gotosocial/vendor/git.iim.gay/grufwub/go-bytes/buffer.go
kim (grufwub) e43a46e982 add git.iim.gay/grufwub/go-store for storage backend, replacing blob.Storage
Signed-off-by: kim (grufwub) <grufwub@gmail.com>
2021-09-11 20:12:47 +01:00

139 lines
2.4 KiB
Go

package bytes
import (
"unicode/utf8"
)
// Buffer is a very simple buffer implementation that allows
// access to and reslicing of the underlying byte slice.
type Buffer struct {
noCopy noCopy
B []byte
}
func NewBuffer(b []byte) Buffer {
return Buffer{
noCopy: noCopy{},
B: b,
}
}
func (b *Buffer) Write(p []byte) (int, error) {
b.Grow(len(p))
return copy(b.B[b.Len()-len(p):], p), nil
}
func (b *Buffer) WriteString(s string) (int, error) {
b.Grow(len(s))
return copy(b.B[b.Len()-len(s):], s), nil
}
func (b *Buffer) WriteByte(c byte) error {
l := b.Len()
b.Grow(1)
b.B[l] = c
return nil
}
func (b *Buffer) WriteRune(r rune) (int, error) {
if r < utf8.RuneSelf {
b.WriteByte(byte(r))
return 1, nil
}
l := b.Len()
b.Grow(utf8.UTFMax)
n := utf8.EncodeRune(b.B[l:b.Len()], r)
b.B = b.B[:l+n]
return n, nil
}
func (b *Buffer) WriteAt(p []byte, start int64) (int, error) {
b.Grow(len(p) - int(int64(b.Len())-start))
return copy(b.B[start:], p), nil
}
func (b *Buffer) WriteStringAt(s string, start int64) (int, error) {
b.Grow(len(s) - int(int64(b.Len())-start))
return copy(b.B[start:], s), nil
}
func (b *Buffer) Truncate(size int) {
b.B = b.B[:b.Len()-size]
}
func (b *Buffer) ShiftByte(index int) {
copy(b.B[index:], b.B[index+1:])
}
func (b *Buffer) Shift(start int64, size int) {
copy(b.B[start:], b.B[start+int64(size):])
}
func (b *Buffer) DeleteByte(index int) {
b.ShiftByte(index)
b.Truncate(1)
}
func (b *Buffer) Delete(start int64, size int) {
b.Shift(start, size)
b.Truncate(size)
}
func (b *Buffer) InsertByte(index int64, c byte) {
l := b.Len()
b.Grow(1)
copy(b.B[index+1:], b.B[index:l])
b.B[index] = c
}
func (b *Buffer) Insert(index int64, p []byte) {
l := b.Len()
b.Grow(len(p))
copy(b.B[index+int64(len(p)):], b.B[index:l])
copy(b.B[index:], p)
}
func (b *Buffer) Bytes() []byte {
return b.B
}
func (b *Buffer) String() string {
return string(b.B)
}
func (b *Buffer) StringPtr() string {
return BytesToString(b.B)
}
func (b *Buffer) Cap() int {
return cap(b.B)
}
func (b *Buffer) Len() int {
return len(b.B)
}
func (b *Buffer) Reset() {
b.B = b.B[:0]
}
func (b *Buffer) Grow(size int) {
b.Guarantee(size)
b.B = b.B[:b.Len()+size]
}
func (b *Buffer) Guarantee(size int) {
if size > b.Cap()-b.Len() {
nb := make([]byte, 2*b.Cap()+size)
copy(nb, b.B)
b.B = nb[:b.Len()]
}
}
type noCopy struct{}
func (n *noCopy) Lock() {}
func (n *noCopy) Unlock() {}