--- /dev/null
+/*
+ * rdcolmap.c
+ *
+ * Copyright (C) 1994-1996, 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 implements djpeg's "-map file" switch. It reads a source image
+ * and constructs a colormap to be supplied to the JPEG decompressor.
+ *
+ * Currently, these file formats are supported for the map file:
+ * GIF: the contents of the GIF's global colormap are used.
+ * PPM (either text or raw flavor): the entire file is read and
+ * each unique pixel value is entered in the map.
+ * Note that reading a large PPM file will be horrendously slow.
+ * Typically, a PPM-format map file should contain just one pixel
+ * of each desired color. Such a file can be extracted from an
+ * ordinary image PPM file with ppmtomap(1).
+ *
+ * Rescaling a PPM that has a maxval unequal to MAXJSAMPLE is not
+ * currently implemented.
+ */
+
+#include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
+
+#ifdef QUANT_2PASS_SUPPORTED /* otherwise can't quantize to supplied map */
+
+/* Portions of this code are based on the PBMPLUS library, which is:
+**
+** Copyright (C) 1988 by Jef Poskanzer.
+**
+** Permission to use, copy, modify, and distribute this software and its
+** documentation for any purpose and without fee is hereby granted, provided
+** that the above copyright notice appear in all copies and that both that
+** copyright notice and this permission notice appear in supporting
+** documentation. This software is provided "as is" without express or
+** implied warranty.
+*/
+
+
+/*
+ * Add a (potentially) new color to the color map.
+ */
+
+LOCAL(void)
+add_map_entry (j_decompress_ptr cinfo, int R, int G, int B)
+{
+ JSAMPROW colormap0 = cinfo->colormap[0];
+ JSAMPROW colormap1 = cinfo->colormap[1];
+ JSAMPROW colormap2 = cinfo->colormap[2];
+ int ncolors = cinfo->actual_number_of_colors;
+ int index;
+
+ /* Check for duplicate color. */
+ for (index = 0; index < ncolors; index++) {
+ if (GETJSAMPLE(colormap0[index]) == R &&
+ GETJSAMPLE(colormap1[index]) == G &&
+ GETJSAMPLE(colormap2[index]) == B)
+ return; /* color is already in map */
+ }
+
+ /* Check for map overflow. */
+ if (ncolors >= (MAXJSAMPLE+1))
+ ERREXIT1(cinfo, JERR_QUANT_MANY_COLORS, (MAXJSAMPLE+1));
+
+ /* OK, add color to map. */
+ colormap0[ncolors] = (JSAMPLE) R;
+ colormap1[ncolors] = (JSAMPLE) G;
+ colormap2[ncolors] = (JSAMPLE) B;
+ cinfo->actual_number_of_colors++;
+}
+
+
+/*
+ * Extract color map from a GIF file.
+ */
+
+LOCAL(void)
+read_gif_map (j_decompress_ptr cinfo, FILE * infile)
+{
+ int header[13];
+ int i, colormaplen;
+ int R, G, B;
+
+ /* Initial 'G' has already been read by read_color_map */
+ /* Read the rest of the GIF header and logical screen descriptor */
+ for (i = 1; i < 13; i++) {
+ if ((header[i] = getc(infile)) == EOF)
+ ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
+ }
+
+ /* Verify GIF Header */
+ if (header[1] != 'I' || header[2] != 'F')
+ ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
+
+ /* There must be a global color map. */
+ if ((header[10] & 0x80) == 0)
+ ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
+
+ /* OK, fetch it. */
+ colormaplen = 2 << (header[10] & 0x07);
+
+ for (i = 0; i < colormaplen; i++) {
+ R = getc(infile);
+ G = getc(infile);
+ B = getc(infile);
+ if (R == EOF || G == EOF || B == EOF)
+ ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
+ add_map_entry(cinfo,
+ R << (BITS_IN_JSAMPLE-8),
+ G << (BITS_IN_JSAMPLE-8),
+ B << (BITS_IN_JSAMPLE-8));
+ }
+}
+
+
+/* Support routines for reading PPM */
+
+
+LOCAL(int)
+pbm_getc (FILE * infile)
+/* Read next char, skipping over any comments */
+/* A comment/newline sequence is returned as a newline */
+{
+ register int ch;
+
+ ch = getc(infile);
+ if (ch == '#') {
+ do {
+ ch = getc(infile);
+ } while (ch != '\n' && ch != EOF);
+ }
+ return ch;
+}
+
+
+LOCAL(unsigned int)
+read_pbm_integer (j_decompress_ptr cinfo, FILE * infile)
+/* Read an unsigned decimal integer from the PPM file */
+/* Swallows one trailing character after the integer */
+/* Note that on a 16-bit-int machine, only values up to 64k can be read. */
+/* This should not be a problem in practice. */
+{
+ register int ch;
+ register unsigned int val;
+
+ /* Skip any leading whitespace */
+ do {
+ ch = pbm_getc(infile);
+ if (ch == EOF)
+ ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
+ } while (ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r');
+
+ if (ch < '0' || ch > '9')
+ ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
+
+ val = ch - '0';
+ while ((ch = pbm_getc(infile)) >= '0' && ch <= '9') {
+ val *= 10;
+ val += ch - '0';
+ }
+ return val;
+}
+
+
+/*
+ * Extract color map from a PPM file.
+ */
+
+LOCAL(void)
+read_ppm_map (j_decompress_ptr cinfo, FILE * infile)
+{
+ int c;
+ unsigned int w, h, maxval, row, col;
+ int R, G, B;
+
+ /* Initial 'P' has already been read by read_color_map */
+ c = getc(infile); /* save format discriminator for a sec */
+
+ /* while we fetch the remaining header info */
+ w = read_pbm_integer(cinfo, infile);
+ h = read_pbm_integer(cinfo, infile);
+ maxval = read_pbm_integer(cinfo, infile);
+
+ if (w <= 0 || h <= 0 || maxval <= 0) /* error check */
+ ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
+
+ /* For now, we don't support rescaling from an unusual maxval. */
+ if (maxval != (unsigned int) MAXJSAMPLE)
+ ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
+
+ switch (c) {
+ case '3': /* it's a text-format PPM file */
+ for (row = 0; row < h; row++) {
+ for (col = 0; col < w; col++) {
+ R = read_pbm_integer(cinfo, infile);
+ G = read_pbm_integer(cinfo, infile);
+ B = read_pbm_integer(cinfo, infile);
+ add_map_entry(cinfo, R, G, B);
+ }
+ }
+ break;
+
+ case '6': /* it's a raw-format PPM file */
+ for (row = 0; row < h; row++) {
+ for (col = 0; col < w; col++) {
+ R = getc(infile);
+ G = getc(infile);
+ B = getc(infile);
+ if (R == EOF || G == EOF || B == EOF)
+ ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
+ add_map_entry(cinfo, R, G, B);
+ }
+ }
+ break;
+
+ default:
+ ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
+ break;
+ }
+}
+
+
+/*
+ * Main entry point from djpeg.c.
+ * Input: opened input file (from file name argument on command line).
+ * Output: colormap and actual_number_of_colors fields are set in cinfo.
+ */
+
+GLOBAL(void)
+read_color_map (j_decompress_ptr cinfo, FILE * infile)
+{
+ /* Allocate space for a color map of maximum supported size. */
+ cinfo->colormap = (*cinfo->mem->alloc_sarray)
+ ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (JDIMENSION) (MAXJSAMPLE+1), (JDIMENSION) 3);
+ cinfo->actual_number_of_colors = 0; /* initialize map to empty */
+
+ /* Read first byte to determine file format */
+ switch (getc(infile)) {
+ case 'G':
+ read_gif_map(cinfo, infile);
+ break;
+ case 'P':
+ read_ppm_map(cinfo, infile);
+ break;
+ default:
+ ERREXIT(cinfo, JERR_BAD_CMAP_FILE);
+ break;
+ }
+}
+
+#endif /* QUANT_2PASS_SUPPORTED */
projects / reactos.git / blobdiff