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1 /* $Id: tif_thunder.c,v 1.13 2016-09-04 21:32:56 erouault 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 #include <assert.h>
29 #ifdef THUNDER_SUPPORT
30 /*
31  * TIFF Library.
32  *
33  * ThunderScan 4-bit Compression Algorithm Support
34  */
35 
36 /*
37  * ThunderScan uses an encoding scheme designed for
38  * 4-bit pixel values.  Data is encoded in bytes, with
39  * each byte split into a 2-bit code word and a 6-bit
40  * data value.  The encoding gives raw data, runs of
41  * pixels, or pixel values encoded as a delta from the
42  * previous pixel value.  For the latter, either 2-bit
43  * or 3-bit delta values are used, with the deltas packed
44  * into a single byte.
45  */
46 #define	THUNDER_DATA		0x3f	/* mask for 6-bit data */
47 #define	THUNDER_CODE		0xc0	/* mask for 2-bit code word */
48 /* code values */
49 #define	THUNDER_RUN		0x00	/* run of pixels w/ encoded count */
50 #define	THUNDER_2BITDELTAS	0x40	/* 3 pixels w/ encoded 2-bit deltas */
51 #define	    DELTA2_SKIP		2	/* skip code for 2-bit deltas */
52 #define	THUNDER_3BITDELTAS	0x80	/* 2 pixels w/ encoded 3-bit deltas */
53 #define	    DELTA3_SKIP		4	/* skip code for 3-bit deltas */
54 #define	THUNDER_RAW		0xc0	/* raw data encoded */
55 
56 static const int twobitdeltas[4] = { 0, 1, 0, -1 };
57 static const int threebitdeltas[8] = { 0, 1, 2, 3, 0, -3, -2, -1 };
58 
59 #define	SETPIXEL(op, v) {                     \
60 	lastpixel = (v) & 0xf;                \
61         if ( npixels < maxpixels )         \
62         {                                     \
63 	  if (npixels++ & 1)                  \
64 	    *op++ |= lastpixel;               \
65 	  else                                \
66 	    op[0] = (uint8) (lastpixel << 4); \
67         }                                     \
68 }
69 
70 static int
ThunderSetupDecode(TIFF * tif)71 ThunderSetupDecode(TIFF* tif)
72 {
73 	static const char module[] = "ThunderSetupDecode";
74 
75         if( tif->tif_dir.td_bitspersample != 4 )
76         {
77                 TIFFErrorExt(tif->tif_clientdata, module,
78                              "Wrong bitspersample value (%d), Thunder decoder only supports 4bits per sample.",
79                              (int) tif->tif_dir.td_bitspersample );
80                 return 0;
81         }
82 
83 
84 	return (1);
85 }
86 
87 static int
ThunderDecode(TIFF * tif,uint8 * op,tmsize_t maxpixels)88 ThunderDecode(TIFF* tif, uint8* op, tmsize_t maxpixels)
89 {
90 	static const char module[] = "ThunderDecode";
91 	register unsigned char *bp;
92 	register tmsize_t cc;
93 	unsigned int lastpixel;
94 	tmsize_t npixels;
95 
96 	bp = (unsigned char *)tif->tif_rawcp;
97 	cc = tif->tif_rawcc;
98 	lastpixel = 0;
99 	npixels = 0;
100 	while (cc > 0 && npixels < maxpixels) {
101 		int n, delta;
102 
103 		n = *bp++;
104 		cc--;
105 		switch (n & THUNDER_CODE) {
106 		case THUNDER_RUN:		/* pixel run */
107 			/*
108 			 * Replicate the last pixel n times,
109 			 * where n is the lower-order 6 bits.
110 			 */
111 			if (npixels & 1) {
112 				op[0] |= lastpixel;
113 				lastpixel = *op++; npixels++; n--;
114 			} else
115 				lastpixel |= lastpixel << 4;
116 			npixels += n;
117 			if (npixels < maxpixels) {
118 				for (; n > 0; n -= 2)
119 					*op++ = (uint8) lastpixel;
120 			}
121 			if (n == -1)
122 				*--op &= 0xf0;
123 			lastpixel &= 0xf;
124 			break;
125 		case THUNDER_2BITDELTAS:	/* 2-bit deltas */
126 			if ((delta = ((n >> 4) & 3)) != DELTA2_SKIP)
127 				SETPIXEL(op, lastpixel + twobitdeltas[delta]);
128 			if ((delta = ((n >> 2) & 3)) != DELTA2_SKIP)
129 				SETPIXEL(op, lastpixel + twobitdeltas[delta]);
130 			if ((delta = (n & 3)) != DELTA2_SKIP)
131 				SETPIXEL(op, lastpixel + twobitdeltas[delta]);
132 			break;
133 		case THUNDER_3BITDELTAS:	/* 3-bit deltas */
134 			if ((delta = ((n >> 3) & 7)) != DELTA3_SKIP)
135 				SETPIXEL(op, lastpixel + threebitdeltas[delta]);
136 			if ((delta = (n & 7)) != DELTA3_SKIP)
137 				SETPIXEL(op, lastpixel + threebitdeltas[delta]);
138 			break;
139 		case THUNDER_RAW:		/* raw data */
140 			SETPIXEL(op, n);
141 			break;
142 		}
143 	}
144 	tif->tif_rawcp = (uint8*) bp;
145 	tif->tif_rawcc = cc;
146 	if (npixels != maxpixels) {
147 #if defined(__WIN32__) && (defined(_MSC_VER) || defined(__MINGW32__))
148 		TIFFErrorExt(tif->tif_clientdata, module,
149 			     "%s data at scanline %lu (%I64u != %I64u)",
150 			     npixels < maxpixels ? "Not enough" : "Too much",
151 			     (unsigned long) tif->tif_row,
152 			     (unsigned __int64) npixels,
153 			     (unsigned __int64) maxpixels);
154 #else
155 		TIFFErrorExt(tif->tif_clientdata, module,
156 			     "%s data at scanline %lu (%llu != %llu)",
157 			     npixels < maxpixels ? "Not enough" : "Too much",
158 			     (unsigned long) tif->tif_row,
159 			     (unsigned long long) npixels,
160 			     (unsigned long long) maxpixels);
161 #endif
162 		return (0);
163 	}
164 
165         return (1);
166 }
167 
168 static int
ThunderDecodeRow(TIFF * tif,uint8 * buf,tmsize_t occ,uint16 s)169 ThunderDecodeRow(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
170 {
171 	static const char module[] = "ThunderDecodeRow";
172 	uint8* row = buf;
173 
174 	(void) s;
175 	if (occ % tif->tif_scanlinesize)
176 	{
177 		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
178 		return (0);
179 	}
180 	while (occ > 0) {
181 		if (!ThunderDecode(tif, row, tif->tif_dir.td_imagewidth))
182 			return (0);
183 		occ -= tif->tif_scanlinesize;
184 		row += tif->tif_scanlinesize;
185 	}
186 	return (1);
187 }
188 
189 int
TIFFInitThunderScan(TIFF * tif,int scheme)190 TIFFInitThunderScan(TIFF* tif, int scheme)
191 {
192 	(void) scheme;
193 
194         tif->tif_setupdecode = ThunderSetupDecode;
195 	tif->tif_decoderow = ThunderDecodeRow;
196 	tif->tif_decodestrip = ThunderDecodeRow;
197 	return (1);
198 }
199 #endif /* THUNDER_SUPPORT */
200 
201 /* vim: set ts=8 sts=8 sw=8 noet: */
202 /*
203  * Local Variables:
204  * mode: c
205  * c-basic-offset: 8
206  * fill-column: 78
207  * End:
208  */
209