forked from KolibriOS/kolibrios
140 lines
2.6 KiB
C
Executable File
140 lines
2.6 KiB
C
Executable File
/*
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jbig2dec
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Copyright (C) 2001 Artifex Software, Inc.
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This software is provided AS-IS with no warranty,
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either express or implied.
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This software is distributed under license and may not
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be copied, modified or distributed except as expressly
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authorized under the terms of the license contained in
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the file LICENSE in this distribution.
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For further licensing information refer to http://artifex.com/ or
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contact Artifex Software, Inc., 7 Mt. Lassen Drive - Suite A-134,
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San Rafael, CA 94903, U.S.A., +1(415)492-9861.
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*/
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/* Annex A */
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "os_types.h"
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#include <stddef.h>
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#include <string.h> /* memset() */
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#include "jbig2.h"
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#include "jbig2_priv.h"
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#include "jbig2_arith.h"
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#include "jbig2_arith_int.h"
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struct _Jbig2ArithIntCtx {
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Jbig2ArithCx IAx[512];
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};
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Jbig2ArithIntCtx *
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jbig2_arith_int_ctx_new(Jbig2Ctx *ctx)
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{
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Jbig2ArithIntCtx *result = jbig2_new(ctx, Jbig2ArithIntCtx, 1);
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memset(result->IAx, 0, sizeof(result->IAx));
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return result;
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}
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/* A.2 */
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/* Return value: -1 on error, 0 on normal value, 1 on OOB return. */
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int
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jbig2_arith_int_decode(Jbig2ArithIntCtx *ctx, Jbig2ArithState *as,
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int32_t *p_result)
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{
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Jbig2ArithCx *IAx = ctx->IAx;
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int PREV = 1;
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int S, V;
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int bit;
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int n_tail, offset;
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int i;
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S = jbig2_arith_decode(as, &IAx[PREV]);
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PREV = (PREV << 1) | S;
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bit = jbig2_arith_decode(as, &IAx[PREV]);
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PREV = (PREV << 1) | bit;
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if (bit)
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{
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bit = jbig2_arith_decode(as, &IAx[PREV]);
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PREV = (PREV << 1) | bit;
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if (bit)
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{
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bit = jbig2_arith_decode(as, &IAx[PREV]);
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PREV = (PREV << 1) | bit;
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if (bit)
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{
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bit = jbig2_arith_decode(as, &IAx[PREV]);
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PREV = (PREV << 1) | bit;
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if (bit)
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{
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bit = jbig2_arith_decode(as, &IAx[PREV]);
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PREV = (PREV << 1) | bit;
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if (bit)
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{
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n_tail = 32;
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offset = 4436;
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}
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else
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{
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n_tail = 12;
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offset = 340;
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}
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}
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else
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{
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n_tail = 8;
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offset = 84;
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}
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}
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else
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{
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n_tail = 6;
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offset = 20;
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}
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}
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else
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{
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n_tail = 4;
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offset = 4;
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}
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}
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else
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{
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n_tail = 2;
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offset = 0;
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}
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V = 0;
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for (i = 0; i < n_tail; i++)
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{
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bit = jbig2_arith_decode(as, &IAx[PREV]);
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PREV = ((PREV << 1) & 511) | (PREV & 256) | bit;
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V = (V << 1) | bit;
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}
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V += offset;
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V = S ? -V : V;
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*p_result = V;
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return S && V == 0 ? 1 : 0;
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}
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void
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jbig2_arith_int_ctx_free(Jbig2Ctx *ctx, Jbig2ArithIntCtx *iax)
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{
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jbig2_free(ctx->allocator, iax);
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}
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