bit_stream_writer.h

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/*
 * Copyright (C) 2025 Mark Roszko <[email protected]>
 * Copyright The KiCad Developers, see AUTHORS.txt for contributors.
 * Copyright (C) 2007 Ecma International (original Java source)
 *
 * 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.
 *
 * License info found here:
 * https://www.loc.gov/preservation/digital/formats/fdd/fdd000491.shtml
 */
 
#pragma once
 
#include <cstdint>
#include <vector>
#include <exporters/u3d/context_manager.h>
#include <exporters/u3d/data_block.h>
#include <memory>
#include <string>
 
namespace U3D
{
class BIT_STREAM_WRITER
{
public:
    BIT_STREAM_WRITER();
 
    void WriteU8( uint8_t aValue );
 
    void WriteU16( uint16_t uValue );
 
    void WriteU32( uint32_t uValue );
 
    void WriteU64( uint64_t uValue );
 
    void WriteI32( int32_t iValue );
 
    void WriteF32( float fValue );
 
    void WriteF64( double aValue );
 
    void WriteCompressedU32( uint32_t aContext, uint32_t uValue );
 
    void WriteCompressedU16( uint32_t aContext, uint16_t uValue );
 
    void WriteCompressedU8( uint32_t aContext, uint8_t uValue );
 
    void WriteString( const std::string& aStr );
 
    void AlignToByte();
 
    void AlignTo4Byte();

    void GetBitCount( int32_t& rCount );
 
    void WriteDataBlock( std::shared_ptr<DATA_BLOCK> b );
 
    std::shared_ptr<DATA_BLOCK> GetDataBlock();
 
private:
    /*
     * Stores the local values of the data to the data array
     */
    void putLocal();
 
    /*
     * Write the given symbol to the datablock in the specified context.
     * rEscape returns as false if the symbol was written successfully.
     * rEscape will return true when writing in dynamically compressed
     * contexts when the symbol to write has not appeared yet in the
     * context's histogram. In this case, the escape symbol, 0, is
     * written.
     */
    void writeSymbol( uint32_t aContext, uint32_t aSymbol, bool& rEscape );

    void swapBits8( uint32_t& rValue );
 
    void writeBit( uint32_t aBit );

    void incrementPosition();

    void checkPosition();
 
 
    std::unique_ptr<CONTEXT_MANAGER> m_contextManager;

    uint32_t              m_high;
    uint32_t              m_low;

    uint32_t              m_underflow;
    bool                  m_compressed;
 
    std::vector<uint32_t> m_data;
    int32_t               m_dataPosition;

    uint32_t              m_dataLocal;

    uint32_t              m_dataLocalNext;

    int32_t               m_dataBitOffset;
 
    const int32_t         m_dataSizeIncrement = 0x000023F8;
};
} // namespace U3D