bool JpegDecoder::readData( Mat& img )
{
bool result = false;
int step = (int)img.step;
bool color = img.channels() > 1;
if( m_state && m_width && m_height )
{
jpeg_decompress_struct* cinfo = &((JpegState*)m_state)->cinfo;
JpegErrorMgr* jerr = &((JpegState*)m_state)->jerr;
JSAMPARRAY buffer = 0;
if( setjmp( jerr->setjmp_buffer ) == 0 )
{
/* check if this is a mjpeg image format */
if ( cinfo->ac_huff_tbl_ptrs[0] == NULL &&
cinfo->ac_huff_tbl_ptrs[1] == NULL &&
cinfo->dc_huff_tbl_ptrs[0] == NULL &&
cinfo->dc_huff_tbl_ptrs[1] == NULL )
{
/* yes, this is a mjpeg image format, so load the correct
huffman table */
my_jpeg_load_dht( cinfo,
my_jpeg_odml_dht,
cinfo->ac_huff_tbl_ptrs,
cinfo->dc_huff_tbl_ptrs );
}
if( color )
{
if( cinfo->num_components != 4 )
{
cinfo->out_color_space = JCS_RGB;
cinfo->out_color_components = 3;
}
else
{
cinfo->out_color_space = JCS_CMYK;
cinfo->out_color_components = 4;
}
}
else
{
if( cinfo->num_components != 4 )
{
cinfo->out_color_space = JCS_GRAYSCALE;
cinfo->out_color_components = 1;
}
else
{
cinfo->out_color_space = JCS_CMYK;
cinfo->out_color_components = 4;
}
}
jpeg_start_decompress( cinfo );
buffer = (*cinfo->mem->alloc_sarray)((j_common_ptr)cinfo,
JPOOL_IMAGE, m_width*4, 1 );
uchar* data = img.data;
for( ; m_height--; data += step )
{
jpeg_read_scanlines( cinfo, buffer, 1 );
if( color )
{
if( cinfo->out_color_components == 3 )
icvCvt_RGB2BGR_8u_C3R( buffer[0], 0, data, 0, cvSize(m_width,1) );
else
icvCvt_CMYK2BGR_8u_C4C3R( buffer[0], 0, data, 0, cvSize(m_width,1) );
}
else
{
if( cinfo->out_color_components == 1 )
memcpy( data, buffer[0], m_width );
else
icvCvt_CMYK2Gray_8u_C4C1R( buffer[0], 0, data, 0, cvSize(m_width,1) );
}
}
result = true;
jpeg_finish_decompress( cinfo );
}
}
close();
return result;
}
void processimage (const void *p, int l)
{
struct jpeg_decompress_struct mycinfo;
struct my_error_mgr myjerr;
JSAMPARRAY jpegbuffer=NULL;
int row_stride;
mycinfo.err = jpeg_std_error(&myjerr.pub);
myjerr.pub.error_exit = my_error_exit;
if (setjmp(myjerr.setjmp_buffer)) {
jpeg_destroy_decompress(&mycinfo);
return ;/*exit(0);*/
}
jpeg_create_decompress(&mycinfo);
jpeg_memory_src(&mycinfo, p, l) ;
((memory_source_mgr *)mycinfo.src)->pub.next_input_byte = (JOCTET*)p;
((memory_source_mgr *)mycinfo.src)->pub.bytes_in_buffer = l;
jpeg_read_header(&mycinfo, TRUE);
mycinfo.out_color_space = JCS_RGB;
mycinfo.dct_method = JDCT_IFAST;
mycinfo.jpeg_color_space = JCS_YCbCr;
my_jpeg_load_dht( &mycinfo,
my_jpeg_odml_dht,
mycinfo.ac_huff_tbl_ptrs,
mycinfo.dc_huff_tbl_ptrs );
jpeg_start_decompress(&mycinfo);
row_stride = mycinfo.image_width * mycinfo.num_components;
if(rgb == NULL){
IMG_WIDTH=mycinfo.image_width;
IMG_HEIGHT=mycinfo.image_height;
rgb = (int *)malloc(sizeof(int) * (IMG_WIDTH*IMG_HEIGHT));
}
if(jpegbuffer==NULL){
jpegbuffer = (*mycinfo.mem->alloc_sarray)
((j_common_ptr) &mycinfo, JPOOL_IMAGE, row_stride, 1);
}
int y = 0;
int *outp=rgb;
while ( mycinfo.output_scanline < mycinfo.image_height) {
jpeg_read_scanlines(&mycinfo, jpegbuffer, 1);
int xx;
int x3;
for(xx = 0, x3 = 0; xx < IMG_WIDTH && x3 < row_stride; xx++, x3 += 3)
{
outp[y+xx] = 0xff000000 | jpegbuffer[0][x3 + 2]<<16
| jpegbuffer[0][x3 + 1]<<8 | jpegbuffer[0][x3 + 0];
}
y+=IMG_WIDTH;
}
jpeg_finish_decompress(&mycinfo);
jpeg_destroy_decompress(&mycinfo);
}
