rdswitch.c

/*
 * rdswitch.c
 *
 * This file was part of the Independent JPEG Group's software:
 * Copyright (C) 1991-1996, Thomas G. Lane.
 * libjpeg-turbo Modifications:
 * Copyright (C) 2010, 2018, D. R. Commander.
 * For conditions of distribution and use, see the accompanying README.ijg
 * 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;
}


#if JPEG_LIB_VERSION < 70
static int q_scale_factor[NUM_QUANT_TBLS] = { 100, 100, 100, 100 };
#endif

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;
    }
#if JPEG_LIB_VERSION >= 70
    jpeg_add_quant_table(cinfo, tblno, table, cinfo->q_scale_factor[tblno],
                         force_baseline);
#else
    jpeg_add_quant_table(cinfo, tblno, table, q_scale_factor[tblno],
                         force_baseline);
#endif
    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 */


#if JPEG_LIB_VERSION < 70
/* These are the sample quantization tables given in Annex K (Clause K.1) of
 * Recommendation ITU-T T.81 (1992) | ISO/IEC 10918-1:1994.
 * The spec says that the values given produce "good" quality, and
 * when divided by 2, "very good" quality.
 */
static const unsigned int std_luminance_quant_tbl[DCTSIZE2] = {
  16,  11,  10,  16,  24,  40,  51,  61,
  12,  12,  14,  19,  26,  58,  60,  55,
  14,  13,  16,  24,  40,  57,  69,  56,
  14,  17,  22,  29,  51,  87,  80,  62,
  18,  22,  37,  56,  68, 109, 103,  77,
  24,  35,  55,  64,  81, 104, 113,  92,
  49,  64,  78,  87, 103, 121, 120, 101,
  72,  92,  95,  98, 112, 100, 103,  99
};
static const unsigned int std_chrominance_quant_tbl[DCTSIZE2] = {
  17,  18,  24,  47,  99,  99,  99,  99,
  18,  21,  26,  66,  99,  99,  99,  99,
  24,  26,  56,  99,  99,  99,  99,  99,
  47,  66,  99,  99,  99,  99,  99,  99,
  99,  99,  99,  99,  99,  99,  99,  99,
  99,  99,  99,  99,  99,  99,  99,  99,
  99,  99,  99,  99,  99,  99,  99,  99,
  99,  99,  99,  99,  99,  99,  99,  99
};


LOCAL(void)
jpeg_default_qtables(j_compress_ptr cinfo, boolean force_baseline)
{
  jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl, q_scale_factor[0],
                       force_baseline);
  jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl, q_scale_factor[1],
                       force_baseline);
}
#endif


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 */
#if JPEG_LIB_VERSION >= 70
      cinfo->q_scale_factor[tblno] = jpeg_quality_scaling(val);
#else
      q_scale_factor[tblno] = jpeg_quality_scaling(val);
#endif
      while (*arg && *arg++ != ','); /* advance to next segment of arg
                                        string */
    } else {
      /* reached end of parameter, set remaining factors to last value */
#if JPEG_LIB_VERSION >= 70
      cinfo->q_scale_factor[tblno] = jpeg_quality_scaling(val);
#else
      q_scale_factor[tblno] = jpeg_quality_scaling(val);
#endif
    }
  }
  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;
}