X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=functions%2Fstring%2Fstrncpy.c;h=efb6480468391a0bf35fae0e8001bee7d0d5c1d9;hb=cd6cfe0f578c4f744ddc9a342243aff6b42f8027;hp=aafb7040a79c958683b2553aef54bcd1fc5968eb;hpb=2d7dabdc5e2d6cff488f45c7e917abe1f7e1559a;p=pdclib.old

diff --git a/functions/string/strncpy.c b/functions/string/strncpy.c
index aafb704..efb6480 100644
--- a/functions/string/strncpy.c
+++ b/functions/string/strncpy.c
@@ -1,7 +1,5 @@
 /* $Id$ */
 
-/* Release $Name$ */
-
 /* strncpy( char *, const char *, size_t )
 
    This file is part of the Public Domain C Library (PDCLib).
@@ -10,21 +8,49 @@
 
 #include <string.h>
 
+#ifndef REGTEST
+
 char * strncpy( char * _PDCLIB_restrict s1, const char * _PDCLIB_restrict s2, size_t n )
 {
     char * rc = s1;
     while ( ( n > 0 ) && ( *s1++ = *s2++ ) )
     {
         /* Cannot do "n--" in the conditional as size_t is unsigned and we have
-           to check it again for >0 in the next loop.
+           to check it again for >0 in the next loop below, so we must not risk
+           underflow.
         */
         --n;
     }
-    while ( n-- )
+    /* Checking against 1 as we missed the last --n in the loop above. */
+    while ( n-- > 1 )
     {
         *s1++ = '\0';
     }
     return rc;
 }
 
-#warning Test driver missing.
+#endif
+
+#ifdef TEST
+#include <_PDCLIB_test.h>
+
+int main( void )
+{
+    char s[] = "xxxxxxx";
+    TESTCASE( strncpy( s, "", 1 ) == s );
+    TESTCASE( s[0] == '\0' );
+    TESTCASE( s[1] == 'x' );
+    TESTCASE( strncpy( s, abcde, 6 ) == s );
+    TESTCASE( s[0] == 'a' );
+    TESTCASE( s[4] == 'e' );
+    TESTCASE( s[5] == '\0' );
+    TESTCASE( s[6] == 'x' );
+    TESTCASE( strncpy( s, abcde, 7 ) == s );
+    TESTCASE( s[6] == '\0' );
+    TESTCASE( strncpy( s, "xxxx", 3 ) == s );
+    TESTCASE( s[0] == 'x' );
+    TESTCASE( s[2] == 'x' );
+    TESTCASE( s[3] == 'd' );
+    return TEST_RESULTS;
+}
+#endif