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Diffstat (limited to 'chromium/media/base/bit_reader.cc')
-rw-r--r--chromium/media/base/bit_reader.cc83
1 files changed, 17 insertions, 66 deletions
diff --git a/chromium/media/base/bit_reader.cc b/chromium/media/base/bit_reader.cc
index e4d83af7410..c0d30d66fdd 100644
--- a/chromium/media/base/bit_reader.cc
+++ b/chromium/media/base/bit_reader.cc
@@ -4,80 +4,31 @@
#include "media/base/bit_reader.h"
-#include <algorithm>
-
namespace media {
-BitReader::BitReader(const uint8* data, off_t size)
- : data_(data), bytes_left_(size), num_remaining_bits_in_curr_byte_(0) {
- DCHECK(data_ != NULL && bytes_left_ > 0);
-
- UpdateCurrByte();
+BitReader::BitReader(const uint8* data, int size)
+ : initial_size_(size),
+ data_(data),
+ bytes_left_(size),
+ bit_reader_core_(this) {
+ DCHECK(data != NULL);
+ DCHECK_GE(size, 0);
}
BitReader::~BitReader() {}
-bool BitReader::SkipBits(int num_bits) {
- DCHECK_GE(num_bits, 0);
- DVLOG_IF(0, num_bits > 100)
- << "BitReader::SkipBits inefficient for large skips";
-
- // Skip any bits in the current byte waiting to be processed, then
- // process full bytes until less than 8 bits remaining.
- while (num_bits > 0 && num_bits > num_remaining_bits_in_curr_byte_) {
- num_bits -= num_remaining_bits_in_curr_byte_;
- num_remaining_bits_in_curr_byte_ = 0;
- UpdateCurrByte();
-
- // If there is no more data remaining, only return true if we
- // skipped all that were requested.
- if (num_remaining_bits_in_curr_byte_ == 0)
- return (num_bits == 0);
- }
-
- // Less than 8 bits remaining to skip. Use ReadBitsInternal to verify
- // that the remaining bits we need exist, and adjust them as necessary
- // for subsequent operations.
- uint64 not_needed;
- return ReadBitsInternal(num_bits, &not_needed);
-}
-
-int BitReader::bits_available() const {
- return 8 * bytes_left_ + num_remaining_bits_in_curr_byte_;
-}
-
-bool BitReader::ReadBitsInternal(int num_bits, uint64* out) {
- DCHECK_LE(num_bits, 64);
-
- *out = 0;
-
- while (num_remaining_bits_in_curr_byte_ != 0 && num_bits != 0) {
- int bits_to_take = std::min(num_remaining_bits_in_curr_byte_, num_bits);
-
- *out <<= bits_to_take;
- *out += curr_byte_ >> (num_remaining_bits_in_curr_byte_ - bits_to_take);
- num_bits -= bits_to_take;
- num_remaining_bits_in_curr_byte_ -= bits_to_take;
- curr_byte_ &= (1 << num_remaining_bits_in_curr_byte_) - 1;
-
- if (num_remaining_bits_in_curr_byte_ == 0)
- UpdateCurrByte();
- }
-
- return num_bits == 0;
-}
-
-void BitReader::UpdateCurrByte() {
- DCHECK_EQ(num_remaining_bits_in_curr_byte_, 0);
+int BitReader::GetBytes(int max_nbytes, const uint8** out) {
+ DCHECK_GE(max_nbytes, 0);
+ DCHECK(out);
- if (bytes_left_ == 0)
- return;
+ int nbytes = max_nbytes;
+ if (nbytes > bytes_left_)
+ nbytes = bytes_left_;
- // Load a new byte and advance pointers.
- curr_byte_ = *data_;
- ++data_;
- --bytes_left_;
- num_remaining_bits_in_curr_byte_ = 8;
+ *out = data_;
+ data_ += nbytes;
+ bytes_left_ -= nbytes;
+ return nbytes;
}
} // namespace media