Segmentation fault with small files with levels 5+

[inikep]

Kanzi fails in decompression in lzbench using level 5 or above with the following files:
https://github.com/inikep/lzbench/blob/master/lz/xz/ChangeLog (255 Bytes)
https://github.com/inikep/lzbench/blob/master/lz/zlib/zlib.pc.in (254 Bytes)

./lzbench -t0,0 -ekanzi,5 zlib/zlib.pc.in
lzbench 2.0.1 (64-bit Linux)  AMD EPYC 9554 64-Core Processor                

Compressor name         Compress. Decompress. Compr. size  Ratio Filename
memcpy                   5291 MB/s  5521 MB/s         254 100.00 zlib/zlib.pc.in
Segmentation fault (core dumped)

./lzbench -t0,0 -ekanzi,5 xz/ChangeLog
lzbench 2.0.1 (64-bit Linux)  AMD EPYC 9554 64-Core Processor                

Compressor name         Compress. Decompress. Compr. size  Ratio Filename
memcpy                   5204 MB/s  5543 MB/s         255 100.00 xz/ChangeLog
Segmentation fault (core dumped)

[flanglet]

Outside of lzbench, I do not get a segfault but the decompression fails both with kanzi 2.3 and at tip. Clearly a bug. Thanks for reporting. The issue only affects the BWT inverse (levels 5, 6, 7) and files just close to 255 bytes in size.

[flanglet]

Fixed at tip in flanglet/kanzi-cpp@68b14b8.

[inikep]

This fix is not applicable to v2.3.0 at https://github.com/flanglet/kanzi-cpp/blob/2.3.0/src/transform/BWTBlockCodec.cpp

[flanglet]

The easiest way to fix 2.3 is to copy over the new version of BWTBlockCodec and patch line 102 with "if (true)". Patching 2.3 directly is more involved. Otherwise, wait for 2.4 which is going to be out in a couple of months.