[src/vasprintf.c] Fixed buffer_cat: replaced incorrect assertion len > 0

by a test.

Note that len == 0 is possible when outputting an integer 0 (either a
native one or mpfr_prec_t) with precision field = 0. The consequence
of this bug:
  * In debug mode (MPFR_ASSERTD assertion checking), one would get an
    assertion failure.
  * Otherwise, there should be no side effects since the code was valid
    for len == 0, possibly except with LTO (very unlikely, though).

This incorrect assertion was added on 2009-03-13 in r6099.

git-svn-id: https://scm.gforge.inria.fr/anonscm/svn/mpfr/trunk@14521 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 7 insertions, 1 deletions

diff --git a/src/vasprintf.c b/src/vasprintf.c
index de3b49fae..ff50a931c 100644
--- a/src/vasprintf.c
+++ b/src/vasprintf.c
@@ -645,7 +645,13 @@ buffer_widen (struct string_buffer *b, size_t len)
 static int
 buffer_cat (struct string_buffer *b, const char *s, size_t len)
 {
-  MPFR_ASSERTD (len > 0);
+  /* If len == 0, which is possible when outputting an integer 0
+     (either a native one or mpfr_prec_t) with precision field = 0,
+     do nothing. This test is not necessary since the code below is
+     valid for len == 0, but this is safer, just in case. */
+  if (len == 0)
+    return 0;
+
   MPFR_ASSERTD (len <= strlen (s));
 
   if (buffer_incr_len (b, len))