X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=functions%2Fstring%2Fstrncpy.c;h=efb6480468391a0bf35fae0e8001bee7d0d5c1d9;hb=cd6cfe0f578c4f744ddc9a342243aff6b42f8027;hp=e89332cfadd633de3444dbb68e4867970bd08d4e;hpb=c8f799d852e3698468a78954d82588e841cc0b70;p=pdclib.old

diff --git a/functions/string/strncpy.c b/functions/string/strncpy.c
index e89332c..efb6480 100644
--- a/functions/string/strncpy.c
+++ b/functions/string/strncpy.c
@@ -1,22 +1,56 @@
-/* ----------------------------------------------------------------------------
- * $Id$
- * ----------------------------------------------------------------------------
- * Public Domain C Library - http://pdclib.sourceforge.net
- * This code is Public Domain. Use, modify, and redistribute at will.
- * --------------------------------------------------------------------------*/
+/* $Id$ */
 
-#include <__size_t.h>
+/* strncpy( char *, const char *, size_t )
 
-char * strncpy( char * restrict dest, const char * restrict src, size_t n )
+   This file is part of the Public Domain C Library (PDCLib).
+   Permission is granted to use, modify, and / or redistribute at will.
+*/
+
+#include <string.h>
+
+#ifndef REGTEST
+
+char * strncpy( char * _PDCLIB_restrict s1, const char * _PDCLIB_restrict s2, size_t n )
 {
-    char * tmp = dest;
-    while ( ( n-- != 0 ) && ( ( *dest++ = *src++ ) != '\0' ) )
+    char * rc = s1;
+    while ( ( n > 0 ) && ( *s1++ = *s2++ ) )
     {
-        /* EMPTY */
+        /* Cannot do "n--" in the conditional as size_t is unsigned and we have
+           to check it again for >0 in the next loop below, so we must not risk
+           underflow.
+        */
+        --n;
     }
-    while ( n-- != 0 )
+    /* Checking against 1 as we missed the last --n in the loop above. */
+    while ( n-- > 1 )
     {
-        *dest++ = '\0';
+        *s1++ = '\0';
     }
-    return tmp;
+    return rc;
+}
+
+#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