abcefgh} values
// are initialized to 0x81. Otherwise, they are copied from the bottom row of
// the macroblock above. The {c} values are then duplicated from row 0 to rows
// 4, 8 and 12 of the ybr workspace.
// Similarly, for leftmost macroblocks (i.e. those with mbx == 0), the {adeigj}
// values are initialized to 0x7f. Otherwise, they are copied from the right
// column of the macroblock to the left.
// For the top-left macroblock (with mby == 0 && mbx == 0), {aeg} is 0x81.
//
// When moving from one macroblock to the next horizontally, the {adeigj}
// values can simply be copied from the workspace to itself, shifted by 8 or
// 16 columns. When moving from one macroblock to the next vertically,
// filtering can occur and hence the row values have to be copied from the
// post-filtered image instead of the pre-filtered workspace.
const (
bCoeffBase = 1*16*16 + 0*8*8
rCoeffBase = 1*16*16 + 1*8*8
whtCoeffBase = 1*16*16 + 2*8*8
)
const (
ybrYX = 8
ybrYY = 1
ybrBX = 8
ybrBY = 18
ybrRX = 24
ybrRY = 18
)
// prepareYBR prepares the {abcdefghij} elements of ybr.
func (d *Decoder) prepareYBR(mbx, mby int) {
if mbx == 0 {
for y := 0; y < 17; y++ {
d.ybr[y][7] = 0x81
}
for y := 17; y < 26; y++ {
d.ybr[y][7] = 0x81
d.ybr[y][23] = 0x81
}
} else {
for y := 0; y < 17; y++ {
d.ybr[y][7] = d.ybr[y][7+16]
}
for y := 17; y < 26; y++ {
d.ybr[y][7] = d.ybr[y][15]
d.ybr[y][23] = d.ybr[y][31]
}
}
if mby == 0 {
for x := 7; x < 28; x++ {
d.ybr[0][x] = 0x7f
}
for x := 7; x < 16; x++ {
d.ybr[17][x] = 0x7f
}
for x := 23; x < 32; x++ {
d.ybr[17][x] = 0x7f
}
} else {
for i := 0; i < 16; i++ {
d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+i]
}
for i := 0; i < 8; i++ {
d.ybr[17][8+i] = d.img.Cb[(8*mby-1)*d.img.CStride+8*mbx+i]
}
for i := 0; i < 8; i++ {
d.ybr[17][24+i] = d.img.Cr[(8*mby-1)*d.img.CStride+8*mbx+i]
}
if mbx == d.mbw-1 {
for i := 16; i < 20; i++ {
d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+15]
}
} else {
for i := 16; i < 20; i++ {
d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+i]
}
}
}
for y := 4; y < 16; y += 4 {
d.ybr[y][24] = d.ybr[0][24]
d.ybr[y][25] = d.ybr[0][25]
d.ybr[y][26] = d.ybr[0][26]
d.ybr[y][27] = d.ybr[0][27]
}
}
// btou converts a bool to a 0/1 value.
func btou(b bool) uint8 {
if b {
return 1
}
return 0
}
// pack packs four 0/1 values into four bits of a uint32.
func pack(x [4]uint8, shift int) uint32 {
u := uint32(x[0])<<0 | uint32(x[1])<<1 | uint32(x[2])<<2 | uint32(x[3])<<3
return u << uint(shift)
}
// unpack unpacks four 0/1 values from a four-bit value.
var unpack = [16][4]uint8{
{0, 0, 0, 0},
{1, 0, 0, 0},
{0, 1, 0, 0},
{1, 1, 0, 0},
{0, 0, 1, 0},
{1, 0, 1, 0},
{0, 1, 1, 0},
{1, 1, 1, 0},
{0, 0, 0, 1},
{1, 0, 0, 1},
{0, 1, 0, 1},
{1, 1, 0, 1},
{0, 0, 1, 1},
{1, 0, 1, 1},
{0, 1, 1, 1},
{1, 1, 1, 1},
}
var (
// The mapping from 4x4 region position to band is specified in section 13.3.
bands = [17]uint8{0, 1, 2, 3, 6, 4, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7, 0}
// Category probabilties are specified in section 13.2.
// Decoding categories 1 and 2 are done inline.
cat3456 = [4][12]uint8{
{173, 148, 140, 0, 0, 0, 0, 0, 0, 0, 0, 0},
{176, 155, 140, 135, 0, 0, 0, 0, 0, 0, 0, 0},
{180, 157, 141, 134, 130, 0, 0, 0, 0, 0, 0, 0},
{254, 254, 243, 230, 196, 177, 153, 140, 133, 130, 129, 0},
}
// The zigzag order is:
// 0 1 5 6
// 2 4 7 12
// 3 8 11 13
// 9 10 14 15
zigzag = [16]uint8{0, 1, 4, 8, 5, 2, 3, 6, 9, 12, 13, 10, 7, 11, 14, 15}
)
// parseResiduals4 parses a 4x4 region of residual coefficients, as specified
// in section 13.3, and returns a 0/1 value indicating whether there was at
// least one non-zero coefficient.
// r is the partition to read bits from.
// plane and context describe which token probability table to use. context is
// either 0, 1 or 2, and equals how many of the macroblock left and macroblock
// above have non-zero coefficients.
// quant are the DC/AC quantization factors.
// skipFirstCoeff is whether the DC coefficient has already been parsed.
// coeffBase is the base index of d.coeff to write to.
func (d *Decoder) parseResiduals4(r *partition, plane int, context uint8, quant [2]uint16, skipFirstCoeff bool, coeffBase int) uint8 {
prob, n := &d.tokenProb[plane], 0
if skipFirstCoeff {
n = 1
}
p := prob[bands[n]][context]
if !r.readBit(p[0]) {
return 0
}
for n != 16 {
n++
if !r.readBit(p[1]) {
p = prob[bands[n]][0]
continue
}
var v uint32
if !r.readBit(p[2]) {
v = 1
p = prob[bands[n]][1]
} else {
if !r.readBit(p[3]) {
if !r.readBit(p[4]) {
v = 2
} else {
v = 3 + r.readUint(p[5], 1)
}
} else if !r.readBit(p[6]) {
if !r.readBit(p[7]) {
// Category 1.
v = 5 + r.readUint(159, 1)
} else {
// Category 2.
v = 7 + 2*r.readUint(165, 1) + r.readUint(145, 1)
}
} else {
// Categories 3, 4, 5 or 6.
b1 := r.readUint(p[8], 1)
b0 := r.readUint(p[9+b1], 1)
cat := 2*b1 + b0
tab := &cat3456[cat]
v = 0
for i := 0; tab[i] != 0; i++ {
v *= 2
v += r.readUint(tab[i], 1)
}
v += 3 + (8 << cat)
}
p = prob[bands[n]][2]
}
z := zigzag[n-1]
c := int32(v) * int32(quant[btou(z > 0)])
if r.readBit(uniformProb) {
c = -c
}
d.coeff[coeffBase+int(z)] = int16(c)
if n == 16 || !r.readBit(p[0]) {
return 1
}
}
return 1
}
// parseResiduals parses the residuals and returns whether inner loop filtering
// should be skipped for this macroblock.
func (d *Decoder) parseResiduals(mbx, mby int) (skip bool) {
partition := &d.op[mby&(d.nOP-1)]
plane := planeY1SansY2
quant := &d.quant[d.segment]
// Parse the DC coefficient of each 4x4 luma region.
if d.usePredY16 {
nz := d.parseResiduals4(partition, planeY2, d.leftMB.nzY16+d.upMB[mbx].nzY16, quant.y2, false, whtCoeffBase)
d.leftMB.nzY16 = nz
d.upMB[mbx].nzY16 = nz
d.inverseWHT16()
plane = planeY1WithY2
}
var (
nzDC, nzAC [4]uint8
nzDCMask, nzACMask uint32
coeffBase int
)
// Parse the luma coefficients.
lnz := unpack[d.leftMB.nzMask&0x0f]
unz := unpack[d.upMB[mbx].nzMask&0x0f]
for y := 0; y < 4; y++ {
nz := lnz[y]
for x := 0; x < 4; x++ {
nz = d.parseResiduals4(partition, plane, nz+unz[x], quant.y1, d.usePredY16, coeffBase)
unz[x] = nz
nzAC[x] = nz
nzDC[x] = btou(d.coeff[coeffBase] != 0)
coeffBase += 16
}
lnz[y] = nz
nzDCMask |= pack(nzDC, y*4)
nzACMask |= pack(nzAC, y*4)
}
lnzMask := pack(lnz, 0)
unzMask := pack(unz, 0)
// Parse the chroma coefficients.
lnz = unpack[d.leftMB.nzMask>>4]
unz = unpack[d.upMB[mbx].nzMask>>4]
for c := 0; c < 4; c += 2 {
for y := 0; y < 2; y++ {
nz := lnz[y+c]
for x := 0; x < 2; x++ {
nz = d.parseResiduals4(partition, planeUV, nz+unz[x+c], quant.uv, false, coeffBase)
unz[x+c] = nz
nzAC[y*2+x] = nz
nzDC[y*2+x] = btou(d.coeff[coeffBase] != 0)
coeffBase += 16
}
lnz[y+c] = nz
}
nzDCMask |= pack(nzDC, 16+c*2)
nzACMask |= pack(nzAC, 16+c*2)
}
lnzMask |= pack(lnz, 4)
unzMask |= pack(unz, 4)
// Save decoder state.
d.leftMB.nzMask = uint8(lnzMask)
d.upMB[mbx].nzMask = uint8(unzMask)
d.nzDCMask = nzDCMask
d.nzACMask = nzACMask
// Section 15.1 of the spec says that "Steps 2 and 4 [of the loop filter]
// are skipped... [if] there is no DCT coefficient coded for the whole
// macroblock."
return nzDCMask == 0 && nzACMask == 0
}
// reconstructMacroblock applies the predictor functions and adds the inverse-
// DCT transformed residuals to recover the YCbCr data.
func (d *Decoder) reconstructMacroblock(mbx, mby int) {
if d.usePredY16 {
p := checkTopLeftPred(mbx, mby, d.predY16)
predFunc16[p](d, 1, 8)
for j := 0; j < 4; j++ {
for i := 0; i < 4; i++ {
n := 4*j + i
y := 4*j + 1
x := 4*i + 8
mask := uint32(1) << uint(n)
if d.nzACMask&mask != 0 {
d.inverseDCT4(y, x, 16*n)
} else if d.nzDCMask&mask != 0 {
d.inverseDCT4DCOnly(y, x, 16*n)
}
}
}
} else {
for j := 0; j < 4; j++ {
for i := 0; i < 4; i++ {
n := 4*j + i
y := 4*j + 1
x := 4*i + 8
predFunc4[d.predY4[j][i]](d, y, x)
mask := uint32(1) << uint(n)
if d.nzACMask&mask != 0 {
d.inverseDCT4(y, x, 16*n)
} else if d.nzDCMask&mask != 0 {
d.inverseDCT4DCOnly(y, x, 16*n)
}
}
}
}
p := checkTopLeftPred(mbx, mby, d.predC8)
predFunc8[p](d, ybrBY, ybrBX)
if d.nzACMask&0x0f0000 != 0 {
d.inverseDCT8(ybrBY, ybrBX, bCoeffBase)
} else if d.nzDCMask&0x0f0000 != 0 {
d.inverseDCT8DCOnly(ybrBY, ybrBX, bCoeffBase)
}
predFunc8[p](d, ybrRY, ybrRX)
if d.nzACMask&0xf00000 != 0 {
d.inverseDCT8(ybrRY, ybrRX, rCoeffBase)
} else if d.nzDCMask&0xf00000 != 0 {
d.inverseDCT8DCOnly(ybrRY, ybrRX, rCoeffBase)
}
}
// reconstruct reconstructs one macroblock and returns whether inner loop
// filtering should be skipped for it.
func (d *Decoder) reconstruct(mbx, mby int) (skip bool) {
if d.segmentHeader.updateMap {
if !d.fp.readBit(d.segmentHeader.prob[0]) {
d.segment = int(d.fp.readUint(d.segmentHeader.prob[1], 1))
} else {
d.segment = int(d.fp.readUint(d.segmentHeader.prob[2], 1)) + 2
}
}
if d.useSkipProb {
skip = d.fp.readBit(d.skipProb)
}
// Prepare the workspace.
for i := range d.coeff {
d.coeff[i] = 0
}
d.prepareYBR(mbx, mby)
// Parse the predictor modes.
d.usePredY16 = d.fp.readBit(145)
if d.usePredY16 {
d.parsePredModeY16(mbx)
} else {
d.parsePredModeY4(mbx)
}
d.parsePredModeC8()
// Parse the residuals.
if !skip {
skip = d.parseResiduals(mbx, mby)
} else {
if d.usePredY16 {
d.leftMB.nzY16 = 0
d.upMB[mbx].nzY16 = 0
}
d.leftMB.nzMask = 0
d.upMB[mbx].nzMask = 0
d.nzDCMask = 0
d.nzACMask = 0
}
// Reconstruct the YCbCr data and copy it to the image.
d.reconstructMacroblock(mbx, mby)
for i, y := (mby*d.img.YStride+mbx)*16, 0; y < 16; i, y = i+d.img.YStride, y+1 {
copy(d.img.Y[i:i+16], d.ybr[ybrYY+y][ybrYX:ybrYX+16])
}
for i, y := (mby*d.img.CStride+mbx)*8, 0; y < 8; i, y = i+d.img.CStride, y+1 {
copy(d.img.Cb[i:i+8], d.ybr[ybrBY+y][ybrBX:ybrBX+8])
copy(d.img.Cr[i:i+8], d.ybr[ybrRY+y][ybrRX:ybrRX+8])
}
return skip
}

381
vendor/golang.org/x/image/vp8/token.go generated vendored Normal file
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8
// This file contains token probabilities for decoding DCT/WHT coefficients, as
// specified in chapter 13.
func (d *Decoder) parseTokenProb() {
for i := range d.tokenProb {
for j := range d.tokenProb[i] {
for k := range d.tokenProb[i][j] {
for l := range d.tokenProb[i][j][k] {
if d.fp.readBit(tokenProbUpdateProb[i][j][k][l]) {
d.tokenProb[i][j][k][l] = uint8(d.fp.readUint(uniformProb, 8))
}
}
}
}
}
}
// The plane enumeration is specified in section 13.3.
const (
planeY1WithY2 = iota
planeY2
planeUV
planeY1SansY2
nPlane
)
const (
nBand = 8
nContext = 3
nProb = 11
)
// Token probability update probabilities are specified in section 13.4.
var tokenProbUpdateProb = [nPlane][nBand][nContext][nProb]uint8{
{
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{176, 246, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{223, 241, 252, 255, 255, 255, 255, 255, 255, 255, 255},
{249, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 244, 252, 255, 255, 255, 255, 255, 255, 255, 255},
{234, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{253, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 246, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{239, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 248, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{251, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{251, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 254, 253, 255, 254, 255, 255, 255, 255, 255, 255},
{250, 255, 254, 255, 254, 255, 255, 255, 255, 255, 255},
{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
},
{
{
{217, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{225, 252, 241, 253, 255, 255, 254, 255, 255, 255, 255},
{234, 250, 241, 250, 253, 255, 253, 254, 255, 255, 255},
},
{
{255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{223, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{238, 253, 254, 254, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 248, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{249, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 253, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{247, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{252, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{253, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 254, 253, 255, 255, 255, 255, 255, 255, 255, 255},
{250, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
},
{
{
{186, 251, 250, 255, 255, 255, 255, 255, 255, 255, 255},
{234, 251, 244, 254, 255, 255, 255, 255, 255, 255, 255},
{251, 251, 243, 253, 254, 255, 254, 255, 255, 255, 255},
},
{
{255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{236, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{251, 253, 253, 254, 254, 255, 255, 255, 255, 255, 255},
},
{
{255, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
},
{
{
{248, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{250, 254, 252, 254, 255, 255, 255, 255, 255, 255, 255},
{248, 254, 249, 253, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255},
{246, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255},
{252, 254, 251, 254, 254, 255, 255, 255, 255, 255, 255},
},
{
{255, 254, 252, 255, 255, 255, 255, 255, 255, 255, 255},
{248, 254, 253, 255, 255, 255, 255, 255, 255, 255, 255},
{253, 255, 254, 254, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 251, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{245, 251, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{253, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 251, 253, 255, 255, 255, 255, 255, 255, 255, 255},
{252, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 252, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{249, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 253, 255, 255, 255, 255, 255, 255, 255, 255},
{250, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
{
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
},
},
}
// Default token probabilities are specified in section 13.5.
var defaultTokenProb = [nPlane][nBand][nContext][nProb]uint8{
{
{
{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
},
{
{253, 136, 254, 255, 228, 219, 128, 128, 128, 128, 128},
{189, 129, 242, 255, 227, 213, 255, 219, 128, 128, 128},
{106, 126, 227, 252, 214, 209, 255, 255, 128, 128, 128},
},
{
{1, 98, 248, 255, 236, 226, 255, 255, 128, 128, 128},
{181, 133, 238, 254, 221, 234, 255, 154, 128, 128, 128},
{78, 134, 202, 247, 198, 180, 255, 219, 128, 128, 128},
},
{
{1, 185, 249, 255, 243, 255, 128, 128, 128, 128, 128},
{184, 150, 247, 255, 236, 224, 128, 128, 128, 128, 128},
{77, 110, 216, 255, 236, 230, 128, 128, 128, 128, 128},
},
{
{1, 101, 251, 255, 241, 255, 128, 128, 128, 128, 128},
{170, 139, 241, 252, 236, 209, 255, 255, 128, 128, 128},
{37, 116, 196, 243, 228, 255, 255, 255, 128, 128, 128},
},
{
{1, 204, 254, 255, 245, 255, 128, 128, 128, 128, 128},
{207, 160, 250, 255, 238, 128, 128, 128, 128, 128, 128},
{102, 103, 231, 255, 211, 171, 128, 128, 128, 128, 128},
},
{
{1, 152, 252, 255, 240, 255, 128, 128, 128, 128, 128},
{177, 135, 243, 255, 234, 225, 128, 128, 128, 128, 128},
{80, 129, 211, 255, 194, 224, 128, 128, 128, 128, 128},
},
{
{1, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
{246, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
{255, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
},
},
{
{
{198, 35, 237, 223, 193, 187, 162, 160, 145, 155, 62},
{131, 45, 198, 221, 172, 176, 220, 157, 252, 221, 1},
{68, 47, 146, 208, 149, 167, 221, 162, 255, 223, 128},
},
{
{1, 149, 241, 255, 221, 224, 255, 255, 128, 128, 128},
{184, 141, 234, 253, 222, 220, 255, 199, 128, 128, 128},
{81, 99, 181, 242, 176, 190, 249, 202, 255, 255, 128},
},
{
{1, 129, 232, 253, 214, 197, 242, 196, 255, 255, 128},
{99, 121, 210, 250, 201, 198, 255, 202, 128, 128, 128},
{23, 91, 163, 242, 170, 187, 247, 210, 255, 255, 128},
},
{
{1, 200, 246, 255, 234, 255, 128, 128, 128, 128, 128},
{109, 178, 241, 255, 231, 245, 255, 255, 128, 128, 128},
{44, 130, 201, 253, 205, 192, 255, 255, 128, 128, 128},
},
{
{1, 132, 239, 251, 219, 209, 255, 165, 128, 128, 128},
{94, 136, 225, 251, 218, 190, 255, 255, 128, 128, 128},
{22, 100, 174, 245, 186, 161, 255, 199, 128, 128, 128},
},
{
{1, 182, 249, 255, 232, 235, 128, 128, 128, 128, 128},
{124, 143, 241, 255, 227, 234, 128, 128, 128, 128, 128},
{35, 77, 181, 251, 193, 211, 255, 205, 128, 128, 128},
},
{
{1, 157, 247, 255, 236, 231, 255, 255, 128, 128, 128},
{121, 141, 235, 255, 225, 227, 255, 255, 128, 128, 128},
{45, 99, 188, 251, 195, 217, 255, 224, 128, 128, 128},
},
{
{1, 1, 251, 255, 213, 255, 128, 128, 128, 128, 128},
{203, 1, 248, 255, 255, 128, 128, 128, 128, 128, 128},
{137, 1, 177, 255, 224, 255, 128, 128, 128, 128, 128},
},
},
{
{
{253, 9, 248, 251, 207, 208, 255, 192, 128, 128, 128},
{175, 13, 224, 243, 193, 185, 249, 198, 255, 255, 128},
{73, 17, 171, 221, 161, 179, 236, 167, 255, 234, 128},
},
{
{1, 95, 247, 253, 212, 183, 255, 255, 128, 128, 128},
{239, 90, 244, 250, 211, 209, 255, 255, 128, 128, 128},
{155, 77, 195, 248, 188, 195, 255, 255, 128, 128, 128},
},
{
{1, 24, 239, 251, 218, 219, 255, 205, 128, 128, 128},
{201, 51, 219, 255, 196, 186, 128, 128, 128, 128, 128},
{69, 46, 190, 239, 201, 218, 255, 228, 128, 128, 128},
},
{
{1, 191, 251, 255, 255, 128, 128, 128, 128, 128, 128},
{223, 165, 249, 255, 213, 255, 128, 128, 128, 128, 128},
{141, 124, 248, 255, 255, 128, 128, 128, 128, 128, 128},
},
{
{1, 16, 248, 255, 255, 128, 128, 128, 128, 128, 128},
{190, 36, 230, 255, 236, 255, 128, 128, 128, 128, 128},
{149, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
},
{
{1, 226, 255, 128, 128, 128, 128, 128, 128, 128, 128},
{247, 192, 255, 128, 128, 128, 128, 128, 128, 128, 128},
{240, 128, 255, 128, 128, 128, 128, 128, 128, 128, 128},
},
{
{1, 134, 252, 255, 255, 128, 128, 128, 128, 128, 128},
{213, 62, 250, 255, 255, 128, 128, 128, 128, 128, 128},
{55, 93, 255, 128, 128, 128, 128, 128, 128, 128, 128},
},
{
{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
},
},
{
{
{202, 24, 213, 235, 186, 191, 220, 160, 240, 175, 255},
{126, 38, 182, 232, 169, 184, 228, 174, 255, 187, 128},
{61, 46, 138, 219, 151, 178, 240, 170, 255, 216, 128},
},
{
{1, 112, 230, 250, 199, 191, 247, 159, 255, 255, 128},
{166, 109, 228, 252, 211, 215, 255, 174, 128, 128, 128},
{39, 77, 162, 232, 172, 180, 245, 178, 255, 255, 128},
},
{
{1, 52, 220, 246, 198, 199, 249, 220, 255, 255, 128},
{124, 74, 191, 243, 183, 193, 250, 221, 255, 255, 128},
{24, 71, 130, 219, 154, 170, 243, 182, 255, 255, 128},
},
{
{1, 182, 225, 249, 219, 240, 255, 224, 128, 128, 128},
{149, 150, 226, 252, 216, 205, 255, 171, 128, 128, 128},
{28, 108, 170, 242, 183, 194, 254, 223, 255, 255, 128},
},
{
{1, 81, 230, 252, 204, 203, 255, 192, 128, 128, 128},
{123, 102, 209, 247, 188, 196, 255, 233, 128, 128, 128},
{20, 95, 153, 243, 164, 173, 255, 203, 128, 128, 128},
},
{
{1, 222, 248, 255, 216, 213, 128, 128, 128, 128, 128},
{168, 175, 246, 252, 235, 205, 255, 255, 128, 128, 128},
{47, 116, 215, 255, 211, 212, 255, 255, 128, 128, 128},
},
{
{1, 121, 236, 253, 212, 214, 255, 255, 128, 128, 128},
{141, 84, 213, 252, 201, 202, 255, 219, 128, 128, 128},
{42, 80, 160, 240, 162, 185, 255, 205, 128, 128, 128},
},
{
{1, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
{244, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
{238, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
},
},
}

603
vendor/golang.org/x/image/vp8l/decode.go generated vendored Normal file
View file

@ -0,0 +1,603 @@
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package vp8l implements a decoder for the VP8L lossless image format.
//
// The VP8L specification is at:
// https://developers.google.com/speed/webp/docs/riff_container
package vp8l // import "golang.org/x/image/vp8l"
import (
"bufio"
"errors"
"image"
"image/color"
"io"
)
var (
errInvalidCodeLengths = errors.New("vp8l: invalid code lengths")
errInvalidHuffmanTree = errors.New("vp8l: invalid Huffman tree")
)
// colorCacheMultiplier is the multiplier used for the color cache hash
// function, specified in section 4.2.3.
const colorCacheMultiplier = 0x1e35a7bd
// distanceMapTable is the look-up table for distanceMap.
var distanceMapTable = [120]uint8{
0x18, 0x07, 0x17, 0x19, 0x28, 0x06, 0x27, 0x29, 0x16, 0x1a,
0x26, 0x2a, 0x38, 0x05, 0x37, 0x39, 0x15, 0x1b, 0x36, 0x3a,
0x25, 0x2b, 0x48, 0x04, 0x47, 0x49, 0x14, 0x1c, 0x35, 0x3b,
0x46, 0x4a, 0x24, 0x2c, 0x58, 0x45, 0x4b, 0x34, 0x3c, 0x03,
0x57, 0x59, 0x13, 0x1d, 0x56, 0x5a, 0x23, 0x2d, 0x44, 0x4c,
0x55, 0x5b, 0x33, 0x3d, 0x68, 0x02, 0x67, 0x69, 0x12, 0x1e,
0x66, 0x6a, 0x22, 0x2e, 0x54, 0x5c, 0x43, 0x4d, 0x65, 0x6b,
0x32, 0x3e, 0x78, 0x01, 0x77, 0x79, 0x53, 0x5d, 0x11, 0x1f,
0x64, 0x6c, 0x42, 0x4e, 0x76, 0x7a, 0x21, 0x2f, 0x75, 0x7b,
0x31, 0x3f, 0x63, 0x6d, 0x52, 0x5e, 0x00, 0x74, 0x7c, 0x41,
0x4f, 0x10, 0x20, 0x62, 0x6e, 0x30, 0x73, 0x7d, 0x51, 0x5f,
0x40, 0x72, 0x7e, 0x61, 0x6f, 0x50, 0x71, 0x7f, 0x60, 0x70,
}
// distanceMap maps a LZ77 backwards reference distance to a two-dimensional
// pixel offset, specified in section 4.2.2.
func distanceMap(w int32, code uint32) int32 {
if int32(code) > int32(len(distanceMapTable)) {
return int32(code) - int32(len(distanceMapTable))
}
distCode := int32(distanceMapTable[code-1])
yOffset := distCode >> 4
xOffset := 8 - distCode&0xf
if d := yOffset*w + xOffset; d >= 1 {
return d
}
return 1
}
// decoder holds the bit-stream for a VP8L image.
type decoder struct {
r io.ByteReader
bits uint32
nBits uint32
}
// read reads the next n bits from the decoder's bit-stream.
func (d *decoder) read(n uint32) (uint32, error) {
for d.nBits < n {
c, err := d.r.ReadByte()
if err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return 0, err
}
d.bits |= uint32(c) << d.nBits
d.nBits += 8
}
u := d.bits & (1<<n - 1)
d.bits >>= n
d.nBits -= n
return u, nil
}
// decodeTransform decodes the next transform and the width of the image after
// transformation (or equivalently, before inverse transformation), specified
// in section 3.
func (d *decoder) decodeTransform(w int32, h int32) (t transform, newWidth int32, err error) {
t.oldWidth = w
t.transformType, err = d.read(2)
if err != nil {
return transform{}, 0, err
}
switch t.transformType {
case transformTypePredictor, transformTypeCrossColor:
t.bits, err = d.read(3)
if err != nil {
return transform{}, 0, err
}
t.bits += 2
t.pix, err = d.decodePix(nTiles(w, t.bits), nTiles(h, t.bits), 0, false)
if err != nil {
return transform{}, 0, err
}
case transformTypeSubtractGreen:
// No-op.
case transformTypeColorIndexing:
nColors, err := d.read(8)
if err != nil {
return transform{}, 0, err
}
nColors++
t.bits = 0
switch {
case nColors <= 2:
t.bits = 3
case nColors <= 4:
t.bits = 2
case nColors <= 16:
t.bits = 1
}
w = nTiles(w, t.bits)
pix, err := d.decodePix(int32(nColors), 1, 4*256, false)
if err != nil {
return transform{}, 0, err
}
for p := 4; p < len(pix); p += 4 {
pix[p+0] += pix[p-4]
pix[p+1] += pix[p-3]
pix[p+2] += pix[p-2]
pix[p+3] += pix[p-1]
}
// The spec says that "if the index is equal or larger than color_table_size,
// the argb color value should be set to 0x00000000 (transparent black)."
// We re-slice up to 256 4-byte pixels.
t.pix = pix[:4*256]
}
return t, w, nil
}
// repeatsCodeLength is the minimum code length for repeated codes.
const repeatsCodeLength = 16
// These magic numbers are specified at the end of section 5.2.2.
// The 3-length arrays apply to code lengths >= repeatsCodeLength.
var (
codeLengthCodeOrder = [19]uint8{
17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
}
repeatBits = [3]uint8{2, 3, 7}
repeatOffsets = [3]uint8{3, 3, 11}
)
// decodeCodeLengths decodes a Huffman tree's code lengths which are themselves
// encoded via a Huffman tree, specified in section 5.2.2.
func (d *decoder) decodeCodeLengths(dst []uint32, codeLengthCodeLengths []uint32) error {
h := hTree{}
if err := h.build(codeLengthCodeLengths); err != nil {
return err
}
maxSymbol := len(dst)
useLength, err := d.read(1)
if err != nil {
return err
}
if useLength != 0 {
n, err := d.read(3)
if err != nil {
return err
}
n = 2 + 2*n
ms, err := d.read(n)
if err != nil {
return err
}
maxSymbol = int(ms) + 2
if maxSymbol > len(dst) {
return errInvalidCodeLengths
}
}
// The spec says that "if code 16 [meaning repeat] is used before
// a non-zero value has been emitted, a value of 8 is repeated."
prevCodeLength := uint32(8)
for symbol := 0; symbol < len(dst); {
if maxSymbol == 0 {
break
}
maxSymbol--
codeLength, err := h.next(d)
if err != nil {
return err
}
if codeLength < repeatsCodeLength {
dst[symbol] = codeLength
symbol++
if codeLength != 0 {
prevCodeLength = codeLength
}
continue
}
repeat, err := d.read(uint32(repeatBits[codeLength-repeatsCodeLength]))
if err != nil {
return err
}
repeat += uint32(repeatOffsets[codeLength-repeatsCodeLength])
if symbol+int(repeat) > len(dst) {
return errInvalidCodeLengths
}
// A code length of 16 repeats the previous non-zero code.
// A code length of 17 or 18 repeats zeroes.
cl := uint32(0)
if codeLength == 16 {
cl = prevCodeLength
}
for ; repeat > 0; repeat-- {
dst[symbol] = cl
symbol++
}
}
return nil
}
// decodeHuffmanTree decodes a Huffman tree into h.
func (d *decoder) decodeHuffmanTree(h *hTree, alphabetSize uint32) error {
useSimple, err := d.read(1)
if err != nil {
return err
}
if useSimple != 0 {
nSymbols, err := d.read(1)
if err != nil {
return err
}
nSymbols++
firstSymbolLengthCode, err := d.read(1)
if err != nil {
return err
}
firstSymbolLengthCode = 7*firstSymbolLengthCode + 1
var symbols [2]uint32
symbols[0], err = d.read(firstSymbolLengthCode)
if err != nil {
return err
}
if nSymbols == 2 {
symbols[1], err = d.read(8)
if err != nil {
return err
}
}
return h.buildSimple(nSymbols, symbols, alphabetSize)
}
nCodes, err := d.read(4)
if err != nil {
return err
}
nCodes += 4
if int(nCodes) > len(codeLengthCodeOrder) {
return errInvalidHuffmanTree
}
codeLengthCodeLengths := [len(codeLengthCodeOrder)]uint32{}
for i := uint32(0); i < nCodes; i++ {
codeLengthCodeLengths[codeLengthCodeOrder[i]], err = d.read(3)
if err != nil {
return err
}
}
codeLengths := make([]uint32, alphabetSize)
if err = d.decodeCodeLengths(codeLengths, codeLengthCodeLengths[:]); err != nil {
return err
}
return h.build(codeLengths)
}
const (
huffGreen = 0
huffRed = 1
huffBlue = 2
huffAlpha = 3
huffDistance = 4
nHuff = 5
)
// hGroup is an array of 5 Huffman trees.
type hGroup [nHuff]hTree
// decodeHuffmanGroups decodes the one or more hGroups used to decode the pixel
// data. If one hGroup is used for the entire image, then hPix and hBits will
// be zero. If more than one hGroup is used, then hPix contains the meta-image
// that maps tiles to hGroup index, and hBits contains the log-2 tile size.
func (d *decoder) decodeHuffmanGroups(w int32, h int32, topLevel bool, ccBits uint32) (
hGroups []hGroup, hPix []byte, hBits uint32, err error) {
maxHGroupIndex := 0
if topLevel {
useMeta, err := d.read(1)
if err != nil {
return nil, nil, 0, err
}
if useMeta != 0 {
hBits, err = d.read(3)
if err != nil {
return nil, nil, 0, err
}
hBits += 2
hPix, err = d.decodePix(nTiles(w, hBits), nTiles(h, hBits), 0, false)
if err != nil {
return nil, nil, 0, err
}
for p := 0; p < len(hPix); p += 4 {
i := int(hPix[p])<<8 | int(hPix[p+1])
if maxHGroupIndex < i {
maxHGroupIndex = i
}
}
}
}
hGroups = make([]hGroup, maxHGroupIndex+1)
for i := range hGroups {
for j, alphabetSize := range alphabetSizes {
if j == 0 && ccBits > 0 {
alphabetSize += 1 << ccBits
}
if err := d.decodeHuffmanTree(&hGroups[i][j], alphabetSize); err != nil {
return nil, nil, 0, err
}
}
}
return hGroups, hPix, hBits, nil
}
const (
nLiteralCodes = 256
nLengthCodes = 24
nDistanceCodes = 40
)
var alphabetSizes = [nHuff]uint32{
nLiteralCodes + nLengthCodes,
nLiteralCodes,
nLiteralCodes,
nLiteralCodes,
nDistanceCodes,
}
// decodePix decodes pixel data, specified in section 5.2.2.
func (d *decoder) decodePix(w int32, h int32, minCap int32, topLevel bool) ([]byte, error) {
// Decode the color cache parameters.
ccBits, ccShift, ccEntries := uint32(0), uint32(0), ([]uint32)(nil)
useColorCache, err := d.read(1)
if err != nil {
return nil, err
}
if useColorCache != 0 {
ccBits, err = d.read(4)
if err != nil {
return nil, err
}
if ccBits < 1 || 11 < ccBits {
return nil, errors.New("vp8l: invalid color cache parameters")
}
ccShift = 32 - ccBits
ccEntries = make([]uint32, 1<<ccBits)
}
// Decode the Huffman groups.
hGroups, hPix, hBits, err := d.decodeHuffmanGroups(w, h, topLevel, ccBits)
if err != nil {
return nil, err
}
hMask, tilesPerRow := int32(0), int32(0)
if hBits != 0 {
hMask, tilesPerRow = 1<<hBits-1, nTiles(w, hBits)
}
// Decode the pixels.
if minCap < 4*w*h {
minCap = 4 * w * h
}
pix := make([]byte, 4*w*h, minCap)
p, cachedP := 0, 0
x, y := int32(0), int32(0)
hg, lookupHG := &hGroups[0], hMask != 0
for p < len(pix) {
if lookupHG {
i := 4 * (tilesPerRow*(y>>hBits) + (x >> hBits))
hg = &hGroups[uint32(hPix[i])<<8|uint32(hPix[i+1])]
}
green, err := hg[huffGreen].next(d)
if err != nil {
return nil, err
}
switch {
case green < nLiteralCodes:
// We have a literal pixel.
red, err := hg[huffRed].next(d)
if err != nil {
return nil, err
}
blue, err := hg[huffBlue].next(d)
if err != nil {
return nil, err
}
alpha, err := hg[huffAlpha].next(d)
if err != nil {
return nil, err
}
pix[p+0] = uint8(red)
pix[p+1] = uint8(green)
pix[p+2] = uint8(blue)
pix[p+3] = uint8(alpha)
p += 4
x++
if x == w {
x, y = 0, y+1
}
lookupHG = hMask != 0 && x&hMask == 0
case green < nLiteralCodes+nLengthCodes:
// We have a LZ77 backwards reference.
length, err := d.lz77Param(green - nLiteralCodes)
if err != nil {
return nil, err
}
distSym, err := hg[huffDistance].next(d)
if err != nil {
return nil, err
}
distCode, err := d.lz77Param(distSym)
if err != nil {
return nil, err
}
dist := distanceMap(w, distCode)
pEnd := p + 4*int(length)
q := p - 4*int(dist)
qEnd := pEnd - 4*int(dist)
if p < 0 || len(pix) < pEnd || q < 0 || len(pix) < qEnd {
return nil, errors.New("vp8l: invalid LZ77 parameters")
}
for ; p < pEnd; p, q = p+1, q+1 {
pix[p] = pix[q]
}
x += int32(length)
for x >= w {
x, y = x-w, y+1
}
lookupHG = hMask != 0
default:
// We have a color cache lookup. First, insert previous pixels
// into the cache. Note that VP8L assumes ARGB order, but the
// Go image.RGBA type is in RGBA order.
for ; cachedP < p; cachedP += 4 {
argb := uint32(pix[cachedP+0])<<16 |
uint32(pix[cachedP+1])<<8 |
uint32(pix[cachedP+2])<<0 |
uint32(pix[cachedP+3])<<24
ccEntries[(argb*colorCacheMultiplier)>>ccShift] = argb
}
green -= nLiteralCodes + nLengthCodes
if int(green) >= len(ccEntries) {
return nil, errors.New("vp8l: invalid color cache index")
}
argb := ccEntries[green]
pix[p+0] = uint8(argb >> 16)
pix[p+1] = uint8(argb >> 8)
pix[p+2] = uint8(argb >> 0)
pix[p+3] = uint8(argb >> 24)
p += 4
x++
if x == w {
x, y = 0, y+1
}
lookupHG = hMask != 0 && x&hMask == 0
}
}
return pix, nil
}
// lz77Param returns the next LZ77 parameter: a length or a distance, specified
// in section 4.2.2.
func (d *decoder) lz77Param(symbol uint32) (uint32, error) {
if symbol < 4 {
return symbol + 1, nil
}
extraBits := (symbol - 2) >> 1
offset := (2 + symbol&1) << extraBits
n, err := d.read(extraBits)
if err != nil {
return 0, err
}
return offset + n + 1, nil
}
// decodeHeader decodes the VP8L header from r.
func decodeHeader(r io.Reader) (d *decoder, w int32, h int32, err error) {
rr, ok := r.(io.ByteReader)
if !ok {
rr = bufio.NewReader(r)
}
d = &decoder{r: rr}
magic, err := d.read(8)
if err != nil {
return nil, 0, 0, err
}
if magic != 0x2f {
return nil, 0, 0, errors.New("vp8l: invalid header")
}
width, err := d.read(14)
if err != nil {
return nil, 0, 0, err
}
width++
height, err := d.read(14)
if err != nil {
return nil, 0, 0, err
}
height++
_, err = d.read(1) // Read and ignore the hasAlpha hint.
if err != nil {
return nil, 0, 0, err
}
version, err := d.read(3)
if err != nil {
return nil, 0, 0, err
}
if version != 0 {
return nil, 0, 0, errors.New("vp8l: invalid version")
}
return d, int32(width), int32(height), nil
}
// DecodeConfig decodes the color model and dimensions of a VP8L image from r.
func DecodeConfig(r io.Reader) (image.Config, error) {
_, w, h, err := decodeHeader(r)
if err != nil {
return image.Config{}, err
}
return image.Config{
ColorModel: color.NRGBAModel,
Width: int(w),
Height: int(h),
}, nil
}
// Decode decodes a VP8L image from r.
func Decode(r io.Reader) (image.Image, error) {
d, w, h, err := decodeHeader(r)
if err != nil {
return nil, err
}
// Decode the transforms.
var (
nTransforms int
transforms [nTransformTypes]transform
transformsSeen [nTransformTypes]bool
originalW = w
)
for {
more, err := d.read(1)
if err != nil {
return nil, err
}
if more == 0 {
break
}
var t transform
t, w, err = d.decodeTransform(w, h)
if err != nil {
return nil, err
}
if transformsSeen[t.transformType] {
return nil, errors.New("vp8l: repeated transform")
}
transformsSeen[t.transformType] = true
transforms[nTransforms] = t
nTransforms++
}
// Decode the transformed pixels.
pix, err := d.decodePix(w, h, 0, true)
if err != nil {
return nil, err
}
// Apply the inverse transformations.
for i := nTransforms - 1; i >= 0; i-- {
t := &transforms[i]
pix = inverseTransforms[t.transformType](t, pix, h)
}
return &image.NRGBA{
Pix: pix,
Stride: 4 * int(originalW),
Rect: image.Rect(0, 0, int(originalW), int(h)),
}, nil
}

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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8l
import (
"io"
)
// reverseBits reverses the bits in a byte.
var reverseBits = [256]uint8{
0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0, 0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8, 0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4, 0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec, 0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2, 0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea, 0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6, 0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee, 0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1, 0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9, 0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5, 0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed, 0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3, 0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb, 0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7, 0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef, 0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
}
// hNode is a node in a Huffman tree.
type hNode struct {
// symbol is the symbol held by this node.
symbol uint32
// children, if positive, is the hTree.nodes index of the first of
// this node's two children. Zero means an uninitialized node,
// and -1 means a leaf node.
children int32
}
const leafNode = -1
// lutSize is the log-2 size of an hTree's look-up table.
const lutSize, lutMask = 7, 1<<7 - 1
// hTree is a Huffman tree.
type hTree struct {
// nodes are the nodes of the Huffman tree. During construction,
// len(nodes) grows from 1 up to cap(nodes) by steps of two.
// After construction, len(nodes) == cap(nodes), and both equal
// 2*theNumberOfSymbols - 1.
nodes []hNode
// lut is a look-up table for walking the nodes. The x in lut[x] is
// the next lutSize bits in the bit-stream. The low 8 bits of lut[x]
// equals 1 plus the number of bits in the next code, or 0 if the
// next code requires more than lutSize bits. The high 24 bits are:
// - the symbol, if the code requires lutSize or fewer bits, or
// - the hTree.nodes index to start the tree traversal from, if
// the next code requires more than lutSize bits.
lut [1 << lutSize]uint32
}
// insert inserts into the hTree a symbol whose encoding is the least
// significant codeLength bits of code.
func (h *hTree) insert(symbol uint32, code uint32, codeLength uint32) error {
if symbol > 0xffff || codeLength > 0xfe {
return errInvalidHuffmanTree
}
baseCode := uint32(0)
if codeLength > lutSize {
baseCode = uint32(reverseBits[(code>>(codeLength-lutSize))&0xff]) >> (8 - lutSize)
} else {
baseCode = uint32(reverseBits[code&0xff]) >> (8 - codeLength)
for i := 0; i < 1<<(lutSize-codeLength); i++ {
h.lut[baseCode|uint32(i)<<codeLength] = symbol<<8 | (codeLength + 1)
}
}
n := uint32(0)
for jump := lutSize; codeLength > 0; {
codeLength--
if int(n) > len(h.nodes) {
return errInvalidHuffmanTree
}
switch h.nodes[n].children {
case leafNode:
return errInvalidHuffmanTree
case 0:
if len(h.nodes) == cap(h.nodes) {
return errInvalidHuffmanTree
}
// Create two empty child nodes.
h.nodes[n].children = int32(len(h.nodes))
h.nodes = h.nodes[:len(h.nodes)+2]
}
n = uint32(h.nodes[n].children) + 1&(code>>codeLength)
jump--
if jump == 0 && h.lut[baseCode] == 0 {
h.lut[baseCode] = n << 8
}
}
switch h.nodes[n].children {
case leafNode:
// No-op.
case 0:
// Turn the uninitialized node into a leaf.
h.nodes[n].children = leafNode
default:
return errInvalidHuffmanTree
}
h.nodes[n].symbol = symbol
return nil
}
// codeLengthsToCodes returns the canonical Huffman codes implied by the
// sequence of code lengths.
func codeLengthsToCodes(codeLengths []uint32) ([]uint32, error) {
maxCodeLength := uint32(0)
for _, cl := range codeLengths {
if maxCodeLength < cl {
maxCodeLength = cl
}
}
const maxAllowedCodeLength = 15
if len(codeLengths) == 0 || maxCodeLength > maxAllowedCodeLength {
return nil, errInvalidHuffmanTree
}
histogram := [maxAllowedCodeLength + 1]uint32{}
for _, cl := range codeLengths {
histogram[cl]++
}
currCode, nextCodes := uint32(0), [maxAllowedCodeLength + 1]uint32{}
for cl := 1; cl < len(nextCodes); cl++ {
currCode = (currCode + histogram[cl-1]) << 1
nextCodes[cl] = currCode
}
codes := make([]uint32, len(codeLengths))
for symbol, cl := range codeLengths {
if cl > 0 {
codes[symbol] = nextCodes[cl]
nextCodes[cl]++
}
}
return codes, nil
}
// build builds a canonical Huffman tree from the given code lengths.
func (h *hTree) build(codeLengths []uint32) error {
// Calculate the number of symbols.
var nSymbols, lastSymbol uint32
for symbol, cl := range codeLengths {
if cl != 0 {
nSymbols++
lastSymbol = uint32(symbol)
}
}
if nSymbols == 0 {
return errInvalidHuffmanTree
}
h.nodes = make([]hNode, 1, 2*nSymbols-1)
// Handle the trivial case.
if nSymbols == 1 {
if len(codeLengths) <= int(lastSymbol) {
return errInvalidHuffmanTree
}
return h.insert(lastSymbol, 0, 0)
}
// Handle the non-trivial case.
codes, err := codeLengthsToCodes(codeLengths)
if err != nil {
return err
}
for symbol, cl := range codeLengths {
if cl > 0 {
if err := h.insert(uint32(symbol), codes[symbol], cl); err != nil {
return err
}
}
}
return nil
}
// buildSimple builds a Huffman tree with 1 or 2 symbols.
func (h *hTree) buildSimple(nSymbols uint32, symbols [2]uint32, alphabetSize uint32) error {
h.nodes = make([]hNode, 1, 2*nSymbols-1)
for i := uint32(0); i < nSymbols; i++ {
if symbols[i] >= alphabetSize {
return errInvalidHuffmanTree
}
if err := h.insert(symbols[i], i, nSymbols-1); err != nil {
return err
}
}
return nil
}
// next returns the next Huffman-encoded symbol from the bit-stream d.
func (h *hTree) next(d *decoder) (uint32, error) {
var n uint32
// Read enough bits so that we can use the look-up table.
if d.nBits < lutSize {
c, err := d.r.ReadByte()
if err != nil {
if err == io.EOF {
// There are no more bytes of data, but we may still be able
// to read the next symbol out of the previously read bits.
goto slowPath
}
return 0, err
}
d.bits |= uint32(c) << d.nBits
d.nBits += 8
}
// Use the look-up table.
n = h.lut[d.bits&lutMask]
if b := n & 0xff; b != 0 {
b--
d.bits >>= b
d.nBits -= b
return n >> 8, nil
}
n >>= 8
d.bits >>= lutSize
d.nBits -= lutSize
slowPath:
for h.nodes[n].children != leafNode {
if d.nBits == 0 {
c, err := d.r.ReadByte()
if err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return 0, err
}
d.bits = uint32(c)
d.nBits = 8
}
n = uint32(h.nodes[n].children) + 1&d.bits
d.bits >>= 1
d.nBits--
}
return h.nodes[n].symbol, nil
}

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vendor/golang.org/x/image/vp8l/transform.go generated vendored Normal file
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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vp8l
// This file deals with image transforms, specified in section 3.
// nTiles returns the number of tiles needed to cover size pixels, where each
// tile's side is 1<<bits pixels long.
func nTiles(size int32, bits uint32) int32 {
return (size + 1<<bits - 1) >> bits
}
const (
transformTypePredictor = 0
transformTypeCrossColor = 1
transformTypeSubtractGreen = 2
transformTypeColorIndexing = 3
nTransformTypes = 4
)
// transform holds the parameters for an invertible transform.
type transform struct {
// transformType is the type of the transform.
transformType uint32
// oldWidth is the width of the image before transformation (or
// equivalently, after inverse transformation). The color-indexing
// transform can reduce the width. For example, a 50-pixel-wide
// image that only needs 4 bits (half a byte) per color index can
// be transformed into a 25-pixel-wide image.
oldWidth int32
// bits is the log-2 size of the transform's tiles, for the predictor
// and cross-color transforms. 8>>bits is the number of bits per
// color index, for the color-index transform.
bits uint32
// pix is the tile values, for the predictor and cross-color
// transforms, and the color palette, for the color-index transform.
pix []byte
}
var inverseTransforms = [nTransformTypes]func(*transform, []byte, int32) []byte{
transformTypePredictor: inversePredictor,
transformTypeCrossColor: inverseCrossColor,
transformTypeSubtractGreen: inverseSubtractGreen,
transformTypeColorIndexing: inverseColorIndexing,
}
func inversePredictor(t *transform, pix []byte, h int32) []byte {
if t.oldWidth == 0 || h == 0 {
return pix
}
// The first pixel's predictor is mode 0 (opaque black).
pix[3] += 0xff
p, mask := int32(4), int32(1)<<t.bits-1
for x := int32(1); x < t.oldWidth; x++ {
// The rest of the first row's predictor is mode 1 (L).
pix[p+0] += pix[p-4]
pix[p+1] += pix[p-3]
pix[p+2] += pix[p-2]
pix[p+3] += pix[p-1]
p += 4
}
top, tilesPerRow := 0, nTiles(t.oldWidth, t.bits)
for y := int32(1); y < h; y++ {
// The first column's predictor is mode 2 (T).
pix[p+0] += pix[top+0]
pix[p+1] += pix[top+1]
pix[p+2] += pix[top+2]
pix[p+3] += pix[top+3]
p, top = p+4, top+4
q := 4 * (y >> t.bits) * tilesPerRow
predictorMode := t.pix[q+1] & 0x0f
q += 4
for x := int32(1); x < t.oldWidth; x++ {
if x&mask == 0 {
predictorMode = t.pix[q+1] & 0x0f
q += 4
}
switch predictorMode {
case 0: // Opaque black.
pix[p+3] += 0xff
case 1: // L.
pix[p+0] += pix[p-4]
pix[p+1] += pix[p-3]
pix[p+2] += pix[p-2]
pix[p+3] += pix[p-1]
case 2: // T.
pix[p+0] += pix[top+0]
pix[p+1] += pix[top+1]
pix[p+2] += pix[top+2]
pix[p+3] += pix[top+3]
case 3: // TR.
pix[p+0] += pix[top+4]
pix[p+1] += pix[top+5]
pix[p+2] += pix[top+6]
pix[p+3] += pix[top+7]
case 4: // TL.
pix[p+0] += pix[top-4]
pix[p+1] += pix[top-3]
pix[p+2] += pix[top-2]
pix[p+3] += pix[top-1]
case 5: // Average2(Average2(L, TR), T).
pix[p+0] += avg2(avg2(pix[p-4], pix[top+4]), pix[top+0])
pix[p+1] += avg2(avg2(pix[p-3], pix[top+5]), pix[top+1])
pix[p+2] += avg2(avg2(pix[p-2], pix[top+6]), pix[top+2])
pix[p+3] += avg2(avg2(pix[p-1], pix[top+7]), pix[top+3])
case 6: // Average2(L, TL).
pix[p+0] += avg2(pix[p-4], pix[top-4])
pix[p+1] += avg2(pix[p-3], pix[top-3])
pix[p+2] += avg2(pix[p-2], pix[top-2])
pix[p+3] += avg2(pix[p-1], pix[top-1])
case 7: // Average2(L, T).
pix[p+0] += avg2(pix[p-4], pix[top+0])
pix[p+1] += avg2(pix[p-3], pix[top+1])
pix[p+2] += avg2(pix[p-2], pix[top+2])
pix[p+3] += avg2(pix[p-1], pix[top+3])
case 8: // Average2(TL, T).
pix[p+0] += avg2(pix[top-4], pix[top+0])
pix[p+1] += avg2(pix[top-3], pix[top+1])
pix[p+2] += avg2(pix[top-2], pix[top+2])
pix[p+3] += avg2(pix[top-1], pix[top+3])
case 9: // Average2(T, TR).
pix[p+0] += avg2(pix[top+0], pix[top+4])
pix[p+1] += avg2(pix[top+1], pix[top+5])
pix[p+2] += avg2(pix[top+2], pix[top+6])
pix[p+3] += avg2(pix[top+3], pix[top+7])
case 10: // Average2(Average2(L, TL), Average2(T, TR)).
pix[p+0] += avg2(avg2(pix[p-4], pix[top-4]), avg2(pix[top+0], pix[top+4]))
pix[p+1] += avg2(avg2(pix[p-3], pix[top-3]), avg2(pix[top+1], pix[top+5]))
pix[p+2] += avg2(avg2(pix[p-2], pix[top-2]), avg2(pix[top+2], pix[top+6]))
pix[p+3] += avg2(avg2(pix[p-1], pix[top-1]), avg2(pix[top+3], pix[top+7]))
case 11: // Select(L, T, TL).
l0 := int32(pix[p-4])
l1 := int32(pix[p-3])
l2 := int32(pix[p-2])
l3 := int32(pix[p-1])
c0 := int32(pix[top-4])
c1 := int32(pix[top-3])
c2 := int32(pix[top-2])
c3 := int32(pix[top-1])
t0 := int32(pix[top+0])
t1 := int32(pix[top+1])
t2 := int32(pix[top+2])
t3 := int32(pix[top+3])
l := abs(c0-t0) + abs(c1-t1) + abs(c2-t2) + abs(c3-t3)
t := abs(c0-l0) + abs(c1-l1) + abs(c2-l2) + abs(c3-l3)
if l < t {
pix[p+0] += uint8(l0)
pix[p+1] += uint8(l1)
pix[p+2] += uint8(l2)
pix[p+3] += uint8(l3)
} else {
pix[p+0] += uint8(t0)
pix[p+1] += uint8(t1)
pix[p+2] += uint8(t2)
pix[p+3] += uint8(t3)
}
case 12: // ClampAddSubtractFull(L, T, TL).
pix[p+0] += clampAddSubtractFull(pix[p-4], pix[top+0], pix[top-4])
pix[p+1] += clampAddSubtractFull(pix[p-3], pix[top+1], pix[top-3])
pix[p+2] += clampAddSubtractFull(pix[p-2], pix[top+2], pix[top-2])
pix[p+3] += clampAddSubtractFull(pix[p-1], pix[top+3], pix[top-1])
case 13: // ClampAddSubtractHalf(Average2(L, T), TL).
pix[p+0] += clampAddSubtractHalf(avg2(pix[p-4], pix[top+0]), pix[top-4])
pix[p+1] += clampAddSubtractHalf(avg2(pix[p-3], pix[top+1]), pix[top-3])
pix[p+2] += clampAddSubtractHalf(avg2(pix[p-2], pix[top+2]), pix[top-2])
pix[p+3] += clampAddSubtractHalf(avg2(pix[p-1], pix[top+3]), pix[top-1])
}
p, top = p+4, top+4
}
}
return pix
}
func inverseCrossColor(t *transform, pix []byte, h int32) []byte {
var greenToRed, greenToBlue, redToBlue int32
p, mask, tilesPerRow := int32(0), int32(1)<<t.bits-1, nTiles(t.oldWidth, t.bits)
for y := int32(0); y < h; y++ {
q := 4 * (y >> t.bits) * tilesPerRow
for x := int32(0); x < t.oldWidth; x++ {
if x&mask == 0 {
redToBlue = int32(int8(t.pix[q+0]))
greenToBlue = int32(int8(t.pix[q+1]))
greenToRed = int32(int8(t.pix[q+2]))
q += 4
}
red := pix[p+0]
green := pix[p+1]
blue := pix[p+2]
red += uint8(uint32(greenToRed*int32(int8(green))) >> 5)
blue += uint8(uint32(greenToBlue*int32(int8(green))) >> 5)
blue += uint8(uint32(redToBlue*int32(int8(red))) >> 5)
pix[p+0] = red
pix[p+2] = blue
p += 4
}
}
return pix
}
func inverseSubtractGreen(t *transform, pix []byte, h int32) []byte {
for p := 0; p < len(pix); p += 4 {
green := pix[p+1]
pix[p+0] += green
pix[p+2] += green
}
return pix
}
func inverseColorIndexing(t *transform, pix []byte, h int32) []byte {
if t.bits == 0 {
for p := 0; p < len(pix); p += 4 {
i := 4 * uint32(pix[p+1])
pix[p+0] = t.pix[i+0]
pix[p+1] = t.pix[i+1]
pix[p+2] = t.pix[i+2]
pix[p+3] = t.pix[i+3]
}
return pix
}
vMask, xMask, bitsPerPixel := uint32(0), int32(0), uint32(8>>t.bits)
switch t.bits {
case 1:
vMask, xMask = 0x0f, 0x01
case 2:
vMask, xMask = 0x03, 0x03
case 3:
vMask, xMask = 0x01, 0x07
}
d, p, v, dst := 0, 0, uint32(0), make([]byte, 4*t.oldWidth*h)
for y := int32(0); y < h; y++ {
for x := int32(0); x < t.oldWidth; x++ {
if x&xMask == 0 {
v = uint32(pix[p+1])
p += 4
}
i := 4 * (v & vMask)
dst[d+0] = t.pix[i+0]
dst[d+1] = t.pix[i+1]
dst[d+2] = t.pix[i+2]
dst[d+3] = t.pix[i+3]
d += 4
v >>= bitsPerPixel
}
}
return dst
}
func abs(x int32) int32 {
if x < 0 {
return -x
}
return x
}
func avg2(a, b uint8) uint8 {
return uint8((int32(a) + int32(b)) / 2)
}
func clampAddSubtractFull(a, b, c uint8) uint8 {
x := int32(a) + int32(b) - int32(c)
if x < 0 {
return 0
}
if x > 255 {
return 255
}
return uint8(x)
}
func clampAddSubtractHalf(a, b uint8) uint8 {
x := int32(a) + (int32(a)-int32(b))/2
if x < 0 {
return 0
}
if x > 255 {
return 255
}
return uint8(x)
}

271
vendor/golang.org/x/image/webp/decode.go generated vendored Normal file
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@ -0,0 +1,271 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package webp
import (
"bytes"
"errors"
"image"
"image/color"
"io"
"golang.org/x/image/riff"
"golang.org/x/image/vp8"
"golang.org/x/image/vp8l"
)
var errInvalidFormat = errors.New("webp: invalid format")
var (
fccALPH = riff.FourCC{'A', 'L', 'P', 'H'}
fccVP8 = riff.FourCC{'V', 'P', '8', ' '}
fccVP8L = riff.FourCC{'V', 'P', '8', 'L'}
fccVP8X = riff.FourCC{'V', 'P', '8', 'X'}
fccWEBP = riff.FourCC{'W', 'E', 'B', 'P'}
)
func decode(r io.Reader, configOnly bool) (image.Image, image.Config, error) {
formType, riffReader, err := riff.NewReader(r)
if err != nil {
return nil, image.Config{}, err
}
if formType != fccWEBP {
return nil, image.Config{}, errInvalidFormat
}
var (
alpha []byte
alphaStride int
wantAlpha bool
widthMinusOne uint32
heightMinusOne uint32
buf [10]byte
)
for {
chunkID, chunkLen, chunkData, err := riffReader.Next()
if err == io.EOF {
err = errInvalidFormat
}
if err != nil {
return nil, image.Config{}, err
}
switch chunkID {
case fccALPH:
if !wantAlpha {
return nil, image.Config{}, errInvalidFormat
}
wantAlpha = false
// Read the Pre-processing | Filter | Compression byte.
if _, err := io.ReadFull(chunkData, buf[:1]); err != nil {
if err == io.EOF {
err = errInvalidFormat
}
return nil, image.Config{}, err
}
alpha, alphaStride, err = readAlpha(chunkData, widthMinusOne, heightMinusOne, buf[0]&0x03)
if err != nil {
return nil, image.Config{}, err
}
unfilterAlpha(alpha, alphaStride, (buf[0]>>2)&0x03)
case fccVP8:
if wantAlpha || int32(chunkLen) < 0 {
return nil, image.Config{}, errInvalidFormat
}
d := vp8.NewDecoder()
d.Init(chunkData, int(chunkLen))
fh, err := d.DecodeFrameHeader()
if err != nil {
return nil, image.Config{}, err
}
if configOnly {
return nil, image.Config{
ColorModel: color.YCbCrModel,
Width: fh.Width,
Height: fh.Height,
}, nil
}
m, err := d.DecodeFrame()
if err != nil {
return nil, image.Config{}, err
}
if alpha != nil {
return &image.NYCbCrA{
YCbCr: *m,
A: alpha,
AStride: alphaStride,
}, image.Config{}, nil
}
return m, image.Config{}, nil
case fccVP8L:
if wantAlpha || alpha != nil {
return nil, image.Config{}, errInvalidFormat
}
if configOnly {
c, err := vp8l.DecodeConfig(chunkData)
return nil, c, err
}
m, err := vp8l.Decode(chunkData)
return m, image.Config{}, err
case fccVP8X:
if chunkLen != 10 {
return nil, image.Config{}, errInvalidFormat
}
if _, err := io.ReadFull(chunkData, buf[:10]); err != nil {
return nil, image.Config{}, err
}
const (
animationBit = 1 << 1
xmpMetadataBit = 1 << 2
exifMetadataBit = 1 << 3
alphaBit = 1 << 4
iccProfileBit = 1 << 5
)
wantAlpha = (buf[0] & alphaBit) != 0
widthMinusOne = uint32(buf[4]) | uint32(buf[5])<<8 | uint32(buf[6])<<16
heightMinusOne = uint32(buf[7]) | uint32(buf[8])<<8 | uint32(buf[9])<<16
if configOnly {
if wantAlpha {
return nil, image.Config{
ColorModel: color.NYCbCrAModel,
Width: int(widthMinusOne) + 1,
Height: int(heightMinusOne) + 1,
}, nil
}
return nil, image.Config{
ColorModel: color.YCbCrModel,
Width: int(widthMinusOne) + 1,
Height: int(heightMinusOne) + 1,
}, nil
}
}
}
}
func readAlpha(chunkData io.Reader, widthMinusOne, heightMinusOne uint32, compression byte) (
alpha []byte, alphaStride int, err error) {
switch compression {
case 0:
w := int(widthMinusOne) + 1
h := int(heightMinusOne) + 1
alpha = make([]byte, w*h)
if _, err := io.ReadFull(chunkData, alpha); err != nil {
return nil, 0, err
}
return alpha, w, nil
case 1:
// Read the VP8L-compressed alpha values. First, synthesize a 5-byte VP8L header:
// a 1-byte magic number, a 14-bit widthMinusOne, a 14-bit heightMinusOne,
// a 1-bit (ignored, zero) alphaIsUsed and a 3-bit (zero) version.
// TODO(nigeltao): be more efficient than decoding an *image.NRGBA just to
// extract the green values to a separately allocated []byte. Fixing this
// will require changes to the vp8l package's API.
if widthMinusOne > 0x3fff || heightMinusOne > 0x3fff {
return nil, 0, errors.New("webp: invalid format")
}
alphaImage, err := vp8l.Decode(io.MultiReader(
bytes.NewReader([]byte{
0x2f, // VP8L magic number.
uint8(widthMinusOne),
uint8(widthMinusOne>>8) | uint8(heightMinusOne<<6),
uint8(heightMinusOne >> 2),
uint8(heightMinusOne >> 10),
}),
chunkData,
))
if err != nil {
return nil, 0, err
}
// The green values of the inner NRGBA image are the alpha values of the
// outer NYCbCrA image.
pix := alphaImage.(*image.NRGBA).Pix
alpha = make([]byte, len(pix)/4)
for i := range alpha {
alpha[i] = pix[4*i+1]
}
return alpha, int(widthMinusOne) + 1, nil
}
return nil, 0, errInvalidFormat
}
func unfilterAlpha(alpha []byte, alphaStride int, filter byte) {
if len(alpha) == 0 || alphaStride == 0 {
return
}
switch filter {
case 1: // Horizontal filter.
for i := 1; i < alphaStride; i++ {
alpha[i] += alpha[i-1]
}
for i := alphaStride; i < len(alpha); i += alphaStride {
// The first column is equivalent to the vertical filter.
alpha[i] += alpha[i-alphaStride]
for j := 1; j < alphaStride; j++ {
alpha[i+j] += alpha[i+j-1]
}
}
case 2: // Vertical filter.
// The first row is equivalent to the horizontal filter.
for i := 1; i < alphaStride; i++ {
alpha[i] += alpha[i-1]
}
for i := alphaStride; i < len(alpha); i++ {
alpha[i] += alpha[i-alphaStride]
}
case 3: // Gradient filter.
// The first row is equivalent to the horizontal filter.
for i := 1; i < alphaStride; i++ {
alpha[i] += alpha[i-1]
}
for i := alphaStride; i < len(alpha); i += alphaStride {
// The first column is equivalent to the vertical filter.
alpha[i] += alpha[i-alphaStride]
// The interior is predicted on the three top/left pixels.
for j := 1; j < alphaStride; j++ {
c := int(alpha[i+j-alphaStride-1])
b := int(alpha[i+j-alphaStride])
a := int(alpha[i+j-1])
x := a + b - c
if x < 0 {
x = 0
} else if x > 255 {
x = 255
}
alpha[i+j] += uint8(x)
}
}
}
}
// Decode reads a WEBP image from r and returns it as an image.Image.
func Decode(r io.Reader) (image.Image, error) {
m, _, err := decode(r, false)
if err != nil {
return nil, err
}
return m, err
}
// DecodeConfig returns the color model and dimensions of a WEBP image without
// decoding the entire image.
func DecodeConfig(r io.Reader) (image.Config, error) {
_, c, err := decode(r, true)
return c, err
}
func init() {
image.RegisterFormat("webp", "RIFF????WEBPVP8", Decode, DecodeConfig)
}

9
vendor/golang.org/x/image/webp/doc.go generated vendored Normal file
View file

@ -0,0 +1,9 @@
// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package webp implements a decoder for WEBP images.
//
// WEBP is defined at:
// https://developers.google.com/speed/webp/docs/riff_container
package webp // import "golang.org/x/image/webp"

8
vendor/modules.txt vendored
View file

@ -569,7 +569,7 @@ github.com/superseriousbusiness/activity/streams/values/rfc2045
github.com/superseriousbusiness/activity/streams/values/rfc5988
github.com/superseriousbusiness/activity/streams/values/string
github.com/superseriousbusiness/activity/streams/vocab
# github.com/superseriousbusiness/exif-terminator v0.4.0
# github.com/superseriousbusiness/exif-terminator v0.5.0
## explicit; go 1.17
github.com/superseriousbusiness/exif-terminator
# github.com/superseriousbusiness/go-jpeg-image-structure/v2 v2.0.0-20220321154430-d89a106fdabe
@ -660,12 +660,16 @@ golang.org/x/crypto/ssh/internal/bcrypt_pbkdf
## explicit; go 1.18
golang.org/x/exp/constraints
golang.org/x/exp/slices
# golang.org/x/image v0.0.0-20220902085622-e7cb96979f69
# golang.org/x/image v0.1.0
## explicit; go 1.12
golang.org/x/image/bmp
golang.org/x/image/ccitt
golang.org/x/image/riff
golang.org/x/image/tiff
golang.org/x/image/tiff/lzw
golang.org/x/image/vp8
golang.org/x/image/vp8l
golang.org/x/image/webp
# golang.org/x/mod v0.6.0-dev.0.20220907135952-02c991387e35
## explicit; go 1.17
golang.org/x/mod/semver