Revert "Revert 279650 "Add VaapiVideoEncodeAccelerator for HW-accelerate...""

media/filters/h264_bitstream_buffer.cc

Index: media/filters/h264_bitstream_buffer.cc
diff --git a/media/filters/h264_bitstream_buffer.cc b/media/filters/h264_bitstream_buffer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..48463a5be174680abdffc418600fec8ffc202d3e
--- /dev/null
+++ b/media/filters/h264_bitstream_buffer.cc
@@ -0,0 +1,152 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/filters/h264_bitstream_buffer.h"
+
+#include "base/sys_byteorder.h"
+
+namespace media {
+
+H264BitstreamBuffer::H264BitstreamBuffer() : data_(NULL) {
+  Reset();
+}
+
+H264BitstreamBuffer::~H264BitstreamBuffer() {
+  free(data_);
+  data_ = NULL;
+}
+
+void H264BitstreamBuffer::Reset() {
+  free(data_);
+  data_ = NULL;
+
+  capacity_ = 0;
+  pos_ = 0;
+  reg_ = 0;
+
+  Grow();
+
+  bits_left_in_reg_ = kRegBitSize;
+}
+
+void H264BitstreamBuffer::Grow() {
+  data_ = static_cast<uint8*>(realloc(data_, capacity_ + kGrowBytes));
+  CHECK(data_) << "Failed growing the buffer";
+  capacity_ += kGrowBytes;
+}
+
+void H264BitstreamBuffer::FlushReg() {
+  // Flush all bytes that have at least one bit cached, but not more
+  // (on Flush(), reg_ may not be full).
+  size_t bits_in_reg = kRegBitSize - bits_left_in_reg_;
+  if (bits_in_reg == 0)
+    return;
+
+  size_t bytes_in_reg = (bits_in_reg + 7) / 8;
+  reg_ <<= (kRegBitSize - bits_in_reg);
+
+  // Convert to MSB and append as such to the stream.
+  reg_ = base::HostToNet64(reg_);
+
+  // Make sure we have enough space. Grow() will CHECK() on allocation failure.
+  if (pos_ + bytes_in_reg < capacity_)
+    Grow();
+
+  memcpy(data_ + pos_, &reg_, bytes_in_reg);
+  pos_ += bytes_in_reg;
+
+  reg_ = 0;
+  bits_left_in_reg_ = kRegBitSize;
+}
+
+void H264BitstreamBuffer::AppendU64(size_t num_bits, uint64 val) {
+  CHECK_LE(num_bits, kRegBitSize);
+
+  while (num_bits > 0) {
+    if (bits_left_in_reg_ == 0)
+      FlushReg();
+
+    uint64 bits_to_write =
+        num_bits > bits_left_in_reg_ ? bits_left_in_reg_ : num_bits;
+    uint64 val_to_write = (val >> (num_bits - bits_to_write));
+    if (bits_to_write < 64)
+      val_to_write &= ((1ull << bits_to_write) - 1);
+    reg_ <<= bits_to_write;
+    reg_ |= val_to_write;
+    num_bits -= bits_to_write;
+    bits_left_in_reg_ -= bits_to_write;
+  }
+}
+
+void H264BitstreamBuffer::AppendBool(bool val) {
+  if (bits_left_in_reg_ == 0)
+    FlushReg();
+
+  reg_ <<= 1;
+  reg_ |= (static_cast<uint64>(val) & 1);
+  --bits_left_in_reg_;
+}
+
+void H264BitstreamBuffer::AppendSE(int val) {
+  if (val > 0)
+    AppendUE(val * 2 - 1);
+  else
+    AppendUE(-val * 2);
+}
+
+void H264BitstreamBuffer::AppendUE(unsigned int val) {
+  size_t num_zeros = 0;
+  unsigned int v = val + 1;
+
+  while (v > 1) {
+    v >>= 1;
+    ++num_zeros;
+  }
+
+  AppendBits(num_zeros, 0);
+  AppendBits(num_zeros + 1, val + 1);
+}
+
+#define DCHECK_FINISHED()                                                      \
+  DCHECK_EQ(bits_left_in_reg_, kRegBitSize) << "Pending bits not yet written " \
+                                               "to the buffer, call "          \
+                                               "FinishNALU() first."
+
+void H264BitstreamBuffer::BeginNALU(H264NALU::Type nalu_type, int nal_ref_idc) {
+  DCHECK_FINISHED();
+
+  DCHECK_LE(nalu_type, H264NALU::kEOStream);
+  DCHECK_GE(nal_ref_idc, 0);
+  DCHECK_LE(nal_ref_idc, 3);
+
+  AppendBits(32, 0x00000001);
+  AppendBits(1, 0);  // forbidden_zero_bit
+  AppendBits(2, nal_ref_idc);
+  AppendBits(5, nalu_type);
+}
+
+void H264BitstreamBuffer::FinishNALU() {
+  // RBSP stop one bit.
+  AppendBits(1, 1);
+
+  // Byte-alignment zero bits.
+  AppendBits(bits_left_in_reg_ % 8, 0);
+
+  if (bits_left_in_reg_ != kRegBitSize)
+    FlushReg();
+}
+
+size_t H264BitstreamBuffer::BytesInBuffer() {
+  DCHECK_FINISHED();
+  return pos_;
+}
+
+uint8* H264BitstreamBuffer::data() {
+  DCHECK(data_);
+  DCHECK_FINISHED();
+
+  return data_;
+}
+
+}  // namespace media