/src/xpdf-4.05/xpdf/JArithmeticDecoder.cc

Source (jump to first uncovered line)
//========================================================================
//
// JArithmeticDecoder.cc
//
// Copyright 2002-2004 Glyph & Cog, LLC
//
//========================================================================

#include <aconf.h>

#include "gmempp.h"
#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] = (Guchar)((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;
  nBytesRead = 0;
  readBuf = -1;
}

inline Guint JArithmeticDecoder::readByte() {
  Guint x;

  if (limitStream) {
    if (readBuf >= 0) {
      x = (Guint)readBuf;
      readBuf = -1;
      return x;
    }
    --dataLen;
    if (dataLen < 0) {
      return 0xff;
    }
  }
  ++nBytesRead;
  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) {
  Guint cAdd;
  GBool prevFF;
  int k, nBits;

  if (dataLen >= 0) {
    dataLen = dataLenA;
  } else if (dataLen == -1) {
    dataLen = dataLenA;
    buf1 = readByte();
  } else {
    k = (-dataLen - 1) * 8 - ct;
    dataLen = dataLenA;
    cAdd = 0;
    prevFF = gFalse;
    while (k > 0) {
      buf0 = readByte();
      if (prevFF) {
  cAdd += 0xfe00 - (buf0 << 9);
  nBits = 7;
      } else {
  cAdd += 0xff00 - (buf0 << 8);
  nBits = 8;
      }
      prevFF = buf0 == 0xff;
      if (k > nBits) {
  cAdd <<= nBits;
  k -= nBits;
      } else {
  cAdd <<= k;
  ct = nBits - k;
  k = 0;
      }
    }
    c += cAdd;
    buf1 = readByte();
  }
}

void JArithmeticDecoder::cleanup() {
  if (limitStream) {
    // This saves one extra byte of data from the end of packet i, to
    // be used in packet i+1.  It's not clear from the JPEG 2000 spec
    // exactly how this should work, but this kludge does seem to fix
    // decode of some problematic JPEG 2000 streams.  It may actually
    // be necessary to buffer an arbitrary number of bytes (not just
    // one byte), but I haven't run into that case yet.
    while (dataLen > 0) {
      readBuf = -1;
      readBuf = 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] = (Guchar)((nlpsTab[iCX] << 1) | (1 - mpsCX));
  } else {
    stats->cxTab[context] = (Guchar)((nlpsTab[iCX] << 1) | mpsCX);
  }
      } else {
  bit = mpsCX;
  stats->cxTab[context] = (Guchar)((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] = (Guchar)((nmpsTab[iCX] << 1) | mpsCX);
    } else {
      bit = 1 - mpsCX;
      if (switchTab[iCX]) {
  stats->cxTab[context] = (Guchar)((nlpsTab[iCX] << 1) | (1 - mpsCX));
      } else {
  stats->cxTab[context] = (Guchar)((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) {
      if (limitStream) {
  buf0 = buf1;
  buf1 = readByte();
  c = c + 0xff00 - (buf0 << 8);
      }
      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;
  }
}

Coverage Report

Created: 2025-08-08 06:36

Line	Count	Source (jump to first uncovered line)
1		//========================================================================
2		//
3		// JArithmeticDecoder.cc
4		//
5		// Copyright 2002-2004 Glyph & Cog, LLC
6		//
7		//========================================================================
8
9		#include <aconf.h>
10
11		#include "gmempp.h"
12		#include "Object.h"
13		#include "Stream.h"
14		#include "JArithmeticDecoder.h"
15
16		//------------------------------------------------------------------------
17		// JArithmeticDecoderStates
18		//------------------------------------------------------------------------
19
20	2.35M	JArithmeticDecoderStats::JArithmeticDecoderStats(int contextSizeA) {
21	2.35M	contextSize = contextSizeA;
22	2.35M	cxTab = (Guchar *)gmallocn(contextSize, sizeof(Guchar));
23	2.35M	reset();
24	2.35M	}
25
26	2.34M	JArithmeticDecoderStats::~JArithmeticDecoderStats() {
27	2.34M	gfree(cxTab);
28	2.34M	}
29
30	215	JArithmeticDecoderStats *JArithmeticDecoderStats::copy() {
31	215	JArithmeticDecoderStats *stats;
32
33	215	stats = new JArithmeticDecoderStats(contextSize);
34	215	memcpy(stats->cxTab, cxTab, contextSize);
35	215	return stats;
36	215	}
37
38	3.44M	void JArithmeticDecoderStats::reset() {
39	3.44M	memset(cxTab, 0, contextSize);
40	3.44M	}
41
42	0	void JArithmeticDecoderStats::copyFrom(JArithmeticDecoderStats *stats) {
43	0	memcpy(cxTab, stats->cxTab, contextSize);
44	0	}
45
46	3.93M	void JArithmeticDecoderStats::setEntry(Guint cx, int i, int mps) {
47	3.93M	cxTab[cx] = (Guchar)((i << 1) + mps);
48	3.93M	}
49
50		//------------------------------------------------------------------------
51		// JArithmeticDecoder
52		//------------------------------------------------------------------------
53
54		Guint JArithmeticDecoder::qeTab[47] = {
55		0x56010000, 0x34010000, 0x18010000, 0x0AC10000,
56		0x05210000, 0x02210000, 0x56010000, 0x54010000,
57		0x48010000, 0x38010000, 0x30010000, 0x24010000,
58		0x1C010000, 0x16010000, 0x56010000, 0x54010000,
59		0x51010000, 0x48010000, 0x38010000, 0x34010000,
60		0x30010000, 0x28010000, 0x24010000, 0x22010000,
61		0x1C010000, 0x18010000, 0x16010000, 0x14010000,
62		0x12010000, 0x11010000, 0x0AC10000, 0x09C10000,
63		0x08A10000, 0x05210000, 0x04410000, 0x02A10000,
64		0x02210000, 0x01410000, 0x01110000, 0x00850000,
65		0x00490000, 0x00250000, 0x00150000, 0x00090000,
66		0x00050000, 0x00010000, 0x56010000
67		};
68
69		int JArithmeticDecoder::nmpsTab[47] = {
70		1, 2, 3, 4, 5, 38, 7, 8, 9, 10, 11, 12, 13, 29, 15, 16,
71		17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,
72		33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 45, 46
73		};
74
75		int JArithmeticDecoder::nlpsTab[47] = {
76		1, 6, 9, 12, 29, 33, 6, 14, 14, 14, 17, 18, 20, 21, 14, 14,
77		15, 16, 17, 18, 19, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
78		30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 46
79		};
80
81		int JArithmeticDecoder::switchTab[47] = {
82		1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
83		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
84		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
85		};
86
87	403k	JArithmeticDecoder::JArithmeticDecoder() {
88	403k	str = NULL;
89	403k	dataLen = 0;
90	403k	limitStream = gFalse;
91	403k	nBytesRead = 0;
92	403k	readBuf = -1;
93	403k	}
94
95	208M	inline Guint JArithmeticDecoder::readByte() {
96	208M	Guint x;
97
98	208M	if (limitStream) {
99	207M	if (readBuf >= 0) {
100	269k	x = (Guint)readBuf;
101	269k	readBuf = -1;
102	269k	return x;
103	269k	}
104	207M	--dataLen;
105	207M	if (dataLen < 0) {
106	1.04M	return 0xff;
107	1.04M	}
108	207M	}
109	207M	++nBytesRead;
110	207M	return (Guint)str->getChar() & 0xff;
111	208M	}
112
113	403k	JArithmeticDecoder::~JArithmeticDecoder() {
114	403k	cleanup();
115	403k	}
116
117	697k	void JArithmeticDecoder::start() {
118	697k	buf0 = readByte();
119	697k	buf1 = readByte();
120
121		// INITDEC
122	697k	c = (buf0 ^ 0xff) << 16;
123	697k	byteIn();
124	697k	c <<= 7;
125	697k	ct -= 7;
126	697k	a = 0x80000000;
127	697k	}
128
129	63.7k	void JArithmeticDecoder::restart(int dataLenA) {
130	63.7k	Guint cAdd;
131	63.7k	GBool prevFF;
132	63.7k	int k, nBits;
133
134	63.7k	if (dataLen >= 0) {
135	60.5k	dataLen = dataLenA;
136	60.5k	} else if (dataLen == -1) {
137	248	dataLen = dataLenA;
138	248	buf1 = readByte();
139	3.01k	} else {
140	3.01k	k = (-dataLen - 1) * 8 - ct;
141	3.01k	dataLen = dataLenA;
142	3.01k	cAdd = 0;
143	3.01k	prevFF = gFalse;
144	75.1k	while (k > 0) {
145	72.1k	buf0 = readByte();
146	72.1k	if (prevFF) {
147	56.2k	cAdd += 0xfe00 - (buf0 << 9);
148	56.2k	nBits = 7;
149	56.2k	} else {
150	15.8k	cAdd += 0xff00 - (buf0 << 8);
151	15.8k	nBits = 8;
152	15.8k	}
153	72.1k	prevFF = buf0 == 0xff;
154	72.1k	if (k > nBits) {
155	69.1k	cAdd <<= nBits;
156	69.1k	k -= nBits;
157	69.1k	} else {
158	3.01k	cAdd <<= k;
159	3.01k	ct = nBits - k;
160	3.01k	k = 0;
161	3.01k	}
162	72.1k	}
163	3.01k	c += cAdd;
164	3.01k	buf1 = readByte();
165	3.01k	}
166	63.7k	}
167
168	1.37M	void JArithmeticDecoder::cleanup() {
169	1.37M	if (limitStream) {
170		// This saves one extra byte of data from the end of packet i, to
171		// be used in packet i+1. It's not clear from the JPEG 2000 spec
172		// exactly how this should work, but this kludge does seem to fix
173		// decode of some problematic JPEG 2000 streams. It may actually
174		// be necessary to buffer an arbitrary number of bytes (not just
175		// one byte), but I haven't run into that case yet.
176	205M	while (dataLen > 0) {
177	203M	readBuf = -1;
178	203M	readBuf = readByte();
179	203M	}
180	1.24M	}
181	1.37M	}
182
183		int JArithmeticDecoder::decodeBit(Guint context,
184	160M	JArithmeticDecoderStats *stats) {
185	160M	int bit;
186	160M	Guint qe;
187	160M	int iCX, mpsCX;
188
189	160M	iCX = stats->cxTab[context] >> 1;
190	160M	mpsCX = stats->cxTab[context] & 1;
191	160M	qe = qeTab[iCX];
192	160M	a -= qe;
193	160M	if (c < a) {
194	143M	if (a & 0x80000000) {
195	125M	bit = mpsCX;
196	125M	} else {
197		// MPS_EXCHANGE
198	18.1M	if (a < qe) {
199	3.00M	bit = 1 - mpsCX;
200	3.00M	if (switchTab[iCX]) {
201	1.85M	stats->cxTab[context] = (Guchar)((nlpsTab[iCX] << 1) \| (1 - mpsCX));
202	1.85M	} else {
203	1.14M	stats->cxTab[context] = (Guchar)((nlpsTab[iCX] << 1) \| mpsCX);
204	1.14M	}
205	15.1M	} else {
206	15.1M	bit = mpsCX;
207	15.1M	stats->cxTab[context] = (Guchar)((nmpsTab[iCX] << 1) \| mpsCX);
208	15.1M	}
209		// RENORMD
210	19.4M	do {
211	19.4M	if (ct == 0) {
212	2.48M	byteIn();
213	2.48M	}
214	19.4M	a <<= 1;
215	19.4M	c <<= 1;
216	19.4M	--ct;
217	19.4M	} while (!(a & 0x80000000));
218	18.1M	}
219	143M	} else {
220	16.9M	c -= a;
221		// LPS_EXCHANGE
222	16.9M	if (a < qe) {
223	3.54M	bit = mpsCX;
224	3.54M	stats->cxTab[context] = (Guchar)((nmpsTab[iCX] << 1) \| mpsCX);
225	13.4M	} else {
226	13.4M	bit = 1 - mpsCX;
227	13.4M	if (switchTab[iCX]) {
228	4.46M	stats->cxTab[context] = (Guchar)((nlpsTab[iCX] << 1) \| (1 - mpsCX));
229	8.94M	} else {
230	8.94M	stats->cxTab[context] = (Guchar)((nlpsTab[iCX] << 1) \| mpsCX);
231	8.94M	}
232	13.4M	}
233	16.9M	a = qe;
234		// RENORMD
235	25.3M	do {
236	25.3M	if (ct == 0) {
237	3.20M	byteIn();
238	3.20M	}
239	25.3M	a <<= 1;
240	25.3M	c <<= 1;
241	25.3M	--ct;
242	25.3M	} while (!(a & 0x80000000));
243	16.9M	}
244	160M	return bit;
245	160M	}
246
247		int JArithmeticDecoder::decodeByte(Guint context,
248	0	JArithmeticDecoderStats *stats) {
249	0	int byte;
250	0	int i;
251
252	0	byte = 0;
253	0	for (i = 0; i < 8; ++i) {
254	0	byte = (byte << 1) \| decodeBit(context, stats);
255	0	}
256	0	return byte;
257	0	}
258
259	1.88M	GBool JArithmeticDecoder::decodeInt(int x, JArithmeticDecoderStats stats) {
260	1.88M	int s;
261	1.88M	Guint v;
262	1.88M	int i;
263
264	1.88M	prev = 1;
265	1.88M	s = decodeIntBit(stats);
266	1.88M	if (decodeIntBit(stats)) {
267	485k	if (decodeIntBit(stats)) {
268	187k	if (decodeIntBit(stats)) {
269	46.6k	if (decodeIntBit(stats)) {
270	18.8k	if (decodeIntBit(stats)) {
271	6.33k	v = 0;
272	209k	for (i = 0; i < 32; ++i) {
273	202k	v = (v << 1) \| decodeIntBit(stats);
274	202k	}
275	6.33k	v += 4436;
276	12.5k	} else {
277	12.5k	v = 0;
278	162k	for (i = 0; i < 12; ++i) {
279	150k	v = (v << 1) \| decodeIntBit(stats);
280	150k	}
281	12.5k	v += 340;
282	12.5k	}
283	27.7k	} else {
284	27.7k	v = 0;
285	250k	for (i = 0; i < 8; ++i) {
286	222k	v = (v << 1) \| decodeIntBit(stats);
287	222k	}
288	27.7k	v += 84;
289	27.7k	}
290	141k	} else {
291	141k	v = 0;
292	988k	for (i = 0; i < 6; ++i) {
293	847k	v = (v << 1) \| decodeIntBit(stats);
294	847k	}
295	141k	v += 20;
296	141k	}
297	297k	} else {
298	297k	v = decodeIntBit(stats);
299	297k	v = (v << 1) \| decodeIntBit(stats);
300	297k	v = (v << 1) \| decodeIntBit(stats);
301	297k	v = (v << 1) \| decodeIntBit(stats);
302	297k	v += 4;
303	297k	}
304	1.39M	} else {
305	1.39M	v = decodeIntBit(stats);
306	1.39M	v = (v << 1) \| decodeIntBit(stats);
307	1.39M	}
308
309	1.88M	if (s) {
310	947k	if (v == 0) {
311	232k	return gFalse;
312	232k	}
313	714k	*x = -(int)v;
314	936k	} else {
315	936k	*x = (int)v;
316	936k	}
317	1.65M	return gTrue;
318	1.88M	}
319
320	9.91M	int JArithmeticDecoder::decodeIntBit(JArithmeticDecoderStats *stats) {
321	9.91M	int bit;
322
323	9.91M	bit = decodeBit(prev, stats);
324	9.91M	if (prev < 0x100) {
325	9.17M	prev = (prev << 1) \| bit;
326	9.17M	} else {
327	736k	prev = (((prev << 1) \| bit) & 0x1ff) \| 0x100;
328	736k	}
329	9.91M	return bit;
330	9.91M	}
331
332		Guint JArithmeticDecoder::decodeIAID(Guint codeLen,
333	965k	JArithmeticDecoderStats *stats) {
334	965k	Guint i;
335	965k	int bit;
336
337	965k	prev = 1;
338	1.11M	for (i = 0; i < codeLen; ++i) {
339	151k	bit = decodeBit(prev, stats);
340	151k	prev = (prev << 1) \| bit;
341	151k	}
342	965k	return prev - (1 << codeLen);
343	965k	}
344
345	6.37M	void JArithmeticDecoder::byteIn() {
346	6.37M	if (buf0 == 0xff) {
347	3.87M	if (buf1 > 0x8f) {
348	3.86M	if (limitStream) {
349	769k	buf0 = buf1;
350	769k	buf1 = readByte();
351	769k	c = c + 0xff00 - (buf0 << 8);
352	769k	}
353	3.86M	ct = 8;
354	3.86M	} else {
355	13.2k	buf0 = buf1;
356	13.2k	buf1 = readByte();
357	13.2k	c = c + 0xfe00 - (buf0 << 9);
358	13.2k	ct = 7;
359	13.2k	}
360	3.87M	} else {
361	2.50M	buf0 = buf1;
362	2.50M	buf1 = readByte();
363	2.50M	c = c + 0xff00 - (buf0 << 8);
364	2.50M	ct = 8;
365	2.50M	}
366	6.37M	}