--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libsip/uri_utils.c	Tue Sep 06 20:29:44 2022 -0800
@@ -0,0 +1,32 @@
+/*
+ * Some utility functions for working with SIP URIs.
+ */
+
+#include <string.h>
+#include <strings.h>
+
+user_from_sip_uri(uri, outbuf, maxlen)
+	char *uri, *outbuf;
+	unsigned maxlen;
+{
+	char *cp, *dp;
+	unsigned n;
+
+	if (strncasecmp(uri, "sip:", 4))
+		return(-1);
+	cp = uri + 4;
+	dp = outbuf;
+	n = 0;
+	for (;;) {
+		if (!*cp)
+			return(-1);
+		if (*cp == '@')
+			break;
+		if (n >= maxlen)
+			return(-2);
+		*dp++ = *cp++;
+		n++;
+	}
+	*dp = '\0';
+	return(0);
+}