Fix memory allocation read_file()

The logic was simply broken and did only work
if the file was less than STD_FILE_BUF.

parser.c

@@ -114,25 +114,32 @@ HE_face *parse_obj(char const * const filename)
 static char *read_file(char const * const filename)
 {
 	char buf[STD_FILE_BUF],
-		 *string = malloc(STD_FILE_BUF);
+		 *string = NULL;
 	int objfile = 0;
 	size_t str_size = 0;
 	ssize_t n;
-	uint8_t i = 0;
 
 	objfile = open(filename, O_RDONLY);
 
 	if (objfile) {
 		/* read and copy chunks */
 		while ((n = read(objfile, buf, STD_FILE_BUF)) > 0) {
-			char *tmp_ptr = string + str_size;
-			memcpy(tmp_ptr, buf, STD_FILE_BUF);
-			str_size += n;
-			string = realloc(string, str_size);
-			i++;
+			char *tmp_ptr = NULL;
+
+			str_size += n; /* count total bytes read */
+
+			tmp_ptr = realloc( /* allocate correct size */
+					string, /* pointer to realloc */
+					str_size /* total bytes read */
+					+ 1); /* space for trailing NULL byte */
+			CHECK_PTR_VAL(tmp_ptr);
+			string = tmp_ptr;
+
+			/* append buffer to string */
+			memcpy(string + (str_size - n), buf, n);
 		}
 		/* add trailing NULL byte */
-		string[str_size + 1] = '\0';
+		string[str_size] = '\0';
 
 		close(objfile);