forked from KolibriOS/kolibrios
395 lines
8.4 KiB
C
395 lines
8.4 KiB
C
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/*
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jbig2dec
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Copyright (C) 2001-2005 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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#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 <stdio.h>
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#include <stdlib.h>
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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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#ifdef JBIG2_DEBUG
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#include <stdio.h>
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#endif
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struct _Jbig2ArithState {
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uint32_t C;
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int A;
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int CT;
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uint32_t next_word;
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int next_word_bytes;
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Jbig2WordStream *ws;
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int offset;
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};
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#undef SOFTWARE_CONVENTION
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/*
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A note on the "software conventions".
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Previously, I had misinterpreted the spec, and had thought that the
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spec's description of the "software convention" was wrong. Now I
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believe that this code is both correct and matches the spec, with
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SOFTWARE_CONVENTION defined or not. Thanks to William Rucklidge for
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the clarification.
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In any case, my benchmarking indicates no speed difference at all.
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Therefore, for now we will just use the normative version.
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*/
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static void
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jbig2_arith_bytein (Jbig2ArithState *as)
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{
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byte B;
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/* invariant: as->next_word_bytes > 0 */
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/* Figure G.3 */
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B = (byte)((as->next_word >> 24) & 0xFF);
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if (B == 0xFF)
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{
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byte B1;
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if (as->next_word_bytes == 1)
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{
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Jbig2WordStream *ws = as->ws;
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as->next_word = ws->get_next_word (ws, as->offset);
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as->offset += 4;
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B1 = (byte)((as->next_word >> 24) & 0xFF);
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if (B1 > 0x8F)
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{
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#ifdef JBIG2_DEBUG_ARITH
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fprintf(stderr, "read %02x (aa)\n", B);
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#endif
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#ifndef SOFTWARE_CONVENTION
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as->C += 0xFF00;
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#endif
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as->CT = 8;
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as->next_word = (0xFF00 | B1) << 16;
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as->next_word_bytes = 2;
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}
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else
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{
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#ifdef JBIG2_DEBUG_ARITH
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fprintf(stderr, "read %02x (a)\n", B);
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#endif
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#ifdef SOFTWARE_CONVENTION
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as->C += 0xFE00 - (B1 << 9);
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#else
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as->C += B1 << 9;
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#endif
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as->CT = 7;
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as->next_word_bytes = 4;
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}
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}
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else
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{
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B1 = (byte)((as->next_word >> 16) & 0xFF);
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if (B1 > 0x8F)
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{
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#ifdef JBIG2_DEBUG_ARITH
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fprintf(stderr, "read %02x (ba)\n", B);
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#endif
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#ifndef SOFTWARE_CONVENTION
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as->C += 0xFF00;
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#endif
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as->CT = 8;
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}
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else
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{
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as->next_word_bytes--;
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as->next_word <<= 8;
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#ifdef JBIG2_DEBUG_ARITH
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fprintf(stderr, "read %02x (b)\n", B);
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#endif
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#ifdef SOFTWARE_CONVENTION
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as->C += 0xFE00 - (B1 << 9);
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#else
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as->C += (B1 << 9);
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#endif
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as->CT = 7;
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}
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}
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}
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else
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{
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#ifdef JBIG2_DEBUG_ARITH
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fprintf(stderr, "read %02x\n", B);
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#endif
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as->CT = 8;
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as->next_word <<= 8;
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as->next_word_bytes--;
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if (as->next_word_bytes == 0)
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{
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Jbig2WordStream *ws = as->ws;
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as->next_word = ws->get_next_word (ws, as->offset);
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as->offset += 4;
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as->next_word_bytes = 4;
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}
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B = (byte)((as->next_word >> 24) & 0xFF);
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#ifdef SOFTWARE_CONVENTION
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as->C += 0xFF00 - (B << 8);
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#else
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as->C += (B << 8);
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#endif
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}
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}
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#if defined(JBIG2_DEBUG) || defined(JBIG2_DEBUG_ARITH)
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#include <stdio.h>
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static void
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jbig2_arith_trace (Jbig2ArithState *as, Jbig2ArithCx cx)
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{
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fprintf(stderr, "I = %2d, MPS = %d, A = %04x, CT = %2d, C = %08x\n",
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cx & 0x7f, cx >> 7, as->A, as->CT, as->C);
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}
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#endif
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/** Allocate and initialize a new arithmetic coding state
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* the returned pointer can simply be freed; this does
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* not affect the associated Jbig2WordStream.
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*/
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Jbig2ArithState *
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jbig2_arith_new (Jbig2Ctx *ctx, Jbig2WordStream *ws)
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{
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Jbig2ArithState *result;
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result = (Jbig2ArithState *)jbig2_alloc(ctx->allocator,
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sizeof(Jbig2ArithState));
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result->ws = ws;
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result->next_word = ws->get_next_word (ws, 0);
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result->next_word_bytes = 4;
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result->offset = 4;
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/* Figure G.1 */
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#ifdef SOFTWARE_CONVENTION
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result->C = (~(result->next_word >> 8)) & 0xFF0000;
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#else
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result->C = (result->next_word >> 8) & 0xFF0000;
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#endif
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jbig2_arith_bytein (result);
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result->C <<= 7;
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result->CT -= 7;
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result->A = 0x8000;
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return result;
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}
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/* could put bit fields in to minimize memory usage */
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typedef struct {
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unsigned short Qe;
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byte mps_xor; /* mps_xor = index ^ NMPS */
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byte lps_xor; /* lps_xor = index ^ NLPS ^ (SWITCH << 7) */
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} Jbig2ArithQe;
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const Jbig2ArithQe jbig2_arith_Qe[] = {
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{ 0x5601, 1 ^ 0, 1 ^ 0 ^ 0x80 },
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{ 0x3401, 2 ^ 1, 6 ^ 1 },
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{ 0x1801, 3 ^ 2, 9 ^ 2 },
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{ 0x0AC1, 4 ^ 3, 12 ^ 3 },
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{ 0x0521, 5 ^ 4, 29 ^ 4 },
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{ 0x0221, 38 ^ 5, 33 ^ 5 },
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{ 0x5601, 7 ^ 6, 6 ^ 6 ^ 0x80 },
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{ 0x5401, 8 ^ 7, 14 ^ 7 },
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{ 0x4801, 9 ^ 8, 14 ^ 8 },
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{ 0x3801, 10 ^ 9, 14 ^ 9 },
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{ 0x3001, 11 ^ 10, 17 ^ 10 },
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{ 0x2401, 12 ^ 11, 18 ^ 11 },
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{ 0x1C01, 13 ^ 12, 20 ^ 12 },
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{ 0x1601, 29 ^ 13, 21 ^ 13 },
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{ 0x5601, 15 ^ 14, 14 ^ 14 ^ 0x80 },
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{ 0x5401, 16 ^ 15, 14 ^ 15 },
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{ 0x5101, 17 ^ 16, 15 ^ 16 },
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{ 0x4801, 18 ^ 17, 16 ^ 17 },
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{ 0x3801, 19 ^ 18, 17 ^ 18 },
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{ 0x3401, 20 ^ 19, 18 ^ 19 },
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{ 0x3001, 21 ^ 20, 19 ^ 20 },
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{ 0x2801, 22 ^ 21, 19 ^ 21 },
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{ 0x2401, 23 ^ 22, 20 ^ 22 },
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{ 0x2201, 24 ^ 23, 21 ^ 23 },
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{ 0x1C01, 25 ^ 24, 22 ^ 24 },
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{ 0x1801, 26 ^ 25, 23 ^ 25 },
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{ 0x1601, 27 ^ 26, 24 ^ 26 },
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{ 0x1401, 28 ^ 27, 25 ^ 27 },
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{ 0x1201, 29 ^ 28, 26 ^ 28 },
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{ 0x1101, 30 ^ 29, 27 ^ 29 },
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{ 0x0AC1, 31 ^ 30, 28 ^ 30 },
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{ 0x09C1, 32 ^ 31, 29 ^ 31 },
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{ 0x08A1, 33 ^ 32, 30 ^ 32 },
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{ 0x0521, 34 ^ 33, 31 ^ 33 },
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{ 0x0441, 35 ^ 34, 32 ^ 34 },
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{ 0x02A1, 36 ^ 35, 33 ^ 35 },
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{ 0x0221, 37 ^ 36, 34 ^ 36 },
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{ 0x0141, 38 ^ 37, 35 ^ 37 },
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{ 0x0111, 39 ^ 38, 36 ^ 38 },
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{ 0x0085, 40 ^ 39, 37 ^ 39 },
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{ 0x0049, 41 ^ 40, 38 ^ 40 },
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{ 0x0025, 42 ^ 41, 39 ^ 41 },
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{ 0x0015, 43 ^ 42, 40 ^ 42 },
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{ 0x0009, 44 ^ 43, 41 ^ 43 },
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{ 0x0005, 45 ^ 44, 42 ^ 44 },
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{ 0x0001, 45 ^ 45, 43 ^ 45 },
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{ 0x5601, 46 ^ 46, 46 ^ 46 }
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};
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static void
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jbig2_arith_renormd (Jbig2ArithState *as)
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{
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/* Figure E.18 */
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do
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{
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if (as->CT == 0)
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jbig2_arith_bytein (as);
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as->A <<= 1;
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as->C <<= 1;
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as->CT--;
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}
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while ((as->A & 0x8000) == 0);
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}
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bool
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jbig2_arith_decode (Jbig2ArithState *as, Jbig2ArithCx *pcx)
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{
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Jbig2ArithCx cx = *pcx;
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const Jbig2ArithQe *pqe = &jbig2_arith_Qe[cx & 0x7f];
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bool D;
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/* Figure G.2 */
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as->A -= pqe->Qe;
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if (
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#ifdef SOFTWARE_CONVENTION
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/* Note: I do not think this is correct. See above. */
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(as->C >> 16) < as->A
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#else
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!((as->C >> 16) < pqe->Qe)
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#endif
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)
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{
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#ifndef SOFTWARE_CONVENTION
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as->C -= pqe->Qe << 16;
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#endif
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if ((as->A & 0x8000) == 0)
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{
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/* MPS_EXCHANGE, Figure E.16 */
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if (as->A < pqe->Qe)
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{
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D = 1 - (cx >> 7);
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*pcx ^= pqe->lps_xor;
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}
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else
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{
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D = cx >> 7;
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*pcx ^= pqe->mps_xor;
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}
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jbig2_arith_renormd (as);
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return D;
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}
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else
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return cx >> 7;
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}
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else
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{
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#ifdef SOFTWARE_CONVENTION
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as->C -= (as->A) << 16;
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#endif
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/* LPS_EXCHANGE, Figure E.17 */
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if (as->A < pqe->Qe)
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{
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as->A = pqe->Qe;
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D = cx >> 7;
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*pcx ^= pqe->mps_xor;
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}
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else
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{
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as->A = pqe->Qe;
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D = 1 - (cx >> 7);
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*pcx ^= pqe->lps_xor;
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}
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jbig2_arith_renormd (as);
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return D;
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}
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}
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#ifdef TEST
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static uint32_t
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test_get_word (Jbig2WordStream *self, int offset)
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{
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byte stream[] = {
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0x84, 0xC7, 0x3B, 0xFC, 0xE1, 0xA1, 0x43, 0x04, 0x02, 0x20, 0x00, 0x00,
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0x41, 0x0D, 0xBB, 0x86, 0xF4, 0x31, 0x7F, 0xFF, 0x88, 0xFF, 0x37, 0x47,
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0x1A, 0xDB, 0x6A, 0xDF, 0xFF, 0xAC,
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0x00, 0x00
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};
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if (offset >= sizeof(stream))
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return 0;
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else
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return (stream[offset] << 24) | (stream[offset + 1] << 16) |
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(stream[offset + 2] << 8) | stream[offset + 3];
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}
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int
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main (int argc, char **argv)
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{
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Jbig2Ctx *ctx;
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Jbig2WordStream ws;
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Jbig2ArithState *as;
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int i;
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Jbig2ArithCx cx = 0;
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ctx = jbig2_ctx_new(NULL, 0, NULL, NULL, NULL);
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ws.get_next_word = test_get_word;
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as = jbig2_arith_new (ctx, &ws);
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#ifdef JBIG2_DEBUG_ARITH
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jbig2_arith_trace (as, cx);
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|
|
#endif
|
||
|
|
|
||
|
|
for (i = 0; i < 256; i++)
|
||
|
|
{
|
||
|
|
bool D;
|
||
|
|
|
||
|
|
D = jbig2_arith_decode (as, &cx);
|
||
|
|
#ifdef JBIG2_DEBUG_ARITH
|
||
|
|
fprintf(stderr, "%3d: D = %d, ", i, D);
|
||
|
|
jbig2_arith_trace (as, cx);
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
jbig2_free(ctx->allocator, as);
|
||
|
|
|
||
|
|
jbig2_ctx_free(ctx);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
#endif
|