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
45 * PROVIDED BY THE COPYRIGHT HOLDERS THAT THE SOFTWARE DOES NOT INFRINGE
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
100static 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. */
107jpc_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
137error:
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. */
146void 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
160void 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
182void 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
189void 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
210void 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
223int 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). */
236int 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). */
247int 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. */
262static 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
298void 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