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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];
101 /** @name Exported functions */
103 /* ----------------------------------------------------------------------- */
106 Return the number of bytes written/read since initialisation
107 @param mqc MQC handle
108 @return Returns the number of bytes already encoded
110 OPJ_UINT32 opj_mqc_numbytes(opj_mqc_t *mqc);
112 Reset the states of all the context of the coder/decoder
113 (each context is set to a state where 0 and 1 are more or less equiprobable)
114 @param mqc MQC handle
116 void opj_mqc_resetstates(opj_mqc_t *mqc);
118 Set the state of a particular context
119 @param mqc MQC handle
120 @param ctxno Number that identifies the context
121 @param msb The MSB of the new state of the context
122 @param prob Number that identifies the probability of the symbols for the new state of the context
124 void opj_mqc_setstate(opj_mqc_t *mqc, OPJ_UINT32 ctxno, OPJ_UINT32 msb,
127 Initialize the encoder
128 @param mqc MQC handle
129 @param bp Pointer to the start of the buffer where the bytes will be written
131 void opj_mqc_init_enc(opj_mqc_t *mqc, OPJ_BYTE *bp);
133 Set the current context used for coding/decoding
134 @param mqc MQC handle
135 @param ctxno Number that identifies the context
137 #define opj_mqc_setcurctx(mqc, ctxno) (mqc)->curctx = &(mqc)->ctxs[(OPJ_UINT32)(ctxno)]
139 Encode a symbol using the MQ-coder
140 @param mqc MQC handle
141 @param d The symbol to be encoded (0 or 1)
143 void opj_mqc_encode(opj_mqc_t *mqc, OPJ_UINT32 d);
145 Flush the encoder, so that all remaining data is written
146 @param mqc MQC handle
148 void opj_mqc_flush(opj_mqc_t *mqc);
150 BYPASS mode switch, initialization operation.
152 @param mqc MQC handle
154 void opj_mqc_bypass_init_enc(opj_mqc_t *mqc);
156 /** Return number of extra bytes to add to opj_mqc_numbytes() for theĀ²
157 size of a non-terminating BYPASS pass
158 @param mqc MQC handle
159 @param erterm 1 if ERTERM is enabled, 0 otherwise
161 OPJ_UINT32 opj_mqc_bypass_get_extra_bytes(opj_mqc_t *mqc, OPJ_BOOL erterm);
164 BYPASS mode switch, coding operation.
166 @param mqc MQC handle
167 @param d The symbol to be encoded (0 or 1)
169 void opj_mqc_bypass_enc(opj_mqc_t *mqc, OPJ_UINT32 d);
171 BYPASS mode switch, flush operation
172 @param mqc MQC handle
173 @param erterm 1 if ERTERM is enabled, 0 otherwise
175 void opj_mqc_bypass_flush_enc(opj_mqc_t *mqc, OPJ_BOOL erterm);
178 @param mqc MQC handle
180 void opj_mqc_reset_enc(opj_mqc_t *mqc);
184 RESTART mode switch (TERMALL)
185 @param mqc MQC handle
186 @return Returns 1 (always)
188 OPJ_UINT32 opj_mqc_restart_enc(opj_mqc_t *mqc);
192 RESTART mode switch (TERMALL) reinitialisation
193 @param mqc MQC handle
195 void opj_mqc_restart_init_enc(opj_mqc_t *mqc);
197 ERTERM mode switch (PTERM)
198 @param mqc MQC handle
200 void opj_mqc_erterm_enc(opj_mqc_t *mqc);
202 SEGMARK mode switch (SEGSYM)
203 @param mqc MQC handle
205 void opj_mqc_segmark_enc(opj_mqc_t *mqc);
208 Initialize the decoder for MQ decoding.
210 opj_mqc_finish_dec() must be absolutely called after finishing the decoding
211 passes, so as to restore the bytes temporarily overwritten.
213 @param mqc MQC handle
214 @param bp Pointer to the start of the buffer from which the bytes will be read
215 Note that OPJ_COMMON_CBLK_DATA_EXTRA bytes at the end of the buffer
216 will be temporarily overwritten with an artificial 0xFF 0xFF marker.
217 (they will be backuped in the mqc structure to be restored later)
218 So bp must be at least len + OPJ_COMMON_CBLK_DATA_EXTRA large, and
220 @param len Length of the input buffer
221 @param extra_writable_bytes Indicate how many bytes after len are writable.
222 This is to indicate your consent that bp must be
225 void opj_mqc_init_dec(opj_mqc_t *mqc, OPJ_BYTE *bp, OPJ_UINT32 len,
226 OPJ_UINT32 extra_writable_bytes);
229 Initialize the decoder for RAW decoding.
231 opj_mqc_finish_dec() must be absolutely called after finishing the decoding
232 passes, so as to restore the bytes temporarily overwritten.
234 @param mqc MQC handle
235 @param bp Pointer to the start of the buffer from which the bytes will be read
236 Note that OPJ_COMMON_CBLK_DATA_EXTRA bytes at the end of the buffer
237 will be temporarily overwritten with an artificial 0xFF 0xFF marker.
238 (they will be backuped in the mqc structure to be restored later)
239 So bp must be at least len + OPJ_COMMON_CBLK_DATA_EXTRA large, and
241 @param len Length of the input buffer
242 @param extra_writable_bytes Indicate how many bytes after len are writable.
243 This is to indicate your consent that bp must be
246 void opj_mqc_raw_init_dec(opj_mqc_t *mqc, OPJ_BYTE *bp, OPJ_UINT32 len,
247 OPJ_UINT32 extra_writable_bytes);
251 Terminate RAW/MQC decoding
253 This restores the bytes temporarily overwritten by opj_mqc_init_dec()/
254 opj_mqc_raw_init_dec()
256 @param mqc MQC handle
258 void opq_mqc_finish_dec(opj_mqc_t *mqc);
262 @param mqc MQC handle
263 @return Returns the decoded symbol (0 or 1)
265 /*static INLINE OPJ_UINT32 opj_mqc_decode(opj_mqc_t * const mqc);*/
266 /* ----------------------------------------------------------------------- */
271 #endif /* OPJ_MQC_H */