1 files changed, 148 insertions, 0 deletions
diff --git a/ext/tarkin/bitcoder.h b/ext/tarkin/bitcoder.h
new file mode 100644
index 00000000..f0b8cd69
--- /dev/null
+++ b/ext/tarkin/bitcoder.h
@@ -0,0 +1,148 @@
+#ifndef __BITCODER_H
+#define __BITCODER_H
+
+#include "mem.h"
+
+#if defined(BITCODER)
+
+#define OUTPUT_BIT(coder,bit)             bitcoder_write_bit(coder,bit)
+#define INPUT_BIT(coder)                  bitcoder_read_bit(coder)
+#define OUTPUT_BIT_DIRECT(coder,bit)      bitcoder_write_bit(coder,bit)
+#define INPUT_BIT_DIRECT(coder)           bitcoder_read_bit(coder)
+#define ENTROPY_CODER                     BitCoderState
+#define ENTROPY_ENCODER_init(coder,limit) bitcoder_coder_init(coder,limit)
+#define ENTROPY_ENCODER_DONE(coder)       bitcoder_encoder_done(coder)
+#define ENTROPY_ENCODER_FLUSH(coder)      bitcoder_flush(coder)
+#define ENTROPY_DECODER_INIT(coder,bitstream,limit) \
+   bitcoder_decoder_init(coder,bitstream,limit)
+#define ENTROPY_DECODER_DONE(coder)       /* nothing to do ... */
+#define ENTROPY_CODER_BITSTREAM(coder)    (coder)->bitstream
+
+#define ENTROPY_CODER_SYMBOL(coder)       1
+#define ENTROPY_CODER_RUNLENGTH(coder)    0
+#define ENTROPY_CODER_SKIP(coder,skip)
+
+#endif
+
+
+typedef struct {
+   int32_t  bit_count;           /*  number of valid bits in byte    */
+   uint8_t   byte;               /*  buffer to save bits             */
+   uint32_t  byte_count;         /*  number of bytes written         */
+   uint8_t  *bitstream;
+   uint32_t  limit;              /*  don't write more bytes to bitstream ... */
+   int       eos;                /*  end of stream reached           */
+} BitCoderState;
+
+
+
+static inline
+void bitcoder_encoder_init (BitCoderState *s, uint32_t limit)
+{
+   s->bit_count = 0;
+   s->byte = 0;
+   s->byte_count = 0;
+   s->bitstream = (uint8_t*) MALLOC (limit);
+   s->limit = limit;
+   s->eos = 0;
+}
+
+
+static inline
+void bitcoder_encoder_done (BitCoderState *s)
+{
+   FREE (s->bitstream);
+}
+
+
+static inline
+void bitcoder_decoder_init (BitCoderState *s, uint8_t *bitstream, uint32_t limit)
+{
+   s->bit_count = -1;
+   s->byte = 0;
+   s->byte_count = 0;
+   s->bitstream = bitstream;
+   s->limit = limit;
+   s->eos = 0;
+}
+
+
+static inline
+uint32_t bitcoder_flush (BitCoderState *s)
+{
+   if (s->bit_count > 0 && s->byte_count < s->limit)
+      s->bitstream [s->byte_count++] = s->byte << (8 - s->bit_count);
+
+//printf ("%s: %i bytes written.\n", __FUNCTION__, s->byte_count);
+//printf ("%s: last bit %i\n", __FUNCTION__, s->bit_count);
+   return s->byte_count;
+}
+
+
+
+static inline
+void bitcoder_write_bit (BitCoderState *s, int bit)
+{
+   s->byte <<= 1;
+   s->byte |= bit & 1;
+
+   s->bit_count++;
+
+   if (s->bit_count == 8) {
+      if (s->byte_count < s->limit) {
+         s->bitstream [s->byte_count++] = s->byte;
+         s->bit_count = 0;
+      } else {
+         s->eos = 1;
+      }
+   }
+}
+
+
+static inline
+int bitcoder_read_bit (BitCoderState *s)
+{
+   int ret;
+
+   if (s->bit_count <= 0) {
+      if (!s->bitstream) {
+         s->eos = 1;
+         return 0;
+      }
+
+      if (s->byte_count < s->limit) {
+         s->byte = s->bitstream [s->byte_count++];
+      } else {
+         s->eos = 1;
+         s->byte = 0;
+      }
+
+      s->bit_count = 8;
+   }
+
+   ret = s->byte >> 7;
+   s->byte <<= 1; 
+   s->bit_count--;
+
+   return ret & 1;
+}
+
+
+
+
+
+
+static inline
+void bit_print (TYPE byte)
+{
+   int bit = 8*sizeof(TYPE);
+
+   do {
+      bit--;
+      printf ((byte & (1 << bit)) ? "1" : "0");
+   } while (bit);
+   printf ("\n");
+}
+
+#endif
+