+++ /dev/null
-//========================================================================
-//
-// JArithmeticDecoder.cc
-//
-// Copyright 2002-2004 Glyph & Cog, LLC
-//
-//========================================================================
-
-#include <aconf.h>
-
-#ifdef USE_GCC_PRAGMAS
-#pragma implementation
-#endif
-
-#include "Object.h"
-#include "Stream.h"
-#include "JArithmeticDecoder.h"
-
-//------------------------------------------------------------------------
-// JArithmeticDecoderStates
-//------------------------------------------------------------------------
-
-JArithmeticDecoderStats::JArithmeticDecoderStats(int contextSizeA) {
- contextSize = contextSizeA;
- cxTab = (Guchar *)gmallocn(contextSize, sizeof(Guchar));
- reset();
-}
-
-JArithmeticDecoderStats::~JArithmeticDecoderStats() {
- gfree(cxTab);
-}
-
-JArithmeticDecoderStats *JArithmeticDecoderStats::copy() {
- JArithmeticDecoderStats *stats;
-
- stats = new JArithmeticDecoderStats(contextSize);
- memcpy(stats->cxTab, cxTab, contextSize);
- return stats;
-}
-
-void JArithmeticDecoderStats::reset() {
- memset(cxTab, 0, contextSize);
-}
-
-void JArithmeticDecoderStats::copyFrom(JArithmeticDecoderStats *stats) {
- memcpy(cxTab, stats->cxTab, contextSize);
-}
-
-void JArithmeticDecoderStats::setEntry(Guint cx, int i, int mps) {
- cxTab[cx] = (i << 1) + mps;
-}
-
-//------------------------------------------------------------------------
-// JArithmeticDecoder
-//------------------------------------------------------------------------
-
-Guint JArithmeticDecoder::qeTab[47] = {
- 0x56010000, 0x34010000, 0x18010000, 0x0AC10000,
- 0x05210000, 0x02210000, 0x56010000, 0x54010000,
- 0x48010000, 0x38010000, 0x30010000, 0x24010000,
- 0x1C010000, 0x16010000, 0x56010000, 0x54010000,
- 0x51010000, 0x48010000, 0x38010000, 0x34010000,
- 0x30010000, 0x28010000, 0x24010000, 0x22010000,
- 0x1C010000, 0x18010000, 0x16010000, 0x14010000,
- 0x12010000, 0x11010000, 0x0AC10000, 0x09C10000,
- 0x08A10000, 0x05210000, 0x04410000, 0x02A10000,
- 0x02210000, 0x01410000, 0x01110000, 0x00850000,
- 0x00490000, 0x00250000, 0x00150000, 0x00090000,
- 0x00050000, 0x00010000, 0x56010000
-};
-
-int JArithmeticDecoder::nmpsTab[47] = {
- 1, 2, 3, 4, 5, 38, 7, 8, 9, 10, 11, 12, 13, 29, 15, 16,
- 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,
- 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 45, 46
-};
-
-int JArithmeticDecoder::nlpsTab[47] = {
- 1, 6, 9, 12, 29, 33, 6, 14, 14, 14, 17, 18, 20, 21, 14, 14,
- 15, 16, 17, 18, 19, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
- 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 46
-};
-
-int JArithmeticDecoder::switchTab[47] = {
- 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
- 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
- 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
-};
-
-JArithmeticDecoder::JArithmeticDecoder() {
- str = NULL;
- dataLen = 0;
- limitStream = gFalse;
-}
-
-inline Guint JArithmeticDecoder::readByte() {
- if (limitStream) {
- --dataLen;
- if (dataLen < 0) {
- return 0xff;
- }
- }
- return (Guint)str->getChar() & 0xff;
-}
-
-JArithmeticDecoder::~JArithmeticDecoder() {
- cleanup();
-}
-
-void JArithmeticDecoder::start() {
- buf0 = readByte();
- buf1 = readByte();
-
- // INITDEC
- c = (buf0 ^ 0xff) << 16;
- byteIn();
- c <<= 7;
- ct -= 7;
- a = 0x80000000;
-}
-
-void JArithmeticDecoder::restart(int dataLenA) {
- int oldDataLen;
-
- oldDataLen = dataLen;
- dataLen = dataLenA;
- if (oldDataLen == -1) {
- buf1 = readByte();
- } else if (oldDataLen <= -2) {
- buf0 = readByte();
- buf1 = readByte();
- }
-}
-
-void JArithmeticDecoder::cleanup() {
- if (limitStream) {
- while (dataLen > 0) {
- buf0 = buf1;
- buf1 = readByte();
- }
- }
-}
-
-int JArithmeticDecoder::decodeBit(Guint context,
- JArithmeticDecoderStats *stats) {
- int bit;
- Guint qe;
- int iCX, mpsCX;
-
- iCX = stats->cxTab[context] >> 1;
- mpsCX = stats->cxTab[context] & 1;
- qe = qeTab[iCX];
- a -= qe;
- if (c < a) {
- if (a & 0x80000000) {
- bit = mpsCX;
- } else {
- // MPS_EXCHANGE
- if (a < qe) {
- bit = 1 - mpsCX;
- if (switchTab[iCX]) {
- stats->cxTab[context] = (nlpsTab[iCX] << 1) | (1 - mpsCX);
- } else {
- stats->cxTab[context] = (nlpsTab[iCX] << 1) | mpsCX;
- }
- } else {
- bit = mpsCX;
- stats->cxTab[context] = (nmpsTab[iCX] << 1) | mpsCX;
- }
- // RENORMD
- do {
- if (ct == 0) {
- byteIn();
- }
- a <<= 1;
- c <<= 1;
- --ct;
- } while (!(a & 0x80000000));
- }
- } else {
- c -= a;
- // LPS_EXCHANGE
- if (a < qe) {
- bit = mpsCX;
- stats->cxTab[context] = (nmpsTab[iCX] << 1) | mpsCX;
- } else {
- bit = 1 - mpsCX;
- if (switchTab[iCX]) {
- stats->cxTab[context] = (nlpsTab[iCX] << 1) | (1 - mpsCX);
- } else {
- stats->cxTab[context] = (nlpsTab[iCX] << 1) | mpsCX;
- }
- }
- a = qe;
- // RENORMD
- do {
- if (ct == 0) {
- byteIn();
- }
- a <<= 1;
- c <<= 1;
- --ct;
- } while (!(a & 0x80000000));
- }
- return bit;
-}
-
-int JArithmeticDecoder::decodeByte(Guint context,
- JArithmeticDecoderStats *stats) {
- int byte;
- int i;
-
- byte = 0;
- for (i = 0; i < 8; ++i) {
- byte = (byte << 1) | decodeBit(context, stats);
- }
- return byte;
-}
-
-GBool JArithmeticDecoder::decodeInt(int *x, JArithmeticDecoderStats *stats) {
- int s;
- Guint v;
- int i;
-
- prev = 1;
- s = decodeIntBit(stats);
- if (decodeIntBit(stats)) {
- if (decodeIntBit(stats)) {
- if (decodeIntBit(stats)) {
- if (decodeIntBit(stats)) {
- if (decodeIntBit(stats)) {
- v = 0;
- for (i = 0; i < 32; ++i) {
- v = (v << 1) | decodeIntBit(stats);
- }
- v += 4436;
- } else {
- v = 0;
- for (i = 0; i < 12; ++i) {
- v = (v << 1) | decodeIntBit(stats);
- }
- v += 340;
- }
- } else {
- v = 0;
- for (i = 0; i < 8; ++i) {
- v = (v << 1) | decodeIntBit(stats);
- }
- v += 84;
- }
- } else {
- v = 0;
- for (i = 0; i < 6; ++i) {
- v = (v << 1) | decodeIntBit(stats);
- }
- v += 20;
- }
- } else {
- v = decodeIntBit(stats);
- v = (v << 1) | decodeIntBit(stats);
- v = (v << 1) | decodeIntBit(stats);
- v = (v << 1) | decodeIntBit(stats);
- v += 4;
- }
- } else {
- v = decodeIntBit(stats);
- v = (v << 1) | decodeIntBit(stats);
- }
-
- if (s) {
- if (v == 0) {
- return gFalse;
- }
- *x = -(int)v;
- } else {
- *x = (int)v;
- }
- return gTrue;
-}
-
-int JArithmeticDecoder::decodeIntBit(JArithmeticDecoderStats *stats) {
- int bit;
-
- bit = decodeBit(prev, stats);
- if (prev < 0x100) {
- prev = (prev << 1) | bit;
- } else {
- prev = (((prev << 1) | bit) & 0x1ff) | 0x100;
- }
- return bit;
-}
-
-Guint JArithmeticDecoder::decodeIAID(Guint codeLen,
- JArithmeticDecoderStats *stats) {
- Guint i;
- int bit;
-
- prev = 1;
- for (i = 0; i < codeLen; ++i) {
- bit = decodeBit(prev, stats);
- prev = (prev << 1) | bit;
- }
- return prev - (1 << codeLen);
-}
-
-void JArithmeticDecoder::byteIn() {
- if (buf0 == 0xff) {
- if (buf1 > 0x8f) {
- ct = 8;
- } else {
- buf0 = buf1;
- buf1 = readByte();
- c = c + 0xfe00 - (buf0 << 9);
- ct = 7;
- }
- } else {
- buf0 = buf1;
- buf1 = readByte();
- c = c + 0xff00 - (buf0 << 8);
- ct = 8;
- }
-}
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