1 files changed, 87 insertions, 0 deletions
diff --git a/third_party/aom/aom_dsp/bitwriter_buffer.c b/third_party/aom/aom_dsp/bitwriter_buffer.c
new file mode 100644
index 0000000000..596246deb2
--- /dev/null
+++ b/third_party/aom/aom_dsp/bitwriter_buffer.c
@@ -0,0 +1,87 @@
+/*
+ * Copyright (c) 2016, Alliance for Open Media. All rights reserved
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+ */
+
+#include <assert.h>
+#include <limits.h>
+#include <stdlib.h>
+
+#include "config/aom_config.h"
+
+#include "aom_dsp/bitwriter_buffer.h"
+
+int aom_wb_is_byte_aligned(const struct aom_write_bit_buffer *wb) {
+  return (wb->bit_offset % CHAR_BIT == 0);
+}
+
+uint32_t aom_wb_bytes_written(const struct aom_write_bit_buffer *wb) {
+  return wb->bit_offset / CHAR_BIT + (wb->bit_offset % CHAR_BIT > 0);
+}
+
+void aom_wb_write_bit(struct aom_write_bit_buffer *wb, int bit) {
+  const int off = (int)wb->bit_offset;
+  const int p = off / CHAR_BIT;
+  const int q = CHAR_BIT - 1 - off % CHAR_BIT;
+  if (q == CHAR_BIT - 1) {
+    // Zero next char and write bit
+    wb->bit_buffer[p] = bit << q;
+  } else {
+    wb->bit_buffer[p] &= ~(1 << q);
+    wb->bit_buffer[p] |= bit << q;
+  }
+  wb->bit_offset = off + 1;
+}
+
+void aom_wb_overwrite_bit(struct aom_write_bit_buffer *wb, int bit) {
+  // Do not zero bytes but overwrite exisiting values
+  const int off = (int)wb->bit_offset;
+  const int p = off / CHAR_BIT;
+  const int q = CHAR_BIT - 1 - off % CHAR_BIT;
+  wb->bit_buffer[p] &= ~(1 << q);
+  wb->bit_buffer[p] |= bit << q;
+  wb->bit_offset = off + 1;
+}
+
+void aom_wb_write_literal(struct aom_write_bit_buffer *wb, int data, int bits) {
+  assert(bits <= 31);
+  int bit;
+  for (bit = bits - 1; bit >= 0; bit--) aom_wb_write_bit(wb, (data >> bit) & 1);
+}
+
+void aom_wb_write_unsigned_literal(struct aom_write_bit_buffer *wb,
+                                   uint32_t data, int bits) {
+  assert(bits <= 32);
+  int bit;
+  for (bit = bits - 1; bit >= 0; bit--) aom_wb_write_bit(wb, (data >> bit) & 1);
+}
+
+void aom_wb_overwrite_literal(struct aom_write_bit_buffer *wb, int data,
+                              int bits) {
+  int bit;
+  for (bit = bits - 1; bit >= 0; bit--)
+    aom_wb_overwrite_bit(wb, (data >> bit) & 1);
+}
+
+void aom_wb_write_inv_signed_literal(struct aom_write_bit_buffer *wb, int data,
+                                     int bits) {
+  aom_wb_write_literal(wb, data, bits + 1);
+}
+
+void aom_wb_write_uvlc(struct aom_write_bit_buffer *wb, uint32_t v) {
+  int64_t shift_val = ++v;
+  int leading_zeroes = 1;
+
+  assert(shift_val > 0);
+
+  while (shift_val >>= 1) leading_zeroes += 2;
+
+  aom_wb_write_literal(wb, 0, leading_zeroes >> 1);
+  aom_wb_write_unsigned_literal(wb, v, (leading_zeroes + 1) >> 1);
+}