Index: third_party/libwebp/utils/bit_reader.c |
diff --git a/third_party/libwebp/utils/bit_reader.c b/third_party/libwebp/utils/bit_reader.c |
index 87b4f462152f0bb5c12f741f5b36454a534547d2..64503e6b92e5f4cea30a80ceb833538a907a2af0 100644 |
--- a/third_party/libwebp/utils/bit_reader.c |
+++ b/third_party/libwebp/utils/bit_reader.c |
@@ -105,9 +105,7 @@ int32_t VP8GetSignedValue(VP8BitReader* const br, int bits) { |
//------------------------------------------------------------------------------ |
// VP8LBitReader |
-#define LBITS 64 // Number of bits prefetched. |
-#define WBITS 32 // Minimum number of bytes needed after VP8LFillBitWindow. |
-#define LOG8_WBITS 4 // Number of bytes needed to store WBITS bits. |
+#define VP8L_LOG8_WBITS 4 // Number of bytes needed to store VP8L_WBITS bits. |
#if !defined(WEBP_FORCE_ALIGNED) && \ |
(defined(__arm__) || defined(_M_ARM) || defined(__aarch64__) || \ |
@@ -151,16 +149,6 @@ void VP8LInitBitReader(VP8LBitReader* const br, const uint8_t* const start, |
br->buf_ = start; |
} |
-// Special version that assumes br->pos_ <= br_len_. |
-static int IsEndOfStreamSpecial(const VP8LBitReader* const br) { |
- assert(br->pos_ <= br->len_); |
- return br->pos_ == br->len_ && br->bit_pos_ >= LBITS; |
-} |
- |
-static int IsEndOfStream(const VP8LBitReader* const br) { |
- return (br->pos_ > br->len_) || IsEndOfStreamSpecial(br); |
-} |
- |
void VP8LBitReaderSetBuffer(VP8LBitReader* const br, |
const uint8_t* const buf, size_t len) { |
assert(br != NULL); |
@@ -168,38 +156,39 @@ void VP8LBitReaderSetBuffer(VP8LBitReader* const br, |
assert(len < 0xfffffff8u); // can't happen with a RIFF chunk. |
br->buf_ = buf; |
br->len_ = len; |
- br->eos_ = IsEndOfStream(br); |
+ // pos_ > len_ should be considered a param error. |
+ br->error_ = (br->pos_ > br->len_); |
+ br->eos_ = br->error_ || VP8LIsEndOfStream(br); |
} |
-// If not at EOS, reload up to LBITS byte-by-byte |
+// If not at EOS, reload up to VP8L_LBITS byte-by-byte |
static void ShiftBytes(VP8LBitReader* const br) { |
while (br->bit_pos_ >= 8 && br->pos_ < br->len_) { |
br->val_ >>= 8; |
- br->val_ |= ((vp8l_val_t)br->buf_[br->pos_]) << (LBITS - 8); |
+ br->val_ |= ((vp8l_val_t)br->buf_[br->pos_]) << (VP8L_LBITS - 8); |
++br->pos_; |
br->bit_pos_ -= 8; |
} |
+ br->eos_ = VP8LIsEndOfStream(br); |
} |
-void VP8LFillBitWindow(VP8LBitReader* const br) { |
- if (br->bit_pos_ >= WBITS) { |
- // TODO(jzern): given the fixed read size it may be possible to force |
- // alignment in this block. |
+void VP8LDoFillBitWindow(VP8LBitReader* const br) { |
+ assert(br->bit_pos_ >= VP8L_WBITS); |
+ // TODO(jzern): given the fixed read size it may be possible to force |
+ // alignment in this block. |
#if defined(VP8L_USE_UNALIGNED_LOAD) |
- if (br->pos_ + sizeof(br->val_) < br->len_) { |
- br->val_ >>= WBITS; |
- br->bit_pos_ -= WBITS; |
- // The expression below needs a little-endian arch to work correctly. |
- // This gives a large speedup for decoding speed. |
- br->val_ |= (vp8l_val_t)*(const uint32_t*)(br->buf_ + br->pos_) << |
- (LBITS - WBITS); |
- br->pos_ += LOG8_WBITS; |
- return; |
- } |
-#endif |
- ShiftBytes(br); // Slow path. |
- br->eos_ = IsEndOfStreamSpecial(br); |
+ if (br->pos_ + sizeof(br->val_) < br->len_) { |
+ br->val_ >>= VP8L_WBITS; |
+ br->bit_pos_ -= VP8L_WBITS; |
+ // The expression below needs a little-endian arch to work correctly. |
+ // This gives a large speedup for decoding speed. |
+ br->val_ |= (vp8l_val_t)*(const uint32_t*)(br->buf_ + br->pos_) << |
+ (VP8L_LBITS - VP8L_WBITS); |
+ br->pos_ += VP8L_LOG8_WBITS; |
+ return; |
} |
+#endif |
+ ShiftBytes(br); // Slow path. |
} |
uint32_t VP8LReadBits(VP8LBitReader* const br, int n_bits) { |
@@ -210,8 +199,6 @@ uint32_t VP8LReadBits(VP8LBitReader* const br, int n_bits) { |
(uint32_t)(br->val_ >> br->bit_pos_) & kBitMask[n_bits]; |
const int new_bits = br->bit_pos_ + n_bits; |
br->bit_pos_ = new_bits; |
- // If this read is going to cross the read buffer, set the eos flag. |
- br->eos_ = IsEndOfStreamSpecial(br); |
ShiftBytes(br); |
return val; |
} else { |