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// Copyright 2014 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
#include "core/fxcodec/jbig2/JBig2_HuffmanTable.h"
#include <algorithm>
#include <limits>
#include <vector>
#include "core/fxcodec/jbig2/JBig2_BitStream.h"
#include "core/fxcodec/jbig2/JBig2_HuffmanTable_Standard.h"
#include "core/fxcrt/fx_memory.h"
#include "third_party/base/numerics/safe_math.h"
CJBig2_HuffmanTable::CJBig2_HuffmanTable(const JBig2TableLine* pTable,
uint32_t nLines,
bool bHTOOB)
: m_bOK(true), HTOOB(bHTOOB), NTEMP(nLines) {
ParseFromStandardTable(pTable);
}
CJBig2_HuffmanTable::CJBig2_HuffmanTable(CJBig2_BitStream* pStream)
: HTOOB(false), NTEMP(0) {
m_bOK = ParseFromCodedBuffer(pStream);
}
CJBig2_HuffmanTable::~CJBig2_HuffmanTable() {}
void CJBig2_HuffmanTable::ParseFromStandardTable(const JBig2TableLine* pTable) {
CODES.resize(NTEMP);
RANGELEN.resize(NTEMP);
RANGELOW.resize(NTEMP);
for (uint32_t i = 0; i < NTEMP; ++i) {
CODES[i].codelen = pTable[i].PREFLEN;
RANGELEN[i] = pTable[i].RANDELEN;
RANGELOW[i] = pTable[i].RANGELOW;
}
InitCodes();
}
bool CJBig2_HuffmanTable::ParseFromCodedBuffer(CJBig2_BitStream* pStream) {
unsigned char cTemp;
if (pStream->read1Byte(&cTemp) == -1)
return false;
HTOOB = !!(cTemp & 0x01);
unsigned char HTPS = ((cTemp >> 1) & 0x07) + 1;
unsigned char HTRS = ((cTemp >> 4) & 0x07) + 1;
uint32_t HTLOW;
uint32_t HTHIGH;
if (pStream->readInteger(&HTLOW) == -1 ||
pStream->readInteger(&HTHIGH) == -1) {
return false;
}
const int low = static_cast<int>(HTLOW);
const int high = static_cast<int>(HTHIGH);
if (low > high)
return false;
ExtendBuffers(false);
pdfium::base::CheckedNumeric<int> cur_low = low;
do {
if ((pStream->readNBits(HTPS, &CODES[NTEMP].codelen) == -1) ||
(pStream->readNBits(HTRS, &RANGELEN[NTEMP]) == -1) ||
(static_cast<size_t>(RANGELEN[NTEMP]) >= 8 * sizeof(cur_low))) {
return false;
}
RANGELOW[NTEMP] = cur_low.ValueOrDie();
if (RANGELEN[NTEMP] >= 32)
return false;
cur_low += (1 << RANGELEN[NTEMP]);
if (!cur_low.IsValid())
return false;
ExtendBuffers(true);
} while (cur_low.ValueOrDie() < high);
if (pStream->readNBits(HTPS, &CODES[NTEMP].codelen) == -1)
return false;
RANGELEN[NTEMP] = 32;
if (low == std::numeric_limits<int>::min())
return false;
RANGELOW[NTEMP] = low - 1;
ExtendBuffers(true);
if (pStream->readNBits(HTPS, &CODES[NTEMP].codelen) == -1)
return false;
RANGELEN[NTEMP] = 32;
RANGELOW[NTEMP] = high;
ExtendBuffers(true);
if (HTOOB) {
if (pStream->readNBits(HTPS, &CODES[NTEMP].codelen) == -1)
return false;
++NTEMP;
}
return InitCodes();
}
bool CJBig2_HuffmanTable::InitCodes() {
int lenmax = 0;
for (uint32_t i = 0; i < NTEMP; ++i)
lenmax = std::max(CODES[i].codelen, lenmax);
std::vector<int> LENCOUNT(lenmax + 1);
std::vector<int> FIRSTCODE(lenmax + 1);
for (uint32_t i = 0; i < NTEMP; ++i)
++LENCOUNT[CODES[i].codelen];
FIRSTCODE[0] = 0;
LENCOUNT[0] = 0;
for (int i = 1; i <= lenmax; ++i) {
pdfium::base::CheckedNumeric<int> shifted = FIRSTCODE[i - 1];
shifted += LENCOUNT[i - 1];
shifted <<= 1;
if (!shifted.IsValid())
return false;
FIRSTCODE[i] = shifted.ValueOrDie();
int CURCODE = FIRSTCODE[i];
for (uint32_t j = 0; j < NTEMP; ++j) {
if (CODES[j].codelen == i)
CODES[j].code = CURCODE++;
}
}
return true;
}
void CJBig2_HuffmanTable::ExtendBuffers(bool increment) {
if (increment)
++NTEMP;
size_t size = CODES.size();
if (NTEMP < size)
return;
size += 16;
ASSERT(NTEMP < size);
CODES.resize(size);
RANGELEN.resize(size);
RANGELOW.resize(size);
}
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