text: /*
   * File:	ximajpg.cpp
   * Purpose:	Platform Independent JPEG Image Class Loader and Writer
   * 07/Aug/2001 Davide Pizzolato - www.xdp.it
   * CxImage version 5.99a 08/Feb/2004
   */
   
  #include "ximajpg.h"
  
  #if CXIMAGE_SUPPORT_JPG
  
  #include "ximaiter.h"
           
  #include <setjmp.h>
  
  struct ima_error_mgr {
  	struct jpeg_error_mgr pub;	/* "public" fields */
  	jmp_buf setjmp_buffer;		/* for return to caller */
  	char* buffer;				/* error message <CSC>*/
  };
  typedef ima_error_mgr *ima_error_ptr;
  
  ////////////////////////////////////////////////////////////////////////////////
  // Here's the routine that will replace the standard error_exit method:
  ////////////////////////////////////////////////////////////////////////////////
  static void
  ima_jpeg_error_exit (j_common_ptr cinfo)
  {
  	/* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
  	ima_error_ptr myerr = (ima_error_ptr) cinfo->err;
  	/* Create the message */
  	myerr->pub.format_message (cinfo, myerr->buffer);
  	/* Send it to stderr, adding a newline */
  	/* Return control to the setjmp point */
  	longjmp(myerr->setjmp_buffer, 1);
  }
  ////////////////////////////////////////////////////////////////////////////////
  CxImageJPG::CxImageJPG(): CxImage(CXIMAGE_FORMAT_JPG)
  {
  #if CXIMAGEJPG_SUPPORT_EXIF
  	memset(&m_exifinfo, 0, sizeof(EXIFINFO));
  #endif
  }
  ////////////////////////////////////////////////////////////////////////////////
  #if CXIMAGEJPG_SUPPORT_EXIF
  bool CxImageJPG::DecodeExif(CxFile * hFile)
  {
  	long pos=hFile->Tell();
  	CxExifInfo exif(&m_exifinfo);
  	exif.DecodeExif(hFile);
  	hFile->Seek(pos,SEEK_SET);
  	return exif.m_exifinfo->IsExif;
  }
  #endif //CXIMAGEJPG_SUPPORT_EXIF
  ////////////////////////////////////////////////////////////////////////////////
  bool CxImageJPG::Decode(CxFile * hFile)
  {
  
  	bool is_exif = false;
  #if CXIMAGEJPG_SUPPORT_EXIF
  	is_exif = DecodeExif(hFile);
  #endif
  
  	CImageIterator iter(this);
  	/* 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;
  	/* We use our private extension JPEG error handler. <CSC> */
  	struct ima_error_mgr jerr;
  	jerr.buffer=info.szLastError;
  	/* More stuff */
  	JSAMPARRAY buffer;	/* Output row buffer */
  	int row_stride;		/* physical row width in output buffer */
  
  	/* 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 */
  	/* We set up the normal JPEG error routines, then override error_exit. */
  	cinfo.err = jpeg_std_error(&jerr.pub);
  	jerr.pub.error_exit = ima_jpeg_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);
  		return 0;
  	}
  	/* Now we can initialize the JPEG decompression object. */
  	jpeg_create_decompress(&cinfo);
  
  	/* Step 2: specify data source (eg, a file) */
  	//jpeg_stdio_src(&cinfo, infile);
  	CxFileJpg src(hFile);
      cinfo.src = &src;
  
  	/* Step 3: read file parameters with jpeg_read_header() */
  	(void) jpeg_read_header(&cinfo, TRUE);
  
  	/* Step 4 <chupeev> handle decoder options*/
  	if ((GetCodecOption() & DECODE_GRAYSCALE) != 0)
  		cinfo.out_color_space = JCS_GRAYSCALE;
  	if ((GetCodecOption() & DECODE_QUANTIZE) != 0) {
  		cinfo.quantize_colors = TRUE;
  		cinfo.desired_number_of_colors = info.nQuality;
  	}
  	if ((GetCodecOption() & DECODE_DITHER) != 0)
  		cinfo.dither_mode = m_nDither;
  	if ((GetCodecOption() & DECODE_ONEPASS) != 0)
  		cinfo.two_pass_quantize = FALSE;
  	if ((GetCodecOption() & DECODE_NOSMOOTH) != 0)
  		cinfo.do_fancy_upsampling = FALSE;
  
  //<DP>: Load true color images as RGB (no quantize) 
  /* Step 4: set parameters for decompression */
  /*  if (cinfo.jpeg_color_space!=JCS_GRAYSCALE) {
   *	cinfo.quantize_colors = TRUE;
   *	cinfo.desired_number_of_colors = 128;
   *}
   */ //</DP>
  
  	// Set the scale <ignacio>
  	cinfo.scale_denom = info.nScale;
  
  	// Borrowed the idea from GIF implementation <ignacio>
  	if (info.nEscape == -1) {
  		// Return output dimensions only
  		jpeg_calc_output_dimensions(&cinfo);
  		head.biWidth = cinfo.output_width;
  		head.biHeight = cinfo.output_height;
  		jpeg_destroy_decompress(&cinfo);
  		return true;
  	}
  
  	/* Step 5: Start decompressor */
  	jpeg_start_decompress(&cinfo);
  
  	/* 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.
  	*/
  	//Create the image using output dimensions <ignacio>
  	//Create(cinfo.image_width, cinfo.image_height, 8*cinfo.output_components, CXIMAGE_FORMAT_JPG);
  	Create(cinfo.output_width, cinfo.output_height, 8*cinfo.output_components, CXIMAGE_FORMAT_JPG);
  
  	if (!pDib) longjmp(jerr.setjmp_buffer, 1);  //<DP> check if the image has been created
  
  	if (is_exif){
  #if CXIMAGEJPG_SUPPORT_EXIF
  	if ((m_exifinfo.Xresolution != 0.0) && (m_exifinfo.ResolutionUnit != 0))
  		SetXDPI((long)(m_exifinfo.Xresolution/m_exifinfo.ResolutionUnit));
  	if ((m_exifinfo.Yresolution != 0.0) && (m_exifinfo.ResolutionUnit != 0))
  		SetYDPI((long)(m_exifinfo.Yresolution/m_exifinfo.ResolutionUnit));
  #endif
  	} else {
  		if (cinfo.density_unit==2){
  			SetXDPI((long)floor(cinfo.X_density * 254.0 / 10000.0 + 0.5));
  			SetYDPI((long)floor(cinfo.Y_density * 254.0 / 10000.0 + 0.5));
  		} else {
  			SetXDPI(cinfo.X_density);
  			SetYDPI(cinfo.Y_density);
  		}
  	}
  
  	if (cinfo.out_color_space==JCS_GRAYSCALE){
  		SetGrayPalette();
  		head.biClrUsed =256;
  	} else {
  		if (cinfo.quantize_colors==TRUE){
  			SetPalette(cinfo.actual_number_of_colors, cinfo.colormap[0], cinfo.colormap[1], cinfo.colormap[2]);
  			head.biClrUsed=cinfo.actual_number_of_colors;
  		} else {
  			head.biClrUsed=0;
  		}
  	}
  
  	/* JSAMPLEs per row in output buffer */
  	row_stride = cinfo.output_width * cinfo.output_components;
  
  	/* 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) */
  	/*           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.
  	*/
  	iter.Upset();
  	while (cinfo.output_scanline < cinfo.output_height) {
  
  		if (info.nEscape) longjmp(jerr.setjmp_buffer, 1); // <vho> - cancel decoding
  		
  		(void) jpeg_read_scanlines(&cinfo, buffer, 1);
  		// info.nProgress = (long)(100*cinfo.output_scanline/cinfo.output_height);
  		//<DP> Step 6a: CMYK->RGB */ 
  		if ((cinfo.num_components==4)&&(cinfo.quantize_colors==FALSE)){
  			BYTE k,*dst,*src;
  			dst=iter.GetRow();
  			src=buffer[0];
  			for(long x3=0,x4=0; x3<(long)info.dwEffWidth && x4<row_stride; x3+=3, x4+=4){
  				k=src[x4+3];
  				dst[x3]  =(BYTE)((k * src[x4+2])/255);
  				dst[x3+1]=(BYTE)((k * src[x4+1])/255);
  				dst[x3+2]=(BYTE)((k * src[x4+0])/255);
  			}
  		} else {
  			/* Assume put_scanline_someplace wants a pointer and sample count. */
  			iter.SetRow(buffer[0], row_stride);
  		}
  			iter.PrevRow();
  	}
  
  	/* Step 7: Finish decompression */
  	(void) jpeg_finish_decompress(&cinfo);
  	/* We can ignore the return value since suspension is not possible
  	* with the stdio data source.
  	*/
  
  	//<DP> Step 7A: Swap red and blue components
  	// not necessary if swapped red and blue definition in jmorecfg.h;ln322 <W. Morrison>
  	if ((cinfo.num_components==3)&&(cinfo.quantize_colors==FALSE)){
  		BYTE* r0=GetBits();
  		for(long y=0;y<head.biHeight;y++){
  			if (info.nEscape) longjmp(jerr.setjmp_buffer, 1); // <vho> - cancel decoding
  			RGBtoBGR(r0,3*head.biWidth);
  			r0+=info.dwEffWidth;
  		}
  	}
  
  	/* Step 8: Release JPEG decompression object */
  	/* This is an important step since it will release a good deal of memory. */
  	jpeg_destroy_decompress(&cinfo);
  
  	/* 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! */
  	return true;
  }
  ////////////////////////////////////////////////////////////////////////////////
  #if CXIMAGE_SUPPORT_ENCODE
  ////////////////////////////////////////////////////////////////////////////////
  bool CxImageJPG::Encode(CxFile * hFile)
  {
  	if (EncodeSafeCheck(hFile)) return false;
  
  	if (head.biClrUsed!=0 && !IsGrayScale()){
  		strcpy(info.szLastError,"JPEG can save only RGB or GreyScale images");
  		return false;
  	}	
  
  	/* This struct contains the JPEG compression parameters and pointers to
  	* working space (which is allocated as needed by the JPEG library).
  	* It is possible to have several such structures, representing multiple
  	* compression/decompression processes, in existence at once.  We refer
  	* to any one struct (and its associated working data) as a "JPEG object".
  	*/
  	struct jpeg_compress_struct cinfo;
  	/* This struct represents a JPEG error handler.  It is declared separately
  	* because applications often want to supply a specialized error handler
  	* (see the second half of this file for an example).  But here we just
  	* take the easy way out and use the standard error handler, which will
  	* print a message on stderr and call exit() if compression fails.
  	* Note that this struct must live as long as the main JPEG parameter
  	* struct, to avoid dangling-pointer problems.
  	*/
  	//struct jpeg_error_mgr jerr;
  	/* We use our private extension JPEG error handler. <CSC> */
  	struct ima_error_mgr jerr;
  	jerr.buffer=info.szLastError;
  	/* More stuff */
  	int row_stride;		/* physical row width in image buffer */
  	JSAMPARRAY buffer;		/* Output row buffer */
  
  	/* Step 1: allocate and initialize JPEG compression object */
  	/* We have to set up the error handler first, in case the initialization
  	* step fails.  (Unlikely, but it could happen if you are out of memory.)
  	* This routine fills in the contents of struct jerr, and returns jerr's
  	* address which we place into the link field in cinfo.
  	*/
  	//cinfo.err = jpeg_std_error(&jerr); <CSC>
  	/* We set up the normal JPEG error routines, then override error_exit. */
  	cinfo.err = jpeg_std_error(&jerr.pub);
  	jerr.pub.error_exit = ima_jpeg_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.
  		*/
  		strcpy(info.szLastError, jerr.buffer); //<CSC>
  		jpeg_destroy_compress(&cinfo);
  		return 0;
  	}
  	
  	/* Now we can initialize the JPEG compression object. */
  	jpeg_create_compress(&cinfo);
  	/* Step 2: specify data destination (eg, a file) */
  	/* Note: steps 2 and 3 can be done in either order. */
  	/* Here we use the library-supplied code to send compressed data to a
  	* stdio stream.  You can also write your own code to do something else.
  	* VERY IMPORTANT: use "b" option to fopen() if you are on a machine that
  	* requires it in order to write binary files.
  	*/
  
  	//jpeg_stdio_dest(&cinfo, outfile);
  	CxFileJpg dest(hFile);
      cinfo.dest = &dest;
  
  	/* Step 3: set parameters for compression */
  	/* First we supply a description of the input image.
  	* Four fields of the cinfo struct must be filled in:
  	*/
  	cinfo.image_width = GetWidth(); 	// image width and height, in pixels
  	cinfo.image_height = GetHeight();
  
  	if (IsGrayScale()){
  		cinfo.input_components = 1;			// # of color components per pixel
  		cinfo.in_color_space = JCS_GRAYSCALE; /* colorspace of input image */
  	} else {
  		cinfo.input_components = 3; 	// # of color components per pixel
  		cinfo.in_color_space = JCS_RGB; /* colorspace of input image */
  	}
  
  	/* Now use the library's routine to set default compression parameters.
  	* (You must set at least cinfo.in_color_space before calling this,
  	* since the defaults depend on the source color space.)
  	*/
  	jpeg_set_defaults(&cinfo);
  	/* Now you can set any non-default parameters you wish to.
  	* Here we just illustrate the use of quality (quantization table) scaling:
  	*/
  	//jpeg_set_quality(&cinfo, info.nQuality, TRUE /* limit to baseline-JPEG values */);
  #ifdef C_ARITH_CODING_SUPPORTED
  	if ((GetCodecOption() & ENCODE_ARITHMETIC) != 0)
  		cinfo.arith_code = TRUE;
  #endif
  #ifdef ENTRPY_OPT_SUPPORTED
  	if ((GetCodecOption() & ENCODE_OPTIMIZE) != 0)
  		cinfo.optimize_coding = TRUE;
  #endif
  	if ((GetCodecOption() & ENCODE_GRAYSCALE) != 0)
  		jpeg_set_colorspace(&cinfo, JCS_GRAYSCALE);
  	if ((GetCodecOption() & ENCODE_SMOOTHING) != 0)
  		cinfo.smoothing_factor = m_nSmoothing;
  	jpeg_set_quality(&cinfo, GetJpegQuality(), (GetCodecOption() & ENCODE_BASELINE) != 0);
  #ifdef C_PROGRESSIVE_SUPPORTED
  	if ((GetCodecOption() & ENCODE_PROGRESSIVE) != 0)
  		jpeg_simple_progression(&cinfo);
  #endif
  #ifdef C_LOSSLES_SUPPORTED
  	if ((GetCodecOption() & ENCODE_LOSSLESS) != 0)
  		jpeg_simple_lossless(&cinfo, m_nPredictor, m_nPointTransform);
  #endif
  
  	cinfo.density_unit=1;
  	cinfo.X_density=(unsigned short)GetXDPI();
  	cinfo.Y_density=(unsigned short)GetYDPI();
  
  	/* Step 4: Start compressor */
  	/* TRUE ensures that we will write a complete interchange-JPEG file.
  	* Pass TRUE unless you are very sure of what you're doing.
  	*/
  	jpeg_start_compress(&cinfo, TRUE);
  
  	/* Step 5: while (scan lines remain to be written) */
  	/*           jpeg_write_scanlines(...); */
  	/* Here we use the library's state variable cinfo.next_scanline as the
  	* loop counter, so that we don't have to keep track ourselves.
  	* To keep things simple, we pass one scanline per call; you can pass
  	* more if you wish, though.
  	*/
  	row_stride = info.dwEffWidth;	/* JSAMPLEs per row in image_buffer */
  
  	//<DP> "8+row_stride" fix heap deallocation problem during debug???
  	buffer = (*cinfo.mem->alloc_sarray)
  		((j_common_ptr) &cinfo, JPOOL_IMAGE, 8+row_stride, 1);
  
  	CImageIterator iter(this);
  
  	iter.Upset();
  	while (cinfo.next_scanline < cinfo.image_height) {
  		// info.nProgress = (long)(100*cinfo.next_scanline/cinfo.image_height);
  		iter.GetRow(buffer[0], row_stride);
  		// not necessary if swapped red and blue definition in jmorecfg.h;ln322 <W. Morrison>
  		if (head.biClrUsed==0){				 // swap R & B for RGB images
  			RGBtoBGR(buffer[0], row_stride); // Lance : 1998/09/01 : Bug ID: EXP-2.1.1-9
  		}
  		iter.PrevRow();
  		(void) jpeg_write_scanlines(&cinfo, buffer, 1);
  	}
  
  	/* Step 6: Finish compression */
  	jpeg_finish_compress(&cinfo);
  
  	/* Step 7: release JPEG compression object */
  	/* This is an important step since it will release a good deal of memory. */
  	jpeg_destroy_compress(&cinfo);
  
  	/* And we're done! */
  	return true;
  }
  ////////////////////////////////////////////////////////////////////////////////
  #endif // CXIMAGE_SUPPORT_ENCODE
  ////////////////////////////////////////////////////////////////////////////////
  #endif // CXIMAGE_SUPPORT_JPG
  
  