diff --git a/config.c b/config.c
index f56eb069c05490457599eedfed0c74829e97d199..1e83beffb11718e0876f832f8e7a30da73804e12 100755
--- a/config.c
+++ b/config.c
@@ -51,6 +51,9 @@ void ast_destroy(struct ast_config *ast)
 	struct ast_category *cat, *catn;
 	struct ast_variable *v, *vn;
 
+	if (!ast)
+		return;
+
 	cat = ast->root;
 	while(cat) {
 		v = cat->root;
diff --git a/include/asterisk/callerid.h b/include/asterisk/callerid.h
new file mode 100755
index 0000000000000000000000000000000000000000..f55ca51323dbd2fba71716ad16f7825802456e66
--- /dev/null
+++ b/include/asterisk/callerid.h
@@ -0,0 +1,66 @@
+/*
+ * Asterisk -- A telephony toolkit for Linux.
+ *
+ * CallerID Generation support 
+ * 
+ * Copyright (C) 1999, Mark Spencer
+ *
+ * Mark Spencer <markster@linux-support.net>
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License.
+ *
+ * Includes code and algorithms from the Zapata library.
+ *
+ */
+
+#ifndef _CALLERID_H
+#define _CALLERID_H
+
+#define MAX_CALLERID_SIZE 32000
+
+#define CID_PRIVATE_NAME 		(1 << 0)
+#define CID_PRIVATE_NUMBER		(1 << 1)
+#define CID_UNKNOWN_NAME		(1 << 2)
+#define CID_UNKNOWN_NUMBER		(1 << 3)
+
+struct callerid_state;
+typedef struct callerid_state CIDSTATE;
+
+/* CallerID Initialization */
+extern void callerid_init(void);
+
+/* Generates a CallerID FSK stream in ulaw
+   format suitable for transmission.  Assumes 8000 Hz.  Use NULL
+   for no number or "P" for "private".  If "buf" is supplied it will
+   use that buffer instead of allocating its own.  "buf" must be
+   at least 32000 bytes in size if you want to be sure you dont
+   have an overrun however.  Returns # of bytes written to buffer.
+   Use "O" or "P" in name */
+extern int callerid_generate(unsigned char *buf, char *number, char *name, int flags);
+
+/* Create a callerID state machine */
+extern struct callerid_state *callerid_new(void);
+
+/* Read samples into the state machine.  Returns -1 on error, 0 for "needs more samples", and 1 for
+   callerID stuff complete */
+extern int callerid_feed(struct callerid_state *cid, unsigned char *buf, int samples);
+
+/* Extract info out of callerID state machine.  Flags are listed above */
+void callerid_get(struct callerid_state *cid, char **number, char **name, int *flags);
+
+/* Free a callerID state */
+extern void callerid_free(struct callerid_state *cid);
+
+/* Generate Caller-ID spill from the "callerid" field of asterisk (in e-mail address like format) */
+extern int ast_callerid_generate(unsigned char *buf, char *astcid);
+
+/* Destructively parse inbuf into name and location (or number) */
+extern int ast_callerid_parse(char *inbuf, char **name, char **location);
+
+/* Shrink a phone number in place to just digits (more accurately it just removes ()'s, .'s, and -'s...  */
+extern void ast_shrink_phone_number(char *n);
+
+/* Check if a string consists only of digits.  Returns non-zero if so */
+extern int ast_isphonenumber(char *n);
+#endif