1 files changed, 188 insertions, 0 deletions
diff --git a/core/fxcodec/jbig2/JBig2_BitStream.cpp b/core/fxcodec/jbig2/JBig2_BitStream.cpp
new file mode 100644
index 0000000000..87451c2d72
--- /dev/null
+++ b/core/fxcodec/jbig2/JBig2_BitStream.cpp
@@ -0,0 +1,188 @@
+// Copyright 2015 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_BitStream.h"
+
+#include <algorithm>
+
+#include "core/include/fpdfapi/cpdf_stream.h"
+
+CJBig2_BitStream::CJBig2_BitStream(CPDF_StreamAcc* pSrcStream)
+    : m_pBuf(pSrcStream->GetData()),
+      m_dwLength(pSrcStream->GetSize()),
+      m_dwByteIdx(0),
+      m_dwBitIdx(0),
+      m_dwObjNum(pSrcStream->GetStream() ? pSrcStream->GetStream()->GetObjNum()
+                                         : 0) {
+  if (m_dwLength > 256 * 1024 * 1024) {
+    m_dwLength = 0;
+    m_pBuf = nullptr;
+  }
+}
+
+CJBig2_BitStream::~CJBig2_BitStream() {}
+
+int32_t CJBig2_BitStream::readNBits(FX_DWORD dwBits, FX_DWORD* dwResult) {
+  FX_DWORD dwBitPos = getBitPos();
+  if (dwBitPos > LengthInBits())
+    return -1;
+
+  *dwResult = 0;
+  if (dwBitPos + dwBits <= LengthInBits())
+    dwBitPos = dwBits;
+  else
+    dwBitPos = LengthInBits() - dwBitPos;
+
+  for (; dwBitPos > 0; --dwBitPos) {
+    *dwResult =
+        (*dwResult << 1) | ((m_pBuf[m_dwByteIdx] >> (7 - m_dwBitIdx)) & 0x01);
+    AdvanceBit();
+  }
+  return 0;
+}
+
+int32_t CJBig2_BitStream::readNBits(FX_DWORD dwBits, int32_t* nResult) {
+  FX_DWORD dwBitPos = getBitPos();
+  if (dwBitPos > LengthInBits())
+    return -1;
+
+  *nResult = 0;
+  if (dwBitPos + dwBits <= LengthInBits())
+    dwBitPos = dwBits;
+  else
+    dwBitPos = LengthInBits() - dwBitPos;
+
+  for (; dwBitPos > 0; --dwBitPos) {
+    *nResult =
+        (*nResult << 1) | ((m_pBuf[m_dwByteIdx] >> (7 - m_dwBitIdx)) & 0x01);
+    AdvanceBit();
+  }
+  return 0;
+}
+
+int32_t CJBig2_BitStream::read1Bit(FX_DWORD* dwResult) {
+  if (!IsInBound())
+    return -1;
+
+  *dwResult = (m_pBuf[m_dwByteIdx] >> (7 - m_dwBitIdx)) & 0x01;
+  AdvanceBit();
+  return 0;
+}
+
+int32_t CJBig2_BitStream::read1Bit(FX_BOOL* bResult) {
+  if (!IsInBound())
+    return -1;
+
+  *bResult = (m_pBuf[m_dwByteIdx] >> (7 - m_dwBitIdx)) & 0x01;
+  AdvanceBit();
+  return 0;
+}
+
+int32_t CJBig2_BitStream::read1Byte(uint8_t* cResult) {
+  if (!IsInBound())
+    return -1;
+
+  *cResult = m_pBuf[m_dwByteIdx];
+  ++m_dwByteIdx;
+  return 0;
+}
+
+int32_t CJBig2_BitStream::readInteger(FX_DWORD* dwResult) {
+  if (m_dwByteIdx + 3 >= m_dwLength)
+    return -1;
+
+  *dwResult = (m_pBuf[m_dwByteIdx] << 24) | (m_pBuf[m_dwByteIdx + 1] << 16) |
+              (m_pBuf[m_dwByteIdx + 2] << 8) | m_pBuf[m_dwByteIdx + 3];
+  m_dwByteIdx += 4;
+  return 0;
+}
+
+int32_t CJBig2_BitStream::readShortInteger(FX_WORD* dwResult) {
+  if (m_dwByteIdx + 1 >= m_dwLength)
+    return -1;
+
+  *dwResult = (m_pBuf[m_dwByteIdx] << 8) | m_pBuf[m_dwByteIdx + 1];
+  m_dwByteIdx += 2;
+  return 0;
+}
+
+void CJBig2_BitStream::alignByte() {
+  if (m_dwBitIdx != 0) {
+    ++m_dwByteIdx;
+    m_dwBitIdx = 0;
+  }
+}
+
+uint8_t CJBig2_BitStream::getCurByte() const {
+  return IsInBound() ? m_pBuf[m_dwByteIdx] : 0;
+}
+
+void CJBig2_BitStream::incByteIdx() {
+  if (IsInBound())
+    ++m_dwByteIdx;
+}
+
+uint8_t CJBig2_BitStream::getCurByte_arith() const {
+  return IsInBound() ? m_pBuf[m_dwByteIdx] : 0xFF;
+}
+
+uint8_t CJBig2_BitStream::getNextByte_arith() const {
+  return m_dwByteIdx + 1 < m_dwLength ? m_pBuf[m_dwByteIdx + 1] : 0xFF;
+}
+
+FX_DWORD CJBig2_BitStream::getOffset() const {
+  return m_dwByteIdx;
+}
+
+void CJBig2_BitStream::setOffset(FX_DWORD dwOffset) {
+  m_dwByteIdx = std::min(dwOffset, m_dwLength);
+}
+
+FX_DWORD CJBig2_BitStream::getBitPos() const {
+  return (m_dwByteIdx << 3) + m_dwBitIdx;
+}
+
+void CJBig2_BitStream::setBitPos(FX_DWORD dwBitPos) {
+  m_dwByteIdx = dwBitPos >> 3;
+  m_dwBitIdx = dwBitPos & 7;
+}
+
+const uint8_t* CJBig2_BitStream::getBuf() const {
+  return m_pBuf;
+}
+
+const uint8_t* CJBig2_BitStream::getPointer() const {
+  return m_pBuf + m_dwByteIdx;
+}
+
+void CJBig2_BitStream::offset(FX_DWORD dwOffset) {
+  m_dwByteIdx += dwOffset;
+}
+
+FX_DWORD CJBig2_BitStream::getByteLeft() const {
+  return m_dwLength - m_dwByteIdx;
+}
+
+void CJBig2_BitStream::AdvanceBit() {
+  if (m_dwBitIdx == 7) {
+    ++m_dwByteIdx;
+    m_dwBitIdx = 0;
+  } else {
+    ++m_dwBitIdx;
+  }
+}
+
+bool CJBig2_BitStream::IsInBound() const {
+  return m_dwByteIdx < m_dwLength;
+}
+
+FX_DWORD CJBig2_BitStream::LengthInBits() const {
+  return m_dwLength << 3;
+}
+
+FX_DWORD CJBig2_BitStream::getObjNum() const {
+  return m_dwObjNum;
+}