Commits on Dec 15, 2022

1. Fix corruption that rarely occurs in 32-bit mode with wlog=25 …

   Fix an off-by-one error in the compressor that emits corrupt blocks if:
   
   * Zstd is compiled in 32-bit mode
   * The windowLog == 25 exactly
   * An offset of 2^25-3, 2^25-2, 2^25-1, or 2^25 is emitted
   * The bitstream had 7 bits leftover before writing the offset
   
   This bug has been present since before v1.0, but wasn't able to easily
   be triggered, since until somewhat recently zstd wasn't able to find
   matches that were within 128KB of the window size.
   
   Add a test case, and fix 2 bugs in `ZSTD_compressSequences()`:
   * The `ZSTD_isRLE()` check was incorrect. It wouldn't produce
     corruption, but it could waste CPU and not emit RLE even if the block
     was RLE
   * One windowSize was `1 << windowLog`, not `1u << windowLog`
   
   Thanks to @tansy for finding the issue, and giving us a reproducer!
   
   Fixes Issue facebook#3350.

   

   terrelln committed Dec 15, 2022
   Configuration menu

   • View commit details
   • Copy full SHA for 036d5ac
   • Browse repository at this point

   Copy the full SHA

   036d5ac View commit details

   Browse the repository at this point in the history