1 files changed, 45 insertions, 0 deletions
diff --git a/core/fxcodec/jbig2/JBig2_HuffmanDecoder.cpp b/core/fxcodec/jbig2/JBig2_HuffmanDecoder.cpp
new file mode 100644
index 0000000000..afcc17a55e
--- /dev/null
+++ b/core/fxcodec/jbig2/JBig2_HuffmanDecoder.cpp
@@ -0,0 +1,45 @@
+// 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_HuffmanDecoder.h"
+
+#include "core/fxcodec/jbig2/JBig2_Define.h"
+
+CJBig2_HuffmanDecoder::CJBig2_HuffmanDecoder(CJBig2_BitStream* pStream)
+    : m_pStream(pStream) {}
+
+CJBig2_HuffmanDecoder::~CJBig2_HuffmanDecoder() {}
+
+int CJBig2_HuffmanDecoder::decodeAValue(CJBig2_HuffmanTable* pTable,
+                                        int* nResult) {
+  int nVal = 0;
+  int nBits = 0;
+  while (1) {
+    FX_DWORD nTmp;
+    if (m_pStream->read1Bit(&nTmp) == -1)
+      break;
+
+    nVal = (nVal << 1) | nTmp;
+    ++nBits;
+    for (FX_DWORD i = 0; i < pTable->Size(); ++i) {
+      if (pTable->GetPREFLEN()[i] == nBits && pTable->GetCODES()[i] == nVal) {
+        if (pTable->IsHTOOB() && i == pTable->Size() - 1)
+          return JBIG2_OOB;
+
+        if (m_pStream->readNBits(pTable->GetRANGELEN()[i], &nTmp) == -1)
+          return -1;
+
+        FX_DWORD offset = pTable->IsHTOOB() ? 3 : 2;
+        if (i == pTable->Size() - offset)
+          *nResult = pTable->GetRANGELOW()[i] - nTmp;
+        else
+          *nResult = pTable->GetRANGELOW()[i] + nTmp;
+        return 0;
+      }
+    }
+  }
+  return -1;
+}