/* Copyright (C) 2001-2012 Artifex Software, Inc.

   All Rights Reserved.

   This software is provided AS-IS with no warranty, either express or

   implied.

   This software is distributed under license and may not be copied,

   modified or distributed except as expressly authorized under the terms

   of the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact

   Artifex Software, Inc.,  7 Mt. Lassen Drive - Suite A-134, San Rafael,

   CA  94903, U.S.A., +1(415)492-9861, for further information.

*/

/*

    jbig2dec

*/

/* Annex A.3 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include "os_types.h"

#include <stddef.h>

#include <string.h>             /* memset() */

#ifdef VERBOSE

#include <stdio.h>              /* for debug printing only */

#endif

#include "jbig2.h"

#include "jbig2_priv.h"

#include "jbig2_arith.h"

#include "jbig2_arith_iaid.h"

struct _Jbig2ArithIaidCtx {

    int SBSYMCODELEN;

    Jbig2ArithCx *IAIDx;

};

Jbig2ArithIaidCtx *

jbig2_arith_iaid_ctx_new(Jbig2Ctx *ctx, int SBSYMCODELEN)

{

    Jbig2ArithIaidCtx *result = jbig2_new(ctx, Jbig2ArithIaidCtx, 1);

    int ctx_size = 1 << SBSYMCODELEN;

    if (result == NULL) {

        jbig2_error(ctx, JBIG2_SEVERITY_FATAL, -1, "failed to allocate storage in jbig2_arith_iaid_ctx_new");

        return result;

    }

    result->SBSYMCODELEN = SBSYMCODELEN;

    result->IAIDx = jbig2_new(ctx, Jbig2ArithCx, ctx_size);

    if (result->IAIDx != NULL) {

        memset(result->IAIDx, 0, ctx_size);

    } else {

        jbig2_error(ctx, JBIG2_SEVERITY_FATAL, -1, "failed to allocate symbol ID storage in jbig2_arith_iaid_ctx_new");

    }

    return result;

}

/* A.3 */

/* Return value: -1 on error, 0 on normal value */

int

jbig2_arith_iaid_decode(Jbig2ArithIaidCtx *ctx, Jbig2ArithState *as, int32_t *p_result)

{

    Jbig2ArithCx *IAIDx = ctx->IAIDx;

    int SBSYMCODELEN = ctx->SBSYMCODELEN;

    int PREV = 1;

    int D;

    int i;

    /* A.3 (2) */

    for (i = 0; i < SBSYMCODELEN; i++) {

        D = jbig2_arith_decode(as, &IAIDx[PREV]);

#ifdef VERBOSE

        fprintf(stderr, "IAID%x: D = %d\n", PREV, D);

#endif

        PREV = (PREV << 1) | D;

    }

    /* A.3 (3) */

    PREV -= 1 << SBSYMCODELEN;

#ifdef VERBOSE

    fprintf(stderr, "IAID result: %d\n", PREV);

#endif

    *p_result = PREV;

    return 0;

}

void

jbig2_arith_iaid_ctx_free(Jbig2Ctx *ctx, Jbig2ArithIaidCtx *iax)

{

    if (iax != NULL) {

        jbig2_free(ctx->allocator, iax->IAIDx);

        jbig2_free(ctx->allocator, iax);

    }

}