X-Git-Url: https://pd.if.org/git/?p=pdclib;a=blobdiff_plain;f=functions%2Fstring%2Fstrncmp.c;h=e1ec0de66e9797c9739555b4b901116ea4813920;hp=ec9c56fb2a780e1a2a40efee5451c4c7836975df;hb=da0f3f353d417fed71f358a48d5d5394145e460d;hpb=0a5395faab237ba9008352b0f4bee9659bbd3d5f

diff --git a/functions/string/strncmp.c b/functions/string/strncmp.c
index ec9c56f..e1ec0de 100644
--- a/functions/string/strncmp.c
+++ b/functions/string/strncmp.c
@@ -1,27 +1,52 @@
-// ----------------------------------------------------------------------------
-// $Id$
-// ----------------------------------------------------------------------------
-// Public Domain C Library - http://pdclib.sourceforge.net
-// This code is Public Domain. Use, modify, and redistribute at will.
-// ----------------------------------------------------------------------------
+/* strncmp( const char *, const char *, size_t )
 
-int strncmp( const char * s1, const char * 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
+
+int strncmp( const char * s1, const char * s2, size_t n )
 {
-    const unsigned char *p1;
-    const unsigned char *p2;
-    size_t x = 0;
-    
-    p1 = (const unsigned char *)s1;
-    p2 = (const unsigned char *)s2;
-    while (x < n)
+    while ( *s1 && n && ( *s1 == *s2 ) )
+    {
+        ++s1;
+        ++s2;
+        --n;
+    }
+    if ( n == 0 )
+    {
+        return 0;
+    }
+    else
     {
-        if (p1[x] < p2[x]) return (-1);
-        else if (p1[x] > p2[x]) return (1);
-        else if (p1[x] == '\0') return (0);
-        x++;
+        return ( *(unsigned char *)s1 - *(unsigned char *)s2 );
     }
-    return (0);
 }
-*/
+
+#endif
+
+#ifdef TEST
+#include "_PDCLIB_test.h"
+
+int main( void )
+{
+    char cmpabcde[] = "abcde\0f";
+    char cmpabcd_[] = "abcde\xfc";
+    char empty[] = "";
+    char x[] = "x";
+    TESTCASE( strncmp( abcde, cmpabcde, 5 ) == 0 );
+    TESTCASE( strncmp( abcde, cmpabcde, 10 ) == 0 );
+    TESTCASE( strncmp( abcde, abcdx, 5 ) < 0 );
+    TESTCASE( strncmp( abcdx, abcde, 5 ) > 0 );
+    TESTCASE( strncmp( empty, abcde, 5 ) < 0 );
+    TESTCASE( strncmp( abcde, empty, 5 ) > 0 );
+    TESTCASE( strncmp( abcde, abcdx, 4 ) == 0 );
+    TESTCASE( strncmp( abcde, x, 0 ) == 0 );
+    TESTCASE( strncmp( abcde, x, 1 ) < 0 );
+    TESTCASE( strncmp( abcde, cmpabcd_, 10 ) < 0 );
+    return TEST_RESULTS;
+}
+#endif