moved ../../pdf2swf/xpdf to .

[swftools.git] / lib / xpdf / JArithmeticDecoder.h

diff --git a/lib/xpdf/JArithmeticDecoder.h b/lib/xpdf/JArithmeticDecoder.h
new file mode 100644 (file)
index 0000000..a40823d
--- /dev/null
+++ b/lib/xpdf/JArithmeticDecoder.h
@@ -0,0 +1,109 @@
+//========================================================================
+//
+// JArithmeticDecoder.h
+//
+// Arithmetic decoder used by the JBIG2 and JPEG2000 decoders.
+//
+// Copyright 2002-2004 Glyph & Cog, LLC
+//
+//========================================================================
+
+#ifndef JARITHMETICDECODER_H
+#define JARITHMETICDECODER_H
+
+#include <aconf.h>
+
+#ifdef USE_GCC_PRAGMAS
+#pragma interface
+#endif
+
+#include "gtypes.h"
+
+class Stream;
+
+//------------------------------------------------------------------------
+// JArithmeticDecoderStats
+//------------------------------------------------------------------------
+
+class JArithmeticDecoderStats {
+public:
+
+  JArithmeticDecoderStats(int contextSizeA);
+  ~JArithmeticDecoderStats();
+  JArithmeticDecoderStats *copy();
+  void reset();
+  int getContextSize() { return contextSize; }
+  void copyFrom(JArithmeticDecoderStats *stats);
+  void setEntry(Guint cx, int i, int mps);
+
+private:
+
+  Guchar *cxTab;               // cxTab[cx] = (i[cx] << 1) + mps[cx]
+  int contextSize;
+
+  friend class JArithmeticDecoder;
+};
+
+//------------------------------------------------------------------------
+// JArithmeticDecoder
+//------------------------------------------------------------------------
+
+class JArithmeticDecoder {
+public:
+
+  JArithmeticDecoder();
+  ~JArithmeticDecoder();
+
+  void setStream(Stream *strA)
+    { str = strA; dataLen = 0; limitStream = gFalse; }
+  void setStream(Stream *strA, int dataLenA)
+    { str = strA; dataLen = dataLenA; limitStream = gTrue; }
+
+  // Start decoding on a new stream.  This fills the byte buffers and
+  // runs INITDEC.
+  void start();
+
+  // Restart decoding on an interrupted stream.  This refills the
+  // buffers if needed, but does not run INITDEC.  (This is used in
+  // JPEG 2000 streams when codeblock data is split across multiple
+  // packets/layers.)
+  void restart(int dataLenA);
+
+  // Read any leftover data in the stream.
+  void cleanup();
+
+  // Decode one bit.
+  int decodeBit(Guint context, JArithmeticDecoderStats *stats);
+
+  // Decode eight bits.
+  int decodeByte(Guint context, JArithmeticDecoderStats *stats);
+
+  // Returns false for OOB, otherwise sets *<x> and returns true.
+  GBool decodeInt(int *x, JArithmeticDecoderStats *stats);
+
+  Guint decodeIAID(Guint codeLen,
+                  JArithmeticDecoderStats *stats);
+
+private:
+
+  Guint readByte();
+  int decodeIntBit(JArithmeticDecoderStats *stats);
+  void byteIn();
+
+  static Guint qeTab[47];
+  static int nmpsTab[47];
+  static int nlpsTab[47];
+  static int switchTab[47];
+
+  Guint buf0, buf1;
+  Guint c, a;
+  int ct;
+
+  Guint prev;                  // for the integer decoder
+
+  Stream *str;
+  int dataLen;
+  GBool limitStream;
+};
+
+#endif