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1 | /* $Header$ */ |
2 | ||
3 | /* | |
4 | * Copyright (c) 1988-1997 Sam Leffler | |
5 | * Copyright (c) 1991-1997 Silicon Graphics, Inc. | |
6 | * | |
615a9936 | 7 | * Permission to use, copy, modify, distribute, and sell this software and |
b47c832e RR |
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. | |
615a9936 DW |
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 | * | |
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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, | |
615a9936 DW |
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 | |
b47c832e RR |
24 | * OF THIS SOFTWARE. |
25 | */ | |
26 | ||
27 | #include "tiffiop.h" | |
28 | #ifdef PACKBITS_SUPPORT | |
29 | /* | |
30 | * TIFF Library. | |
31 | * | |
32 | * PackBits Compression Algorithm Support | |
33 | */ | |
34 | #include <assert.h> | |
35 | #include <stdio.h> | |
36 | ||
37 | static int | |
38 | PackBitsPreEncode(TIFF* tif, tsample_t s) | |
39 | { | |
40 | (void) s; | |
41 | /* | |
42 | * Calculate the scanline/tile-width size in bytes. | |
43 | */ | |
44 | if (isTiled(tif)) | |
45 | tif->tif_data = (tidata_t) TIFFTileRowSize(tif); | |
46 | else | |
47 | tif->tif_data = (tidata_t) TIFFScanlineSize(tif); | |
48 | return (1); | |
49 | } | |
50 | ||
51 | /* | |
52 | * NB: tidata is the type representing *(tidata_t); | |
53 | * if tidata_t is made signed then this type must | |
54 | * be adjusted accordingly. | |
55 | */ | |
56 | typedef unsigned char tidata; | |
57 | ||
58 | /* | |
59 | * Encode a run of pixels. | |
60 | */ | |
615a9936 | 61 | static int LINKAGEMODE |
b47c832e RR |
62 | PackBitsEncode(TIFF* tif, tidata_t buf, tsize_t cc, tsample_t s) |
63 | { | |
64 | u_char* bp = (u_char*) buf; | |
65 | tidata_t op, ep, lastliteral; | |
66 | long n, slop; | |
67 | int b; | |
68 | enum { BASE, LITERAL, RUN, LITERAL_RUN } state; | |
69 | ||
70 | (void) s; | |
71 | op = tif->tif_rawcp; | |
72 | ep = tif->tif_rawdata + tif->tif_rawdatasize; | |
73 | state = BASE; | |
74 | lastliteral = 0; | |
75 | while (cc > 0) { | |
76 | /* | |
77 | * Find the longest string of identical bytes. | |
78 | */ | |
79 | b = *bp++, cc--, n = 1; | |
80 | for (; cc > 0 && b == *bp; cc--, bp++) | |
81 | n++; | |
82 | again: | |
83 | if (op + 2 >= ep) { /* insure space for new data */ | |
84 | /* | |
85 | * Be careful about writing the last | |
86 | * literal. Must write up to that point | |
87 | * and then copy the remainder to the | |
88 | * front of the buffer. | |
89 | */ | |
90 | if (state == LITERAL || state == LITERAL_RUN) { | |
91 | slop = op - lastliteral; | |
92 | tif->tif_rawcc += lastliteral - tif->tif_rawcp; | |
93 | if (!TIFFFlushData1(tif)) | |
94 | return (-1); | |
95 | op = tif->tif_rawcp; | |
96 | while (slop-- > 0) | |
97 | *op++ = *lastliteral++; | |
98 | lastliteral = tif->tif_rawcp; | |
99 | } else { | |
100 | tif->tif_rawcc += op - tif->tif_rawcp; | |
101 | if (!TIFFFlushData1(tif)) | |
102 | return (-1); | |
103 | op = tif->tif_rawcp; | |
104 | } | |
105 | } | |
106 | switch (state) { | |
107 | case BASE: /* initial state, set run/literal */ | |
108 | if (n > 1) { | |
109 | state = RUN; | |
110 | if (n > 128) { | |
111 | *op++ = (tidata) -127; | |
112 | *op++ = b; | |
113 | n -= 128; | |
114 | goto again; | |
115 | } | |
116 | *op++ = (tidataval_t)(-(n-1)); | |
117 | *op++ = b; | |
118 | } else { | |
119 | lastliteral = op; | |
120 | *op++ = 0; | |
121 | *op++ = b; | |
122 | state = LITERAL; | |
123 | } | |
124 | break; | |
125 | case LITERAL: /* last object was literal string */ | |
126 | if (n > 1) { | |
127 | state = LITERAL_RUN; | |
128 | if (n > 128) { | |
129 | *op++ = (tidata) -127; | |
130 | *op++ = b; | |
131 | n -= 128; | |
132 | goto again; | |
133 | } | |
134 | *op++ = (tidataval_t)(-(n-1)); /* encode run */ | |
135 | *op++ = b; | |
136 | } else { /* extend literal */ | |
137 | if (++(*lastliteral) == 127) | |
138 | state = BASE; | |
139 | *op++ = b; | |
140 | } | |
141 | break; | |
142 | case RUN: /* last object was run */ | |
143 | if (n > 1) { | |
144 | if (n > 128) { | |
145 | *op++ = (tidata) -127; | |
146 | *op++ = b; | |
147 | n -= 128; | |
148 | goto again; | |
149 | } | |
150 | *op++ = (tidataval_t)(-(n-1)); | |
151 | *op++ = b; | |
152 | } else { | |
153 | lastliteral = op; | |
154 | *op++ = 0; | |
155 | *op++ = b; | |
156 | state = LITERAL; | |
157 | } | |
158 | break; | |
159 | case LITERAL_RUN: /* literal followed by a run */ | |
160 | /* | |
161 | * Check to see if previous run should | |
162 | * be converted to a literal, in which | |
163 | * case we convert literal-run-literal | |
164 | * to a single literal. | |
165 | */ | |
166 | if (n == 1 && op[-2] == (tidata) -1 && | |
167 | *lastliteral < 126) { | |
168 | state = (((*lastliteral) += 2) == 127 ? | |
169 | BASE : LITERAL); | |
170 | op[-2] = op[-1]; /* replicate */ | |
171 | } else | |
172 | state = RUN; | |
173 | goto again; | |
174 | } | |
175 | } | |
176 | tif->tif_rawcc += op - tif->tif_rawcp; | |
177 | tif->tif_rawcp = op; | |
178 | return (1); | |
179 | } | |
180 | ||
181 | /* | |
182 | * Encode a rectangular chunk of pixels. We break it up | |
183 | * into row-sized pieces to insure that encoded runs do | |
184 | * not span rows. Otherwise, there can be problems with | |
185 | * the decoder if data is read, for example, by scanlines | |
186 | * when it was encoded by strips. | |
187 | */ | |
615a9936 | 188 | static int LINKAGEMODE |
b47c832e RR |
189 | PackBitsEncodeChunk(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s) |
190 | { | |
191 | tsize_t rowsize = (tsize_t) tif->tif_data; | |
192 | ||
193 | assert(rowsize > 0); | |
194 | while ((long)cc > 0) { | |
195 | if (PackBitsEncode(tif, bp, rowsize, s) < 0) | |
196 | return (-1); | |
197 | bp += rowsize; | |
198 | cc -= rowsize; | |
199 | } | |
200 | return (1); | |
201 | } | |
202 | ||
615a9936 | 203 | static int LINKAGEMODE |
b47c832e RR |
204 | PackBitsDecode(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s) |
205 | { | |
206 | char *bp; | |
207 | tsize_t cc; | |
208 | long n; | |
209 | int b; | |
210 | ||
211 | (void) s; | |
212 | bp = (char*) tif->tif_rawcp; | |
213 | cc = tif->tif_rawcc; | |
214 | while (cc > 0 && (long)occ > 0) { | |
215 | n = (long) *bp++, cc--; | |
216 | /* | |
217 | * Watch out for compilers that | |
218 | * don't sign extend chars... | |
219 | */ | |
220 | if (n >= 128) | |
221 | n -= 256; | |
222 | if (n < 0) { /* replicate next byte -n+1 times */ | |
223 | if (n == -128) /* nop */ | |
224 | continue; | |
225 | n = -n + 1; | |
226 | occ -= n; | |
227 | b = *bp++, cc--; | |
228 | while (n-- > 0) | |
229 | *op++ = b; | |
230 | } else { /* copy next n+1 bytes literally */ | |
231 | _TIFFmemcpy(op, bp, ++n); | |
232 | op += n; occ -= n; | |
233 | bp += n; cc -= n; | |
234 | } | |
235 | } | |
236 | tif->tif_rawcp = (tidata_t) bp; | |
237 | tif->tif_rawcc = cc; | |
238 | if (occ > 0) { | |
239 | TIFFError(tif->tif_name, | |
240 | "PackBitsDecode: Not enough data for scanline %ld", | |
241 | (long) tif->tif_row); | |
242 | return (0); | |
243 | } | |
244 | /* check for buffer overruns? */ | |
245 | return (1); | |
246 | } | |
247 | ||
248 | int | |
249 | TIFFInitPackBits(TIFF* tif, int scheme) | |
250 | { | |
251 | (void) scheme; | |
252 | tif->tif_decoderow = PackBitsDecode; | |
253 | tif->tif_decodestrip = PackBitsDecode; | |
254 | tif->tif_decodetile = PackBitsDecode; | |
255 | tif->tif_preencode = PackBitsPreEncode; | |
256 | tif->tif_encoderow = PackBitsEncode; | |
257 | tif->tif_encodestrip = PackBitsEncodeChunk; | |
258 | tif->tif_encodetile = PackBitsEncodeChunk; | |
259 | return (1); | |
260 | } | |
261 | #endif /* PACKBITS_SUPPORT */ |