lib/srutils: added small api for internal unique id generator

- uses prefix, server id, timestamp, pid and a counter for an unique
  string

lib/srutils/sruid.c

@@ -0,0 +1,105 @@
+/*
+ * $Id$
+ *
+ * sruid - unique id generator
+ *
+ * Copyright (C) 2012 Daniel-Constantin Mierla (asipto.com)
+ *
+ * This file is part of Kamailio, a free SIP server.
+ *
+ * Kamailio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version
+ *
+ * Kamailio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License 
+ * along with this program; if not, write to the Free Software 
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include "../../dprint.h"
+#include "../../globals.h"
+#include "../../pt.h"
+
+#include "sruid.h"
+
+/**
+ *
+ */
+int sruid_init(sruid_t *sid, char sep, char *cid)
+{
+	int i;
+
+	if(sid==NULL)
+		return -1;
+	memset(sid, 0, sizeof(sruid_t));
+	memcpy(sid->buf, "srid", 4);
+	if(cid!=NULL)
+	{
+		for(i=0; i<4 && cid[i]!='\0'; i++)
+			sid->buf[i] = cid[i];
+	}
+	sid->buf[4] = sep;
+
+	if(server_id!=0)
+		i = snprintf(sid->buf+5, SRUID_SIZE - 5 /*so far*/ - 8 /* extra int */,
+			"%x%c%x%c%x%c", (unsigned int)server_id, sep,
+			(unsigned int)time(NULL), sep, (unsigned int)my_pid(), sep);
+	else
+		i = snprintf(sid->buf+5, SRUID_SIZE - 5 /*so far*/ - 8 /* extra int */,
+			"%x%c%x%c",
+			(unsigned int)time(NULL), sep, (unsigned int)my_pid(), sep);
+	if(i<=0 || i>SRUID_SIZE-13)
+	{
+		LM_ERR("could not initialize sruid struct - output len: %d\n", i);
+		return -1;
+	}
+	sid->out = sid->buf + i + 5;
+	sid->uid.s = sid->buf;
+	LM_DBG("root for sruid is [%.*s] (%u / %d)\n", i+5, sid->uid.s,
+			sid->counter, i+5);
+	return 0;
+}
+
+/**
+ *
+ */
+int sruid_next(sruid_t *sid)
+{
+	unsigned short digit;
+	int i;
+	unsigned int val;
+
+	if(sid==NULL)
+		return -1;
+
+	sid->counter++;
+	if(sid->counter==0)
+		sid->counter=1;
+
+	val = sid->counter;
+	i = 0;
+	while(val!=0)
+	{
+		digit =  val & 0x0f;
+		sid->out[i++] = (digit >= 10) ? digit + 'a' - 10 : digit + '0';
+		val >>= 4;
+	}
+	sid->out[i] = '\0';
+	sid->uid.len = sid->out + i - sid->buf;
+	LM_DBG("new sruid is [%.*s] (%u / %d)\n", sid->uid.len, sid->uid.s,
+			sid->counter, sid->uid.len);
+	return 0;
+}
+

lib/srutils/sruid.h

@@ -0,0 +1,42 @@
+/*
+ * $Id$
+ *
+ * sruid - unique id generator
+ *
+ * Copyright (C) 2012 Daniel-Constantin Mierla (asipto.com)
+ *
+ * This file is part of Kamailio, a free SIP server.
+ *
+ * Kamailio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version
+ *
+ * Kamailio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License 
+ * along with this program; if not, write to the Free Software 
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef _SRUID_H_
+#define _SRUID_H_
+
+#include "../../str.h"
+
+#define SRUID_SIZE	40
+
+typedef struct sruid {
+	char buf[SRUID_SIZE];
+	char *out;
+	str uid;
+	unsigned int counter;
+} sruid_t;
+
+int sruid_init(sruid_t *sid, char sep, char *cid);
+int sruid_next(sruid_t *sid);
+
+#endif