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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include <cstdint>
#include <cstddef>
namespace search {
/**
* A buffer with an input point and an output point. The space
* is dynamically allocated by the constructor, and can be extended
* when needed. Buffer contents may be moved around when there is
* insufficient room.
*/
class RawBuf
{
private:
char* _bufStart; // ref. to start of buffer (don't move this!)
char* _bufEnd; // ref. to byte after last in buffer (don't mo)
char* _bufFillPos; // ref. to byte where next should be put in
char* _bufDrainPos; // ref. to next byte to take out of buffer
char* _initialBufStart;
size_t _initialSize;
void ensureSizeInternal(size_t size);
void expandBuf(size_t needlen);
/**
* Convert unsigned int.s 'src', to interNet highendian order, at 'dst'
* or _bufFillPos. Update or return ref to next char after those filled in.
*/
static unsigned char* ToInet(uint32_t src, unsigned char* dst) {
*(dst + 3) = src; // The least significant 8 bits
src >>= 8; // of 'src' are stored.
*(dst + 2) = src;
src >>= 8;
*(dst + 1) = src;
src >>= 8;
*dst = src;
return dst + 4;
};
static unsigned char* ToInet(uint64_t src, unsigned char* dst) {
ToInet(static_cast<uint32_t>(src >> 32), dst);
ToInet(static_cast<uint32_t>(src & 0xffffffffull), dst + 4);
return dst + 8;
};
public:
RawBuf(const RawBuf &) = delete;
RawBuf& operator=(const RawBuf &) = delete;
explicit RawBuf(size_t size); // malloc-s given size, assigns to _bufStart
~RawBuf(); // Frees _bufStart, i.e. the char[].
void addNum(size_t num, size_t fieldw, char fill);
void addNum32(int32_t num, size_t fieldw, char fill);
void addNum64(int64_t num, size_t fieldw, char fill);
void append(const void *data, size_t len);
void append(const char *data);
void append(uint8_t byte);
void appendCompressedPositiveNumber(uint64_t n);
void appendCompressedNumber(int64_t n);
size_t GetFreeLen() const { return _bufEnd - _bufFillPos; }
size_t GetDrainLen() const { return _bufDrainPos - _bufStart; }
const char *GetDrainPos() const { return _bufDrainPos; }
const char *GetFillPos() const { return _bufFillPos; }
char * GetWritableFillPos(size_t len) { preAlloc(len); return _bufFillPos; }
void preAlloc(size_t len); // Ensure room for 'len' more bytes.
void reset() { _bufDrainPos = _bufFillPos = _bufStart; }
void Reuse();
size_t GetUsedAndDrainLen() const { return _bufFillPos - _bufStart; }
size_t GetUsedLen() const { return _bufFillPos - _bufDrainPos; }
void Drain(size_t len); // Adjust drain pos.
void Fill(size_t len) { _bufFillPos += len; }
void ensureSize(size_t size) {
if (static_cast<size_t>(_bufEnd - _bufFillPos) < size) {
ensureSizeInternal(size);
}
}
void PutToInet(uint32_t src) {
ensureSize(4);
_bufFillPos = reinterpret_cast<char *>(ToInet(src,reinterpret_cast<unsigned char*>(_bufFillPos)));
};
void Put64ToInet(uint64_t src) {
ensureSize(8);
_bufFillPos = reinterpret_cast<char *>(ToInet(src,reinterpret_cast<unsigned char*>(_bufFillPos)));
};
};
}
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