1 /*
2  * Copyright (c) 1999-2000 Image Power, Inc. and the University of
3  *   British Columbia.
4  * Copyright (c) 2001-2003 Michael David Adams.
5  * All rights reserved.
6  */
7 
8 /* __START_OF_JASPER_LICENSE__
9  *
10  * JasPer License Version 2.0
11  *
12  * Copyright (c) 2001-2006 Michael David Adams
13  * Copyright (c) 1999-2000 Image Power, Inc.
14  * Copyright (c) 1999-2000 The University of British Columbia
15  *
16  * All rights reserved.
17  *
18  * Permission is hereby granted, free of charge, to any person (the
19  * "User") obtaining a copy of this software and associated documentation
20  * files (the "Software"), to deal in the Software without restriction,
21  * including without limitation the rights to use, copy, modify, merge,
22  * publish, distribute, and/or sell copies of the Software, and to permit
23  * persons to whom the Software is furnished to do so, subject to the
24  * following conditions:
25  *
26  * 1.  The above copyright notices and this permission notice (which
27  * includes the disclaimer below) shall be included in all copies or
28  * substantial portions of the Software.
29  *
30  * 2.  The name of a copyright holder shall not be used to endorse or
31  * promote products derived from the Software without specific prior
32  * written permission.
33  *
34  * THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS
35  * LICENSE.  NO USE OF THE SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER
36  * THIS DISCLAIMER.  THE SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS
37  * "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
38  * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
39  * PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.  IN NO
40  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL
41  * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING
42  * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
43  * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
44  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.  NO ASSURANCES ARE
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46  * THE PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS OF ANY OTHER ENTITY.
47  * EACH COPYRIGHT HOLDER DISCLAIMS ANY LIABILITY TO THE USER FOR CLAIMS
48  * BROUGHT BY ANY OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL
49  * PROPERTY RIGHTS OR OTHERWISE.  AS A CONDITION TO EXERCISING THE RIGHTS
50  * GRANTED HEREUNDER, EACH USER HEREBY ASSUMES SOLE RESPONSIBILITY TO SECURE
51  * ANY OTHER INTELLECTUAL PROPERTY RIGHTS NEEDED, IF ANY.  THE SOFTWARE
52  * IS NOT FAULT-TOLERANT AND IS NOT INTENDED FOR USE IN MISSION-CRITICAL
53  * SYSTEMS, SUCH AS THOSE USED IN THE OPERATION OF NUCLEAR FACILITIES,
54  * AIRCRAFT NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL
55  * SYSTEMS, DIRECT LIFE SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH
56  * THE FAILURE OF THE SOFTWARE OR SYSTEM COULD LEAD DIRECTLY TO DEATH,
57  * PERSONAL INJURY, OR SEVERE PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH
58  * RISK ACTIVITIES").  THE COPYRIGHT HOLDERS SPECIFICALLY DISCLAIM ANY
59  * EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR HIGH RISK ACTIVITIES.
60  *
61  * __END_OF_JASPER_LICENSE__
62  */
63 
64 /*
65  * MQ Arithmetic Decoder
66  *
67  * $Id: jpc_mqdec.c,v 1.2 2008-05-26 09:40:52 vp153 Exp $
68  */
69 
70 /******************************************************************************\
71 * Includes.
72 \******************************************************************************/
73 
74 #include <assert.h>
75 #include <stdlib.h>
76 #include <stdarg.h>
77 
78 #include "jasper/jas_types.h"
79 #include "jasper/jas_malloc.h"
80 #include "jasper/jas_math.h"
81 #include "jasper/jas_debug.h"
82 
83 #include "jpc_mqdec.h"
84 
85 /******************************************************************************\
86 * Local macros.
87 \******************************************************************************/
88 
89 #if defined(DEBUG)
90 #define	MQDEC_CALL(n, x) \
91     ((jas_getdbglevel() >= (n)) ? ((void)(x)) : ((void)0))
92 #else
93 #define	MQDEC_CALL(n, x)
94 #endif
95 
96 /******************************************************************************\
97 * Local function prototypes.
98 \******************************************************************************/
99 
100 static void jpc_mqdec_bytein(jpc_mqdec_t *mqdec);
101 
102 /******************************************************************************\
103 * Code for creation and destruction of a MQ decoder.
104 \******************************************************************************/
105 
106 /* Create a MQ decoder. */
jpc_mqdec_create(int maxctxs,jas_stream_t * in)107 jpc_mqdec_t *jpc_mqdec_create(int maxctxs, jas_stream_t *in)
108 {
109     jpc_mqdec_t *mqdec;
110 
111     /* There must be at least one context. */
112     assert(maxctxs > 0);
113 
114     /* Allocate memory for the MQ decoder. */
115     if (!(mqdec = jas_malloc(sizeof(jpc_mqdec_t)))) {
116         goto error;
117     }
118     mqdec->in = in;
119     mqdec->maxctxs = maxctxs;
120     /* Allocate memory for the per-context state information. */
121     if (!(mqdec->ctxs = jas_alloc2(mqdec->maxctxs, sizeof(jpc_mqstate_t *)))) {
122         goto error;
123     }
124     /* Set the current context to the first context. */
125     mqdec->curctx = mqdec->ctxs;
126 
127     /* If an input stream has been associated with the MQ decoder,
128       initialize the decoder state from the stream. */
129     if (mqdec->in) {
130         jpc_mqdec_init(mqdec);
131     }
132     /* Initialize the per-context state information. */
133     jpc_mqdec_setctxs(mqdec, 0, 0);
134 
135     return mqdec;
136 
137 error:
138     /* Oops...  Something has gone wrong. */
139     if (mqdec) {
140         jpc_mqdec_destroy(mqdec);
141     }
142     return 0;
143 }
144 
145 /* Destroy a MQ decoder. */
jpc_mqdec_destroy(jpc_mqdec_t * mqdec)146 void jpc_mqdec_destroy(jpc_mqdec_t *mqdec)
147 {
148     if (mqdec->ctxs) {
149         jas_free(mqdec->ctxs);
150     }
151     jas_free(mqdec);
152 }
153 
154 /******************************************************************************\
155 * Code for initialization of a MQ decoder.
156 \******************************************************************************/
157 
158 /* Initialize the state of a MQ decoder. */
159 
jpc_mqdec_init(jpc_mqdec_t * mqdec)160 void jpc_mqdec_init(jpc_mqdec_t *mqdec)
161 {
162     int c;
163 
164     mqdec->eof = 0;
165     mqdec->creg = 0;
166     /* Get the next byte from the input stream. */
167     if ((c = jas_stream_getc(mqdec->in)) == EOF) {
168         /* We have encountered an I/O error or EOF. */
169         c = 0xff;
170         mqdec->eof = 1;
171     }
172     mqdec->inbuffer = c;
173     mqdec->creg += mqdec->inbuffer << 16;
174     jpc_mqdec_bytein(mqdec);
175     mqdec->creg <<= 7;
176     mqdec->ctreg -= 7;
177     mqdec->areg = 0x8000;
178 }
179 
180 /* Set the input stream for a MQ decoder. */
181 
jpc_mqdec_setinput(jpc_mqdec_t * mqdec,jas_stream_t * in)182 void jpc_mqdec_setinput(jpc_mqdec_t *mqdec, jas_stream_t *in)
183 {
184     mqdec->in = in;
185 }
186 
187 /* Initialize one or more contexts. */
188 
jpc_mqdec_setctxs(jpc_mqdec_t * mqdec,int numctxs,jpc_mqctx_t * ctxs)189 void jpc_mqdec_setctxs(jpc_mqdec_t *mqdec, int numctxs, jpc_mqctx_t *ctxs)
190 {
191     jpc_mqstate_t **ctx;
192     int n;
193 
194     ctx = mqdec->ctxs;
195     n = JAS_MIN(mqdec->maxctxs, numctxs);
196     while (--n >= 0) {
197         *ctx = &jpc_mqstates[2 * ctxs->ind + ctxs->mps];
198         ++ctx;
199         ++ctxs;
200     }
201     n = mqdec->maxctxs - numctxs;
202     while (--n >= 0) {
203         *ctx = &jpc_mqstates[0];
204         ++ctx;
205     }
206 }
207 
208 /* Initialize a context. */
209 
jpc_mqdec_setctx(jpc_mqdec_t * mqdec,int ctxno,jpc_mqctx_t * ctx)210 void jpc_mqdec_setctx(jpc_mqdec_t *mqdec, int ctxno, jpc_mqctx_t *ctx)
211 {
212     jpc_mqstate_t **ctxi;
213     ctxi = &mqdec->ctxs[ctxno];
214     *ctxi = &jpc_mqstates[2 * ctx->ind + ctx->mps];
215 }
216 
217 /******************************************************************************\
218 * Code for decoding a bit.
219 \******************************************************************************/
220 
221 /* Decode a bit. */
222 
jpc_mqdec_getbit_func(register jpc_mqdec_t * mqdec)223 int jpc_mqdec_getbit_func(register jpc_mqdec_t *mqdec)
224 {
225     int bit;
226     JAS_DBGLOG(100, ("jpc_mqdec_getbit_func(%p)\n", mqdec));
227     MQDEC_CALL(100, jpc_mqdec_dump(mqdec, stderr));
228     bit = jpc_mqdec_getbit_macro(mqdec);
229     MQDEC_CALL(100, jpc_mqdec_dump(mqdec, stderr));
230     JAS_DBGLOG(100, ("ctx = %d, decoded %d\n", mqdec->curctx -
231       mqdec->ctxs, bit));
232     return bit;
233 }
234 
235 /* Apply MPS_EXCHANGE algorithm (with RENORMD). */
jpc_mqdec_mpsexchrenormd(register jpc_mqdec_t * mqdec)236 int jpc_mqdec_mpsexchrenormd(register jpc_mqdec_t *mqdec)
237 {
238     int ret;
239     register jpc_mqstate_t *state = *mqdec->curctx;
240     jpc_mqdec_mpsexchange(mqdec->areg, state->qeval, mqdec->curctx, ret);
241     jpc_mqdec_renormd(mqdec->areg, mqdec->creg, mqdec->ctreg, mqdec->in,
242       mqdec->eof, mqdec->inbuffer);
243     return ret;
244 }
245 
246 /* Apply LPS_EXCHANGE algorithm (with RENORMD). */
jpc_mqdec_lpsexchrenormd(register jpc_mqdec_t * mqdec)247 int jpc_mqdec_lpsexchrenormd(register jpc_mqdec_t *mqdec)
248 {
249     int ret;
250     register jpc_mqstate_t *state = *mqdec->curctx;
251     jpc_mqdec_lpsexchange(mqdec->areg, state->qeval, mqdec->curctx, ret);
252     jpc_mqdec_renormd(mqdec->areg, mqdec->creg, mqdec->ctreg, mqdec->in,
253       mqdec->eof, mqdec->inbuffer);
254     return ret;
255 }
256 
257 /******************************************************************************\
258 * Support code.
259 \******************************************************************************/
260 
261 /* Apply the BYTEIN algorithm. */
jpc_mqdec_bytein(jpc_mqdec_t * mqdec)262 static void jpc_mqdec_bytein(jpc_mqdec_t *mqdec)
263 {
264     int c;
265     unsigned char prevbuf;
266 
267     if (!mqdec->eof) {
268         if ((c = jas_stream_getc(mqdec->in)) == EOF) {
269             mqdec->eof = 1;
270             c = 0xff;
271         }
272         prevbuf = mqdec->inbuffer;
273         mqdec->inbuffer = c;
274         if (prevbuf == 0xff) {
275             if (c > 0x8f) {
276                 mqdec->creg += 0xff00;
277                 mqdec->ctreg = 8;
278             } else {
279                 mqdec->creg += c << 9;
280                 mqdec->ctreg = 7;
281             }
282         } else {
283             mqdec->creg += c << 8;
284             mqdec->ctreg = 8;
285         }
286     } else {
287         mqdec->creg += 0xff00;
288         mqdec->ctreg = 8;
289     }
290 }
291 
292 /******************************************************************************\
293 * Code for debugging.
294 \******************************************************************************/
295 
296 /* Dump a MQ decoder to a stream for debugging. */
297 
jpc_mqdec_dump(jpc_mqdec_t * mqdec,FILE * out)298 void jpc_mqdec_dump(jpc_mqdec_t *mqdec, FILE *out)
299 {
300     fprintf(out, "MQDEC A = %08lx, C = %08lx, CT=%08lx, ",
301       (unsigned long) mqdec->areg, (unsigned long) mqdec->creg,
302       (unsigned long) mqdec->ctreg);
303     fprintf(out, "CTX = %d, ", (int)(mqdec->curctx - mqdec->ctxs));
304     fprintf(out, "IND %d, MPS %d, QEVAL %x\n", (int)(*mqdec->curctx -
305       jpc_mqstates), (int)(*mqdec->curctx)->mps, (int)(*mqdec->curctx)->qeval);
306 }
307