mirror of
https://github.com/superseriousbusiness/gotosocial.git
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112 lines
2.6 KiB
Go
112 lines
2.6 KiB
Go
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// Copyright 2022 Dolthub, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// This file incorporates work covered by the following copyright and
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// permission notice:
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//
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// Copyright 2022 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build go1.18 || go1.19
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// +build go1.18 go1.19
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package maphash
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import (
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"math/rand"
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"unsafe"
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)
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type hashfn func(unsafe.Pointer, uintptr) uintptr
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func getRuntimeHasher[K comparable]() (h hashfn) {
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a := any(make(map[K]struct{}))
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i := (*mapiface)(unsafe.Pointer(&a))
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h = i.typ.hasher
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return
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}
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func newHashSeed() uintptr {
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return uintptr(rand.Int())
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}
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// noescape hides a pointer from escape analysis. It is the identity function
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// but escape analysis doesn't think the output depends on the input.
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// noescape is inlined and currently compiles down to zero instructions.
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// USE CAREFULLY!
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// This was copied from the runtime (via pkg "strings"); see issues 23382 and 7921.
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//
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//go:nosplit
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//go:nocheckptr
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func noescape(p unsafe.Pointer) unsafe.Pointer {
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x := uintptr(p)
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return unsafe.Pointer(x ^ 0)
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}
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type mapiface struct {
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typ *maptype
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val *hmap
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}
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// go/src/runtime/type.go
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type maptype struct {
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typ _type
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key *_type
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elem *_type
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bucket *_type
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// function for hashing keys (ptr to key, seed) -> hash
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hasher func(unsafe.Pointer, uintptr) uintptr
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keysize uint8
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elemsize uint8
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bucketsize uint16
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flags uint32
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}
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// go/src/runtime/map.go
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type hmap struct {
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count int
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flags uint8
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B uint8
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noverflow uint16
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// hash seed
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hash0 uint32
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buckets unsafe.Pointer
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oldbuckets unsafe.Pointer
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nevacuate uintptr
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// true type is *mapextra
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// but we don't need this data
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extra unsafe.Pointer
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}
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// go/src/runtime/type.go
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type tflag uint8
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type nameOff int32
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type typeOff int32
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// go/src/runtime/type.go
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type _type struct {
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size uintptr
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ptrdata uintptr
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hash uint32
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tflag tflag
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align uint8
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fieldAlign uint8
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kind uint8
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equal func(unsafe.Pointer, unsafe.Pointer) bool
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gcdata *byte
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str nameOff
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ptrToThis typeOff
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}
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