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// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef NET_WEBSOCKETS_WEBSOCKET_DEFLATER_H_
#define NET_WEBSOCKETS_WEBSOCKET_DEFLATER_H_
#include <stddef.h>
#include <memory>
#include <vector>
#include "base/containers/circular_deque.h"
#include "base/containers/span.h"
#include "base/memory/scoped_refptr.h"
#include "net/base/net_export.h"
extern "C" struct z_stream_s;
namespace net {
class IOBufferWithSize;
class NET_EXPORT_PRIVATE WebSocketDeflater {
public:
enum ContextTakeOverMode {
DO_NOT_TAKE_OVER_CONTEXT,
TAKE_OVER_CONTEXT,
NUM_CONTEXT_TAKEOVER_MODE_TYPES,
};
explicit WebSocketDeflater(ContextTakeOverMode mode);
WebSocketDeflater(const WebSocketDeflater&) = delete;
WebSocketDeflater& operator=(const WebSocketDeflater&) = delete;
~WebSocketDeflater();
// Returns true if there is no error and false otherwise.
// This function must be called exactly once before calling any of
// following methods.
// `window_bits` must be between 8 and 15 (both inclusive).
bool Initialize(int window_bits);
// Adds bytes to `stream_`.
// Returns true if there is no error and false otherwise.
bool AddBytes(base::span<const uint8_t> data);
// Flushes the current processing data.
// Returns true if there is no error and false otherwise.
bool Finish();
// Pushes "\x00\x00\xff\xff" to the end of the buffer.
void PushSyncMark();
// Returns the current deflated output.
// If the current output is larger than `size` bytes,
// returns the first `size` bytes of the current output.
// The returned bytes will be dropped from the current output and never be
// returned thereafter.
scoped_refptr<IOBufferWithSize> GetOutput(size_t size);
// Returns the size of the current deflated output.
size_t CurrentOutputSize() const { return buffer_.size(); }
private:
void ResetContext();
int Deflate(int flush);
std::unique_ptr<z_stream_s> stream_;
ContextTakeOverMode mode_;
base::circular_deque<uint8_t> buffer_;
std::vector<uint8_t> fixed_buffer_;
// true if bytes were added after last Finish().
bool are_bytes_added_ = false;
};
} // namespace net
#endif // NET_WEBSOCKETS_WEBSOCKET_DEFLATER_H_
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