BUG: compression: do not always increment the round counter on allocation failure
Zlib (at least 1.2 and 1.3) aborts when it fails to allocate the state, so we
must not count a round on this event. If the state succeeds, then it allocates
all the 4 remaining counters at once.
diff --git a/src/compression.c b/src/compression.c
index 300a0bd..abceddf 100644
--- a/src/compression.c
+++ b/src/compression.c
@@ -393,7 +393,13 @@
end:
- round = (round + 1) % 5; /* there are 5 zalloc call in deflateInit2 */
+ /* deflateInit2() first allocates and checks the deflate_state, then if
+ * it succeeds, it allocates all other 4 areas at ones and checks them
+ * at the end. So we want to correctly count the rounds depending on when
+ * zlib is supposed to abort.
+ */
+ if (buf || round)
+ round = (round + 1) % 5;
return buf;
}