jpc_mqenc.h

/*
 * Copyright (c) 1999-2000 Image Power, Inc. and the University of
 *   British Columbia.
 * Copyright (c) 2001-2002 Michael David Adams.
 * All rights reserved.
 */
 
/* __START_OF_JASPER_LICENSE__
 * 
 * JasPer License Version 2.0
 * 
 * Copyright (c) 2001-2006 Michael David Adams
 * Copyright (c) 1999-2000 Image Power, Inc.
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 */
 
/*
 * MQ Arithmetic Encoder
 *
 * $Id$
 */
 
#ifndef JPC_MQENC_H
#define JPC_MQENC_H
 
/******************************************************************************\
* Includes.
\******************************************************************************/
 
#include "jasper/jas_types.h"
#include "jasper/jas_stream.h"
 
#include "jpc_mqcod.h"
 
/******************************************************************************\
* Constants.
\******************************************************************************/
 
/*
 * Termination modes.
 */
 
#define JPC_MQENC_DEFTERM       0       /* default termination */
#define JPC_MQENC_PTERM         1       /* predictable termination */
 
/******************************************************************************\
* Types.
\******************************************************************************/
 
/* MQ arithmetic encoder class. */
 
typedef struct {
 
        /* The C register. */
        uint_fast32_t creg;
 
        /* The A register. */
        uint_fast32_t areg;
 
        /* The CT register. */
        uint_fast32_t ctreg;
 
        /* The maximum number of contexts. */
        int maxctxs;
 
        /* The per-context information. */
        jpc_mqstate_t **ctxs;
 
        /* The current context. */
        jpc_mqstate_t **curctx;
 
        /* The stream for encoder output. */
        jas_stream_t *out;
 
        /* The byte buffer (i.e., the B variable in the standard). */
        int_fast16_t outbuf;
 
        /* The last byte output. */
        int_fast16_t lastbyte;
 
        /* The error indicator. */
        int err;
        
} jpc_mqenc_t;
 
/* MQ arithmetic encoder state information. */
 
typedef struct {
 
        /* The A register. */
        unsigned areg;
 
        /* The C register. */
        unsigned creg;
 
        /* The CT register. */
        unsigned ctreg;
 
        /* The last byte output by the encoder. */
        int lastbyte;
 
} jpc_mqencstate_t;
 
/******************************************************************************\
* Functions/macros for construction and destruction.
\******************************************************************************/
 
/* Create a MQ encoder. */
jpc_mqenc_t *jpc_mqenc_create(int maxctxs, jas_stream_t *out);
 
/* Destroy a MQ encoder. */
void jpc_mqenc_destroy(jpc_mqenc_t *enc);
 
/******************************************************************************\
* Functions/macros for initialization.
\******************************************************************************/
 
/* Initialize a MQ encoder. */
void jpc_mqenc_init(jpc_mqenc_t *enc);
 
/******************************************************************************\
* Functions/macros for context manipulation.
\******************************************************************************/
 
/* Set the current context. */
#define jpc_mqenc_setcurctx(enc, ctxno) \
        ((enc)->curctx = &(enc)->ctxs[ctxno]);
 
/* Set the state information for a particular context. */
void jpc_mqenc_setctx(jpc_mqenc_t *enc, int ctxno, jpc_mqctx_t *ctx);
 
/* Set the state information for multiple contexts. */
void jpc_mqenc_setctxs(jpc_mqenc_t *enc, int numctxs, jpc_mqctx_t *ctxs);
 
/******************************************************************************\
* Miscellaneous functions/macros.
\******************************************************************************/
 
/* Get the error state of a MQ encoder. */
#define jpc_mqenc_error(enc) \
        ((enc)->err)
 
/* Get the current encoder state. */
void jpc_mqenc_getstate(jpc_mqenc_t *enc, jpc_mqencstate_t *state);
 
/* Terminate the code. */
int jpc_mqenc_flush(jpc_mqenc_t *enc, int termmode);
 
/******************************************************************************\
* Functions/macros for encoding bits.
\******************************************************************************/
 
/* Encode a bit. */
#if !defined(DEBUG)
#define jpc_mqenc_putbit(enc, bit)      jpc_mqenc_putbit_macro(enc, bit)
#else
#define jpc_mqenc_putbit(enc, bit)      jpc_mqenc_putbit_func(enc, bit)
#endif
 
/******************************************************************************\
* Functions/macros for debugging.
\******************************************************************************/
 
int jpc_mqenc_dump(jpc_mqenc_t *mqenc, FILE *out);
 
/******************************************************************************\
* Implementation-specific details.
\******************************************************************************/
 
/* Note: This macro is included only to satisfy the needs of
  the mqenc_putbit macro. */
#define jpc_mqenc_putbit_macro(enc, bit) \
        (((*((enc)->curctx))->mps == (bit)) ? \
          (((enc)->areg -= (*(enc)->curctx)->qeval), \
          ((!((enc)->areg & 0x8000)) ? (jpc_mqenc_codemps2(enc)) : \
          ((enc)->creg += (*(enc)->curctx)->qeval))) : \
          jpc_mqenc_codelps(enc))
 
/* Note: These function prototypes are included only to satisfy the
  needs of the mqenc_putbit_macro macro.  Do not call any of these
  functions directly. */
int jpc_mqenc_codemps2(jpc_mqenc_t *enc);
int jpc_mqenc_codelps(jpc_mqenc_t *enc);
 
/* Note: This function prototype is included only to satisfy the needs of
  the mqenc_putbit macro. */
int jpc_mqenc_putbit_func(jpc_mqenc_t *enc, int bit);
 
#endif