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8 * Copyright (c) 2002-2014, Professor Benoit Macq
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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 const struct opj_mqc_state *nmps;
65 /** next state if the next encoded symbol is the LPS */
66 const 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 /* only used by decoder, to count the number of times a terminating 0xFF >0x8F marker is read */
82 OPJ_UINT32 end_of_byte_stream_counter;
83 /** pointer to the current position in the buffer */
85 /** pointer to the start of the buffer */
87 /** pointer to the end of the buffer */
89 /** Array of contexts */
90 const opj_mqc_state_t *ctxs[MQC_NUMCTXS];
92 const opj_mqc_state_t **curctx;
93 /* lut_ctxno_zc shifted by (1 << 9) * bandno */
94 const OPJ_BYTE* lut_ctxno_zc_orient;
95 /** Original value of the 2 bytes at end[0] and end[1] */
96 OPJ_BYTE backup[OPJ_COMMON_CBLK_DATA_EXTRA];
99 #define BYPASS_CT_INIT 0xDEADBEEF
103 /** @name Exported functions */
105 /* ----------------------------------------------------------------------- */
108 Return the number of bytes written/read since initialisation
109 @param mqc MQC handle
110 @return Returns the number of bytes already encoded
112 OPJ_UINT32 opj_mqc_numbytes(opj_mqc_t *mqc);
114 Reset the states of all the context of the coder/decoder
115 (each context is set to a state where 0 and 1 are more or less equiprobable)
116 @param mqc MQC handle
118 void opj_mqc_resetstates(opj_mqc_t *mqc);
120 Set the state of a particular context
121 @param mqc MQC handle
122 @param ctxno Number that identifies the context
123 @param msb The MSB of the new state of the context
124 @param prob Number that identifies the probability of the symbols for the new state of the context
126 void opj_mqc_setstate(opj_mqc_t *mqc, OPJ_UINT32 ctxno, OPJ_UINT32 msb,
129 Initialize the encoder
130 @param mqc MQC handle
131 @param bp Pointer to the start of the buffer where the bytes will be written
133 void opj_mqc_init_enc(opj_mqc_t *mqc, OPJ_BYTE *bp);
135 Set the current context used for coding/decoding
136 @param mqc MQC handle
137 @param ctxno Number that identifies the context
139 #define opj_mqc_setcurctx(mqc, ctxno) (mqc)->curctx = &(mqc)->ctxs[(OPJ_UINT32)(ctxno)]
142 Flush the encoder, so that all remaining data is written
143 @param mqc MQC handle
145 void opj_mqc_flush(opj_mqc_t *mqc);
147 BYPASS mode switch, initialization operation.
149 @param mqc MQC handle
151 void opj_mqc_bypass_init_enc(opj_mqc_t *mqc);
153 /** Return number of extra bytes to add to opj_mqc_numbytes() for theĀ²
154 size of a non-terminating BYPASS pass
155 @param mqc MQC handle
156 @param erterm 1 if ERTERM is enabled, 0 otherwise
158 OPJ_UINT32 opj_mqc_bypass_get_extra_bytes(opj_mqc_t *mqc, OPJ_BOOL erterm);
161 BYPASS mode switch, coding operation.
163 @param mqc MQC handle
164 @param d The symbol to be encoded (0 or 1)
166 void opj_mqc_bypass_enc(opj_mqc_t *mqc, OPJ_UINT32 d);
168 BYPASS mode switch, flush operation
169 @param mqc MQC handle
170 @param erterm 1 if ERTERM is enabled, 0 otherwise
172 void opj_mqc_bypass_flush_enc(opj_mqc_t *mqc, OPJ_BOOL erterm);
175 @param mqc MQC handle
177 void opj_mqc_reset_enc(opj_mqc_t *mqc);
181 RESTART mode switch (TERMALL)
182 @param mqc MQC handle
183 @return Returns 1 (always)
185 OPJ_UINT32 opj_mqc_restart_enc(opj_mqc_t *mqc);
189 RESTART mode switch (TERMALL) reinitialisation
190 @param mqc MQC handle
192 void opj_mqc_restart_init_enc(opj_mqc_t *mqc);
194 ERTERM mode switch (PTERM)
195 @param mqc MQC handle
197 void opj_mqc_erterm_enc(opj_mqc_t *mqc);
199 SEGMARK mode switch (SEGSYM)
200 @param mqc MQC handle
202 void opj_mqc_segmark_enc(opj_mqc_t *mqc);
205 Initialize the decoder for MQ decoding.
207 opj_mqc_finish_dec() must be absolutely called after finishing the decoding
208 passes, so as to restore the bytes temporarily overwritten.
210 @param mqc MQC handle
211 @param bp Pointer to the start of the buffer from which the bytes will be read
212 Note that OPJ_COMMON_CBLK_DATA_EXTRA bytes at the end of the buffer
213 will be temporarily overwritten with an artificial 0xFF 0xFF marker.
214 (they will be backuped in the mqc structure to be restored later)
215 So bp must be at least len + OPJ_COMMON_CBLK_DATA_EXTRA large, and
217 @param len Length of the input buffer
218 @param extra_writable_bytes Indicate how many bytes after len are writable.
219 This is to indicate your consent that bp must be
222 void opj_mqc_init_dec(opj_mqc_t *mqc, OPJ_BYTE *bp, OPJ_UINT32 len,
223 OPJ_UINT32 extra_writable_bytes);
226 Initialize the decoder for RAW decoding.
228 opj_mqc_finish_dec() must be absolutely called after finishing the decoding
229 passes, so as to restore the bytes temporarily overwritten.
231 @param mqc MQC handle
232 @param bp Pointer to the start of the buffer from which the bytes will be read
233 Note that OPJ_COMMON_CBLK_DATA_EXTRA bytes at the end of the buffer
234 will be temporarily overwritten with an artificial 0xFF 0xFF marker.
235 (they will be backuped in the mqc structure to be restored later)
236 So bp must be at least len + OPJ_COMMON_CBLK_DATA_EXTRA large, and
238 @param len Length of the input buffer
239 @param extra_writable_bytes Indicate how many bytes after len are writable.
240 This is to indicate your consent that bp must be
243 void opj_mqc_raw_init_dec(opj_mqc_t *mqc, OPJ_BYTE *bp, OPJ_UINT32 len,
244 OPJ_UINT32 extra_writable_bytes);
248 Terminate RAW/MQC decoding
250 This restores the bytes temporarily overwritten by opj_mqc_init_dec()/
251 opj_mqc_raw_init_dec()
253 @param mqc MQC handle
255 void opq_mqc_finish_dec(opj_mqc_t *mqc);
259 @param mqc MQC handle
260 @return Returns the decoded symbol (0 or 1)
262 /*static INLINE OPJ_UINT32 opj_mqc_decode(opj_mqc_t * const mqc);*/
263 /* ----------------------------------------------------------------------- */
268 #endif /* OPJ_MQC_H */