[libc] Add stpcpy()

Signed-off-by: Michael Brown <[email protected]>

src/core/string.c

@@ -321,9 +321,9 @@ char * strstr ( const char *haystack, const char *needle ) {
  *
  * @v dest		Destination string
  * @v src		Source string
- * @ret dest		Destination string
+ * @ret dnul		Terminating NUL of destination string
  */
-char * strcpy ( char *dest, const char *src ) {
+char * stpcpy ( char *dest, const char *src ) {
 	const uint8_t *src_bytes = ( ( const uint8_t * ) src );
 	uint8_t *dest_bytes = ( ( uint8_t * ) dest );
 
@@ -333,6 +333,19 @@ char * strcpy ( char *dest, const char *src ) {
 		if ( ! *dest_bytes )
 			break;
 	}
+	return ( ( char * ) dest_bytes );
+}
+
+/**
+ * Copy string
+ *
+ * @v dest		Destination string
+ * @v src		Source string
+ * @ret dest		Destination string
+ */
+char * strcpy ( char *dest, const char *src ) {
+
+	stpcpy ( dest, src );
 	return dest;
 }
 

src/include/string.h

@@ -43,6 +43,7 @@ extern char * __pure strchr ( const char *src, int character ) __nonnull;
 extern char * __pure strrchr ( const char *src, int character ) __nonnull;
 extern char * __pure strstr ( const char *haystack,
 			      const char *needle ) __nonnull;
+extern char * stpcpy ( char *dest, const char *src ) __nonnull;
 extern char * strcpy ( char *dest, const char *src ) __nonnull;
 extern char * strncpy ( char *dest, const char *src, size_t max ) __nonnull;
 extern char * strcat ( char *dest, const char *src ) __nonnull;

src/tests/string_test.c

@@ -204,6 +204,24 @@ static void string_test_exec ( void ) {
 		free ( dup );
 	}
 
+	/* Test stpcpy() */
+	{
+		const char longer[12] = "duplicateme";
+		const char shorter[6] = "hello";
+		char dest[12];
+		char *dnul;
+
+		dnul = stpcpy ( dest, longer );
+		ok ( *dnul == '\0' );
+		ok ( dnul == &dest[11] );
+		ok ( memcmp ( dest, longer, 12 ) == 0 );
+		dnul = stpcpy ( dest, shorter );
+		ok ( *dnul == '\0' );
+		ok ( dnul == &dest[5] );
+		ok ( memcmp ( dest, shorter, 6 ) == 0 );
+		ok ( memcmp ( ( dest + 6 ), ( longer + 6 ), 6 ) == 0 );
+	}
+
 	/* Test strcpy() */
 	{
 		const char longer[7] = "copyme";