mirror of
https://github.com/XTLS/Xray-core.git
synced 2024-08-22 04:36:26 +00:00
252 lines
4.9 KiB
Go
252 lines
4.9 KiB
Go
package buf
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import (
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"io"
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"github.com/xtls/xray-core/common/bytespool"
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"github.com/xtls/xray-core/common/net"
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)
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const (
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// Size of a regular buffer.
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Size = 8192
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)
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var pool = bytespool.GetPool(Size)
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// Buffer is a recyclable allocation of a byte array. Buffer.Release() recycles
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// the buffer into an internal buffer pool, in order to recreate a buffer more
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// quickly.
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type Buffer struct {
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v []byte
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start int32
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end int32
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UDP *net.Destination
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}
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// New creates a Buffer with 0 length and 8K capacity.
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func New() *Buffer {
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buf := pool.Get().([]byte)
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if cap(buf) >= Size {
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buf = buf[:Size]
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} else {
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buf = make([]byte, Size)
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}
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return &Buffer{
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v: buf,
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}
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}
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func NewExisted(b []byte) *Buffer {
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if cap(b) < Size {
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panic("Invalid buffer")
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}
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oLen := len(b)
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if oLen < Size {
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b = b[:Size]
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}
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return &Buffer{
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v: b,
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end: int32(oLen),
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}
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}
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// StackNew creates a new Buffer object on stack.
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// This method is for buffers that is released in the same function.
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func StackNew() Buffer {
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buf := pool.Get().([]byte)
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if cap(buf) >= Size {
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buf = buf[:Size]
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} else {
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buf = make([]byte, Size)
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}
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return Buffer{
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v: buf,
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}
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}
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// Release recycles the buffer into an internal buffer pool.
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func (b *Buffer) Release() {
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if b == nil || b.v == nil {
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return
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}
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p := b.v
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b.v = nil
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b.Clear()
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if cap(p) == Size {
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pool.Put(p)
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}
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b.UDP = nil
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}
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// Clear clears the content of the buffer, results an empty buffer with
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// Len() = 0.
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func (b *Buffer) Clear() {
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b.start = 0
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b.end = 0
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}
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// Byte returns the bytes at index.
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func (b *Buffer) Byte(index int32) byte {
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return b.v[b.start+index]
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}
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// SetByte sets the byte value at index.
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func (b *Buffer) SetByte(index int32, value byte) {
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b.v[b.start+index] = value
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}
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// Bytes returns the content bytes of this Buffer.
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func (b *Buffer) Bytes() []byte {
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return b.v[b.start:b.end]
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}
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// Extend increases the buffer size by n bytes, and returns the extended part.
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// It panics if result size is larger than buf.Size.
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func (b *Buffer) Extend(n int32) []byte {
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end := b.end + n
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if end > int32(len(b.v)) {
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panic("extending out of bound")
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}
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ext := b.v[b.end:end]
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b.end = end
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return ext
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}
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// BytesRange returns a slice of this buffer with given from and to boundary.
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func (b *Buffer) BytesRange(from, to int32) []byte {
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if from < 0 {
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from += b.Len()
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}
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if to < 0 {
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to += b.Len()
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}
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return b.v[b.start+from : b.start+to]
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}
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// BytesFrom returns a slice of this Buffer starting from the given position.
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func (b *Buffer) BytesFrom(from int32) []byte {
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if from < 0 {
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from += b.Len()
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}
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return b.v[b.start+from : b.end]
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}
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// BytesTo returns a slice of this Buffer from start to the given position.
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func (b *Buffer) BytesTo(to int32) []byte {
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if to < 0 {
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to += b.Len()
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}
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if to < 0 {
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to = 0
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}
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return b.v[b.start : b.start+to]
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}
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// Resize cuts the buffer at the given position.
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func (b *Buffer) Resize(from, to int32) {
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if from < 0 {
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from += b.Len()
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}
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if to < 0 {
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to += b.Len()
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}
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if to < from {
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panic("Invalid slice")
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}
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b.end = b.start + to
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b.start += from
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}
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// Advance cuts the buffer at the given position.
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func (b *Buffer) Advance(from int32) {
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if from < 0 {
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from += b.Len()
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}
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b.start += from
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}
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// Len returns the length of the buffer content.
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func (b *Buffer) Len() int32 {
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if b == nil {
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return 0
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}
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return b.end - b.start
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}
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// IsEmpty returns true if the buffer is empty.
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func (b *Buffer) IsEmpty() bool {
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return b.Len() == 0
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}
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// IsFull returns true if the buffer has no more room to grow.
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func (b *Buffer) IsFull() bool {
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return b != nil && b.end == int32(len(b.v))
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}
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// Write implements Write method in io.Writer.
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func (b *Buffer) Write(data []byte) (int, error) {
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nBytes := copy(b.v[b.end:], data)
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b.end += int32(nBytes)
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return nBytes, nil
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}
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// WriteByte writes a single byte into the buffer.
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func (b *Buffer) WriteByte(v byte) error {
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if b.IsFull() {
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return newError("buffer full")
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}
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b.v[b.end] = v
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b.end++
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return nil
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}
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// WriteString implements io.StringWriter.
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func (b *Buffer) WriteString(s string) (int, error) {
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return b.Write([]byte(s))
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}
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// Read implements io.Reader.Read().
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func (b *Buffer) Read(data []byte) (int, error) {
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if b.Len() == 0 {
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return 0, io.EOF
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}
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nBytes := copy(data, b.v[b.start:b.end])
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if int32(nBytes) == b.Len() {
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b.Clear()
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} else {
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b.start += int32(nBytes)
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}
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return nBytes, nil
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}
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// ReadFrom implements io.ReaderFrom.
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func (b *Buffer) ReadFrom(reader io.Reader) (int64, error) {
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n, err := reader.Read(b.v[b.end:])
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b.end += int32(n)
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return int64(n), err
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}
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// ReadFullFrom reads exact size of bytes from given reader, or until error occurs.
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func (b *Buffer) ReadFullFrom(reader io.Reader, size int32) (int64, error) {
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end := b.end + size
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if end > int32(len(b.v)) {
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v := end
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return 0, newError("out of bound: ", v)
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}
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n, err := io.ReadFull(reader, b.v[b.end:end])
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b.end += int32(n)
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return int64(n), err
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}
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// String returns the string form of this Buffer.
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func (b *Buffer) String() string {
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return string(b.Bytes())
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}
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