fix false negatives with periodic needles in strstr, wcsstr, and memmem

in cases where the memorized match range from the right factor
exceeded the length of the left factor, it was wrongly treated as a
mismatch rather than a match.

issue reported by Yves Bastide.

diff --git a/src/string/memmem.c b/src/string/memmem.c
index a5a249f..3b1ae18 100644 (file)
--- a/src/string/memmem.c
+++ b/src/string/memmem.c
@@ -120,7 +120,7 @@ static char *twoway_memmem(const unsigned char *h, const unsigned char *z, const
                }
                /* Compare left half */
                for (k=ms+1; k>mem && n[k-1] == h[k-1]; k--);
-               if (k == mem) return (char *)h;
+               if (k <= mem) return (char *)h;
                h += p;
                mem = mem0;
        }

diff --git a/src/string/strstr.c b/src/string/strstr.c
index 915c0a2..cd06912 100644 (file)
--- a/src/string/strstr.c
+++ b/src/string/strstr.c
@@ -130,7 +130,7 @@ static char *twoway_strstr(const unsigned char *h, const unsigned char *n)
                }
                /* Compare left half */
                for (k=ms+1; k>mem && n[k-1] == h[k-1]; k--);
-               if (k == mem) return (char *)h;
+               if (k <= mem) return (char *)h;
                h += p;
                mem = mem0;
        }

diff --git a/src/string/wcsstr.c b/src/string/wcsstr.c
index 3e28e28..4caaef3 100644 (file)
--- a/src/string/wcsstr.c
+++ b/src/string/wcsstr.c
@@ -84,7 +84,7 @@ static wchar_t *twoway_wcsstr(const wchar_t *h, const wchar_t *n)
                }
                /* Compare left half */
                for (k=ms+1; k>mem && n[k-1] == h[k-1]; k--);
-               if (k == mem) return (wchar_t *)h;
+               if (k <= mem) return (wchar_t *)h;
                h += p;
                mem = mem0;
        }