jpeg_toolbox (1).zip_jpeg_jpeg toolbox_jpeg_toolbox

/* * jpeg_read.c * * JPEGOBJ = JPEG_READ(FILENAME) * * Returns JPEGOBJ, a Matlab struct containing the JPEG header information, * quantization tables, and the DCT coefficients. * * This software is based in part on the work of the Independent JPEG Group. * In order to compile, you must first build IJG's JPEG Tools code library, * available at ftp://ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz. * * Phil Sallee 6/2003 * * Copyright (c) 2003 The Regents of the University of California. * All Rights Reserved. * * Permission to use, copy, modify, and distribute this software and its * documentation for educational, research and non-profit purposes, * without fee, and without a written agreement is hereby granted, * provided that the above copyright notice, this paragraph and the * following three paragraphs appear in all copies. * * Permission to incorporate this software into commercial products may * be obtained by contacting the University of California. Contact Jo Clare * Peterman, University of California, 428 Mrak Hall, Davis, CA, 95616. * * This software program and documentation are copyrighted by The Regents * of the University of California. The software program and * documentation are supplied "as is", without any accompanying services * from The Regents. The Regents does not warrant that the operation of * the program will be uninterrupted or error-free. The end-user * understands that the program was developed for research purposes and * is advised not to rely exclusively on the program for any reason. * * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY * FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, * INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND * ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. THE UNIVERSITY OF * CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" * BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATIONS TO PROVIDE * MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. * */ #include <stdio.h> #include <stdlib.h> #include <jerror.h> #include <jpeglib.h> #include <setjmp.h> #include "mex.h" /* We need to create our own error handler so that we can override the * default handler in case a fatal error occurs. The standard error_exit * method calls exit() which doesn't clean things up properly and also * exits Matlab. This is described in the example.c routine provided in * the IJG's code library. */ struct my_error_mgr { struct jpeg_error_mgr pub; /* "public" fields */ jmp_buf setjmp_buffer; /* for return to caller */ }; /* The default output_message routine causes a seg fault in Matlab, * at least on Windows. Its generally used to emit warnings, since * fatal errors call the error_exit routine, so we emit a Matlab * warning instead. If desired, warnings can be turned off by the * user with "warnings off". -- PAS 10/03 */ METHODDEF(void) my_output_message (j_common_ptr cinfo) { char buffer[JMSG_LENGTH_MAX]; /* Create the message */ (*cinfo->err->format_message) (cinfo, buffer); mexWarnMsgTxt(buffer); } typedef struct my_error_mgr * my_error_ptr; METHODDEF(void) my_error_exit (j_common_ptr cinfo) { char buffer[JMSG_LENGTH_MAX]; /* cinfo->err really points to a my_error_mgr struct, so coerce pointer */ my_error_ptr myerr = (my_error_ptr) cinfo->err; /* create the message */ (*cinfo->err->format_message) (cinfo, buffer); printf("Error: %s\n",buffer); /* return control to the setjmp point */ longjmp(myerr->setjmp_buffer, 1); } /* Substitute for mxCreateDoubleScalar, which is not available * on earlier versions of Matlab */ mxArray *mxCDS(double val) { mxArray *mxtemp; double *p; mxtemp = mxCreateDoubleMatrix(1, 1, mxREAL); p = mxGetPr(mxtemp); *p = val; return mxtemp; } /* mex function */ void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]) { struct jpeg_decompress_struct cinfo; struct my_error_mgr jerr; jpeg_component_info *compptr; jvirt_barray_ptr *coef_arrays; jpeg_saved_marker_ptr marker_ptr; FILE *infile; JDIMENSION blk_x,blk_y; JBLOCKARRAY buffer; JCOEFPTR bufptr; JQUANT_TBL *quant_ptr; JHUFF_TBL *huff_ptr; int strlen, c_width, c_height, ci, i, j, n, dims[2]; char *filename; double *mp, *mptop; mxChar *mcp; mxArray *mxtemp, *mxjpeg_obj, *mxcoef_arrays, *mxcomments; mxArray *mxquant_tables, *mxhuff_tables, *mxcomp_info; /* field names jpeg_obj Matlab struct */ const char *jobj_field_names[] = { "image_width", /* image width in pixels */ "image_height", /* image height in pixels */ "image_components", /* number of image color components */ "image_color_space", /* in/out_color_space */ "jpeg_components", /* number of JPEG color components */ "jpeg_color_space", /* color space of DCT coefficients */ "comments", /* COM markers, if any */ "coef_arrays", /* DCT arrays for each component */ "quant_tables", /* quantization tables */ "ac_huff_tables", /* AC huffman encoding tables */ "dc_huff_tables", /* DC huffman encoding tables */ "optimize_coding", /* flag to optimize huffman tables */ "comp_info", /* component info struct array */ "progressive_mode", /* is progressive mode */ }; const int num_jobj_fields = 14; /* field names comp_info struct */ const char *comp_field_names[] = { "component_id", /* JPEG one byte identifier code */ "h_samp_factor", /* horizontal sampling factor */ "v_samp_factor", /* vertical sampling factor */ "quant_tbl_no", /* quantization table number for component */ "dc_tbl_no", /* DC entropy coding table number */ "ac_tbl_no" /* AC entropy encoding table number */ }; const int num_comp_fields = 6; const char *huff_field_names[] = {"counts","symbols"}; /* check input value */ if (nrhs != 1) mexErrMsgTxt("One input argument required."); if (mxIsChar(prhs[0]) != 1) mexErrMsgTxt("Filename must be a string"); /* check output return jpegobj struct */ if (nlhs > 1) mexErrMsgTxt("Too many output arguments"); /* get filename */ strlen = mxGetM(prhs[0])*mxGetN(prhs[0]) + 1; filename = mxCalloc(strlen, sizeof(char)); mxGetString(prhs[0],filename,strlen); /* open file */ if ((infile = fopen(filename, "rb")) == NULL) mexErrMsgTxt("Can't open file"); /* 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; jerr.pub.output_message = my_output_message; /* establish the setjmp return context for my_error_exit to use. */ if (setjmp(jerr.setjmp_buffer)) { jpeg_destroy_decompress(&cinfo); fclose(infile); mexErrMsgTxt("Error reading file"); } /* initialize JPEG decompression object */ jpeg_create_decompress(&cinfo); jpeg_stdio_src(&cinfo, infile); /* save contents of markers */ jpeg_save_markers(&cinfo, JPEG_COM, 0xFFFF); /* read header and coefficients */ jpeg_read_header(&cinfo, TRUE); /* create Matlab jpegobj struct */ mxjpeg_obj = mxCreateStructMatrix(1,1,num_jobj_fields,jobj_field_names); /* for some reason out_color_components isn't being set by jpeg_read_header, so we will infer it from out_color_space: */ switch (cinfo.out_color_space) { case JCS_GRAYSCALE: cinfo.out_color_components = 1