mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-12-18 16:31:06 +00:00
370 lines
7.4 KiB
Go
370 lines
7.4 KiB
Go
package bytesize
|
|
|
|
import (
|
|
"errors"
|
|
"math/bits"
|
|
"strconv"
|
|
"unsafe"
|
|
)
|
|
|
|
const (
|
|
// SI units
|
|
KB Size = 1e3
|
|
MB Size = 1e6
|
|
GB Size = 1e9
|
|
TB Size = 1e12
|
|
PB Size = 1e15
|
|
EB Size = 1e18
|
|
|
|
// IEC units
|
|
KiB Size = 1024
|
|
MiB Size = KiB * 1024
|
|
GiB Size = MiB * 1024
|
|
TiB Size = GiB * 1024
|
|
PiB Size = TiB * 1024
|
|
EiB Size = PiB * 1024
|
|
)
|
|
|
|
var (
|
|
// ErrInvalidUnit is returned when an invalid IEC/SI is provided.
|
|
ErrInvalidUnit = errors.New("bytesize: invalid unit")
|
|
|
|
// ErrInvalidFormat is returned when an invalid size value is provided.
|
|
ErrInvalidFormat = errors.New("bytesize: invalid format")
|
|
|
|
// iecpows is a precomputed table of 1024^n.
|
|
iecpows = [...]float64{
|
|
float64(KiB),
|
|
float64(MiB),
|
|
float64(GiB),
|
|
float64(TiB),
|
|
float64(PiB),
|
|
float64(EiB),
|
|
}
|
|
|
|
// sipows is a precomputed table of 1000^n.
|
|
sipows = [...]float64{
|
|
float64(KB),
|
|
float64(MB),
|
|
float64(GB),
|
|
float64(TB),
|
|
float64(PB),
|
|
float64(EB),
|
|
}
|
|
|
|
// bvals is a precomputed table of IEC unit values.
|
|
iecvals = [...]float64{
|
|
'k': float64(KiB),
|
|
'K': float64(KiB),
|
|
'M': float64(MiB),
|
|
'G': float64(GiB),
|
|
'T': float64(TiB),
|
|
'P': float64(PiB),
|
|
'E': float64(EiB),
|
|
}
|
|
|
|
// sivals is a precomputed table of SI unit values.
|
|
sivals = [...]float64{
|
|
// ASCII numbers _aren't_ valid SI unit values,
|
|
// BUT if the space containing a possible unit
|
|
// char is checked with this table -- it is valid
|
|
// to provide no unit char so unit=1 works.
|
|
'0': 1,
|
|
'1': 1,
|
|
'2': 1,
|
|
'3': 1,
|
|
'4': 1,
|
|
'5': 1,
|
|
'6': 1,
|
|
'7': 1,
|
|
'8': 1,
|
|
'9': 1,
|
|
|
|
'k': float64(KB),
|
|
'K': float64(KB),
|
|
'M': float64(MB),
|
|
'G': float64(GB),
|
|
'T': float64(TB),
|
|
'P': float64(PB),
|
|
'E': float64(EB),
|
|
}
|
|
)
|
|
|
|
// Size is a casting for uint64 types that provides formatting
|
|
// methods for byte sizes in both IEC and SI units.
|
|
type Size uint64
|
|
|
|
// ParseSize will parse a valid Size from given string. Both IEC and SI units are supported.
|
|
func ParseSize(s string) (Size, error) {
|
|
// Parse units from string
|
|
unit, l, err := parseUnit(s)
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
// Parse remaining string as 64bit float
|
|
f, err := strconv.ParseFloat(s[:l], 64)
|
|
if err != nil {
|
|
return 0, errctx(ErrInvalidFormat, err.Error())
|
|
}
|
|
|
|
return Size(f * unit), nil
|
|
}
|
|
|
|
// Set implements flag.Value{}.
|
|
func (sz *Size) Set(in string) error {
|
|
s, err := ParseSize(in)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
*sz = s
|
|
return nil
|
|
}
|
|
|
|
// MarshalText implements encoding.TextMarshaler{}.
|
|
func (sz *Size) MarshalText() ([]byte, error) {
|
|
const maxLen = 7 // max IEC string length
|
|
return sz.AppendFormatIEC(make([]byte, 0, maxLen)), nil
|
|
}
|
|
|
|
// UnmarshalText implements encoding.TextUnmarshaler{}.
|
|
func (sz *Size) UnmarshalText(text []byte) error {
|
|
return sz.Set(*(*string)(unsafe.Pointer(&text)))
|
|
}
|
|
|
|
// AppendFormat defaults to using Size.AppendFormatIEC().
|
|
func (sz Size) AppendFormat(dst []byte) []byte {
|
|
return sz.AppendFormatIEC(dst) // default
|
|
}
|
|
|
|
// AppendFormatSI will append SI formatted size to 'dst'.
|
|
func (sz Size) AppendFormatSI(dst []byte) []byte {
|
|
if uint64(sz) < 1000 {
|
|
dst = itoa(dst, uint64(sz))
|
|
dst = append(dst, 'B')
|
|
return dst
|
|
} // above is fast-path, .appendFormat() is outlined
|
|
return sz.appendFormat(dst, 1000, &sipows, "B")
|
|
}
|
|
|
|
// AppendFormatIEC will append IEC formatted size to 'dst'.
|
|
func (sz Size) AppendFormatIEC(dst []byte) []byte {
|
|
if uint64(sz) < 1024 {
|
|
dst = itoa(dst, uint64(sz))
|
|
dst = append(dst, 'B')
|
|
return dst
|
|
} // above is fast-path, .appendFormat() is outlined
|
|
return sz.appendFormat(dst, 1024, &iecpows, "iB")
|
|
}
|
|
|
|
// appendFormat will append formatted Size to 'dst', depending on base, powers table and single unit suffix.
|
|
func (sz Size) appendFormat(dst []byte, base uint64, pows *[6]float64, sunit string) []byte {
|
|
const (
|
|
// min "small" unit threshold
|
|
min = 0.75
|
|
|
|
// binary unit chars.
|
|
units = `kMGTPE`
|
|
)
|
|
|
|
// Larger number: get value of
|
|
// i / unit size. We have a 'min'
|
|
// threshold after which we prefer
|
|
// using the unit 1 down
|
|
n := bits.Len64(uint64(sz)) / 10
|
|
f := float64(sz) / pows[n-1]
|
|
if f < min {
|
|
f *= float64(base)
|
|
n--
|
|
}
|
|
|
|
// Append formatted float with units
|
|
dst = ftoa(dst, f)
|
|
dst = append(dst, units[n-1])
|
|
dst = append(dst, sunit...)
|
|
return dst
|
|
}
|
|
|
|
// StringSI returns an SI unit string format of Size.
|
|
func (sz Size) StringSI() string {
|
|
const maxLen = 6 // max SI string length
|
|
b := sz.AppendFormatSI(make([]byte, 0, maxLen))
|
|
return *(*string)(unsafe.Pointer(&b))
|
|
}
|
|
|
|
// StringIEC returns an IEC unit string format of Size.
|
|
func (sz Size) StringIEC() string {
|
|
const maxLen = 7 // max IEC string length
|
|
b := sz.AppendFormatIEC(make([]byte, 0, maxLen))
|
|
return *(*string)(unsafe.Pointer(&b))
|
|
}
|
|
|
|
// String returns a string format of Size, defaults to IEC unit format.
|
|
func (sz Size) String() string {
|
|
return sz.StringIEC()
|
|
}
|
|
|
|
// parseUnit will parse the byte size unit from string 's'.
|
|
func parseUnit(s string) (float64, int, error) {
|
|
// Check for string
|
|
if len(s) < 1 {
|
|
return 0, 0, ErrInvalidFormat
|
|
}
|
|
|
|
// Strip 'byte' unit suffix
|
|
if l := len(s) - 1; s[l] == 'B' {
|
|
s = s[:l]
|
|
|
|
if len(s) < 1 {
|
|
// No remaining str before unit suffix
|
|
return 0, 0, ErrInvalidFormat
|
|
}
|
|
}
|
|
|
|
// Strip IEC binary unit suffix
|
|
if l := len(s) - 1; s[l] == 'i' {
|
|
s = s[:l]
|
|
|
|
if len(s) < 1 {
|
|
// No remaining str before unit suffix
|
|
return 0, 0, ErrInvalidFormat
|
|
}
|
|
|
|
// Location of unit char.
|
|
l := len(s) - 1
|
|
c := int(s[l])
|
|
|
|
// Check valid unit char was provided
|
|
if len(iecvals) < c || iecvals[c] == 0 {
|
|
return 0, 0, errctx(ErrInvalidUnit, s[l:])
|
|
}
|
|
|
|
// Return parsed IEC unit size
|
|
return iecvals[c], l, nil
|
|
}
|
|
|
|
// Location of unit char.
|
|
l := len(s) - 1
|
|
c := int(s[l])
|
|
|
|
switch {
|
|
// Check valid unit char provided
|
|
case len(sivals) < c || sivals[c] == 0:
|
|
return 0, 0, errctx(ErrInvalidUnit, s[l:])
|
|
|
|
// No unit char (only ascii number)
|
|
case sivals[c] == 1:
|
|
l++
|
|
}
|
|
|
|
// Return parsed SI unit size
|
|
return sivals[c], l, nil
|
|
}
|
|
|
|
// ftoa appends string formatted 'f' to 'dst', assumed < ~800.
|
|
func ftoa(dst []byte, f float64) []byte {
|
|
switch i := uint64(f); {
|
|
// Append with 2 d.p.
|
|
case i < 10:
|
|
f *= 10
|
|
|
|
// Calculate next dec. value
|
|
d1 := uint8(uint64(f) % 10)
|
|
|
|
f *= 10
|
|
|
|
// Calculate next dec. value
|
|
d2 := uint8(uint64(f) % 10)
|
|
|
|
// Round the final value
|
|
if uint64(f*10)%10 > 4 {
|
|
d2++
|
|
|
|
// Overflow, incr 'd1'
|
|
if d2 == 10 {
|
|
d2 = 0
|
|
d1++
|
|
|
|
// Overflow, incr 'i'
|
|
if d1 == 10 {
|
|
d1 = 0
|
|
i++
|
|
}
|
|
}
|
|
}
|
|
|
|
// Append decimal value
|
|
dst = itoa(dst, i)
|
|
dst = append(dst,
|
|
'.',
|
|
'0'+d1,
|
|
'0'+d2,
|
|
)
|
|
|
|
// Append with 1 d.p.
|
|
case i < 100:
|
|
f *= 10
|
|
|
|
// Calculate next dec. value
|
|
d1 := uint8(uint64(f) % 10)
|
|
|
|
// Round the final value
|
|
if uint64(f*10)%10 > 4 {
|
|
d1++
|
|
|
|
// Overflow, incr 'i'
|
|
if d1 == 10 {
|
|
d1 = 0
|
|
i++
|
|
}
|
|
}
|
|
|
|
// Append decimal value
|
|
dst = itoa(dst, i)
|
|
dst = append(dst, '.', '0'+d1)
|
|
|
|
// No decimal places
|
|
default:
|
|
dst = itoa(dst, i)
|
|
}
|
|
|
|
return dst
|
|
}
|
|
|
|
// itoa appends string formatted 'i' to 'dst'.
|
|
func itoa(dst []byte, i uint64) []byte {
|
|
// Assemble uint in reverse order.
|
|
var b [4]byte
|
|
bp := len(b) - 1
|
|
|
|
// Append integer
|
|
for i >= 10 {
|
|
q := i / 10
|
|
b[bp] = byte('0' + i - q*10)
|
|
bp--
|
|
i = q
|
|
} // i < 10
|
|
b[bp] = byte('0' + i)
|
|
|
|
return append(dst, b[bp:]...)
|
|
}
|
|
|
|
// errwithctx wraps an error
|
|
// with extra context info.
|
|
type errwithctx struct {
|
|
err error
|
|
ctx string
|
|
}
|
|
|
|
func errctx(err error, ctx string) error {
|
|
return &errwithctx{err: err, ctx: ctx}
|
|
}
|
|
|
|
func (err *errwithctx) Unwrap() error {
|
|
return err.err
|
|
}
|
|
|
|
func (err *errwithctx) Error() string {
|
|
return err.err.Error() + ": " + err.ctx
|
|
}
|