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
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36 @brief Implementation of an MQ-Coder (MQC)
38 The functions in MQC.C have for goal to realize the MQ-coder operations. The functions
39 in MQC.C are used by some function in T1.C.
42 /** @defgroup MQC MQC - Implementation of an MQ-Coder */
46 This struct defines the state of a context.
48 typedef struct opj_mqc_state {
49 /** the probability of the Least Probable Symbol (0.75->0x8000, 1.5->0xffff) */
51 /** the Most Probable Symbol (0 or 1) */
53 /** next state if the next encoded symbol is the MPS */
54 struct opj_mqc_state *nmps;
55 /** next state if the next encoded symbol is the LPS */
56 struct opj_mqc_state *nlps;
59 #define MQC_NUMCTXS 19
64 typedef struct opj_mqc {
71 opj_mqc_state_t *ctxs[MQC_NUMCTXS];
72 opj_mqc_state_t **curctx;
75 /** @name Exported functions */
77 /* ----------------------------------------------------------------------- */
79 Create a new MQC handle
80 @return Returns a new MQC handle if successful, returns NULL otherwise
82 opj_mqc_t* mqc_create(void);
84 Destroy a previously created MQC handle
85 @param mqc MQC handle to destroy
87 void mqc_destroy(opj_mqc_t *mqc);
89 Return the number of bytes written/read since initialisation
91 @return Returns the number of bytes already encoded
93 int mqc_numbytes(opj_mqc_t *mqc);
95 Reset the states of all the context of the coder/decoder
96 (each context is set to a state where 0 and 1 are more or less equiprobable)
99 void mqc_resetstates(opj_mqc_t *mqc);
101 Set the state of a particular context
102 @param mqc MQC handle
103 @param ctxno Number that identifies the context
104 @param msb The MSB of the new state of the context
105 @param prob Number that identifies the probability of the symbols for the new state of the context
107 void mqc_setstate(opj_mqc_t *mqc, int ctxno, int msb, int prob);
109 Initialize the encoder
110 @param mqc MQC handle
111 @param bp Pointer to the start of the buffer where the bytes will be written
113 void mqc_init_enc(opj_mqc_t *mqc, unsigned char *bp);
115 Set the current context used for coding/decoding
116 @param mqc MQC handle
117 @param ctxno Number that identifies the context
119 #define mqc_setcurctx(mqc, ctxno) (mqc)->curctx = &(mqc)->ctxs[(int)(ctxno)]
121 Encode a symbol using the MQ-coder
122 @param mqc MQC handle
123 @param d The symbol to be encoded (0 or 1)
125 void mqc_encode(opj_mqc_t *mqc, int d);
127 Flush the encoder, so that all remaining data is written
128 @param mqc MQC handle
130 void mqc_flush(opj_mqc_t *mqc);
132 BYPASS mode switch, initialization operation.
134 <h2>Not fully implemented and tested !!</h2>
135 @param mqc MQC handle
137 void mqc_bypass_init_enc(opj_mqc_t *mqc);
139 BYPASS mode switch, coding operation.
141 <h2>Not fully implemented and tested !!</h2>
142 @param mqc MQC handle
143 @param d The symbol to be encoded (0 or 1)
145 void mqc_bypass_enc(opj_mqc_t *mqc, int d);
147 BYPASS mode switch, flush operation
148 <h2>Not fully implemented and tested !!</h2>
149 @param mqc MQC handle
150 @return Returns 1 (always)
152 int mqc_bypass_flush_enc(opj_mqc_t *mqc);
155 @param mqc MQC handle
157 void mqc_reset_enc(opj_mqc_t *mqc);
159 RESTART mode switch (TERMALL)
160 @param mqc MQC handle
161 @return Returns 1 (always)
163 int mqc_restart_enc(opj_mqc_t *mqc);
165 RESTART mode switch (TERMALL) reinitialisation
166 @param mqc MQC handle
168 void mqc_restart_init_enc(opj_mqc_t *mqc);
170 ERTERM mode switch (PTERM)
171 @param mqc MQC handle
173 void mqc_erterm_enc(opj_mqc_t *mqc);
175 SEGMARK mode switch (SEGSYM)
176 @param mqc MQC handle
178 void mqc_segmark_enc(opj_mqc_t *mqc);
180 Initialize the decoder
181 @param mqc MQC handle
182 @param bp Pointer to the start of the buffer from which the bytes will be read
183 @param len Length of the input buffer
185 void mqc_init_dec(opj_mqc_t *mqc, unsigned char *bp, int len);
188 @param mqc MQC handle
189 @return Returns the decoded symbol (0 or 1)
191 int mqc_decode(opj_mqc_t *mqc);
192 /* ----------------------------------------------------------------------- */