xfnw/plan9fox
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

libflate: force non-empty huffman table in mkzprecode() for deflate

Browse source 
busybox gunzip fails on empty (offset) huffman tables,
so force one entry.

gzip states in a comment:

The pkzip format requires that at least one distance code exists,
and that at least one bit should be sent even if there is only one
possible code.
This commit is contained in:
cinap_lenrek 2017-12-09 18:20:29 +01:00
parent 303fb49686
commit a7ac020664
1 changed files with 5 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
sys/src/libflate/deflate.c
View file

@ -1063,6 +1063,11 @@ mkgzprecode(Huff *tab, ulong *count, int n, int maxbits)
}
if(bitcount[0] != 0)
return 0;
if(nbits == 0){
bitcount[1] = 1;
nbits = 1;
tab[0].bits = 1;
}
return hufftabinit(tab, n, bitcount, nbits);
}