diff options
Diffstat (limited to 'src/puffer.cc')
| -rw-r--r-- | src/puffer.cc | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/src/puffer.cc b/src/puffer.cc index a514968..f3a54f8 100644 --- a/src/puffer.cc +++ b/src/puffer.cc @@ -23,7 +23,12 @@ using std::vector; namespace puffin { -Puffer::Puffer() : dyn_ht_(new HuffmanTable()), fix_ht_(new HuffmanTable()) {} +Puffer::Puffer(bool exclude_bad_distance_caches) + : dyn_ht_(new HuffmanTable()), + fix_ht_(new HuffmanTable()), + exclude_bad_distance_caches_(exclude_bad_distance_caches) {} + +Puffer::Puffer() : Puffer(false) {} Puffer::~Puffer() {} @@ -129,6 +134,10 @@ bool Puffer::PuffDeflate(BitReaderInterface* br, return false; } + // If true and the list of output |deflates| is non-null, the current + // deflate location will be added to that list. + bool include_deflate = true; + while (true) { // Breaks when the end of block is reached. auto max_bits = cur_ht->LitLenMaxBits(); if (!br->CacheBits(max_bits)) { @@ -152,7 +161,7 @@ bool Puffer::PuffDeflate(BitReaderInterface* br, } else if (256 == lit_len_alphabet) { pd.type = PuffData::Type::kEndOfBlock; TEST_AND_RETURN_FALSE(pw->Insert(pd)); - if (deflates != nullptr) { + if (deflates != nullptr && include_deflate) { deflates->emplace_back(start_bit_offset, br->OffsetInBits() - start_bit_offset); } @@ -170,8 +179,21 @@ bool Puffer::PuffDeflate(BitReaderInterface* br, } auto length = kLengthBases[len_code_start] + extra_bits_value; - TEST_AND_RETURN_FALSE(br->CacheBits(cur_ht->DistanceMaxBits())); - auto bits = br->ReadBits(cur_ht->DistanceMaxBits()); + auto bits_to_cache = cur_ht->DistanceMaxBits(); + if (!br->CacheBits(bits_to_cache)) { + // This is a corner case that is present in the older versions of the + // puffin. So we need to catch it and correctly discard this kind of + // deflate when we encounter it. See crbug.com/915559 for more info. + bits_to_cache = br->BitsRemaining(); + TEST_AND_RETURN_FALSE(br->CacheBits(bits_to_cache)); + if (exclude_bad_distance_caches_) { + include_deflate = false; + } + LOG(WARNING) << "A rare condition that older puffin clients fail to" + << " recognize happened. Nothing to worry about." + << " See crbug.com/915559"; + } + auto bits = br->ReadBits(bits_to_cache); uint16_t distance_alphabet; size_t nbits; TEST_AND_RETURN_FALSE( |