+#define FILE_CHAR_TEST(c, mask) (filechr_table[(unsigned char)(c)] & (mask))
+
+/* Shorthands for the table: */
+#define U filechr_not_unix
+#define W filechr_not_windows
+#define C filechr_control
+
+#define UW U|W
+#define UWC U|W|C
+
+/* Table of characters unsafe under various conditions (see above).
+
+ Arguably we could also claim `%' to be unsafe, since we use it as
+ the escape character. If we ever want to be able to reliably
+ translate file name back to URL, this would become important
+ crucial. Right now, it's better to be minimal in escaping. */
+
+static const unsigned char filechr_table[256] =
+{
+UWC, C, C, C, C, C, C, C, /* NUL SOH STX ETX EOT ENQ ACK BEL */
+ C, C, C, C, C, C, C, C, /* BS HT LF VT FF CR SO SI */
+ C, C, C, C, C, C, C, C, /* DLE DC1 DC2 DC3 DC4 NAK SYN ETB */
+ C, C, C, C, C, C, C, C, /* CAN EM SUB ESC FS GS RS US */
+ 0, 0, W, 0, 0, 0, 0, 0, /* SP ! " # $ % & ' */
+ 0, 0, W, 0, 0, 0, 0, UW, /* ( ) * + , - . / */
+ 0, 0, 0, 0, 0, 0, 0, 0, /* 0 1 2 3 4 5 6 7 */
+ 0, 0, W, 0, W, 0, W, W, /* 8 9 : ; < = > ? */
+ 0, 0, 0, 0, 0, 0, 0, 0, /* @ A B C D E F G */
+ 0, 0, 0, 0, 0, 0, 0, 0, /* H I J K L M N O */
+ 0, 0, 0, 0, 0, 0, 0, 0, /* P Q R S T U V W */
+ 0, 0, 0, 0, W, 0, 0, 0, /* X Y Z [ \ ] ^ _ */
+ 0, 0, 0, 0, 0, 0, 0, 0, /* ` a b c d e f g */
+ 0, 0, 0, 0, 0, 0, 0, 0, /* h i j k l m n o */
+ 0, 0, 0, 0, 0, 0, 0, 0, /* p q r s t u v w */
+ 0, 0, 0, 0, 0, 0, 0, 0, /* x y z { | } ~ DEL */
+
+ C, C, C, C, C, C, C, C, C, C, C, C, C, C, C, C, /* 128-143 */
+ C, C, C, C, C, C, C, C, C, C, C, C, C, C, C, C, /* 144-159 */
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+};
+#undef U
+#undef W
+#undef C
+#undef UW
+#undef UWC
+
+/* FN_PORT_SEP is the separator between host and port in file names
+ for non-standard port numbers. On Unix this is normally ':', as in
+ "www.xemacs.org:4001/index.html". Under Windows, we set it to +
+ because Windows can't handle ':' in file names. */
+#define FN_PORT_SEP (opt.restrict_files_os != restrict_windows ? ':' : '+')
+
+/* FN_QUERY_SEP is the separator between the file name and the URL
+ query, normally '?'. Since Windows cannot handle '?' as part of
+ file name, we use '@' instead there. */
+#define FN_QUERY_SEP (opt.restrict_files_os != restrict_windows ? '?' : '@')
+
+/* Quote path element, characters in [b, e), as file name, and append
+ the quoted string to DEST. Each character is quoted as per
+ file_unsafe_char and the corresponding table.
+
+ If ESCAPED is true, the path element is considered to be
+ URL-escaped and will be unescaped prior to inspection. */
+
+static void
+append_uri_pathel (const char *b, const char *e, bool escaped,
+ struct growable *dest)
+{
+ const char *p;
+ int quoted, outlen;
+
+ int mask;
+ if (opt.restrict_files_os == restrict_unix)
+ mask = filechr_not_unix;