107 lines
2.7 KiB
C
107 lines
2.7 KiB
C
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/* Copyright (C) 2001-2019 Artifex Software, Inc.
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All Rights Reserved.
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This software is provided AS-IS with no warranty, either express or
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implied.
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This software is distributed under license and may not be copied,
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modified or distributed except as expressly authorized under the terms
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of the license contained in the file LICENSE in this distribution.
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Refer to licensing information at http://www.artifex.com or contact
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Artifex Software, Inc., 1305 Grant Avenue - Suite 200, Novato,
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CA 94945, U.S.A., +1(415)492-9861, for further information.
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*/
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/*
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jbig2dec
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*/
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/* Annex A.3 */
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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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#ifdef VERBOSE
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#include <stdio.h> /* for debug printing only */
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#endif
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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_iaid.h"
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struct _Jbig2ArithIaidCtx {
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int SBSYMCODELEN;
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Jbig2ArithCx *IAIDx;
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};
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Jbig2ArithIaidCtx *
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jbig2_arith_iaid_ctx_new(Jbig2Ctx *ctx, int SBSYMCODELEN)
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{
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Jbig2ArithIaidCtx *result = jbig2_new(ctx, Jbig2ArithIaidCtx, 1);
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int ctx_size = 1 << SBSYMCODELEN;
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if (result == NULL) {
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jbig2_error(ctx, JBIG2_SEVERITY_FATAL, -1, "failed to allocate IAID arithmetic coding state");
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return NULL;
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}
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result->SBSYMCODELEN = SBSYMCODELEN;
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result->IAIDx = jbig2_new(ctx, Jbig2ArithCx, ctx_size);
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if (result->IAIDx == NULL)
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{
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jbig2_free(ctx->allocator, result);
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jbig2_error(ctx, JBIG2_SEVERITY_FATAL, -1, "failed to allocate symbol ID in IAID arithmetic coding state");
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return NULL;
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}
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memset(result->IAIDx, 0, ctx_size);
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return result;
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}
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/* A.3 */
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/* Return value: -1 on error, 0 on normal value */
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int
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jbig2_arith_iaid_decode(Jbig2Ctx *ctx, Jbig2ArithIaidCtx *actx, Jbig2ArithState *as, int32_t *p_result)
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{
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Jbig2ArithCx *IAIDx = actx->IAIDx;
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int SBSYMCODELEN = actx->SBSYMCODELEN;
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int PREV = 1;
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int D;
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int i;
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int code = 0;
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/* A.3 (2) */
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for (i = 0; i < SBSYMCODELEN; i++) {
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D = jbig2_arith_decode(as, &IAIDx[PREV], &code);
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if (code)
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return jbig2_error(ctx, JBIG2_SEVERITY_FATAL, -1, "failed to decode IAIDx code");
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#ifdef VERBOSE
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fprintf(stderr, "IAID%x: D = %d\n", PREV, D);
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#endif
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PREV = (PREV << 1) | D;
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}
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/* A.3 (3) */
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PREV -= 1 << SBSYMCODELEN;
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#ifdef VERBOSE
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fprintf(stderr, "IAID result: %d\n", PREV);
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#endif
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*p_result = PREV;
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return 0;
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}
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void
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jbig2_arith_iaid_ctx_free(Jbig2Ctx *ctx, Jbig2ArithIaidCtx *iax)
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{
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if (iax != NULL) {
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jbig2_free(ctx->allocator, iax->IAIDx);
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jbig2_free(ctx->allocator, iax);
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}
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}
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