-
-//----------------------------------------------------------------------------
-
-
-/**
- * \brief routine for JPEG decompression from a memory buffer.
- * routine for JPEG decompression from a memory buffer. This routine
- * only reads one JPEG image at a time, but returns information about
- * how many bytes have been consumed from the \c input_buffer, and
- * how many bytes have been written into the output \c image_buffer.
- *
- * @param input_buffer pointer to a memory buffer containing the jpeg
- * compressed data.
- * @param buflen length of the memory buffer.
- * @param image_buffer pointer to the location where the decompressed
- * image will be filled.
- * @param howManyRead returns how many bytes have been consumed from the
- * input_buffer.
- * @param howManyWritten returns how many bytes have been written into
- * the output image_buffer.
- * @return 1 on success, 0 on error
- */
-
-bool gdcm_read_JPEG_memory ( const JOCTET* input_buffer, const size_t buflen,
- void* image_buffer,
- size_t *howManyRead, size_t *howManyWritten)
-{
- volatile char * pimage=(volatile char *)image_buffer;
- JOCTET* input = (JOCTET*) input_buffer;
-
- /* This struct contains the JPEG decompression parameters and pointers to
- * working space (which is allocated as needed by the JPEG library).
- */
- struct jpeg_decompress_struct cinfo;
-
- /* -------------- inside, we found :
- * JDIMENSION image_width; // input image width
- * JDIMENSION image_height; // input image height
- * int input_components; // nb of color components in input image
- * J_COLOR_SPACE in_color_space; // colorspace of input image
- * double input_gamma; // image gamma of input image
- * -------------- */
-
- /* We use our private extension JPEG error handler.
- * Note that this struct must live as long as the main JPEG parameter
- * struct, to avoid dangling-pointer problems.
- */
- struct my_error_mgr jerr;
- /* More stuff */
-
- JSAMPARRAY buffer;/* Output row buffer */
-
- // rappel :
- // ------
- // typedef unsigned char JSAMPLE;
- // typedef JSAMPLE FAR *JSAMPROW;/* ptr to one image row of pixel samples. */
- // typedef JSAMPROW *JSAMPARRAY;/* ptr to some rows (a 2-D sample array) */
- // typedef JSAMPARRAY *JSAMPIMAGE;/* a 3-D sample array: top index is color */
-
- int row_stride;/* physical row width in output buffer */
-
-#ifdef GDCM_JPG_DEBUG
- printf("entree dans File::gdcm_read_JPEG_file (i.e. 8), depuis gdcmJpeg\n");
-#endif //GDCM_JPG_DEBUG
-
- /* In this example we want to open the input file before doing anything else,
- * so that the setjmp() error recovery below can assume the file is open.
- * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
- * requires it in order to read binary files.
- */
-
- /* Step 1: allocate and initialize JPEG decompression object */
-#ifdef GDCM_JPG_DEBUG
- printf("Entree Step 1\n");
-#endif //GDCM_JPG_DEBUG
-
- /* We set up the normal JPEG error routines, then override error_exit. */
-
- cinfo.err = jpeg_std_error(&jerr.pub);
- jerr.pub.error_exit = my_error_exit;
-
- /* Establish the setjmp return context for my_error_exit to use. */
- if (setjmp(jerr.setjmp_buffer))
- {
- /* If we get here, the JPEG code has signaled an error.
- * We need to clean up the JPEG object, close the input file, and return.
- */
- jpeg_destroy_decompress(&cinfo);
-
- *howManyRead += input - input_buffer;
- *howManyWritten += pimage - (char *)image_buffer;
- return 0;
- }
-
- /* Now we can initialize the JPEG decompression object. */
- jpeg_create_decompress(&cinfo);
-
- /* Step 2: specify data source (eg, a file) */
-#ifdef GDCM_JPG_DEBUG
- printf("Entree Step 2\n");
-#endif //GDCM_JPG_DEBUG
-
- jpeg_memory_src(&cinfo, input, buflen);
-
- /* Step 3: read file parameters with jpeg_read_header() */
-#ifdef GDCM_JPG_DEBUG
- printf("Entree Step 3\n");
-#endif //GDCM_JPG_DEBUG
-
- (void) jpeg_read_header(&cinfo, TRUE);
-
- /* We can ignore the return value from jpeg_read_header since
- * (a) suspension is not possible with the stdio data source, and
- * (b) we passed TRUE to reject a tables-only JPEG file as an error.
- * See libjpeg.doc for more info.
- */
-
- // prevent the library from performing any color space conversion
- if( cinfo.process == JPROC_LOSSLESS )
- {
- cinfo.jpeg_color_space = JCS_UNKNOWN;
- cinfo.out_color_space = JCS_UNKNOWN;
- }
-
-#ifdef GDCM_JPG_DEBUG
- printf("--------------Header contents :----------------\n");
- printf("image_width %d image_height %d\n",
- cinfo.image_width , cinfo.image_height);
- printf("bits of precision in image data %d \n",
- cinfo.output_components);
- printf("nb of color components returned %d \n",
- cinfo.data_precision);
-#endif //GDCM_JPG_DEBUG
-
-
- /*
- * JDIMENSION image_width; // input image width
- * JDIMENSION image_height; // input image height
- * int output_components; // # of color components returned
- * J_COLOR_SPACE in_color_space; // colorspace of input image
- * double input_gamma; // image gamma of input image
- * int data_precision; // bits of precision in image data
- */
-
- /* Step 4: set parameters for decompression */
-#ifdef GDCM_JPG_DEBUG
- printf("Entree Step 4\n");
-#endif //GDCM_JPG_DEBUG
- /* In this example, we don't need to change any of the defaults set by
- * jpeg_read_header(), so we do nothing here.
- */
-
- /* Step 5: Start decompressor */
-#ifdef GDCM_JPG_DEBUG
- printf("Entree Step 5\n");
-#endif //GDCM_JPG_DEBUG
-
- (void) jpeg_start_decompress(&cinfo);
- /* We can ignore the return value since suspension is not possible
- * with the stdio data source.
- */
-
- /* We may need to do some setup of our own at this point before reading
- * the data. After jpeg_start_decompress() we have the correct scaled
- * output image dimensions available, as well as the output colormap
- * if we asked for color quantization.
- * In this example, we need to make an output work buffer of the right size.
- */
-
- /* JSAMPLEs per row in output buffer */
- row_stride = cinfo.output_width * cinfo.output_components*2;
-
-#ifdef GDCM_JPG_DEBUG
- printf ("cinfo.output_width %d cinfo.output_components %d row_stride %d\n",
- cinfo.output_width, cinfo.output_components,row_stride);
-#endif //GDCM_JPG_DEBUG
-
- /* Make a one-row-high sample array that will go away when done with image */
- buffer = (*cinfo.mem->alloc_sarray)
- ((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);
-
-
- /* Step 6: while (scan lines remain to be read) */
-#ifdef GDCM_JPG_DEBUG
- printf("Entree Step 6\n");
-#endif //GDCM_JPG_DEBUG
- /* jpeg_read_scanlines(...); */
-
- /* Here we use the library's state variable cinfo.output_scanline as the
- * loop counter, so that we don't have to keep track ourselves.
- */
-#ifdef GDCM_JPG_DEBUG
- printf ("cinfo.output_height %d cinfo.output_width %d\n",
- cinfo.output_height,cinfo.output_width);
-#endif //GDCM_JPG_DEBUG
-
- int bufsize = cinfo.output_width * cinfo.output_components;
- size_t rowsize = bufsize * sizeof(JSAMPLE);
-
- while (cinfo.output_scanline < cinfo.output_height) {
- /* jpeg_read_scanlines expects an array of pointers to scanlines.
- * Here the array is only one element long, but you could ask for
- * more than one scanline at a time if that's more convenient.
- */
-
- //printf( "scanlines: %d\n",cinfo.output_scanline);
- (void) jpeg_read_scanlines(&cinfo, buffer, 1);
-#if defined(GDCM_WORDS_BIGENDIAN) && (CMAKE_BITS_IN_JSAMPLE != 8)
- uint16_t *buffer16 = (uint16_t*)*buffer;
- uint16_t *pimage16 = (uint16_t*)pimage;
- for(unsigned int i=0;i<rowsize/2;i++)
- pimage16[i] = (buffer16[i] >> 8) | (buffer16[i] << 8 );
-#else
- memcpy( (void*)pimage, *buffer,rowsize);
-#endif //GDCM_WORDS_BIGENDIAN
- pimage+=rowsize;
- }
-
- /* Step 7: Finish decompression */
-#ifdef GDCM_JPG_DEBUG
- printf("Entree Step 7\n");
-#endif //GDCM_JPG_DEBUG
-
- input = (JOCTET *)cinfo.src->next_input_byte;
-
- (void) jpeg_finish_decompress(&cinfo);
-
- /* We can ignore the return value since suspension is not possible
- * with the stdio data source.
- */
-
- /* Step 8: Release JPEG decompression object */
-
-#ifdef GDCM_JPG_DEBUG
- printf("Entree Step 8\n");
-#endif //GDCM_JPG_DEBUG
-
- /* This is an important step since it will release a good deal of memory. */
-
- jpeg_destroy_decompress(&cinfo);
-
-
- /* After finish_decompress, we can close the input file.
- * Here we postpone it until after no more JPEG errors are possible,
- * so as to simplify the setjmp error logic above. (Actually, I don't
- * think that jpeg_destroy can do an error exit, but why assume anything...)
- */
-
- /* At this point you may want to check to see whether any corrupt-data
- * warnings occurred (test whether jerr.pub.num_warnings is nonzero).
- */
-
- /* And we're done! */
- *howManyRead += input - input_buffer;
- *howManyWritten += pimage - (char *)image_buffer;
-
- return true;
-}