// Copyright 2019 The Crashpad Authors. All rights reserved.
|
//
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
// you may not use this file except in compliance with the License.
|
// You may obtain a copy of the License at
|
//
|
// http://www.apache.org/licenses/LICENSE-2.0
|
//
|
// Unless required by applicable law or agreed to in writing, software
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
// See the License for the specific language governing permissions and
|
// limitations under the License.
|
|
#ifndef CRASHPAD_UTIL_STREAM_BASE94_OUTPUT_STREAM_H_
|
#define CRASHPAD_UTIL_STREAM_BASE94_OUTPUT_STREAM_H_
|
|
#include <stddef.h>
|
#include <stdint.h>
|
|
#include <memory>
|
#include <vector>
|
|
#include "base/macros.h"
|
#include "util/stream/output_stream_interface.h"
|
|
namespace crashpad {
|
|
//! \brief This class implements Base94 encoding/decoding, it uses all
|
//! printable characters except space for encoding, and no padding is required.
|
//!
|
//! This implementation uses two base94 symbols to encoding 13 or 14 bit data,
|
//! To maximize encoding efficiency, 14-bit data is encoded into two base94
|
//! symbols if its low 13-bit is less than 644 ( = 94^2 - 2^13), otherwise
|
//! 13-bit data is encoded.
|
class Base94OutputStream : public OutputStreamInterface {
|
public:
|
//! \brief Whether this object is configured to encode or decode data.
|
enum class Mode : bool {
|
//! \brief Data passed through this object is encoded.
|
kEncode = false,
|
//! \brief Data passed through this object is decoded.
|
kDecode = true
|
};
|
|
//! \param[in] mode The work mode of this object.
|
//! \param[in] output_stream The output_stream that this object writes to.
|
Base94OutputStream(Mode mode,
|
std::unique_ptr<OutputStreamInterface> output_stream);
|
~Base94OutputStream() override;
|
|
// OutputStreamInterface:
|
bool Write(const uint8_t* data, size_t size) override;
|
bool Flush() override;
|
|
private:
|
bool Encode(const uint8_t* data, size_t size);
|
bool Decode(const uint8_t* data, size_t size);
|
bool FinishEncoding();
|
bool FinishDecoding();
|
// Write encoded/decoded data to |output_stream_| and empty the |buffer_|.
|
bool WriteOutputStream();
|
|
Mode mode_;
|
std::unique_ptr<OutputStreamInterface> output_stream_;
|
std::vector<uint8_t> buffer_;
|
uint32_t bit_buf_;
|
// The number of valid bit in bit_buf_.
|
size_t bit_count_;
|
char symbol_buffer_;
|
bool flush_needed_;
|
bool flushed_;
|
|
DISALLOW_COPY_AND_ASSIGN(Base94OutputStream);
|
};
|
|
} // namespace crashpad
|
|
#endif // CRASHPAD_UTIL_STREAM_BASE94_OUTPUT_STREAM_H_
|
