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|
package buffer
import (
"encoding/binary"
"io"
)
// buffer is similar to bytes.Buffer but specialized for this package
type Buffer struct {
b []byte
i int
}
func New(b []byte) *Buffer {
return &Buffer{b: b}
}
func (b *Buffer) Next(n int64) ([]byte, bool) {
if b.readCheck(n) {
buf := b.b[b.i:len(b.b)]
b.i = len(b.b)
return buf, false
}
buf := b.b[b.i : b.i+int(n)]
b.i += int(n)
return buf, true
}
func (b *Buffer) Skip(n int) {
b.i += n
}
func (b *Buffer) Reset() {
b.b = b.b[:0]
b.i = 0
}
// reclaim shifts used buffer space to the beginning of the
// underlying slice.
func (b *Buffer) Reclaim() {
l := b.Len()
copy(b.b[:l], b.b[b.i:])
b.b = b.b[:l]
b.i = 0
}
func (b *Buffer) readCheck(n int64) bool {
return int64(b.i)+n > int64(len(b.b))
}
func (b *Buffer) ReadByte() (byte, error) {
if b.readCheck(1) {
return 0, io.EOF
}
byte_ := b.b[b.i]
b.i++
return byte_, nil
}
func (b *Buffer) PeekByte() (byte, error) {
if b.readCheck(1) {
return 0, io.EOF
}
return b.b[b.i], nil
}
func (b *Buffer) ReadUint16() (uint16, error) {
if b.readCheck(2) {
return 0, io.EOF
}
n := binary.BigEndian.Uint16(b.b[b.i:])
b.i += 2
return n, nil
}
func (b *Buffer) ReadUint32() (uint32, error) {
if b.readCheck(4) {
return 0, io.EOF
}
n := binary.BigEndian.Uint32(b.b[b.i:])
b.i += 4
return n, nil
}
func (b *Buffer) ReadUint64() (uint64, error) {
if b.readCheck(8) {
return 0, io.EOF
}
n := binary.BigEndian.Uint64(b.b[b.i : b.i+8])
b.i += 8
return n, nil
}
func (b *Buffer) ReadFromOnce(r io.Reader) error {
const minRead = 512
l := len(b.b)
if cap(b.b)-l < minRead {
total := l * 2
if total == 0 {
total = minRead
}
new := make([]byte, l, total)
copy(new, b.b)
b.b = new
}
n, err := r.Read(b.b[l:cap(b.b)])
b.b = b.b[:l+n]
return err
}
func (b *Buffer) Append(p []byte) {
b.b = append(b.b, p...)
}
func (b *Buffer) AppendByte(bb byte) {
b.b = append(b.b, bb)
}
func (b *Buffer) AppendString(s string) {
b.b = append(b.b, s...)
}
func (b *Buffer) Len() int {
return len(b.b) - b.i
}
func (b *Buffer) Size() int {
return b.i
}
func (b *Buffer) Bytes() []byte {
return b.b[b.i:]
}
func (b *Buffer) Detach() []byte {
temp := b.b
b.b = nil
b.i = 0
return temp
}
func (b *Buffer) AppendUint16(n uint16) {
b.b = append(b.b,
byte(n>>8),
byte(n),
)
}
func (b *Buffer) AppendUint32(n uint32) {
b.b = append(b.b,
byte(n>>24),
byte(n>>16),
byte(n>>8),
byte(n),
)
}
func (b *Buffer) AppendUint64(n uint64) {
b.b = append(b.b,
byte(n>>56),
byte(n>>48),
byte(n>>40),
byte(n>>32),
byte(n>>24),
byte(n>>16),
byte(n>>8),
byte(n),
)
}
|
