First stab at porting mplex

Original commit message from CVS:
First stab at porting mplex

1 files changed, 82 insertions, 0 deletions

diff --git a/ext/mplex/bits.hh b/ext/mplex/bits.hh
new file mode 100644
index 00000000..275b8c0f
--- /dev/null
+++ b/ext/mplex/bits.hh
@@ -0,0 +1,82 @@
+#ifndef __BITS_H__
+#define __BITS_H__
+
+#include <config.h>
+#include <stdio.h>
+
+typedef uint64_t bitcount_t;
+
+
+class BitStreamUndo
+{
+//protected:
+public:
+  uint8_t outbyte;
+  unsigned int byteidx;
+  int bitidx;
+  unsigned int bufcount;
+  fpos_t actpos;
+  bitcount_t totbits;
+  bitcount_t buffer_start;
+  bitcount_t readpos;
+  uint8_t *bfr;
+  unsigned int bfr_size;
+public:
+  bool eobs;
+};
+
+typedef class BitStream _BitStream;
+
+typedef size_t (*ReadCallback) 	(_BitStream *bs, uint8_t *dest, size_t size, void *user_data);
+
+class BitStream : public BitStreamUndo
+{
+public:
+  void *user_data;
+  static const unsigned int BUFFER_SIZE = 4 * 1024;
+public:
+    BitStream ();
+   ~BitStream ();
+  inline bitcount_t bitcount ()
+  {
+    return totbits;
+  }
+  inline bool eos ()
+  {
+    return eobs;
+  }
+};
+
+
+//
+// Input bit stream class.   Supports the "scanning" of a stream
+// into a large buffer which is flushed once it has been read.
+// N.b. if you scan ahead a long way and don't read its your
+// responsibility to flush manually...
+//
+
+class IBitStream:public BitStream
+{
+public:
+  void open (ReadCallback read_callback, void *user_data, unsigned int buf_size = BUFFER_SIZE);
+  void SetBufSize (unsigned int buf_size);
+  void close ();
+  uint32_t get1bit ();
+  uint32_t getbits (int N);
+  void prepareundo (BitStreamUndo & undobuf);
+  void undochanges (BitStreamUndo & undobuf);
+  bool seek_sync (unsigned int sync, int N, int lim);
+  void flush (bitcount_t bitposition);
+  inline unsigned int buffered_bytes ()
+  {
+    return (buffer_start + bufcount - readpos);
+  }
+  unsigned int read_buffered_bytes (uint8_t * dst, unsigned int length_bytes);
+
+private:
+  bool refill_buffer ();
+  static uint8_t masks[8];
+  ReadCallback read_callback;
+};
+
+#endif // __BITS_H__