diff options
Diffstat (limited to 'snappy.h')
| -rw-r--r-- | snappy.h | 17 |
1 files changed, 9 insertions, 8 deletions
@@ -142,15 +142,16 @@ namespace snappy { bool IsValidCompressedBuffer(const char* compressed, size_t compressed_length); - // *** DO NOT CHANGE THE VALUE OF kBlockSize *** + // The size of a compression block. Note that many parts of the compression + // code assumes that kBlockSize <= 65536; in particular, the hash table + // can only store 16-bit offsets, and EmitCopy() also assumes the offset + // is 65535 bytes or less. Note also that if you change this, it will + // affect the framing format (see framing_format.txt). // - // New Compression code chops up the input into blocks of at most - // the following size. This ensures that back-references in the - // output never cross kBlockSize block boundaries. This can be - // helpful in implementing blocked decompression. However the - // decompression code should not rely on this guarantee since older - // compression code may not obey it. - static const int kBlockLog = 15; + // Note that there might be older data around that is compressed with larger + // block sizes, so the decompression code should not rely on the + // non-existence of long backreferences. + static const int kBlockLog = 16; static const size_t kBlockSize = 1 << kBlockLog; static const int kMaxHashTableBits = 14; |