1 files changed, 49 insertions, 0 deletions
diff --git a/utils/ctrlparse.c b/utils/ctrlparse.c
new file mode 100644
index 00000000..86f87902
--- /dev/null
+++ b/utils/ctrlparse.c
@@ -0,0 +1,49 @@
+/*
+ * 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
+ */
+
+#include <stdlib.h>
+
+#include "defs.h"
+#include "misc.h"
+
+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;
+}