mirror of
https://github.com/v2fly/v2ray-core.git
synced 2024-09-12 06:54:23 -04:00
215 lines
4.5 KiB
Go
215 lines
4.5 KiB
Go
// Package alloc provides a light-weight memory allocation mechanism.
|
|
package alloc
|
|
|
|
import (
|
|
"hash"
|
|
"io"
|
|
|
|
"v2ray.com/core/common/serial"
|
|
)
|
|
|
|
const (
|
|
defaultOffset = 16
|
|
)
|
|
|
|
// Buffer is a recyclable allocation of a byte array. Buffer.Release() recycles
|
|
// the buffer into an internal buffer pool, in order to recreate a buffer more
|
|
// quickly.
|
|
type Buffer struct {
|
|
head []byte
|
|
pool Pool
|
|
Value []byte
|
|
offset int
|
|
}
|
|
|
|
func CreateBuffer(container []byte, parent Pool) *Buffer {
|
|
b := new(Buffer)
|
|
b.head = container
|
|
b.pool = parent
|
|
b.Value = b.head[defaultOffset:]
|
|
b.offset = defaultOffset
|
|
return b
|
|
}
|
|
|
|
// Release recycles the buffer into an internal buffer pool.
|
|
func (b *Buffer) Release() {
|
|
if b == nil || b.head == nil {
|
|
return
|
|
}
|
|
if b.pool != nil {
|
|
b.pool.Free(b)
|
|
}
|
|
b.head = nil
|
|
b.Value = nil
|
|
b.pool = nil
|
|
}
|
|
|
|
// Clear clears the content of the buffer, results an empty buffer with
|
|
// Len() = 0.
|
|
func (b *Buffer) Clear() *Buffer {
|
|
b.offset = defaultOffset
|
|
b.Value = b.head[b.offset:b.offset]
|
|
return b
|
|
}
|
|
|
|
// Reset resets this Buffer into its original state.
|
|
func (b *Buffer) Reset() *Buffer {
|
|
b.offset = defaultOffset
|
|
b.Value = b.head[b.offset:]
|
|
return b
|
|
}
|
|
|
|
// AppendBytes appends one or more bytes to the end of the buffer.
|
|
func (b *Buffer) AppendBytes(bytes ...byte) *Buffer {
|
|
b.Value = append(b.Value, bytes...)
|
|
return b
|
|
}
|
|
|
|
// Append appends a byte array to the end of the buffer.
|
|
func (b *Buffer) Append(data []byte) *Buffer {
|
|
b.Value = append(b.Value, data...)
|
|
return b
|
|
}
|
|
|
|
// AppendString appends a given string to the end of the buffer.
|
|
func (b *Buffer) AppendString(s string) *Buffer {
|
|
b.Value = append(b.Value, s...)
|
|
return b
|
|
}
|
|
|
|
func (b *Buffer) AppendUint16(v uint16) *Buffer {
|
|
b.Value = serial.Uint16ToBytes(v, b.Value)
|
|
return b
|
|
}
|
|
|
|
func (b *Buffer) AppendUint32(v uint32) *Buffer {
|
|
b.Value = serial.Uint32ToBytes(v, b.Value)
|
|
return b
|
|
}
|
|
|
|
// Prepend prepends bytes in front of the buffer. Caller must ensure total bytes prepended is
|
|
// no more than 16 bytes.
|
|
func (b *Buffer) Prepend(data []byte) *Buffer {
|
|
b.SliceBack(len(data))
|
|
copy(b.Value, data)
|
|
return b
|
|
}
|
|
|
|
func (b *Buffer) PrependBytes(data ...byte) *Buffer {
|
|
return b.Prepend(data)
|
|
}
|
|
|
|
func (b *Buffer) PrependUint16(v uint16) *Buffer {
|
|
b.SliceBack(2)
|
|
serial.Uint16ToBytes(v, b.Value[:0])
|
|
return b
|
|
}
|
|
|
|
func (b *Buffer) PrependUint32(v uint32) *Buffer {
|
|
b.SliceBack(4)
|
|
serial.Uint32ToBytes(v, b.Value[:0])
|
|
return b
|
|
}
|
|
|
|
func (b *Buffer) PrependHash(h hash.Hash) *Buffer {
|
|
b.SliceBack(h.Size())
|
|
h.Sum(b.Value[:0])
|
|
return b
|
|
}
|
|
|
|
// Bytes returns the content bytes of this Buffer.
|
|
func (b *Buffer) Bytes() []byte {
|
|
return b.Value
|
|
}
|
|
|
|
// Slice cuts the buffer at the given position.
|
|
func (b *Buffer) Slice(from, to int) *Buffer {
|
|
b.offset += from
|
|
b.Value = b.Value[from:to]
|
|
return b
|
|
}
|
|
|
|
// SliceFrom cuts the buffer at the given position.
|
|
func (b *Buffer) SliceFrom(from int) *Buffer {
|
|
b.offset += from
|
|
b.Value = b.Value[from:]
|
|
return b
|
|
}
|
|
|
|
// SliceBack extends the Buffer to its front by offset bytes.
|
|
// Caller must ensure cumulated offset is no more than 16.
|
|
func (b *Buffer) SliceBack(offset int) *Buffer {
|
|
newoffset := b.offset - offset
|
|
if newoffset < 0 {
|
|
panic("Negative buffer offset.")
|
|
}
|
|
b.Value = b.head[newoffset : b.offset+len(b.Value)]
|
|
b.offset = newoffset
|
|
return b
|
|
}
|
|
|
|
// Len returns the length of the buffer content.
|
|
func (b *Buffer) Len() int {
|
|
if b == nil {
|
|
return 0
|
|
}
|
|
return len(b.Value)
|
|
}
|
|
|
|
func (b *Buffer) IsEmpty() bool {
|
|
return b.Len() == 0
|
|
}
|
|
|
|
// IsFull returns true if the buffer has no more room to grow.
|
|
func (b *Buffer) IsFull() bool {
|
|
return len(b.Value) == cap(b.Value)
|
|
}
|
|
|
|
// Write implements Write method in io.Writer.
|
|
func (b *Buffer) Write(data []byte) (int, error) {
|
|
b.Append(data)
|
|
return len(data), nil
|
|
}
|
|
|
|
// Read implements io.Reader.Read().
|
|
func (b *Buffer) Read(data []byte) (int, error) {
|
|
if b.Len() == 0 {
|
|
return 0, io.EOF
|
|
}
|
|
nBytes := copy(data, b.Value)
|
|
if nBytes == b.Len() {
|
|
b.Clear()
|
|
} else {
|
|
b.Value = b.Value[nBytes:]
|
|
b.offset += nBytes
|
|
}
|
|
return nBytes, nil
|
|
}
|
|
|
|
func (b *Buffer) FillFrom(reader io.Reader) (int, error) {
|
|
begin := b.Len()
|
|
b.Value = b.Value[:cap(b.Value)]
|
|
nBytes, err := reader.Read(b.Value[begin:])
|
|
if err == nil {
|
|
b.Value = b.Value[:begin+nBytes]
|
|
}
|
|
return nBytes, err
|
|
}
|
|
|
|
func (b *Buffer) String() string {
|
|
return string(b.Value)
|
|
}
|
|
|
|
// NewBuffer creates a Buffer with 8K bytes of arbitrary content.
|
|
func NewBuffer() *Buffer {
|
|
return mediumPool.Allocate()
|
|
}
|
|
|
|
func NewSmallBuffer() *Buffer {
|
|
return smallPool.Allocate()
|
|
}
|
|
|
|
func NewLocalBuffer(size int) *Buffer {
|
|
return CreateBuffer(make([]byte, size), nil)
|
|
}
|