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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package io
// Byte buffer for marshaling nested messages.
import (
"io";
"os";
)
// A simple implementation of the io.Read and io.Write interfaces.
// A newly allocated ByteBuffer is ready to use.
// TODO(r): Do better memory management.
func bytecopy(dst []byte, doff int, src []byte, soff int, count int) {
for i := 0; i < count; i++ {
dst[doff] = src[soff];
doff++;
soff++;
}
}
export type ByteBuffer struct {
buf []byte;
off int; // Read from here
len int; // Write to here
cap int;
}
func (b *ByteBuffer) Reset() {
b.off = 0;
b.len = 0;
}
func (b *ByteBuffer) Write(p []byte) (n int, err *os.Error) {
plen := len(p);
if len(b.buf) == 0 {
b.cap = plen + 1024;
b.buf = make([]byte, b.cap);
b.len = 0;
}
if b.len + len(p) > b.cap {
b.cap = 2*(b.cap + plen);
nb := make([]byte, b.cap);
bytecopy(nb, 0, b.buf, 0, b.len);
b.buf = nb;
}
bytecopy(b.buf, b.len, p, 0, plen);
b.len += plen;
return plen, nil;
}
func (b *ByteBuffer) Read(p []byte) (n int, err *os.Error) {
plen := len(p);
if len(b.buf) == 0 {
return 0, nil
}
if b.off == b.len { // empty buffer
b.Reset();
return 0, nil
}
if plen > b.len - b.off {
plen = b.len - b.off
}
bytecopy(p, 0, b.buf, b.off, plen);
b.off += plen;
return plen, nil;
}
func (b *ByteBuffer) Len() int {
return b.len
}
func (b *ByteBuffer) Data() []byte {
return b.buf[b.off:b.len]
}
export func NewByteBufferFromArray(buf []byte) *ByteBuffer {
b := new(ByteBuffer);
b.buf = buf;
b.off = 0;
b.len = len(buf);
b.cap = len(buf);
return b;
}
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