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      1 /* $Id: tif_next.c,v 1.13 2010-03-10 18:56:48 bfriesen Exp $ */
      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, uint8* buf, tmsize_t occ, uint16 s)
     50 {
     51     static const char module[] = "NeXTDecode";
     52     unsigned char *bp, *op;
     53     tmsize_t cc;
     54     uint8* row;
     55     tmsize_t scanline, n;
     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 = (unsigned char*) 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     if (occ % scanline)
     70     {
     71         TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
     72         return (0);
     73     }
     74     for (row = buf; occ > 0; occ -= scanline, row += scanline) {
     75         n = *bp++, cc--;
     76         switch (n) {
     77         case LITERALROW:
     78             /*
     79              * The entire scanline is given as literal values.
     80              */
     81             if (cc < scanline)
     82                 goto bad;
     83             _TIFFmemcpy(row, bp, scanline);
     84             bp += scanline;
     85             cc -= scanline;
     86             break;
     87         case LITERALSPAN: {
     88             tmsize_t off;
     89             /*
     90              * The scanline has a literal span that begins at some
     91              * offset.
     92              */
     93             off = (bp[0] * 256) + bp[1];
     94             n = (bp[2] * 256) + bp[3];
     95             if (cc < 4+n || off+n > scanline)
     96                 goto bad;
     97             _TIFFmemcpy(row+off, bp+4, n);
     98             bp += 4+n;
     99             cc -= 4+n;
    100             break;
    101         }
    102         default: {
    103             uint32 npixels = 0, grey;
    104             uint32 imagewidth = tif->tif_dir.td_imagewidth;
    105 
    106             /*
    107              * The scanline is composed of a sequence of constant
    108              * color ``runs''.  We shift into ``run mode'' and
    109              * interpret bytes as codes of the form
    110              * <color><npixels> until we've filled the scanline.
    111              */
    112             op = row;
    113             for (;;) {
    114                 grey = (uint32)((n>>6) & 0x3);
    115                 n &= 0x3f;
    116                 /*
    117                  * Ensure the run does not exceed the scanline
    118                  * bounds, potentially resulting in a security
    119                  * issue.
    120                  */
    121                 while (n-- > 0 && npixels < imagewidth)
    122                     SETPIXEL(op, grey);
    123                 if (npixels >= imagewidth)
    124                     break;
    125                 if (cc == 0)
    126                     goto bad;
    127                 n = *bp++, cc--;
    128             }
    129             break;
    130         }
    131         }
    132     }
    133     tif->tif_rawcp = (uint8*) bp;
    134     tif->tif_rawcc = cc;
    135     return (1);
    136 bad:
    137     TIFFErrorExt(tif->tif_clientdata, module, "Not enough data for scanline %ld",
    138         (long) tif->tif_row);
    139     return (0);
    140 }
    141 
    142 int
    143 TIFFInitNeXT(TIFF* tif, int scheme)
    144 {
    145     (void) scheme;
    146     tif->tif_decoderow = NeXTDecode;
    147     tif->tif_decodestrip = NeXTDecode;
    148     tif->tif_decodetile = NeXTDecode;
    149     return (1);
    150 }
    151 #endif /* NEXT_SUPPORT */
    152 
    153 /* vim: set ts=8 sts=8 sw=8 noet: */
    154 /*
    155  * Local Variables:
    156  * mode: c
    157  * c-basic-offset: 8
    158  * fill-column: 78
    159  * End:
    160  */
    161