Extract IVF parser from VP8 parser unittest

media/filters/ivf_parser.cc

+#include "base/logging.h"
+#include "base/sys_byteorder.h"
+#include "media/filters/ivf_parser.h"
+
+namespace {

[xhwang, 2015/07/29 16:43:42]

nit: Move this whole block into namespace media.

[kcwu, 2015/07/30 11:52:52]

Done.

+
+const size_t kIvfFileHeaderSize = 32;

[wuchengli, 2015/07/30 06:26:13]

Can we use sizeof(IvfFileHeader)? Same for kIvfFrameHeaderSize.

[kcwu, 2015/07/30 11:52:52]

Done.

+const size_t kIvfFrameHeaderSize = 12;
+
+uint16_t ReadU16(const uint8_t* buffer) {
+  return base::ByteSwapToLE16(*reinterpret_cast<const uint16_t*>(buffer));
+}
+
+uint32_t ReadU32(const uint8_t* buffer) {
+  return base::ByteSwapToLE32(*reinterpret_cast<const uint32_t*>(buffer));
+}
+
+uint64_t ReadU64(const uint8_t* buffer) {
+  return base::ByteSwapToLE64(*reinterpret_cast<const uint64_t*>(buffer));
+}
+
+}  // namespace
+
+namespace media {
+
+IvfParser::IvfParser() : ptr_(nullptr), end_(nullptr) {}
+
+bool IvfParser::Initialize(const uint8_t* stream,
+                           size_t size,
+                           IvfFileHeader* file_header) {
+  DCHECK(stream);
+  DCHECK(file_header);
+  if (size < kIvfFileHeaderSize) {
+    DLOG(ERROR) << "EOF before file header";
+    return false;
+  }
+
+  ptr_ = stream;
+  end_ = stream + size;
+
+  // signature
+  if (ptr_[0] != 'D' || ptr_[1] != 'K' || ptr_[2] != 'I' || ptr_[3] != 'F') {
+    DLOG(ERROR) << "IVF signature mismatch";
+    return false;
+  }
+
+  file_header->version = ReadU16(ptr_ + 4);
+  file_header->header_size = ReadU16(ptr_ + 6);
+  if (file_header->header_size != kIvfFileHeaderSize) {
+    DLOG(ERROR) << "IVF file header size mismatch";
+    return false;
+  }
+  file_header->fourcc = ReadU32(ptr_ + 8);
+  file_header->width = ReadU16(ptr_ + 12);
+  file_header->height = ReadU16(ptr_ + 14);
+  file_header->timebase_denum = ReadU32(ptr_ + 16);
+  file_header->timebase_num = ReadU32(ptr_ + 20);
+  file_header->num_frames = ReadU32(ptr_ + 24);
+  file_header->unused = ReadU32(ptr_ + 28);

[xhwang, 2015/07/29 16:43:42]

Does media::BitReader work for you?

https://code.google.com/p/chromium/codesearch#chromium/src/media/base/bit_rea...

Manually adding offsets is error prone....

[kcwu, 2015/07/30 11:52:52]

Ah, great! I was finding it in base/ . I will use it in my other CLs.
Revised.

+
+  ptr_ += kIvfFileHeaderSize;
+
+  return true;
+}
+
+bool IvfParser::ParseNextFrame(IvfFrameHeader* frame_header) {
+  DCHECK(ptr_);
+  if (ptr_ + kIvfFrameHeaderSize > end_) {
+    DLOG_IF(ERROR, ptr_ != end_) << "Incomplete frame header";
+    return false;
+  }
+  frame_header->data_size = ReadU32(ptr_);
+  frame_header->timestamp = ReadU64(ptr_);

[xhwang, 2015/07/29 16:43:42]

ptr_ + 4 ?

[kcwu, 2015/07/30 11:52:52]

Revised.

+  ptr_ += kIvfFrameHeaderSize;
+
+  if (ptr_ + frame_header->data_size > end_) {
+    DLOG(ERROR) << "Not enough frame data";
+    return false;
+  }
+
+  frame_header->data = ptr_;
+  ptr_ += frame_header->data_size;
+  return true;
+}
+
+}  // namespace media