# dlib C++ Library - rdswitch.c

    /*
     * rdswitch.c
     *
     * Copyright (C) 1991-1996, Thomas G. Lane.
     * This file is part of the Independent JPEG Group's software.
     * For conditions of distribution and use, see the accompanying README file.
     *
     * This file contains routines to process some of cjpeg's more complicated
     * command-line switches.  Switches processed here are:
     *	-qtables file		Read quantization tables from text file
     *	-scans file		Read scan script from text file
     *	-quality N[,N,...]	Set quality ratings
     *	-qslots N[,N,...]	Set component quantization table selectors
     *	-sample HxV[,HxV,...]	Set component sampling factors
     */

    #include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */
    #include <ctype.h>		/* to declare isdigit(), isspace() */

    LOCAL(int)
    text_getc (FILE * file)
    /* Read next char, skipping over any comments (# to end of line) */
    /* A comment/newline sequence is returned as a newline */
    {
      register int ch;

      ch = getc(file);
      if (ch == '#') {
        do {
          ch = getc(file);
        } while (ch != '\n' && ch != EOF);
      }
      return ch;
    }

    LOCAL(boolean)
    read_text_integer (FILE * file, long * result, int * termchar)
    /* Read an unsigned decimal integer from a file, store it in result */
    /* Reads one trailing character after the integer; returns it in termchar */
    {
      register int ch;
      register long val;

      /* Skip any leading whitespace, detect EOF */
      do {
        ch = text_getc(file);
        if (ch == EOF) {
          *termchar = ch;
          return FALSE;
        }
      } while (isspace(ch));

      if (! isdigit(ch)) {
        *termchar = ch;
        return FALSE;
      }

      val = ch - '0';
      while ((ch = text_getc(file)) != EOF) {
        if (! isdigit(ch))
          break;
        val *= 10;
        val += ch - '0';
      }
      *result = val;
      *termchar = ch;
      return TRUE;
    }

    GLOBAL(boolean)
    read_quant_tables (j_compress_ptr cinfo, char * filename, boolean force_baseline)
    /* Read a set of quantization tables from the specified file.
     * The file is plain ASCII text: decimal numbers with whitespace between.
     * Comments preceded by '#' may be included in the file.
     * There may be one to NUM_QUANT_TBLS tables in the file, each of 64 values.
     * The tables are implicitly numbered 0,1,etc.
     * NOTE: does not affect the qslots mapping, which will default to selecting
     * table 0 for luminance (or primary) components, 1 for chrominance components.
     * You must use -qslots if you want a different component->table mapping.
     */
    {
      FILE * fp;
      int tblno, i, termchar;
      long val;
      unsigned int table[DCTSIZE2];

      if ((fp = fopen(filename, "r")) == NULL) {
        fprintf(stderr, "Can't open table file %s\n", filename);
        return FALSE;
      }
      tblno = 0;

      while (read_text_integer(fp, &val, &termchar)) { /* read 1st element of table */
        if (tblno >= NUM_QUANT_TBLS) {
          fprintf(stderr, "Too many tables in file %s\n", filename);
          fclose(fp);
          return FALSE;
        }
        table[0] = (unsigned int) val;
        for (i = 1; i < DCTSIZE2; i++) {
          if (! read_text_integer(fp, &val, &termchar)) {
    	fprintf(stderr, "Invalid table data in file %s\n", filename);
    	fclose(fp);
    	return FALSE;
          }
          table[i] = (unsigned int) val;
        }
        jpeg_add_quant_table(cinfo, tblno, table, cinfo->q_scale_factor[tblno],
    			 force_baseline);
        tblno++;
      }

      if (termchar != EOF) {
        fprintf(stderr, "Non-numeric data in file %s\n", filename);
        fclose(fp);
        return FALSE;
      }

      fclose(fp);
      return TRUE;
    }

    #ifdef C_MULTISCAN_FILES_SUPPORTED

    LOCAL(boolean)
    read_scan_integer (FILE * file, long * result, int * termchar)
    /* Variant of read_text_integer that always looks for a non-space termchar;
     * this simplifies parsing of punctuation in scan scripts.
     */
    {
      register int ch;

      if (! read_text_integer(file, result, termchar))
        return FALSE;
      ch = *termchar;
      while (ch != EOF && isspace(ch))
        ch = text_getc(file);
      if (isdigit(ch)) {		/* oops, put it back */
        if (ungetc(ch, file) == EOF)
          return FALSE;
        ch = ' ';
      } else {
        /* Any separators other than ';' and ':' are ignored;
         * this allows user to insert commas, etc, if desired.
         */
        if (ch != EOF && ch != ';' && ch != ':')
          ch = ' ';
      }
      *termchar = ch;
      return TRUE;
    }

    GLOBAL(boolean)
    read_scan_script (j_compress_ptr cinfo, char * filename)
    /* Read a scan script from the specified text file.
     * Each entry in the file defines one scan to be emitted.
     * Entries are separated by semicolons ';'.
     * An entry contains one to four component indexes,
     * optionally followed by a colon ':' and four progressive-JPEG parameters.
     * The component indexes denote which component(s) are to be transmitted
     * in the current scan.  The first component has index 0.
     * Sequential JPEG is used if the progressive-JPEG parameters are omitted.
     * The file is free format text: any whitespace may appear between numbers
     * and the ':' and ';' punctuation marks.  Also, other punctuation (such
     * as commas or dashes) can be placed between numbers if desired.
     * Comments preceded by '#' may be included in the file.
     * Note: we do very little validity checking here;
     * jcmaster.c will validate the script parameters.
     */
    {
      FILE * fp;
      int scanno, ncomps, termchar;
      long val;
      jpeg_scan_info * scanptr;
    #define MAX_SCANS  100		/* quite arbitrary limit */
      jpeg_scan_info scans[MAX_SCANS];

      if ((fp = fopen(filename, "r")) == NULL) {
        fprintf(stderr, "Can't open scan definition file %s\n", filename);
        return FALSE;
      }
      scanptr = scans;
      scanno = 0;

      while (read_scan_integer(fp, &val, &termchar)) {
        if (scanno >= MAX_SCANS) {
          fprintf(stderr, "Too many scans defined in file %s\n", filename);
          fclose(fp);
          return FALSE;
        }
        scanptr->component_index[0] = (int) val;
        ncomps = 1;
        while (termchar == ' ') {
          if (ncomps >= MAX_COMPS_IN_SCAN) {
    	fprintf(stderr, "Too many components in one scan in file %s\n",
    		filename);
    	fclose(fp);
    	return FALSE;
          }
          if (! read_scan_integer(fp, &val, &termchar))
    	goto bogus;
          scanptr->component_index[ncomps] = (int) val;
          ncomps++;
        }
        scanptr->comps_in_scan = ncomps;
        if (termchar == ':') {
          if (! read_scan_integer(fp, &val, &termchar) || termchar != ' ')
    	goto bogus;
          scanptr->Ss = (int) val;
          if (! read_scan_integer(fp, &val, &termchar) || termchar != ' ')
    	goto bogus;
          scanptr->Se = (int) val;
          if (! read_scan_integer(fp, &val, &termchar) || termchar != ' ')
    	goto bogus;
          scanptr->Ah = (int) val;
          if (! read_scan_integer(fp, &val, &termchar))
    	goto bogus;
          scanptr->Al = (int) val;
        } else {
          /* set non-progressive parameters */
          scanptr->Ss = 0;
          scanptr->Se = DCTSIZE2-1;
          scanptr->Ah = 0;
          scanptr->Al = 0;
        }
        if (termchar != ';' && termchar != EOF) {
    bogus:
          fprintf(stderr, "Invalid scan entry format in file %s\n", filename);
          fclose(fp);
          return FALSE;
        }
        scanptr++, scanno++;
      }

      if (termchar != EOF) {
        fprintf(stderr, "Non-numeric data in file %s\n", filename);
        fclose(fp);
        return FALSE;
      }

      if (scanno > 0) {
        /* Stash completed scan list in cinfo structure.
         * NOTE: for cjpeg's use, JPOOL_IMAGE is the right lifetime for this data,
         * but if you want to compress multiple images you'd want JPOOL_PERMANENT.
         */
        scanptr = (jpeg_scan_info *)
          (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
    				  scanno * SIZEOF(jpeg_scan_info));
        MEMCOPY(scanptr, scans, scanno * SIZEOF(jpeg_scan_info));
        cinfo->scan_info = scanptr;
        cinfo->num_scans = scanno;
      }

      fclose(fp);
      return TRUE;
    }

    #endif /* C_MULTISCAN_FILES_SUPPORTED */

    GLOBAL(boolean)
    set_quality_ratings (j_compress_ptr cinfo, char *arg, boolean force_baseline)
    /* Process a quality-ratings parameter string, of the form
     *     N[,N,...]
     * If there are more q-table slots than parameters, the last value is replicated.
     */
    {
      int val = 75;			/* default value */
      int tblno;
      char ch;

      for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {
        if (*arg) {
          ch = ',';			/* if not set by sscanf, will be ',' */
          if (sscanf(arg, "%d%c", &val, &ch) < 1)
    	return FALSE;
          if (ch != ',')		/* syntax check */
    	return FALSE;
          /* Convert user 0-100 rating to percentage scaling */
          cinfo->q_scale_factor[tblno] = jpeg_quality_scaling(val);
          while (*arg && *arg++ != ',') /* advance to next segment of arg string */
    	;
        } else {
          /* reached end of parameter, set remaining factors to last value */
          cinfo->q_scale_factor[tblno] = jpeg_quality_scaling(val);
        }
      }
      jpeg_default_qtables(cinfo, force_baseline);
      return TRUE;
    }

    GLOBAL(boolean)
    set_quant_slots (j_compress_ptr cinfo, char *arg)
    /* Process a quantization-table-selectors parameter string, of the form
     *     N[,N,...]
     * If there are more components than parameters, the last value is replicated.
     */
    {
      int val = 0;			/* default table # */
      int ci;
      char ch;

      for (ci = 0; ci < MAX_COMPONENTS; ci++) {
        if (*arg) {
          ch = ',';			/* if not set by sscanf, will be ',' */
          if (sscanf(arg, "%d%c", &val, &ch) < 1)
    	return FALSE;
          if (ch != ',')		/* syntax check */
    	return FALSE;
          if (val < 0 || val >= NUM_QUANT_TBLS) {
    	fprintf(stderr, "JPEG quantization tables are numbered 0..%d\n",
    		NUM_QUANT_TBLS-1);
    	return FALSE;
          }
          cinfo->comp_info[ci].quant_tbl_no = val;
          while (*arg && *arg++ != ',') /* advance to next segment of arg string */
    	;
        } else {
          /* reached end of parameter, set remaining components to last table */
          cinfo->comp_info[ci].quant_tbl_no = val;
        }
      }
      return TRUE;
    }

    GLOBAL(boolean)
    set_sample_factors (j_compress_ptr cinfo, char *arg)
    /* Process a sample-factors parameter string, of the form
     *     HxV[,HxV,...]
     * If there are more components than parameters, "1x1" is assumed for the rest.
     */
    {
      int ci, val1, val2;
      char ch1, ch2;

      for (ci = 0; ci < MAX_COMPONENTS; ci++) {
        if (*arg) {
          ch2 = ',';		/* if not set by sscanf, will be ',' */
          if (sscanf(arg, "%d%c%d%c", &val1, &ch1, &val2, &ch2) < 3)
    	return FALSE;
          if ((ch1 != 'x' && ch1 != 'X') || ch2 != ',') /* syntax check */
    	return FALSE;
          if (val1 <= 0 || val1 > 4 || val2 <= 0 || val2 > 4) {
    	fprintf(stderr, "JPEG sampling factors must be 1..4\n");
    	return FALSE;
          }
          cinfo->comp_info[ci].h_samp_factor = val1;
          cinfo->comp_info[ci].v_samp_factor = val2;
          while (*arg && *arg++ != ',') /* advance to next segment of arg string */
    	;
        } else {
          /* reached end of parameter, set remaining components to 1x1 sampling */
          cinfo->comp_info[ci].h_samp_factor = 1;
          cinfo->comp_info[ci].v_samp_factor = 1;
        }
      }
      return TRUE;
    }