1 files changed, 88 insertions, 0 deletions
diff --git a/src/idgen.c b/src/idgen.c
new file mode 100644
index 0000000..3e43310
--- /dev/null
+++ b/src/idgen.c
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2018 "IoT.bzh"
+ * Author José Bollo <jose.bollo@iot.bzh>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/******************************************************************************/
+/******************************************************************************/
+/* CONVERTION OF EXPIRATIONS TO AND FROM TEXT                                 */
+/******************************************************************************/
+/******************************************************************************/
+
+#include <stdbool.h>
+#include <string.h>
+
+#include "idgen.h"
+
+static char i2c[] =
+	"0123456789"
+	"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	"abcdefghijklmnopqrstuvwxyz"
+	"-+*/<%$#@?!,.&~^>=|_"
+;
+static char nxt[96];
+
+#define ZERO i2c[0]
+#define ONE i2c[1]
+
+static char next(char c)
+{
+	unsigned i;
+	char r;
+
+	if ((signed char)c <= 32)
+		r = ONE;
+	else {
+		r = nxt[c - 32];
+		if (!r) {
+			memset(nxt, ONE, sizeof(nxt));
+			for (i = 0 ; (r = i2c[i]) ; i++)
+				nxt[r - 32] = i2c[i + 1] ?: ZERO;
+			r = nxt[c - 32];
+		}
+	}
+	return r;
+}
+
+void
+idgen_init(
+	idgen_t idgen
+) {
+	memset(idgen, 0, sizeof(idgen_t));
+	idgen[0] = ZERO;
+}
+
+void
+idgen_next(
+	idgen_t idgen
+) {
+	unsigned i;
+	char c;
+
+	i = 0;
+	do {
+		c = next(idgen[i]);
+		idgen[i++] = c;
+	} while (c == ZERO && i < sizeof(idgen_t) - 1);
+}
+
+bool
+idgen_is_valid(
+	idgen_t idgen
+) {
+	unsigned i = 0;
+	while (i < sizeof(idgen_t) && idgen[i] && strchr(i2c, idgen[i]))
+		i++;
+	return i && i < sizeof(idgen_t) && !idgen[i];
+}