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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.
#include <string>
#include "base/basictypes.h"
#include "base/logging.h"
#include "base/port.h"
#include "base/strings/string_piece.h"
#include "net/base/int128.h"
#include "net/base/net_export.h"
#include "net/quic/quic_protocol.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 {
explicit QuicDataWriter(size_t length);
// Returns the size of the QuicDataWriter's data.
size_t length() const { return length_; }
// Takes the buffer from the QuicDataWriter.
char* take();
// 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);
bool WriteUInt16(uint16 value);
bool WriteUInt32(uint32 value);
bool WriteUInt48(uint64 value);
bool WriteUInt64(uint64 value);
// Write unsigned floating point corresponding to the value. Large values are
// clamped to the maximum representable (kUFloat16MaxValue). Values that can
// not be represented directly are rounded down.
bool WriteUFloat16(uint64 value);
bool WriteStringPiece16(base::StringPiece val);
bool WriteIOVector(const IOVector& data);
bool WriteBytes(const void* data, size_t data_len);
bool WriteRepeatedByte(uint8 byte, size_t count);
// Fills the remaining buffer with null characters.
void WritePadding();
// Methods for editing the payload at a specific offset, where the
// offset must be within the writer's capacity.
// Return true if there is enough space at that offset, false otherwise.
bool WriteUInt8ToOffset(uint8 value, size_t offset);
bool WriteUInt32ToOffset(uint32 value, size_t offset);
bool WriteUInt48ToOffset(uint64 value, size_t offset);
size_t capacity() const {
return capacity_;
// 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