X-Git-Url: https://pd.if.org/git/?p=pdclib;a=blobdiff_plain;f=functions%2Fstring%2Fstrncat.c;h=18d8ed596e9fc0cd20b872f90f99200d2a68b6bb;hp=1bc202398636595fb72da31940acc6c4d47bdd88;hb=da0f3f353d417fed71f358a48d5d5394145e460d;hpb=0a5395faab237ba9008352b0f4bee9659bbd3d5f

diff --git a/functions/string/strncat.c b/functions/string/strncat.c
index 1bc2023..18d8ed5 100644
--- a/functions/string/strncat.c
+++ b/functions/string/strncat.c
@@ -1,26 +1,58 @@
-// ----------------------------------------------------------------------------
-// $Id$
-// ----------------------------------------------------------------------------
-// Public Domain C Library - http://pdclib.sourceforge.net
-// This code is Public Domain. Use, modify, and redistribute at will.
-// ----------------------------------------------------------------------------
+/* strncat( char *, const char *, size_t )
 
-char * strncat( char * restrict s1, const char * restrict s2, size_t n ) { /* TODO */ };
+   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>
 
-/* PDPC code - unreviewed
+#ifndef REGTEST
+
+char * strncat( char * _PDCLIB_restrict s1, const char * _PDCLIB_restrict s2, size_t n )
 {
-    char *p = s1;
-    size_t x = 0;
-    
-    while (*p != '\0') p++;
-    while ((*s2 != '\0') && (x < n))
+    char * rc = s1;
+    while ( *s1 )
+    {
+        ++s1;
+    }
+    while ( n && ( *s1++ = *s2++ ) )
+    {
+        --n;
+    }
+    if ( n == 0 )
     {
-        *p = *s2;
-        p++;
-        s2++;
-        x++;
+        *s1 = '\0';
     }
-    *p = '\0';
-    return (s1);
+    return rc;
 }
-*/
+
+#endif
+
+#ifdef TEST
+#include "_PDCLIB_test.h"
+
+int main( void )
+{
+    char s[] = "xx\0xxxxxx";
+    TESTCASE( strncat( s, abcde, 10 ) == s );
+    TESTCASE( s[2] == 'a' );
+    TESTCASE( s[6] == 'e' );
+    TESTCASE( s[7] == '\0' );
+    TESTCASE( s[8] == 'x' );
+    s[0] = '\0';
+    TESTCASE( strncat( s, abcdx, 10 ) == s );
+    TESTCASE( s[4] == 'x' );
+    TESTCASE( s[5] == '\0' );
+    TESTCASE( strncat( s, "\0", 10 ) == s );
+    TESTCASE( s[5] == '\0' );
+    TESTCASE( s[6] == 'e' );
+    TESTCASE( strncat( s, abcde, 0 ) == s );
+    TESTCASE( s[5] == '\0' );
+    TESTCASE( s[6] == 'e' );
+    TESTCASE( strncat( s, abcde, 3 ) == s );
+    TESTCASE( s[5] == 'a' );
+    TESTCASE( s[7] == 'c' );
+    TESTCASE( s[8] == '\0' );
+    return TEST_RESULTS;
+}
+#endif