src/tiff/libtiff/tif_next.c

   1 /* $Id$ */
   2
   3 /*
   4  * Copyright (c) 1988-1997 Sam Leffler
   5  * Copyright (c) 1991-1997 Silicon Graphics, Inc.
   6  *
   7  * Permission to use, copy, modify, distribute, and sell this software and
   8  * its documentation for any purpose is hereby granted without fee, provided
   9  * that (i) the above copyright notices and this permission notice appear in
  10  * all copies of the software and related documentation, and (ii) the names of
  11  * Sam Leffler and Silicon Graphics may not be used in any advertising or
  12  * publicity relating to the software without the specific, prior written
  13  * permission of Sam Leffler and Silicon Graphics.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
  17  * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  18  *
  19  * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
  20  * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
  21  * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
  22  * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
  23  * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  24  * OF THIS SOFTWARE.
  25  */
  26
  27 #include "tiffiop.h"
  28 #ifdef NEXT_SUPPORT
  29 /*
  30  * TIFF Library.
  31  *
  32  * NeXT 2-bit Grey Scale Compression Algorithm Support
  33  */
  34
  35 #define SETPIXEL(op, v) {                       \
  36         switch (npixels++ & 3) {                \
  37         case 0: op[0]  = (unsigned char) ((v) << 6); break;     \
  38         case 1: op[0] |= (v) << 4; break;       \
  39         case 2: op[0] |= (v) << 2; break;       \
  40         case 3: *op++ |= (v);      break;       \
  41         }                                       \
  42 }
  43
  44 #define LITERALROW      0x00
  45 #define LITERALSPAN     0x40
  46 #define WHITE           ((1<<2)-1)
  47
  48 static int
  49 NeXTDecode(TIFF* tif, tidata_t buf, tsize_t occ, tsample_t s)
  50 {
  51         register unsigned char *bp, *op;
  52         register tsize_t cc;
  53         register int n;
  54         tidata_t row;
  55         tsize_t scanline;
  56
  57         (void) s;
  58         /*
  59          * Each scanline is assumed to start off as all
  60          * white (we assume a PhotometricInterpretation
  61          * of ``min-is-black'').
  62          */
  63         for (op = buf, cc = occ; cc-- > 0;)
  64                 *op++ = 0xff;
  65
  66         bp = (unsigned char *)tif->tif_rawcp;
  67         cc = tif->tif_rawcc;
  68         scanline = tif->tif_scanlinesize;
  69         for (row = buf; (long)occ > 0; occ -= scanline, row += scanline) {
  70                 n = *bp++, cc--;
  71                 switch (n) {
  72                 case LITERALROW:
  73                         /*
  74                          * The entire scanline is given as literal values.
  75                          */
  76                         if (cc < scanline)
  77                                 goto bad;
  78                         _TIFFmemcpy(row, bp, scanline);
  79                         bp += scanline;
  80                         cc -= scanline;
  81                         break;
  82                 case LITERALSPAN: {
  83                         int off;
  84                         /*
  85                          * The scanline has a literal span
  86                          * that begins at some offset.
  87                          */
  88                         off = (bp[0] * 256) + bp[1];
  89                         n = (bp[2] * 256) + bp[3];
  90                         if (cc < 4+n || off+n > scanline)
  91                                 goto bad;
  92                         _TIFFmemcpy(row+off, bp+4, n);
  93                         bp += 4+n;
  94                         cc -= 4+n;
  95                         break;
  96                 }
  97                 default: {
  98                         register int npixels = 0, grey;
  99                         unsigned long imagewidth = tif->tif_dir.td_imagewidth;
 100
 101                         /*
 102                          * The scanline is composed of a sequence
 103                          * of constant color ``runs''.  We shift
 104                          * into ``run mode'' and interpret bytes
 105                          * as codes of the form <color><npixels>
 106                          * until we've filled the scanline.
 107                          */
 108                         op = row;
 109                         for (;;) {
 110                                 grey = (n>>6) & 0x3;
 111                                 n &= 0x3f;
 112                                 while (n-- > 0)
 113                                         SETPIXEL(op, grey);
 114                                 if (npixels >= (int) imagewidth)
 115                                         break;
 116                                 if (cc == 0)
 117                                         goto bad;
 118                                 n = *bp++, cc--;
 119                         }
 120                         break;
 121                 }
 122                 }
 123         }
 124         tif->tif_rawcp = (tidata_t) bp;
 125         tif->tif_rawcc = cc;
 126         return (1);
 127 bad:
 128         TIFFErrorExt(tif->tif_clientdata, tif->tif_name, "NeXTDecode: Not enough data for scanline %ld",
 129             (long) tif->tif_row);
 130         return (0);
 131 }
 132
 133 int
 134 TIFFInitNeXT(TIFF* tif, int scheme)
 135 {
 136         (void) scheme;
 137         tif->tif_decoderow = NeXTDecode;
 138         tif->tif_decodestrip = NeXTDecode;
 139         tif->tif_decodetile = NeXTDecode;
 140         return (1);
 141 }
 142 #endif /* NEXT_SUPPORT */
 143
 144 /* vim: set ts=8 sts=8 sw=8 noet: */