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__
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 * JasPer License Version 2.0
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 * Copyright (c) 2001-2006 Michael David Adams
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/*
 * MQ Arithmetic Encoder
 *
 * $Id: jpc_mqenc.h,v 1.2 2008-05-26 09:40:52 vp153 Exp $
 */

#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