diff --git a/rdswitch.c b/rdswitch.c
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--- /dev/null
+++ b/rdswitch.c
@@ -0,0 +1,342 @@
+/*
+ * rdswitch.c
+ *
+ * Copyright (C) 1991-1995, 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
+ *	-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() */
+
+
+/* Hack: get access to jpeg_zigzag_order[] table in jutils.c.
+ * Since it's declared in jpegint.h, normally can't see it from an application.
+ */
+#ifdef NEED_SHORT_EXTERNAL_NAMES
+#define jpeg_zigzag_order	jZIGTable
+#endif
+extern const int jpeg_zigzag_order[];
+
+
+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,
+		   int scale_factor, 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;
+      }
+      /* Convert from natural order in the file to zigzag table order. */
+      table[jpeg_zigzag_order[i]] = (unsigned int) val;
+    }
+    jpeg_add_quant_table(cinfo, tblno, table, scale_factor, 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_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;
+}