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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef NET_QUIC_QUIC_DATA_WRITER_H_
#define NET_QUIC_QUIC_DATA_WRITER_H_
#include <string>
#include "base/basictypes.h"
#include "base/logging.h"
#include "base/port.h"
#include "base/string_piece.h"
#include "net/base/net_export.h"
#include "net/quic/quic_protocol.h"
#include "net/quic/uint128.h"
namespace net {
// This class provides facilities for packing QUIC data.
//
// The QuicDataWriter supports appending primitive values (int, string, etc)
// to a frame instance. The QuicDataWriter grows its internal memory buffer
// dynamically to hold the sequence of primitive values. The internal memory
// buffer is exposed as the "data" of the QuicDataWriter.
class NET_EXPORT_PRIVATE QuicDataWriter {
public:
explicit QuicDataWriter(size_t length);
~QuicDataWriter();
// Returns the size of the QuicDataWriter's data.
size_t length() const { return length_; }
// Takes the buffer from the QuicDataWriter.
// TODO(rch): move non-trivial methods into .cc file.
char* take() {
char* rv = buffer_;
buffer_ = NULL;
capacity_ = 0;
length_ = 0;
return rv;
}
// Methods for adding to the payload. These values are appended to the end
// of the QuicDataWriter payload. Note - binary integers are written in
// host byte order (little endian) not network byte order (big endian).
bool WriteUInt8(uint8 value) {
return WriteBytes(&value, sizeof(value));
}
bool WriteUInt16(uint16 value) {
return WriteBytes(&value, sizeof(value));
}
bool WriteUInt32(uint32 value) {
return WriteBytes(&value, sizeof(value));
}
bool WriteUInt48(uint64 value) {
uint32 hi = value >> 32;
uint32 lo = value & GG_UINT64_C(0x00000000FFFFFFFF);
return WriteUInt32(lo) && WriteUInt16(hi);
}
bool WriteUInt64(uint64 value) {
return WriteBytes(&value, sizeof(value));
}
bool WriteUInt128(uint128 value) {
return WriteUInt64(value.lo) && WriteUInt64(value.hi);
}
bool WriteStringPiece16(base::StringPiece val) {
if (val.length() > std::numeric_limits<uint16>::max()) {
return false;
}
if (!WriteUInt16(val.size())) {
return false;
}
return WriteBytes(val.data(), val.size());
}
bool AdvancePointer(uint32 len);
bool WriteBytes(const void* data, uint32 data_len);
static void WriteUint64ToBuffer(uint64 value, char* buffer);
static void WriteUint128ToBuffer(uint128 value, char* buffer);
size_t capacity() const {
return capacity_;
}
protected:
const char* end_of_payload() const { return buffer_ + length_; }
private:
// Returns the location that the data should be written at, or NULL if there
// is not enough room. Call EndWrite with the returned offset and the given
// length to pad out for the next write.
char* BeginWrite(size_t length);
char* buffer_;
size_t capacity_; // Allocation size of payload (or -1 if buffer is const).
size_t length_; // Current length of the buffer.
};
} // namespace net
#endif // NET_QUIC_QUIC_DATA_WRITER_H_
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