src/tiff/libtiff/tif_thunder.c

   1
   2 /*
   3  * Copyright (c) 1988-1997 Sam Leffler
   4  * Copyright (c) 1991-1997 Silicon Graphics, Inc.
   5  *
   6  * Permission to use, copy, modify, distribute, and sell this software and
   7  * its documentation for any purpose is hereby granted without fee, provided
   8  * that (i) the above copyright notices and this permission notice appear in
   9  * all copies of the software and related documentation, and (ii) the names of
  10  * Sam Leffler and Silicon Graphics may not be used in any advertising or
  11  * publicity relating to the software without the specific, prior written
  12  * permission of Sam Leffler and Silicon Graphics.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
  15  * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
  16  * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  17  *
  18  * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
  19  * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
  20  * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
  21  * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
  22  * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  23  * OF THIS SOFTWARE.
  24  */
  25
  26 #include "tiffiop.h"
  27 #include <assert.h>
  28 #ifdef THUNDER_SUPPORT
  29 /*
  30  * TIFF Library.
  31  *
  32  * ThunderScan 4-bit Compression Algorithm Support
  33  */
  34
  35 /*
  36  * ThunderScan uses an encoding scheme designed for
  37  * 4-bit pixel values.  Data is encoded in bytes, with
  38  * each byte split into a 2-bit code word and a 6-bit
  39  * data value.  The encoding gives raw data, runs of
  40  * pixels, or pixel values encoded as a delta from the
  41  * previous pixel value.  For the latter, either 2-bit
  42  * or 3-bit delta values are used, with the deltas packed
  43  * into a single byte.
  44  */
  45 #define THUNDER_DATA            0x3f    /* mask for 6-bit data */
  46 #define THUNDER_CODE            0xc0    /* mask for 2-bit code word */
  47 /* code values */
  48 #define THUNDER_RUN             0x00    /* run of pixels w/ encoded count */
  49 #define THUNDER_2BITDELTAS      0x40    /* 3 pixels w/ encoded 2-bit deltas */
  50 #define     DELTA2_SKIP         2       /* skip code for 2-bit deltas */
  51 #define THUNDER_3BITDELTAS      0x80    /* 2 pixels w/ encoded 3-bit deltas */
  52 #define     DELTA3_SKIP         4       /* skip code for 3-bit deltas */
  53 #define THUNDER_RAW             0xc0    /* raw data encoded */
  54
  55 static const int twobitdeltas[4] = { 0, 1, 0, -1 };
  56 static const int threebitdeltas[8] = { 0, 1, 2, 3, 0, -3, -2, -1 };
  57
  58 #define SETPIXEL(op, v) {                     \
  59         lastpixel = (v) & 0xf;                \
  60         if ( npixels < maxpixels )         \
  61         {                                     \
  62           if (npixels++ & 1)                  \
  63             *op++ |= lastpixel;               \
  64           else                                \
  65             op[0] = (uint8) (lastpixel << 4); \
  66         }                                     \
  67 }
  68
  69 static int
  70 ThunderSetupDecode(TIFF* tif)
  71 {
  72         static const char module[] = "ThunderSetupDecode";
  73
  74         if( tif->tif_dir.td_bitspersample != 4 )
  75         {
  76                 TIFFErrorExt(tif->tif_clientdata, module,
  77                              "Wrong bitspersample value (%d), Thunder decoder only supports 4bits per sample.",
  78                              (int) tif->tif_dir.td_bitspersample );
  79                 return 0;
  80         }
  81
  82
  83         return (1);
  84 }
  85
  86 static int
  87 ThunderDecode(TIFF* tif, uint8* op, tmsize_t maxpixels)
  88 {
  89         static const char module[] = "ThunderDecode";
  90         register unsigned char *bp;
  91         register tmsize_t cc;
  92         unsigned int lastpixel;
  93         tmsize_t npixels;
  94
  95         bp = (unsigned char *)tif->tif_rawcp;
  96         cc = tif->tif_rawcc;
  97         lastpixel = 0;
  98         npixels = 0;
  99         while (cc > 0 && npixels < maxpixels) {
 100                 int n, delta;
 101
 102                 n = *bp++, cc--;
 103                 switch (n & THUNDER_CODE) {
 104                 case THUNDER_RUN:               /* pixel run */
 105                         /*
 106                          * Replicate the last pixel n times,
 107                          * where n is the lower-order 6 bits.
 108                          */
 109                         if (npixels & 1) {
 110                                 op[0] |= lastpixel;
 111                                 lastpixel = *op++; npixels++; n--;
 112                         } else
 113                                 lastpixel |= lastpixel << 4;
 114                         npixels += n;
 115                         if (npixels < maxpixels) {
 116                                 for (; n > 0; n -= 2)
 117                                         *op++ = (uint8) lastpixel;
 118                         }
 119                         if (n == -1)
 120                                 *--op &= 0xf0;
 121                         lastpixel &= 0xf;
 122                         break;
 123                 case THUNDER_2BITDELTAS:        /* 2-bit deltas */
 124                         if ((delta = ((n >> 4) & 3)) != DELTA2_SKIP)
 125                                 SETPIXEL(op, lastpixel + twobitdeltas[delta]);
 126                         if ((delta = ((n >> 2) & 3)) != DELTA2_SKIP)
 127                                 SETPIXEL(op, lastpixel + twobitdeltas[delta]);
 128                         if ((delta = (n & 3)) != DELTA2_SKIP)
 129                                 SETPIXEL(op, lastpixel + twobitdeltas[delta]);
 130                         break;
 131                 case THUNDER_3BITDELTAS:        /* 3-bit deltas */
 132                         if ((delta = ((n >> 3) & 7)) != DELTA3_SKIP)
 133                                 SETPIXEL(op, lastpixel + threebitdeltas[delta]);
 134                         if ((delta = (n & 7)) != DELTA3_SKIP)
 135                                 SETPIXEL(op, lastpixel + threebitdeltas[delta]);
 136                         break;
 137                 case THUNDER_RAW:               /* raw data */
 138                         SETPIXEL(op, n);
 139                         break;
 140                 }
 141         }
 142         tif->tif_rawcp = (uint8*) bp;
 143         tif->tif_rawcc = cc;
 144         if (npixels != maxpixels) {
 145 #if defined(__WIN32__) && (defined(_MSC_VER) || defined(__MINGW32__))
 146                 TIFFErrorExt(tif->tif_clientdata, module,
 147                              "%s data at scanline %lu (%I64u != %I64u)",
 148                              npixels < maxpixels ? "Not enough" : "Too much",
 149                              (unsigned long) tif->tif_row,
 150                              (unsigned __int64) npixels,
 151                              (unsigned __int64) maxpixels);
 152 #else
 153                 TIFFErrorExt(tif->tif_clientdata, module,
 154                              "%s data at scanline %lu (%llu != %llu)",
 155                              npixels < maxpixels ? "Not enough" : "Too much",
 156                              (unsigned long) tif->tif_row,
 157                              (unsigned long long) npixels,
 158                              (unsigned long long) maxpixels);
 159 #endif
 160                 return (0);
 161         }
 162
 163         return (1);
 164 }
 165
 166 static int
 167 ThunderDecodeRow(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
 168 {
 169         static const char module[] = "ThunderDecodeRow";
 170         uint8* row = buf;
 171
 172         (void) s;
 173         if (occ % tif->tif_scanlinesize)
 174         {
 175                 TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
 176                 return (0);
 177         }
 178         while (occ > 0) {
 179                 if (!ThunderDecode(tif, row, tif->tif_dir.td_imagewidth))
 180                         return (0);
 181                 occ -= tif->tif_scanlinesize;
 182                 row += tif->tif_scanlinesize;
 183         }
 184         return (1);
 185 }
 186
 187 int
 188 TIFFInitThunderScan(TIFF* tif, int scheme)
 189 {
 190         (void) scheme;
 191
 192         tif->tif_setupdecode = ThunderSetupDecode;
 193         tif->tif_decoderow = ThunderDecodeRow;
 194         tif->tif_decodestrip = ThunderDecodeRow;
 195         return (1);
 196 }
 197 #endif /* THUNDER_SUPPORT */
 198
 199 /* vim: set ts=8 sts=8 sw=8 noet: */
 200 /*
 201  * Local Variables:
 202  * mode: c
 203  * c-basic-offset: 8
 204  * fill-column: 78
 205  * End:
 206  */