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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include "rawbuf.h"
#include <cassert>
#include <cstdlib>
namespace search {
/**
* Allocate a new buffer at least as large as the parameter value,
* move any content to the new and delete the old buffer.
*/
void
RawBuf::expandBuf(size_t needlen)
{
size_t size = (_bufEnd - _bufStart) * 2;
if (size < 1)
size = 2;
needlen += _bufEnd - _bufStart;
while (size < needlen)
size *= 2;
char* nbuf = static_cast<char *>(malloc(size));
if (_bufFillPos != _bufDrainPos)
memcpy(nbuf, _bufDrainPos, _bufFillPos - _bufDrainPos);
_bufFillPos = _bufFillPos - _bufDrainPos + nbuf;
_bufDrainPos = nbuf;
free(_bufStart);
_bufStart = nbuf;
_bufEnd = _bufStart + size;
}
/**
* Compact any free space from the beginning of the buffer, by
* copying the contents to the start of the buffer.
* If the resulting buffer doesn't have room for 'len' more
* bytes of contents, make it large enough.
*/
void
RawBuf::preAlloc(size_t len)
{
size_t curfree = _bufEnd - _bufFillPos;
if (curfree >= len)
return;
if (_bufEnd - _bufStart < len + _bufFillPos - _bufDrainPos) {
expandBuf(len);
assert(_bufEnd - _bufStart >= len + _bufFillPos - _bufDrainPos);
curfree = _bufEnd - _bufFillPos;
if (curfree >= len)
return;
}
memmove(_bufStart, _bufDrainPos, _bufFillPos - _bufDrainPos);
_bufFillPos -= (_bufDrainPos - _bufStart);
_bufDrainPos = _bufStart;
assert(static_cast<size_t>(_bufEnd -_bufFillPos) >= len);
}
void
RawBuf::ensureSizeInternal(size_t size) {
expandBuf(size);
assert(static_cast<size_t>(_bufEnd - _bufFillPos) >= size);
}
}
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