Initial import

1 files changed, 172 insertions, 0 deletions

diff --git a/tools/bitstream.h b/tools/bitstream.h
new file mode 100644
index 00000000..99b5d888
--- /dev/null
+++ b/tools/bitstream.h
@@ -0,0 +1,172 @@
+/*
+ * bitstream.h: generic bitstream parsing
+ *
+ * See the main source file 'xineliboutput.c' for copyright information and
+ * how to reach the author.
+ *
+ * $Id: bitstream.h,v 1.1 2008-01-29 23:14:53 phintuka Exp $
+ *
+ */
+
+#ifndef _XINELIBOUTPUT_BITSTREAM_H_
+#define _XINELIBOUTPUT_BITSTREAM_H_
+
+
+# ifdef NOCACHE
+
+
+typedef struct {
+  uint8_t *data;
+  int      count; /* in bits */
+  int      index; /* in bits */
+} br_state;
+
+#define BR_INIT(data,bytes) { data, 8*bytes, 0 }
+
+static inline void br_init(br_state *br, uint8_t *data, int bytes)
+{
+  br->data  = data;
+  br->count = 8*bytes;
+  br->index = 0;
+}
+
+static inline int br_get_bit(br_state *br)
+{
+  if(br->index >= br->count)
+    return 1; /* -> no infinite colomb's ... */
+
+  int r = (br->data[br->index>>3] >> (7 - (br->index&7))) & 1;
+  br->index++;
+  return r;
+}
+
+static inline uint32_t br_get_bits(br_state *br, uint32_t n)
+{
+  uint32_t r = 0;
+  while(n--)
+    r = r | (br_get_bit(br) << n);
+  return r;
+}
+
+#define br_skip_bit(br) br_skip_bits(br,1)
+
+static inline void br_skip_bits(br_state *br, int n)
+{
+  br->index += n;
+}
+
+
+# else /* NOCACHE */
+
+
+typedef struct {
+  uint8_t *data;
+  uint8_t *data_end;
+  uint32_t cache; 
+  uint32_t cache_bits;
+} br_state;
+
+#define BR_INIT(data,bytes) { data, data+bytes, 0, 0 }
+
+static inline void br_init(br_state *br, uint8_t *data, int bytes)
+{
+  br->data       = data;
+  br->data_end   = data + bytes;
+  br->cache      = 0;
+  br->cache_bits = 0;
+}
+
+#define BR_GET_BYTE(br) \
+   (br->data < br->data_end ? *br->data++ : 0xff)
+
+static inline uint32_t br_get_bits(br_state *br, uint32_t n)
+{
+  if(n > 24)
+    return (br_get_bits(br, 16) << 16) | br_get_bits(br, n-16);
+
+  while (br->cache_bits < 24) {
+    br->cache = (br->cache<<8) | BR_GET_BYTE(br);
+    br->cache_bits += 8;
+  }
+
+  br->cache_bits -= n;
+  return (br->cache >> br->cache_bits) & ((1<<n) - 1);
+}
+
+static inline int br_get_bit(br_state *br)
+{
+  if(!br->cache_bits) {
+    br->cache = BR_GET_BYTE(br);
+    br->cache_bits = 7;
+  } else {
+    br->cache_bits--;
+  }
+  return (br->cache >> br->cache_bits) & 1;
+}
+
+static inline void br_skip_bit(br_state *br)
+{
+  if(!br->cache_bits) {
+    br->cache = BR_GET_BYTE(br);
+    br->cache_bits = 7;
+  } else {
+    br->cache_bits--;
+  }
+}
+
+static inline void br_skip_bits(br_state *br, int n)
+{
+  if(br->cache_bits >= n) {
+    br->cache_bits -= n;
+  } else {
+    /* drop cached bits */
+    n -= br->cache_bits;
+  
+    /* drop full bytes */
+    br->data += (n >> 3);
+    n &= 7;
+
+    /* update cache */
+    if(n) {
+      br->cache = BR_GET_BYTE(br);
+      br->cache_bits = 8 - n;
+    } else {
+      br->cache_bits = 0;
+    }
+  }
+}
+ 
+
+# endif /* NOCACHE */
+
+
+#define br_get_u8(br)         br_get_bits(br, 8)
+#define br_get_u16(br)        ((br_get_bits(br, 8)<<8) | br_get_bits(br, 8))
+
+static inline uint32_t br_get_ue_golomb(br_state *br)
+{
+  int n = 0;
+  while (!br_get_bit(br) && n < 32)
+    n++;
+  return n ? ((1<<n) - 1) + br_get_bits(br, n) : 0;
+}
+
+static inline int32_t br_get_se_golomb(br_state *br)
+{
+  uint32_t r = br_get_ue_golomb(br) + 1;
+  return (r&1) ? -(r>>1) : (r>>1);
+}
+
+static inline void br_skip_golomb(br_state *br)
+{
+  int n = 0;
+  while (!br_get_bit(br) && n < 32)
+    n++;
+  br_skip_bits(br, n);
+}
+
+#define br_skip_ue_golomb(br) br_skip_golomb(br)
+#define br_skip_se_golomb(br) br_skip_golomb(br)
+
+
+#endif /* _XINELIBOUTPUT_BITSTREAM_H_ */