diff options
| -rw-r--r-- | snappy.cc | 81 |
1 files changed, 45 insertions, 36 deletions
@@ -653,45 +653,54 @@ class SnappyDecompressor { // Process the next item found in the input. // Returns true if successful, false on error or end of input. template <class Writer> - bool Step(Writer* writer) { + void DecompressAllTags(Writer* writer) { const char* ip = ip_; - if (ip_limit_ - ip < 5) { - if (!RefillTag()) return false; - ip = ip_; - } - - const unsigned char c = *(reinterpret_cast<const unsigned char*>(ip++)); - const uint32 entry = char_table[c]; - const uint32 trailer = LittleEndian::Load32(ip) & wordmask[entry >> 11]; - ip += entry >> 11; - const uint32 length = entry & 0xff; + for ( ;; ) { + if (ip_limit_ - ip < 5) { + ip_ = ip; + if (!RefillTag()) return; + ip = ip_; + } - if ((c & 0x3) == LITERAL) { - uint32 literal_length = length + trailer; - uint32 avail = ip_limit_ - ip; - while (avail < literal_length) { + const unsigned char c = *(reinterpret_cast<const unsigned char*>(ip++)); + const uint32 entry = char_table[c]; + const uint32 trailer = LittleEndian::Load32(ip) & wordmask[entry >> 11]; + ip += entry >> 11; + const uint32 length = entry & 0xff; + + if ((c & 0x3) == LITERAL) { + uint32 literal_length = length + trailer; + uint32 avail = ip_limit_ - ip; + while (avail < literal_length) { + bool allow_fast_path = (avail >= 16); + if (!writer->Append(ip, avail, allow_fast_path)) goto end; + literal_length -= avail; + reader_->Skip(peeked_); + size_t n; + ip = reader_->Peek(&n); + avail = n; + peeked_ = avail; + if (avail == 0) goto end; // Premature end of input + ip_limit_ = ip + avail; + } bool allow_fast_path = (avail >= 16); - if (!writer->Append(ip, avail, allow_fast_path)) return false; - literal_length -= avail; - reader_->Skip(peeked_); - size_t n; - ip = reader_->Peek(&n); - avail = n; - peeked_ = avail; - if (avail == 0) return false; // Premature end of input - ip_limit_ = ip + avail; + if (!writer->Append(ip, literal_length, allow_fast_path)) { + goto end; + } + ip += literal_length; + } else { + // copy_offset/256 is encoded in bits 8..10. By just fetching + // those bits, we get copy_offset (since the bit-field starts at + // bit 8). + const uint32 copy_offset = entry & 0x700; + if (!writer->AppendFromSelf(copy_offset + trailer, length)) { + goto end; + } } - ip_ = ip + literal_length; - bool allow_fast_path = (avail >= 16); - return writer->Append(ip, literal_length, allow_fast_path); - } else { - ip_ = ip; - // copy_offset/256 is encoded in bits 8..10. By just fetching - // those bits, we get copy_offset (since the bit-field starts at - // bit 8). - const uint32 copy_offset = entry & 0x700; - return writer->AppendFromSelf(copy_offset + trailer, length); } + +end: + ip_ = ip; } }; @@ -770,7 +779,7 @@ static bool InternalUncompress(Source* r, writer->SetExpectedLength(uncompressed_len); // Process the entire input - while (decompressor.Step(writer)) { } + decompressor.DecompressAllTags(writer); return (decompressor.eof() && writer->CheckLength()); } @@ -866,7 +875,7 @@ size_t Compress(Source* reader, Sink* writer) { // A type that writes to a flat array. // Note that this is not a "ByteSink", but a type that matches the -// Writer template argument to SnappyDecompressor::Step(). +// Writer template argument to SnappyDecompressor::DecompressAllTags(). class SnappyArrayWriter { private: char* base_; |