/*M///////////////////////////////////////////////////////////////////////////////////////
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//                           License Agreement
//                For Open Source Computer Vision Library
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//M*/

#include "precomp.hpp"
#include "grfmt_bmp.hpp"

namespace cv
{

static const char* fmtSignBmp = "BM";

/************************ BMP decoder *****************************/

BmpDecoder::BmpDecoder()
{
    m_signature = fmtSignBmp;
    m_offset = -1;
    m_buf_supported = true;
}


BmpDecoder::~BmpDecoder()
{
}


void  BmpDecoder::close()
{
    m_strm.close();
}

ImageDecoder BmpDecoder::newDecoder() const
{
    return new BmpDecoder;
}

bool  BmpDecoder::readHeader()
{
    bool result = false;
    bool iscolor = false;

    if( !m_buf.empty() )
    {
        if( !m_strm.open( m_buf ) )
            return false;
    }
    else if( !m_strm.open( m_filename ))
        return false;

    try
    {
        m_strm.skip( 10 );
        m_offset = m_strm.getDWord();

        int  size = m_strm.getDWord();

        if( size >= 36 )
        {
            m_width  = m_strm.getDWord();
            m_height = m_strm.getDWord();
            m_bpp    = m_strm.getDWord() >> 16;
            m_rle_code = (BmpCompression)m_strm.getDWord();
            m_strm.skip(12);
            int clrused = m_strm.getDWord();
            m_strm.skip( size - 36 );

            if( m_width > 0 && m_height != 0 &&
             (((m_bpp == 1 || m_bpp == 4 || m_bpp == 8 ||
                m_bpp == 24 || m_bpp == 32 ) && m_rle_code == BMP_RGB) ||
               (m_bpp == 16 && (m_rle_code == BMP_RGB || m_rle_code == BMP_BITFIELDS)) ||
               (m_bpp == 4 && m_rle_code == BMP_RLE4) ||
               (m_bpp == 8 && m_rle_code == BMP_RLE8)))
            {
                iscolor = true;
                result = true;

                if( m_bpp <= 8 )
                {
                    memset( m_palette, 0, sizeof(m_palette));
                    m_strm.getBytes( m_palette, (clrused == 0? 1<<m_bpp : clrused)*4 );
                    iscolor = IsColorPalette( m_palette, m_bpp );
                }
                else if( m_bpp == 16 && m_rle_code == BMP_BITFIELDS )
                {
                    int redmask = m_strm.getDWord();
                    int greenmask = m_strm.getDWord();
                    int bluemask = m_strm.getDWord();

                    if( bluemask == 0x1f && greenmask == 0x3e0 && redmask == 0x7c00 )
                        m_bpp = 15;
                    else if( bluemask == 0x1f && greenmask == 0x7e0 && redmask == 0xf800 )
                        ;
                    else
                        result = false;
                }
                else if( m_bpp == 16 && m_rle_code == BMP_RGB )
                    m_bpp = 15;
            }
        }
        else if( size == 12 )
        {
            m_width  = m_strm.getWord();
            m_height = m_strm.getWord();
            m_bpp    = m_strm.getDWord() >> 16;
            m_rle_code = BMP_RGB;

            if( m_width > 0 && m_height != 0 &&
               (m_bpp == 1 || m_bpp == 4 || m_bpp == 8 ||
                m_bpp == 24 || m_bpp == 32 ))
            {
                if( m_bpp <= 8 )
                {
                    uchar buffer[256*3];
                    int j, clrused = 1 << m_bpp;
                    m_strm.getBytes( buffer, clrused*3 );
                    for( j = 0; j < clrused; j++ )
                    {
                        m_palette[j].b = buffer[3*j+0];
                        m_palette[j].g = buffer[3*j+1];
                        m_palette[j].r = buffer[3*j+2];
                    }
                }
                result = true;
            }
        }
    }
    catch(...)
    {
    }

    m_type = iscolor ? CV_8UC3 : CV_8UC1;
    m_origin = m_height > 0 ? IPL_ORIGIN_BL : IPL_ORIGIN_TL;
    m_height = std::abs(m_height);
    
    if( !result )
    {
        m_offset = -1;
        m_width = m_height = -1;
        m_strm.close();
    }
    return result;
}


bool  BmpDecoder::readData( Mat& img )
{
    uchar* data = img.data;
    int step = (int)img.step;
    bool color = img.channels() > 1;
    uchar  gray_palette[256];
    bool   result = false;
    int  src_pitch = ((m_width*(m_bpp != 15 ? m_bpp : 16) + 7)/8 + 3) & -4;
    int  nch = color ? 3 : 1;
    int  y, width3 = m_width*nch;

    if( m_offset < 0 || !m_strm.isOpened())
        return false;

    if( m_origin == IPL_ORIGIN_BL )
    {
        data += (m_height - 1)*step;
        step = -step;
    }

    AutoBuffer<uchar> _src, _bgr;
    _src.allocate(src_pitch + 32);

    if( !color )
    {
        if( m_bpp <= 8 )
        {
            CvtPaletteToGray( m_palette, gray_palette, 1 << m_bpp );
        }
        _bgr.allocate(m_width*3 + 32);
    }
    uchar *src = _src, *bgr = _bgr;

    try
    {
        m_strm.setPos( m_offset );

        switch( m_bpp )
        {
        /************************* 1 BPP ************************/
        case 1:
            for( y = 0; y < m_height; y++, data += step )
            {
                m_strm.getBytes( src, src_pitch );
                FillColorRow1( color ? data : bgr, src, m_width, m_palette );
                if( !color )
                    icvCvt_BGR2Gray_8u_C3C1R( bgr, 0, data, 0, cvSize(m_width,1) );
            }
            result = true;
            break;

        /************************* 4 BPP ************************/
        case 4:
            if( m_rle_code == BMP_RGB )
            {
                for( y = 0; y < m_height; y++, data += step )
                {
                    m_strm.getBytes( src, src_pitch );
                    if( color )
                        FillColorRow4( data, src, m_width, m_palette );
                    else
                        FillGrayRow4( data, src, m_width, gray_palette );
                }
                result = true;
            }
            else if( m_rle_code == BMP_RLE4 ) // rle4 compression
            {
                uchar* line_end = data + width3;
                y = 0;

                for(;;)
                {
                    int code = m_strm.getWord();
                    int len = code & 255;
                    code >>= 8;
                    if( len != 0 ) // encoded mode
                    {
                        PaletteEntry clr[2];
                        uchar gray_clr[2];
                        int t = 0;

                        clr[0] = m_palette[code >> 4];
                        clr[1] = m_palette[code & 15];
                        gray_clr[0] = gray_palette[code >> 4];
                        gray_clr[1] = gray_palette[code & 15];

                        uchar* end = data + len*nch;
                        if( end > line_end ) goto decode_rle4_bad;
                        do
                        {
                            if( color )
                                WRITE_PIX( data, clr[t] );
                            else
                                *data = gray_clr[t];
                            t ^= 1;
                        }
                        while( (data += nch) < end );
                    }
                    else if( code > 2 ) // absolute mode
                    {
                        if( data + code*nch > line_end ) goto decode_rle4_bad;
                        m_strm.getBytes( src, (((code + 1)>>1) + 1) & -2 );
                        if( color )
                            data = FillColorRow4( data, src, code, m_palette );
                        else
                            data = FillGrayRow4( data, src, code, gray_palette );
                    }
                    else
                    {
                        int x_shift3 = (int)(line_end - data);
                        int y_shift = m_height - y;

                        if( code == 2 )
                        {
                            x_shift3 = m_strm.getByte()*nch;
                            y_shift = m_strm.getByte();
                        }

                        len = x_shift3 + ((y_shift * width3) & ((code == 0) - 1));

                        if( color )
                            data = FillUniColor( data, line_end, step, width3,
                                                 y, m_height, x_shift3,
                                                 m_palette[0] );
                        else
                            data = FillUniGray( data, line_end, step, width3,
                                                y, m_height, x_shift3,
                                                gray_palette[0] );

                        if( y >= m_height )
                            break;
                    }
                }

                result = true;
decode_rle4_bad: ;
            }
            break;

        /************************* 8 BPP ************************/
        case 8:
            if( m_rle_code == BMP_RGB )
            {
                for( y = 0; y < m_height; y++, data += step )
                {
                    m_strm.getBytes( src, src_pitch );
                    if( color )
                        FillColorRow8( data, src, m_width, m_palette );
                    else
                        FillGrayRow8( data, src, m_width, gray_palette );
                }
                result = true;
            }
            else if( m_rle_code == BMP_RLE8 ) // rle8 compression
            {
                uchar* line_end = data + width3;
                int line_end_flag = 0;
                y = 0;

                for(;;)
                {
                    int code = m_strm.getWord();
                    int len = code & 255;
                    code >>= 8;
                    if( len != 0 ) // encoded mode
                    {
                        int prev_y = y;
                        len *= nch;

                        if( data + len > line_end )
                            goto decode_rle8_bad;

                        if( color )
                            data = FillUniColor( data, line_end, step, width3,
                                                 y, m_height, len,
                                                 m_palette[code] );
                        else
                            data = FillUniGray( data, line_end, step, width3,
                                                y, m_height, len,
                                                gray_palette[code] );

                        line_end_flag = y - prev_y;
                    }
                    else if( code > 2 ) // absolute mode
                    {
                        int prev_y = y;
                        int code3 = code*nch;

                        if( data + code3 > line_end )
                            goto decode_rle8_bad;
                        m_strm.getBytes( src, (code + 1) & -2 );
                        if( color )
                            data = FillColorRow8( data, src, code, m_palette );
                        else
                            data = FillGrayRow8( data, src, code, gray_palette );

                        line_end_flag = y - prev_y;
                    }
                    else
                    {
                        int x_shift3 = (int)(line_end - data);
                        int y_shift = m_height - y;

                        if( code || !line_end_flag || x_shift3 < width3 )
                        {
                            if( code == 2 )
                            {
                                x_shift3 = m_strm.getByte()*nch;
                                y_shift = m_strm.getByte();
                            }

                            x_shift3 += (y_shift * width3) & ((code == 0) - 1);

                            if( y >= m_height )
                                break;

                            if( color )
                                data = FillUniColor( data, line_end, step, width3,
                                                     y, m_height, x_shift3,
                                                     m_palette[0] );
                            else
                                data = FillUniGray( data, line_end, step, width3,
                                                    y, m_height, x_shift3,
                                                    gray_palette[0] );

                            if( y >= m_height )
                                break;
                        }

                        line_end_flag = 0;
                    }
                }

                result = true;
decode_rle8_bad: ;
            }
            break;
        /************************* 15 BPP ************************/
        case 15:
            for( y = 0; y < m_height; y++, data += step )
            {
                m_strm.getBytes( src, src_pitch );
                if( !color )
                    icvCvt_BGR5552Gray_8u_C2C1R( src, 0, data, 0, cvSize(m_width,1) );
                else
                    icvCvt_BGR5552BGR_8u_C2C3R( src, 0, data, 0, cvSize(m_width,1) );
            }
            result = true;
            break;
        /************************* 16 BPP ************************/
        case 16:
            for( y = 0; y < m_height; y++, data += step )
            {
                m_strm.getBytes( src, src_pitch );
                if( !color )
                    icvCvt_BGR5652Gray_8u_C2C1R( src, 0, data, 0, cvSize(m_width,1) );
                else
                    icvCvt_BGR5652BGR_8u_C2C3R( src, 0, data, 0, cvSize(m_width,1) );
            }
            result = true;
            break;
        /************************* 24 BPP ************************/
        case 24:
            for( y = 0; y < m_height; y++, data += step )
            {
                m_strm.getBytes( src, src_pitch );
                if(!color)
                    icvCvt_BGR2Gray_8u_C3C1R( src, 0, data, 0, cvSize(m_width,1) );
                else
                    memcpy( data, src, m_width*3 );
            }
            result = true;
            break;
        /************************* 32 BPP ************************/
        case 32:
            for( y = 0; y < m_height; y++, data += step )
            {
                m_strm.getBytes( src, src_pitch );

                if( !color )
                    icvCvt_BGRA2Gray_8u_C4C1R( src, 0, data, 0, cvSize(m_width,1) );
                else
                    icvCvt_BGRA2BGR_8u_C4C3R( src, 0, data, 0, cvSize(m_width,1) );
            }
            result = true;
            break;
        default:
            assert(0);
        }
    }
    catch(...)
    {
    }

    return result;
}


//////////////////////////////////////////////////////////////////////////////////////////

BmpEncoder::BmpEncoder()
{
    m_description = "Windows bitmap (*.bmp;*.dib)";
    m_buf_supported = true;
}


BmpEncoder::~BmpEncoder()
{
}

ImageEncoder BmpEncoder::newEncoder() const
{
    return new BmpEncoder;
}

bool  BmpEncoder::write( const Mat& img, const vector<int>& )
{
    int width = img.cols, height = img.rows, channels = img.channels();
    int fileStep = (width*channels + 3) & -4;
    uchar zeropad[] = "\0\0\0\0";
    WLByteStream strm;

    if( m_buf )
    {
        if( !strm.open( *m_buf ) )
            return false;
    }
    else if( !strm.open( m_filename ))
        return false;

    int  bitmapHeaderSize = 40;
    int  paletteSize = channels > 1 ? 0 : 1024;
    int  headerSize = 14 /* fileheader */ + bitmapHeaderSize + paletteSize;
    int  fileSize = fileStep*height + headerSize;
    PaletteEntry palette[256];

    if( m_buf )
        m_buf->reserve( alignSize(fileSize + 16, 256) );

    // write signature 'BM'
    strm.putBytes( fmtSignBmp, (int)strlen(fmtSignBmp) );

    // write file header
    strm.putDWord( fileSize ); // file size
    strm.putDWord( 0 );
    strm.putDWord( headerSize );

    // write bitmap header
    strm.putDWord( bitmapHeaderSize );
    strm.putDWord( width );
    strm.putDWord( height );
    strm.putWord( 1 );
    strm.putWord( channels << 3 );
    strm.putDWord( BMP_RGB );
    strm.putDWord( 0 );
    strm.putDWord( 0 );
    strm.putDWord( 0 );
    strm.putDWord( 0 );
    strm.putDWord( 0 );

    if( channels == 1 )
    {
        FillGrayPalette( palette, 8 );
        strm.putBytes( palette, sizeof(palette));
    }

    width *= channels;
    for( int y = height - 1; y >= 0; y-- )
    {
        strm.putBytes( img.data + img.step*y, width );
        if( fileStep > width )
            strm.putBytes( zeropad, fileStep - width );
    }

    strm.close();
    return true;
}

}