Upstream version 10.39.225.0

[platform/framework/web/crosswalk.git] / src / media / base / bit_reader_core.cc

diff --git a/src/media/base/bit_reader_core.cc b/src/media/base/bit_reader_core.cc
index 2f168ff..f292f97 100644 (file)
--- a/src/media/base/bit_reader_core.cc
+++ b/src/media/base/bit_reader_core.cc
@@ -51,11 +51,8 @@ int BitReaderCore::PeekBitsMsbAligned(int num_bits, uint64* out) {
   return nbits_;
 }
 
-bool BitReaderCore::SkipBits(int num_bits) {
+bool BitReaderCore::SkipBitsSmall(int num_bits) {
   DCHECK_GE(num_bits, 0);
-  DVLOG_IF(0, num_bits > 100)
-      << "BitReader::SkipBits inefficient for large skips";
-
   uint64 dummy;
   while (num_bits >= kRegWidthInBits) {
     if (!ReadBitsInternal(kRegWidthInBits, &dummy))
@@ -65,6 +62,39 @@ bool BitReaderCore::SkipBits(int num_bits) {
   return ReadBitsInternal(num_bits, &dummy);
 }
 
+bool BitReaderCore::SkipBits(int num_bits) {
+  DCHECK_GE(num_bits, 0);
+
+  const int remaining_bits = nbits_ + nbits_next_;
+  if (remaining_bits >= num_bits)
+    return SkipBitsSmall(num_bits);
+
+  // Skip first the remaining available bits.
+  num_bits -= remaining_bits;
+  bits_read_ += remaining_bits;
+  nbits_ = 0;
+  reg_ = 0;
+  nbits_next_ = 0;
+  reg_next_ = 0;
+
+  // Next, skip an integer number of bytes.
+  const int nbytes = num_bits / 8;
+  if (nbytes > 0) {
+    const uint8* byte_stream_window;
+    const int window_size =
+        byte_stream_provider_->GetBytes(nbytes, &byte_stream_window);
+    DCHECK_GE(window_size, 0);
+    DCHECK_LE(window_size, nbytes);
+    if (window_size < nbytes)
+      return false;
+    num_bits -= 8 * nbytes;
+    bits_read_ += 8 * nbytes;
+  }
+
+  // Skip the remaining bits.
+  return SkipBitsSmall(num_bits);
+}
+
 int BitReaderCore::bits_read() const {
   return bits_read_;
 }