1 /* 2 * Copyright (c) 1988-1997 Sam Leffler 3 * Copyright (c) 1991-1997 Silicon Graphics, Inc. 4 * 5 * Permission to use, copy, modify, distribute, and sell this software and 6 * its documentation for any purpose is hereby granted without fee, provided 7 * that (i) the above copyright notices and this permission notice appear in 8 * all copies of the software and related documentation, and (ii) the names of 9 * Sam Leffler and Silicon Graphics may not be used in any advertising or 10 * publicity relating to the software without the specific, prior written 11 * permission of Sam Leffler and Silicon Graphics. 12 * 13 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 14 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 15 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 16 * 17 * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR 18 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, 19 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, 20 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF 21 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 22 * OF THIS SOFTWARE. 23 */ 24 25 #include <precomp.h> 26 27 #ifdef NEXT_SUPPORT 28 /* 29 * TIFF Library. 30 * 31 * NeXT 2-bit Grey Scale Compression Algorithm Support 32 */ 33 34 #define SETPIXEL(op, v) { \ 35 switch (npixels++ & 3) { \ 36 case 0: op[0] = (unsigned char) ((v) << 6); break; \ 37 case 1: op[0] |= (v) << 4; break; \ 38 case 2: op[0] |= (v) << 2; break; \ 39 case 3: *op++ |= (v); op_offset++; break; \ 40 } \ 41 } 42 43 #define LITERALROW 0x00 44 #define LITERALSPAN 0x40 45 #define WHITE ((1<<2)-1) 46 47 static int 48 NeXTDecode(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s) 49 { 50 static const char module[] = "NeXTDecode"; 51 unsigned char *bp, *op; 52 tmsize_t cc; 53 uint8* row; 54 tmsize_t scanline, n; 55 56 (void) s; 57 /* 58 * Each scanline is assumed to start off as all 59 * white (we assume a PhotometricInterpretation 60 * of ``min-is-black''). 61 */ 62 for (op = (unsigned char*) buf, cc = occ; cc-- > 0;) 63 *op++ = 0xff; 64 65 bp = (unsigned char *)tif->tif_rawcp; 66 cc = tif->tif_rawcc; 67 scanline = tif->tif_scanlinesize; 68 if (occ % scanline) 69 { 70 TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read"); 71 return (0); 72 } 73 for (row = buf; cc > 0 && occ > 0; occ -= scanline, row += scanline) { 74 n = *bp++; 75 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 if( cc < 4 ) 94 goto bad; 95 off = (bp[0] * 256) + bp[1]; 96 n = (bp[2] * 256) + bp[3]; 97 if (cc < 4+n || off+n > scanline) 98 goto bad; 99 _TIFFmemcpy(row+off, bp+4, n); 100 bp += 4+n; 101 cc -= 4+n; 102 break; 103 } 104 default: { 105 uint32 npixels = 0, grey; 106 tmsize_t op_offset = 0; 107 uint32 imagewidth = tif->tif_dir.td_imagewidth; 108 if( isTiled(tif) ) 109 imagewidth = tif->tif_dir.td_tilewidth; 110 111 /* 112 * The scanline is composed of a sequence of constant 113 * color ``runs''. We shift into ``run mode'' and 114 * interpret bytes as codes of the form 115 * <color><npixels> until we've filled the scanline. 116 */ 117 op = row; 118 for (;;) { 119 grey = (uint32)((n>>6) & 0x3); 120 n &= 0x3f; 121 /* 122 * Ensure the run does not exceed the scanline 123 * bounds, potentially resulting in a security 124 * issue. 125 */ 126 while (n-- > 0 && npixels < imagewidth && op_offset < scanline) 127 SETPIXEL(op, grey); 128 if (npixels >= imagewidth) 129 break; 130 if (op_offset >= scanline ) { 131 TIFFErrorExt(tif->tif_clientdata, module, "Invalid data for scanline %ld", 132 (long) tif->tif_row); 133 return (0); 134 } 135 if (cc == 0) 136 goto bad; 137 n = *bp++; 138 cc--; 139 } 140 break; 141 } 142 } 143 } 144 tif->tif_rawcp = (uint8*) bp; 145 tif->tif_rawcc = cc; 146 return (1); 147 bad: 148 TIFFErrorExt(tif->tif_clientdata, module, "Not enough data for scanline %ld", 149 (long) tif->tif_row); 150 return (0); 151 } 152 153 static int 154 NeXTPreDecode(TIFF* tif, uint16 s) 155 { 156 static const char module[] = "NeXTPreDecode"; 157 TIFFDirectory *td = &tif->tif_dir; 158 (void)s; 159 160 if( td->td_bitspersample != 2 ) 161 { 162 TIFFErrorExt(tif->tif_clientdata, module, "Unsupported BitsPerSample = %d", 163 td->td_bitspersample); 164 return (0); 165 } 166 return (1); 167 } 168 169 int 170 TIFFInitNeXT(TIFF* tif, int scheme) 171 { 172 (void) scheme; 173 tif->tif_predecode = NeXTPreDecode; 174 tif->tif_decoderow = NeXTDecode; 175 tif->tif_decodestrip = NeXTDecode; 176 tif->tif_decodetile = NeXTDecode; 177 return (1); 178 } 179 #endif /* NEXT_SUPPORT */ 180 181 /* vim: set ts=8 sts=8 sw=8 noet: */ 182 /* 183 * Local Variables: 184 * mode: c 185 * c-basic-offset: 8 186 * fill-column: 78 187 * End: 188 */ 189