2 * Copyright (c) 2002-2007, Communications and Remote Sensing Laboratory, Universite catholique de Louvain (UCL), Belgium
3 * Copyright (c) 2002-2007, Professor Benoit Macq
4 * Copyright (c) 2001-2003, David Janssens
5 * Copyright (c) 2002-2003, Yannick Verschueren
6 * Copyright (c) 2003-2007, Francois-Olivier Devaux and Antonin Descampe
7 * Copyright (c) 2005, Herve Drolon, FreeImage Team
8 * Copyright (c) 2008, Jerome Fimes, Communications & Systemes <jerome.fimes@c-s.fr>
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37 @brief Implementation of an MQ-Coder (MQC)
39 The functions in MQC.C have for goal to realize the MQ-coder operations. The functions
40 in MQC.C are used by some function in T1.C.
43 /** @defgroup MQC MQC - Implementation of an MQ-Coder */
47 This struct defines the state of a context.
49 typedef struct opj_mqc_state {
50 /** the probability of the Least Probable Symbol (0.75->0x8000, 1.5->0xffff) */
52 /** the Most Probable Symbol (0 or 1) */
54 /** next state if the next encoded symbol is the MPS */
55 struct opj_mqc_state *nmps;
56 /** next state if the next encoded symbol is the LPS */
57 struct opj_mqc_state *nlps;
60 #define MQC_NUMCTXS 19
65 typedef struct opj_mqc {
72 opj_mqc_state_t *ctxs[MQC_NUMCTXS];
73 opj_mqc_state_t **curctx;
75 unsigned char *buffer;
79 /** @name Exported functions */
81 /* ----------------------------------------------------------------------- */
83 Create a new MQC handle
84 @return Returns a new MQC handle if successful, returns NULL otherwise
86 opj_mqc_t* opj_mqc_create(void);
88 Destroy a previously created MQC handle
89 @param mqc MQC handle to destroy
91 void opj_mqc_destroy(opj_mqc_t *mqc);
93 Return the number of bytes written/read since initialisation
95 @return Returns the number of bytes already encoded
97 OPJ_UINT32 opj_mqc_numbytes(opj_mqc_t *mqc);
99 Reset the states of all the context of the coder/decoder
100 (each context is set to a state where 0 and 1 are more or less equiprobable)
101 @param mqc MQC handle
103 void opj_mqc_resetstates(opj_mqc_t *mqc);
105 Set the state of a particular context
106 @param mqc MQC handle
107 @param ctxno Number that identifies the context
108 @param msb The MSB of the new state of the context
109 @param prob Number that identifies the probability of the symbols for the new state of the context
111 void opj_mqc_setstate(opj_mqc_t *mqc, OPJ_UINT32 ctxno, OPJ_UINT32 msb, OPJ_INT32 prob);
113 Initialize the encoder
114 @param mqc MQC handle
115 @param bp Pointer to the start of the buffer where the bytes will be written
117 void opj_mqc_init_enc(opj_mqc_t *mqc, OPJ_BYTE *bp);
119 Set the current context used for coding/decoding
120 @param mqc MQC handle
121 @param ctxno Number that identifies the context
123 #define opj_mqc_setcurctx(mqc, ctxno) (mqc)->curctx = &(mqc)->ctxs[(OPJ_UINT32)(ctxno)]
125 Encode a symbol using the MQ-coder
126 @param mqc MQC handle
127 @param d The symbol to be encoded (0 or 1)
129 void opj_mqc_encode(opj_mqc_t *mqc, OPJ_UINT32 d);
131 Flush the encoder, so that all remaining data is written
132 @param mqc MQC handle
134 void opj_mqc_flush(opj_mqc_t *mqc);
136 BYPASS mode switch, initialization operation.
138 <h2>Not fully implemented and tested !!</h2>
139 @param mqc MQC handle
141 void opj_mqc_bypass_init_enc(opj_mqc_t *mqc);
143 BYPASS mode switch, coding operation.
145 <h2>Not fully implemented and tested !!</h2>
146 @param mqc MQC handle
147 @param d The symbol to be encoded (0 or 1)
149 void opj_mqc_bypass_enc(opj_mqc_t *mqc, OPJ_UINT32 d);
151 BYPASS mode switch, flush operation
152 <h2>Not fully implemented and tested !!</h2>
153 @param mqc MQC handle
154 @return Returns 1 (always)
156 OPJ_UINT32 opj_mqc_bypass_flush_enc(opj_mqc_t *mqc);
159 @param mqc MQC handle
161 void opj_mqc_reset_enc(opj_mqc_t *mqc);
163 RESTART mode switch (TERMALL)
164 @param mqc MQC handle
165 @return Returns 1 (always)
167 OPJ_UINT32 opj_mqc_restart_enc(opj_mqc_t *mqc);
169 RESTART mode switch (TERMALL) reinitialisation
170 @param mqc MQC handle
172 void opj_mqc_restart_init_enc(opj_mqc_t *mqc);
174 ERTERM mode switch (PTERM)
175 @param mqc MQC handle
177 void opj_mqc_erterm_enc(opj_mqc_t *mqc);
179 SEGMARK mode switch (SEGSYM)
180 @param mqc MQC handle
182 void opj_mqc_segmark_enc(opj_mqc_t *mqc);
184 Initialize the decoder
185 @param mqc MQC handle
186 @param bp Pointer to the start of the buffer from which the bytes will be read
187 @param len Length of the input buffer
189 opj_bool opj_mqc_init_dec(opj_mqc_t *mqc, OPJ_BYTE *bp, OPJ_UINT32 len);
192 @param mqc MQC handle
193 @return Returns the decoded symbol (0 or 1)
195 OPJ_INT32 opj_mqc_decode(opj_mqc_t * const mqc);
196 /* ----------------------------------------------------------------------- */