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8 * Copyright (c) 2002-2014, Professor Benoit Macq
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10 * Copyright (c) 2002-2003, Yannick Verschueren
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12 * Copyright (c) 2003-2014, Antonin Descampe
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42 #include "opj_common.h"
46 @brief Implementation of an MQ-Coder (MQC)
48 The functions in MQC.C have for goal to realize the MQ-coder operations. The functions
49 in MQC.C are used by some function in T1.C.
52 /** @defgroup MQC MQC - Implementation of an MQ-Coder */
56 This struct defines the state of a context.
58 typedef struct opj_mqc_state {
59 /** the probability of the Least Probable Symbol (0.75->0x8000, 1.5->0xffff) */
61 /** the Most Probable Symbol (0 or 1) */
63 /** next state if the next encoded symbol is the MPS */
64 struct opj_mqc_state *nmps;
65 /** next state if the next encoded symbol is the LPS */
66 struct opj_mqc_state *nlps;
69 #define MQC_NUMCTXS 19
74 typedef struct opj_mqc {
75 /** temporary buffer where bits are coded or decoded */
77 /** only used by MQ decoder */
79 /** number of bits already read or free to write */
81 /** pointer to the current position in the buffer */
83 /** pointer to the start of the buffer */
85 /** pointer to the end of the buffer */
87 /** Array of contexts */
88 opj_mqc_state_t *ctxs[MQC_NUMCTXS];
90 opj_mqc_state_t **curctx;
91 /* lut_ctxno_zc shifted by (1 << 9) * bandno */
92 const OPJ_BYTE* lut_ctxno_zc_orient;
93 /** Original value of the 2 bytes at end[0] and end[1] */
94 OPJ_BYTE backup[OPJ_COMMON_CBLK_DATA_EXTRA];
99 /** @name Exported functions */
101 /* ----------------------------------------------------------------------- */
104 Return the number of bytes written/read since initialisation
105 @param mqc MQC handle
106 @return Returns the number of bytes already encoded
108 OPJ_UINT32 opj_mqc_numbytes(opj_mqc_t *mqc);
110 Reset the states of all the context of the coder/decoder
111 (each context is set to a state where 0 and 1 are more or less equiprobable)
112 @param mqc MQC handle
114 void opj_mqc_resetstates(opj_mqc_t *mqc);
116 Set the state of a particular context
117 @param mqc MQC handle
118 @param ctxno Number that identifies the context
119 @param msb The MSB of the new state of the context
120 @param prob Number that identifies the probability of the symbols for the new state of the context
122 void opj_mqc_setstate(opj_mqc_t *mqc, OPJ_UINT32 ctxno, OPJ_UINT32 msb,
125 Initialize the encoder
126 @param mqc MQC handle
127 @param bp Pointer to the start of the buffer where the bytes will be written
129 void opj_mqc_init_enc(opj_mqc_t *mqc, OPJ_BYTE *bp);
131 Set the current context used for coding/decoding
132 @param mqc MQC handle
133 @param ctxno Number that identifies the context
135 #define opj_mqc_setcurctx(mqc, ctxno) (mqc)->curctx = &(mqc)->ctxs[(OPJ_UINT32)(ctxno)]
137 Encode a symbol using the MQ-coder
138 @param mqc MQC handle
139 @param d The symbol to be encoded (0 or 1)
141 void opj_mqc_encode(opj_mqc_t *mqc, OPJ_UINT32 d);
143 Flush the encoder, so that all remaining data is written
144 @param mqc MQC handle
146 void opj_mqc_flush(opj_mqc_t *mqc);
148 BYPASS mode switch, initialization operation.
150 <h2>Not fully implemented and tested !!</h2>
151 @param mqc MQC handle
153 void opj_mqc_bypass_init_enc(opj_mqc_t *mqc);
155 BYPASS mode switch, coding operation.
157 <h2>Not fully implemented and tested !!</h2>
158 @param mqc MQC handle
159 @param d The symbol to be encoded (0 or 1)
161 void opj_mqc_bypass_enc(opj_mqc_t *mqc, OPJ_UINT32 d);
163 BYPASS mode switch, flush operation
164 <h2>Not fully implemented and tested !!</h2>
165 @param mqc MQC handle
166 @return Returns 1 (always)
168 OPJ_UINT32 opj_mqc_bypass_flush_enc(opj_mqc_t *mqc);
171 @param mqc MQC handle
173 void opj_mqc_reset_enc(opj_mqc_t *mqc);
175 RESTART mode switch (TERMALL)
176 @param mqc MQC handle
177 @return Returns 1 (always)
179 OPJ_UINT32 opj_mqc_restart_enc(opj_mqc_t *mqc);
181 RESTART mode switch (TERMALL) reinitialisation
182 @param mqc MQC handle
184 void opj_mqc_restart_init_enc(opj_mqc_t *mqc);
186 ERTERM mode switch (PTERM)
187 @param mqc MQC handle
189 void opj_mqc_erterm_enc(opj_mqc_t *mqc);
191 SEGMARK mode switch (SEGSYM)
192 @param mqc MQC handle
194 void opj_mqc_segmark_enc(opj_mqc_t *mqc);
197 Initialize the decoder for MQ decoding.
199 opj_mqc_finish_dec() must be absolutely called after finishing the decoding
200 passes, so as to restore the bytes temporarily overwritten.
202 @param mqc MQC handle
203 @param bp Pointer to the start of the buffer from which the bytes will be read
204 Note that OPJ_COMMON_CBLK_DATA_EXTRA bytes at the end of the buffer
205 will be temporarily overwritten with an artificial 0xFF 0xFF marker.
206 (they will be backuped in the mqc structure to be restored later)
207 So bp must be at least len + OPJ_COMMON_CBLK_DATA_EXTRA large, and
209 @param len Length of the input buffer
210 @param extra_writable_bytes Indicate how many bytes after len are writable.
211 This is to indicate your consent that bp must be
214 void opj_mqc_init_dec(opj_mqc_t *mqc, OPJ_BYTE *bp, OPJ_UINT32 len,
215 OPJ_UINT32 extra_writable_bytes);
218 Initialize the decoder for RAW decoding.
220 opj_mqc_finish_dec() must be absolutely called after finishing the decoding
221 passes, so as to restore the bytes temporarily overwritten.
223 @param mqc MQC handle
224 @param bp Pointer to the start of the buffer from which the bytes will be read
225 Note that OPJ_COMMON_CBLK_DATA_EXTRA bytes at the end of the buffer
226 will be temporarily overwritten with an artificial 0xFF 0xFF marker.
227 (they will be backuped in the mqc structure to be restored later)
228 So bp must be at least len + OPJ_COMMON_CBLK_DATA_EXTRA large, and
230 @param len Length of the input buffer
231 @param extra_writable_bytes Indicate how many bytes after len are writable.
232 This is to indicate your consent that bp must be
235 void opj_mqc_raw_init_dec(opj_mqc_t *mqc, OPJ_BYTE *bp, OPJ_UINT32 len,
236 OPJ_UINT32 extra_writable_bytes);
240 Terminate RAW/MQC decoding
242 This restores the bytes temporarily overwritten by opj_mqc_init_dec()/
243 opj_mqc_raw_init_dec()
245 @param mqc MQC handle
247 void opq_mqc_finish_dec(opj_mqc_t *mqc);
251 @param mqc MQC handle
252 @return Returns the decoded symbol (0 or 1)
254 /*static INLINE OPJ_UINT32 opj_mqc_decode(opj_mqc_t * const mqc);*/
255 /* ----------------------------------------------------------------------- */