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buffer.go
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buffer.go
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package buf
import (
"io"
)
// Supplier is a writer that writes contents into the given buffer.
type Supplier func([]byte) (int, error)
// 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 {
v []byte
start int32
end int32
}
// Release recycles the buffer into an internal buffer pool.
func (b *Buffer) Release() {
if b == nil || b.v == nil {
return
}
freeBytes(b.v)
b.v = nil
b.start = 0
b.end = 0
}
// Clear clears the content of the buffer, results an empty buffer with
// Len() = 0.
func (b *Buffer) Clear() {
b.start = 0
b.end = 0
}
// AppendBytes appends one or more bytes to the end of the buffer.
func (b *Buffer) AppendBytes(bytes ...byte) int {
return b.Append(bytes)
}
// Append appends a byte array to the end of the buffer.
func (b *Buffer) Append(data []byte) int {
nBytes := copy(b.v[b.end:], data)
b.end += int32(nBytes)
return nBytes
}
// AppendSupplier appends the content of a BytesWriter to the buffer.
func (b *Buffer) AppendSupplier(writer Supplier) error {
nBytes, err := writer(b.v[b.end:])
b.end += int32(nBytes)
return err
}
// Byte returns the bytes at index.
func (b *Buffer) Byte(index int32) byte {
return b.v[b.start+index]
}
// SetByte sets the byte value at index.
func (b *Buffer) SetByte(index int32, value byte) {
b.v[b.start+index] = value
}
// Bytes returns the content bytes of this Buffer.
func (b *Buffer) Bytes() []byte {
return b.v[b.start:b.end]
}
// Reset resets the content of the Buffer with a supplier.
func (b *Buffer) Reset(writer Supplier) error {
nBytes, err := writer(b.v)
b.start = 0
b.end = int32(nBytes)
return err
}
// BytesRange returns a slice of this buffer with given from and to boundary.
func (b *Buffer) BytesRange(from, to int32) []byte {
if from < 0 {
from += b.Len()
}
if to < 0 {
to += b.Len()
}
return b.v[b.start+from : b.start+to]
}
// BytesFrom returns a slice of this Buffer starting from the given position.
func (b *Buffer) BytesFrom(from int32) []byte {
if from < 0 {
from += b.Len()
}
return b.v[b.start+from : b.end]
}
// BytesTo returns a slice of this Buffer from start to the given position.
func (b *Buffer) BytesTo(to int32) []byte {
if to < 0 {
to += b.Len()
}
return b.v[b.start : b.start+to]
}
// Slice cuts the buffer at the given position.
func (b *Buffer) Slice(from, to int32) {
if from < 0 {
from += b.Len()
}
if to < 0 {
to += b.Len()
}
if to < from {
panic("Invalid slice")
}
b.end = b.start + to
b.start += from
}
// SliceFrom cuts the buffer at the given position.
func (b *Buffer) SliceFrom(from int32) {
if from < 0 {
from += b.Len()
}
b.start += from
}
// Len returns the length of the buffer content.
func (b *Buffer) Len() int32 {
if b == nil {
return 0
}
return b.end - b.start
}
// IsEmpty returns true if the buffer is empty.
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 b.end == int32(len(b.v))
}
// Write implements Write method in io.Writer.
func (b *Buffer) Write(data []byte) (int, error) {
nBytes := copy(b.v[b.end:], data)
b.end += int32(nBytes)
return nBytes, 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.v[b.start:b.end])
if int32(nBytes) == b.Len() {
b.Clear()
} else {
b.start += int32(nBytes)
}
return nBytes, nil
}
// String returns the string form of this Buffer.
func (b *Buffer) String() string {
return string(b.Bytes())
}
// New creates a Buffer with 0 length and 2K capacity.
func New() *Buffer {
return &Buffer{
v: pool[0].Get().([]byte),
}
}
// NewSize creates and returns a buffer with 0 length and at least the given capacity. Capacity must be positive.
func NewSize(capacity int32) *Buffer {
return &Buffer{
v: newBytes(capacity),
}
}