1 files changed, 120 insertions, 0 deletions
diff --git a/media/libvpx/libvpx/vpx_dsp/bitwriter.h b/media/libvpx/libvpx/vpx_dsp/bitwriter.h
new file mode 100644
index 0000000000..5f1ee69ec2
--- /dev/null
+++ b/media/libvpx/libvpx/vpx_dsp/bitwriter.h
@@ -0,0 +1,120 @@
+/*
+ *  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 VPX_VPX_DSP_BITWRITER_H_
+#define VPX_VPX_DSP_BITWRITER_H_
+
+#include <stdio.h>
+
+#include "vpx_ports/compiler_attributes.h"
+#include "vpx_ports/mem.h"
+
+#include "vpx_dsp/prob.h"
+#if CONFIG_BITSTREAM_DEBUG
+#include "vpx_util/vpx_debug_util.h"
+#endif  // CONFIG_BITSTREAM_DEBUG
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct vpx_writer {
+  unsigned int lowvalue;
+  unsigned int range;
+  int count;
+  unsigned int pos;
+  uint8_t *buffer;
+} vpx_writer;
+
+void vpx_start_encode(vpx_writer *br, uint8_t *source);
+void vpx_stop_encode(vpx_writer *br);
+
+static INLINE VPX_NO_UNSIGNED_SHIFT_CHECK void vpx_write(vpx_writer *br,
+                                                         int bit,
+                                                         int probability) {
+  unsigned int split;
+  int count = br->count;
+  unsigned int range = br->range;
+  unsigned int lowvalue = br->lowvalue;
+  int shift;
+
+#if CONFIG_BITSTREAM_DEBUG
+  /*
+  int queue_r = 0;
+  int frame_idx_r = 0;
+  int queue_w = bitstream_queue_get_write();
+  int frame_idx_w = bitstream_queue_get_frame_write();
+  if (frame_idx_w == frame_idx_r && queue_w == queue_r) {
+    fprintf(stderr, "\n *** bitstream queue at frame_idx_w %d queue_w %d\n",
+            frame_idx_w, queue_w);
+    assert(0);
+  }
+  */
+  bitstream_queue_push(bit, probability);
+#endif
+
+  split = 1 + (((range - 1) * probability) >> 8);
+
+  range = split;
+
+  if (bit) {
+    lowvalue += split;
+    range = br->range - split;
+  }
+
+  shift = vpx_norm[range];
+
+  range <<= shift;
+  count += shift;
+
+  if (count >= 0) {
+    int offset = shift - count;
+
+    if ((lowvalue << (offset - 1)) & 0x80000000) {
+      int x = br->pos - 1;
+
+      while (x >= 0 && br->buffer[x] == 0xff) {
+        br->buffer[x] = 0;
+        x--;
+      }
+
+      br->buffer[x] += 1;
+    }
+
+    br->buffer[br->pos++] = (lowvalue >> (24 - offset)) & 0xff;
+    lowvalue <<= offset;
+    shift = count;
+    lowvalue &= 0xffffff;
+    count -= 8;
+  }
+
+  lowvalue <<= shift;
+  br->count = count;
+  br->lowvalue = lowvalue;
+  br->range = range;
+}
+
+static INLINE void vpx_write_bit(vpx_writer *w, int bit) {
+  vpx_write(w, bit, 128);  // vpx_prob_half
+}
+
+static INLINE void vpx_write_literal(vpx_writer *w, int data, int bits) {
+  int bit;
+
+  for (bit = bits - 1; bit >= 0; bit--) vpx_write_bit(w, 1 & (data >> bit));
+}
+
+#define vpx_write_prob(w, v) vpx_write_literal((w), (v), 8)
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // VPX_VPX_DSP_BITWRITER_H_