1 files changed, 141 insertions, 0 deletions
diff --git a/media/libvpx/vp8/decoder/dboolhuff.h b/media/libvpx/vp8/decoder/dboolhuff.h
new file mode 100644
index 000000000..51c5adc28
--- /dev/null
+++ b/media/libvpx/vp8/decoder/dboolhuff.h
@@ -0,0 +1,141 @@
+/*
+ *  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_DECODER_DBOOLHUFF_H_
+#define VP8_DECODER_DBOOLHUFF_H_
+
+#include <stddef.h>
+#include <limits.h>
+
+#include "vpx_config.h"
+#include "vpx_ports/mem.h"
+#include "vpx/vp8dx.h"
+#include "vpx/vpx_integer.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef size_t VP8_BD_VALUE;
+
+#define VP8_BD_VALUE_SIZE ((int)sizeof(VP8_BD_VALUE)*CHAR_BIT)
+
+/*This is meant to be a large, positive constant that can still be efficiently
+   loaded as an immediate (on platforms like ARM, for example).
+  Even relatively modest values like 100 would work fine.*/
+#define VP8_LOTS_OF_BITS (0x40000000)
+
+typedef struct
+{
+    const unsigned char *user_buffer_end;
+    const unsigned char *user_buffer;
+    VP8_BD_VALUE         value;
+    int                  count;
+    unsigned int         range;
+    vpx_decrypt_cb       decrypt_cb;
+    void                *decrypt_state;
+} BOOL_DECODER;
+
+DECLARE_ALIGNED(16, extern const unsigned char, vp8_norm[256]);
+
+int vp8dx_start_decode(BOOL_DECODER *br,
+                       const unsigned char *source,
+                       unsigned int source_sz,
+                       vpx_decrypt_cb decrypt_cb,
+                       void *decrypt_state);
+
+void vp8dx_bool_decoder_fill(BOOL_DECODER *br);
+
+
+static int vp8dx_decode_bool(BOOL_DECODER *br, int probability) {
+    unsigned int bit = 0;
+    VP8_BD_VALUE value;
+    unsigned int split;
+    VP8_BD_VALUE bigsplit;
+    int count;
+    unsigned int range;
+
+    split = 1 + (((br->range - 1) * probability) >> 8);
+
+    if(br->count < 0)
+        vp8dx_bool_decoder_fill(br);
+
+    value = br->value;
+    count = br->count;
+
+    bigsplit = (VP8_BD_VALUE)split << (VP8_BD_VALUE_SIZE - 8);
+
+    range = split;
+
+    if (value >= bigsplit)
+    {
+        range = br->range - split;
+        value = value - bigsplit;
+        bit = 1;
+    }
+
+    {
+        register unsigned int shift = vp8_norm[range];
+        range <<= shift;
+        value <<= shift;
+        count -= shift;
+    }
+    br->value = value;
+    br->count = count;
+    br->range = range;
+
+    return bit;
+}
+
+static int vp8_decode_value(BOOL_DECODER *br, int bits)
+{
+    int z = 0;
+    int bit;
+
+    for (bit = bits - 1; bit >= 0; bit--)
+    {
+        z |= (vp8dx_decode_bool(br, 0x80) << bit);
+    }
+
+    return z;
+}
+
+static int vp8dx_bool_error(BOOL_DECODER *br)
+{
+    /* Check if we have reached the end of the buffer.
+     *
+     * Variable 'count' stores the number of bits in the 'value' buffer, minus
+     * 8. The top byte is part of the algorithm, and the remainder is buffered
+     * to be shifted into it. So if count == 8, the top 16 bits of 'value' are
+     * occupied, 8 for the algorithm and 8 in the buffer.
+     *
+     * When reading a byte from the user's buffer, count is filled with 8 and
+     * one byte is filled into the value buffer. When we reach the end of the
+     * data, count is additionally filled with VP8_LOTS_OF_BITS. So when
+     * count == VP8_LOTS_OF_BITS - 1, the user's data has been exhausted.
+     */
+    if ((br->count > VP8_BD_VALUE_SIZE) && (br->count < VP8_LOTS_OF_BITS))
+    {
+       /* We have tried to decode bits after the end of
+        * stream was encountered.
+        */
+        return 1;
+    }
+
+    /* No error. */
+    return 0;
+}
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // VP8_DECODER_DBOOLHUFF_H_