1 files changed, 134 insertions, 0 deletions
diff --git a/media/libvpx/vp8/encoder/treewriter.h b/media/libvpx/vp8/encoder/treewriter.h
new file mode 100644
index 000000000..cfb2730ab
--- /dev/null
+++ b/media/libvpx/vp8/encoder/treewriter.h
@@ -0,0 +1,134 @@
+/*
+ *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+
+#ifndef VP8_ENCODER_TREEWRITER_H_
+#define VP8_ENCODER_TREEWRITER_H_
+
+/* Trees map alphabets into huffman-like codes suitable for an arithmetic
+   bit coder.  Timothy S Murphy  11 October 2004 */
+
+#include "vp8/common/treecoder.h"
+
+#include "boolhuff.h"       /* for now */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef BOOL_CODER vp8_writer;
+
+#define vp8_write vp8_encode_bool
+#define vp8_write_literal vp8_encode_value
+#define vp8_write_bit( W, V) vp8_write( W, V, vp8_prob_half)
+
+#define vp8bc_write vp8bc_write_bool
+#define vp8bc_write_literal vp8bc_write_bits
+#define vp8bc_write_bit( W, V) vp8bc_write_bits( W, V, 1)
+
+
+/* Approximate length of an encoded bool in 256ths of a bit at given prob */
+
+#define vp8_cost_zero( x) ( vp8_prob_cost[x])
+#define vp8_cost_one( x)  vp8_cost_zero( vp8_complement(x))
+
+#define vp8_cost_bit( x, b) vp8_cost_zero( (b)?  vp8_complement(x) : (x) )
+
+/* VP8BC version is scaled by 2^20 rather than 2^8; see bool_coder.h */
+
+
+/* Both of these return bits, not scaled bits. */
+
+static unsigned int vp8_cost_branch(const unsigned int ct[2], vp8_prob p)
+{
+    /* Imitate existing calculation */
+
+    return ((ct[0] * vp8_cost_zero(p))
+            + (ct[1] * vp8_cost_one(p))) >> 8;
+}
+
+/* Small functions to write explicit values and tokens, as well as
+   estimate their lengths. */
+
+static void vp8_treed_write
+(
+    vp8_writer *const w,
+    vp8_tree t,
+    const vp8_prob *const p,
+    int v,
+    int n               /* number of bits in v, assumed nonzero */
+)
+{
+    vp8_tree_index i = 0;
+
+    do
+    {
+        const int b = (v >> --n) & 1;
+        vp8_write(w, b, p[i>>1]);
+        i = t[i+b];
+    }
+    while (n);
+}
+static void vp8_write_token
+(
+    vp8_writer *const w,
+    vp8_tree t,
+    const vp8_prob *const p,
+    vp8_token *const x
+)
+{
+    vp8_treed_write(w, t, p, x->value, x->Len);
+}
+
+static int vp8_treed_cost(
+    vp8_tree t,
+    const vp8_prob *const p,
+    int v,
+    int n               /* number of bits in v, assumed nonzero */
+)
+{
+    int c = 0;
+    vp8_tree_index i = 0;
+
+    do
+    {
+        const int b = (v >> --n) & 1;
+        c += vp8_cost_bit(p[i>>1], b);
+        i = t[i+b];
+    }
+    while (n);
+
+    return c;
+}
+static int vp8_cost_token
+(
+    vp8_tree t,
+    const vp8_prob *const p,
+    vp8_token *const x
+)
+{
+    return vp8_treed_cost(t, p, x->value, x->Len);
+}
+
+/* Fill array of costs for all possible token values. */
+
+void vp8_cost_tokens(
+    int *Costs, const vp8_prob *, vp8_tree
+);
+
+void vp8_cost_tokens2(
+    int *Costs, const vp8_prob *, vp8_tree, int
+);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // VP8_ENCODER_TREEWRITER_H_