jpc_mqdec.h
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
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39 * PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. IN NO
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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,
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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 * $Id$
68 */
69
70 #ifndef JPC_MQDEC_H
71 #define JPC_MQDEC_H
72
73 /******************************************************************************\
74 * Includes.
75 \******************************************************************************/
76
77 #include "jasper/jas_types.h"
78 #include "jasper/jas_stream.h"
79
80 #include "jpc_mqcod.h"
81
82 /******************************************************************************\
83 * Types.
84 \******************************************************************************/
85
86 /* MQ arithmetic decoder. */
87
88 typedef struct {
89
90 /* The C register. */
91 uint_fast32_t creg;
92
93 /* The A register. */
94 uint_fast32_t areg;
95
96 /* The CT register. */
97 uint_fast32_t ctreg;
98
99 /* The current context. */
100 jpc_mqstate_t **curctx;
101
102 /* The per-context information. */
103 jpc_mqstate_t **ctxs;
104
105 /* The maximum number of contexts. */
106 int maxctxs;
107
108 /* The stream from which to read data. */
109 jas_stream_t *in;
110
111 /* The last character read. */
112 jas_uchar inbuffer;
113
114 /* The EOF indicator. */
115 int eof;
116
117 } jpc_mqdec_t;
118
119 /******************************************************************************\
120 * Functions/macros for construction and destruction.
121 \******************************************************************************/
122
123 /* Create a MQ decoder. */
124 jpc_mqdec_t *jpc_mqdec_create(int maxctxs, jas_stream_t *in);
125
126 /* Destroy a MQ decoder. */
127 void jpc_mqdec_destroy(jpc_mqdec_t *dec);
128
129 /******************************************************************************\
130 * Functions/macros for initialization.
131 \******************************************************************************/
132
133 /* Set the input stream associated with a MQ decoder. */
134 void jpc_mqdec_setinput(jpc_mqdec_t *dec, jas_stream_t *in);
135
136 /* Initialize a MQ decoder. */
137 void jpc_mqdec_init(jpc_mqdec_t *dec);
138
139 /******************************************************************************\
140 * Functions/macros for manipulating contexts.
141 \******************************************************************************/
142
143 /* Set the current context for a MQ decoder. */
144 #define jpc_mqdec_setcurctx(dec, ctxno) \
145 ((mqdec)->curctx = &(mqdec)->ctxs[ctxno]);
146
147 /* Set the state information for a particular context of a MQ decoder. */
148 void jpc_mqdec_setctx(jpc_mqdec_t *dec, int ctxno, jpc_mqctx_t *ctx);
149
150 /* Set the state information for all contexts of a MQ decoder. */
151 void jpc_mqdec_setctxs(jpc_mqdec_t *dec, int numctxs, jpc_mqctx_t *ctxs);
152
153 /******************************************************************************\
154 * Functions/macros for decoding bits.
155 \******************************************************************************/
156
157 /* Decode a symbol. */
158 #if !defined(DEBUG)
159 #define jpc_mqdec_getbit(dec) \
160 jpc_mqdec_getbit_macro(dec)
161 #else
162 #define jpc_mqdec_getbit(dec) \
163 jpc_mqdec_getbit_func(dec)
164 #endif
165
166 /* Decode a symbol (assuming an unskewed probability distribution). */
167 #if !defined(DEBUG)
168 #define jpc_mqdec_getbitnoskew(dec) \
169 jpc_mqdec_getbit_macro(dec)
170 #else
171 #define jpc_mqdec_getbitnoskew(dec) \
172 jpc_mqdec_getbit_func(dec)
173 #endif
174
175 /******************************************************************************\
176 * Functions/macros for debugging.
177 \******************************************************************************/
178
179 /* Dump the MQ decoder state for debugging. */
180 void jpc_mqdec_dump(jpc_mqdec_t *dec, FILE *out);
181
182 /******************************************************************************\
183 * EVERYTHING BELOW THIS POINT IS IMPLEMENTATION SPECIFIC AND NOT PART OF THE
184 * APPLICATION INTERFACE. DO NOT RELY ON ANY OF THE INTERNAL FUNCTIONS/MACROS
185 * GIVEN BELOW.
186 \******************************************************************************/
187
188 #define jpc_mqdec_getbit_macro(dec) \
189 ((((dec)->areg -= (*(dec)->curctx)->qeval), \
190 (dec)->creg >> 16 >= (*(dec)->curctx)->qeval) ? \
191 ((((dec)->creg -= (*(dec)->curctx)->qeval << 16), \
192 (dec)->areg & 0x8000) ? (*(dec)->curctx)->mps : \
193 jpc_mqdec_mpsexchrenormd(dec)) : \
194 jpc_mqdec_lpsexchrenormd(dec))
195
196 #define jpc_mqdec_mpsexchange(areg, delta, curctx, bit) \
197 { \
198 if ((areg) < (delta)) { \
199 register jpc_mqstate_t *state = *(curctx); \
200 /* LPS decoded. */ \
201 (bit) = state->mps ^ 1; \
202 *(curctx) = state->nlps; \
203 } else { \
204 register jpc_mqstate_t *state = *(curctx); \
205 /* MPS decoded. */ \
206 (bit) = state->mps; \
207 *(curctx) = state->nmps; \
208 } \
209 }
210
211 #define jpc_mqdec_lpsexchange(areg, delta, curctx, bit) \
212 { \
213 if ((areg) >= (delta)) { \
214 register jpc_mqstate_t *state = *(curctx); \
215 (areg) = (delta); \
216 (bit) = state->mps ^ 1; \
217 *(curctx) = state->nlps; \
218 } else { \
219 register jpc_mqstate_t *state = *(curctx); \
220 (areg) = (delta); \
221 (bit) = state->mps; \
222 *(curctx) = state->nmps; \
223 } \
224 }
225
226 #define jpc_mqdec_renormd(areg, creg, ctreg, in, eof, inbuf) \
227 { \
228 do { \
229 if (!(ctreg)) { \
230 jpc_mqdec_bytein2(creg, ctreg, in, eof, inbuf); \
231 } \
232 (areg) <<= 1; \
233 (creg) <<= 1; \
234 --(ctreg); \
235 } while (!((areg) & 0x8000)); \
236 }
237
238 #define jpc_mqdec_bytein2(creg, ctreg, in, eof, inbuf) \
239 { \
240 int c; \
241 unsigned char prevbuf; \
242 if (!(eof)) { \
243 if ((c = jas_stream_getc(in)) == EOF) { \
244 (eof) = 1; \
245 c = 0xff; \
246 } \
247 prevbuf = (inbuf); \
248 (inbuf) = c; \
249 if (prevbuf == 0xff) { \
250 if (c > 0x8f) { \
251 (creg) += 0xff00; \
252 (ctreg) = 8; \
253 } else { \
254 (creg) += c << 9; \
255 (ctreg) = 7; \
256 } \
257 } else { \
258 (creg) += c << 8; \
259 (ctreg) = 8; \
260 } \
261 } else { \
262 (creg) += 0xff00; \
263 (ctreg) = 8; \
264 } \
265 }
266
267 int jpc_mqdec_getbit_func(jpc_mqdec_t *dec);
268 int jpc_mqdec_mpsexchrenormd(jpc_mqdec_t *dec);
269 int jpc_mqdec_lpsexchrenormd(jpc_mqdec_t *dec);
270
271 #endif