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 "tiffiop.h"
26 #ifdef NEXT_SUPPORT
27 /*
28 * TIFF Library.
29 *
30 * NeXT 2-bit Grey Scale Compression Algorithm Support
31 */
32
33 #define SETPIXEL(op, v) { \
34 switch (npixels++ & 3) { \
35 case 0: op[0] = (unsigned char) ((v) << 6); break; \
36 case 1: op[0] |= (v) << 4; break; \
37 case 2: op[0] |= (v) << 2; break; \
38 case 3: *op++ |= (v); op_offset++; break; \
39 } \
40 }
41
42 #define LITERALROW 0x00
43 #define LITERALSPAN 0x40
44 #define WHITE ((1<<2)-1)
45
46 static int
NeXTDecode(TIFF * tif,uint8 * buf,tmsize_t occ,uint16 s)47 NeXTDecode(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
48 {
49 static const char module[] = "NeXTDecode";
50 unsigned char *bp, *op;
51 tmsize_t cc;
52 uint8* row;
53 tmsize_t scanline, n;
54
55 (void) s;
56 /*
57 * Each scanline is assumed to start off as all
58 * white (we assume a PhotometricInterpretation
59 * of ``min-is-black'').
60 */
61 for (op = (unsigned char*) buf, cc = occ; cc-- > 0;)
62 *op++ = 0xff;
63
64 bp = (unsigned char *)tif->tif_rawcp;
65 cc = tif->tif_rawcc;
66 scanline = tif->tif_scanlinesize;
67 if (occ % scanline)
68 {
69 TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
70 return (0);
71 }
72 for (row = buf; cc > 0 && occ > 0; occ -= scanline, row += scanline) {
73 n = *bp++;
74 cc--;
75 switch (n) {
76 case LITERALROW:
77 /*
78 * The entire scanline is given as literal values.
79 */
80 if (cc < scanline)
81 goto bad;
82 _TIFFmemcpy(row, bp, scanline);
83 bp += scanline;
84 cc -= scanline;
85 break;
86 case LITERALSPAN: {
87 tmsize_t off;
88 /*
89 * The scanline has a literal span that begins at some
90 * offset.
91 */
92 if( cc < 4 )
93 goto bad;
94 off = (bp[0] * 256) + bp[1];
95 n = (bp[2] * 256) + bp[3];
96 if (cc < 4+n || off+n > scanline)
97 goto bad;
98 _TIFFmemcpy(row+off, bp+4, n);
99 bp += 4+n;
100 cc -= 4+n;
101 break;
102 }
103 default: {
104 uint32 npixels = 0, grey;
105 tmsize_t op_offset = 0;
106 uint32 imagewidth = tif->tif_dir.td_imagewidth;
107 if( isTiled(tif) )
108 imagewidth = tif->tif_dir.td_tilewidth;
109
110 /*
111 * The scanline is composed of a sequence of constant
112 * color ``runs''. We shift into ``run mode'' and
113 * interpret bytes as codes of the form
114 * <color><npixels> until we've filled the scanline.
115 */
116 op = row;
117 for (;;) {
118 grey = (uint32)((n>>6) & 0x3);
119 n &= 0x3f;
120 /*
121 * Ensure the run does not exceed the scanline
122 * bounds, potentially resulting in a security
123 * issue.
124 */
125 while (n-- > 0 && npixels < imagewidth && op_offset < scanline)
126 SETPIXEL(op, grey);
127 if (npixels >= imagewidth)
128 break;
129 if (op_offset >= scanline ) {
130 TIFFErrorExt(tif->tif_clientdata, module, "Invalid data for scanline %ld",
131 (long) tif->tif_row);
132 return (0);
133 }
134 if (cc == 0)
135 goto bad;
136 n = *bp++;
137 cc--;
138 }
139 break;
140 }
141 }
142 }
143 tif->tif_rawcp = (uint8*) bp;
144 tif->tif_rawcc = cc;
145 return (1);
146 bad:
147 TIFFErrorExt(tif->tif_clientdata, module, "Not enough data for scanline %ld",
148 (long) tif->tif_row);
149 return (0);
150 }
151
152 static int
NeXTPreDecode(TIFF * tif,uint16 s)153 NeXTPreDecode(TIFF* tif, uint16 s)
154 {
155 static const char module[] = "NeXTPreDecode";
156 TIFFDirectory *td = &tif->tif_dir;
157 (void)s;
158
159 if( td->td_bitspersample != 2 )
160 {
161 TIFFErrorExt(tif->tif_clientdata, module, "Unsupported BitsPerSample = %d",
162 td->td_bitspersample);
163 return (0);
164 }
165 return (1);
166 }
167
168 int
TIFFInitNeXT(TIFF * tif,int scheme)169 TIFFInitNeXT(TIFF* tif, int scheme)
170 {
171 (void) scheme;
172 tif->tif_predecode = NeXTPreDecode;
173 tif->tif_decoderow = NeXTDecode;
174 tif->tif_decodestrip = NeXTDecode;
175 tif->tif_decodetile = NeXTDecode;
176 return (1);
177 }
178 #endif /* NEXT_SUPPORT */
179
180 /* vim: set ts=8 sts=8 sw=8 noet: */
181 /*
182 * Local Variables:
183 * mode: c
184 * c-basic-offset: 8
185 * fill-column: 78
186 * End:
187 */
188