X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/putty/blobdiff_plain/0d1193675cedd34690779da3e38b756c56832ae6..c6e05bdcc58c3dfe7aa245fe3a7b23160cebeaa5:/misc.c

diff --git a/misc.c b/misc.c
index 17d8f39b..9d71a8d4 100644
--- a/misc.c
+++ b/misc.c
@@ -43,6 +43,50 @@ unsigned long parse_blocksize(const char *bs)
     return r;
 }
 
+/*
+ * Parse a ^C style character specification.
+ * Returns NULL in `next' if we didn't recognise it as a control character,
+ * in which case `c' should be ignored.
+ * The precise current parsing is an oddity inherited from the terminal
+ * answerback-string parsing code. All sequences start with ^; all except
+ * ^<123> are two characters. The ones that are worth keeping are probably:
+ *   ^?		    127
+ *   ^@A-Z[\]^_	    0-31
+ *   a-z	    1-26
+ *   <num>	    specified by number (decimal, 0octal, 0xHEX)
+ *   ~		    ^ escape
+ */
+char ctrlparse(char *s, char **next)
+{
+    char c = 0;
+    if (*s != '^') {
+	*next = NULL;
+    } else {
+	s++;
+	if (*s == '\0') {
+	    *next = NULL;
+	} else if (*s == '<') {
+	    s++;
+	    c = (char)strtol(s, next, 0);
+	    if ((*next == s) || (**next != '>')) {
+		c = 0;
+		*next = NULL;
+	    } else
+		(*next)++;
+	} else if (*s >= 'a' && *s <= 'z') {
+	    c = (*s - ('a' - 1));
+	    *next = s+1;
+	} else if ((*s >= '@' && *s <= '_') || *s == '?' || (*s & 0x80)) {
+	    c = ('@' ^ *s);
+	    *next = s+1;
+	} else if (*s == '~') {
+	    c = '^';
+	    *next = s+1;
+	}
+    }
+    return c;
+}
+
 /* ----------------------------------------------------------------------
  * String handling routines.
  */