Add cron functionality

apps/time/cron.h

@@ -0,0 +1,91 @@
+/*
+ * Definitions for cron
+ * Inspired by vixie's cron by Paul Vixie which is
+ * Copyright 1988,1990,1993,1994 by Paul Vixie
+ * 
+ * Distribute freely, except: don't remove my name from the source or
+ * documentation (don't take credit for my work), mark your changes (don't
+ * get me blamed for your possible bugs), don't alter or remove this
+ * notice.  May be sold if buildable source is provided to buyer.  No
+ * warrantee of any kind, express or implied, is included with this
+ * software; use at your own risk, responsibility for damages (if any) to
+ * anyone resulting from the use of this software rests entirely with the
+ * user.
+ * Changes to make this work on a microcontroller by Ralf Schlatterbeck
+ * In fact this is mostly a rewrite but keeps central algorithms of the
+ * original.
+ * Copyright 2016 Ralf Schlatterbeck, distribute with the conditions
+ * given above.
+ */
+
+#ifndef _cron_h_
+#define _cron_h_
+
+#include "bitstring.h"
+
+#define SECONDS_PER_MINUTE 60
+
+#define FIRST_MINUTE    0
+#define LAST_MINUTE     59
+#define MINUTE_COUNT    (LAST_MINUTE - FIRST_MINUTE + 1)
+
+#define FIRST_HOUR      0
+#define LAST_HOUR       23
+#define HOUR_COUNT      (LAST_HOUR - FIRST_HOUR + 1)
+
+#define FIRST_DOM       1
+#define LAST_DOM        31
+#define DOM_COUNT       (LAST_DOM - FIRST_DOM + 1)
+
+#define FIRST_MONTH     1
+#define LAST_MONTH      12
+#define MONTH_COUNT     (LAST_MONTH - FIRST_MONTH + 1)
+
+/* note on DOW: 0 and 7 are both Sunday, for compatibility reasons. */
+#define FIRST_DOW       0
+#define LAST_DOW        7
+#define DOW_COUNT       (LAST_DOW - FIRST_DOW + 1)
+
+#ifndef MAX_CRON_ENTRIES
+#define MAX_CRON_ENTRIES 5
+#endif
+
+#ifndef MAX_CRON_COMMANDS
+#define MAX_CRON_COMMANDS 5
+#endif
+
+struct cron_cmd {
+    const char *name;
+    void      (*function)(void *);
+    void       *parameter;
+};
+
+struct cron_entry {
+    struct cron_entry *next;
+    struct cron_cmd   *cmd;
+    bitstr_t           bit_decl(minute, MINUTE_COUNT);
+    bitstr_t           bit_decl(hour,   HOUR_COUNT);
+    bitstr_t           bit_decl(dom,    DOM_COUNT);
+    bitstr_t           bit_decl(month,  MONTH_COUNT);
+    bitstr_t           bit_decl(dow,    DOW_COUNT);
+    int                flags;
+
+#define DOM_STAR        0x01
+#define DOW_STAR        0x02
+#define WHEN_REBOOT     0x04
+#define MIN_STAR        0x08
+#define HR_STAR         0x10
+#define VALID           0x20
+};
+
+extern int parse_crontab_line
+    (const char *line, struct cron_entry *e, const char **err);
+extern int cron_register_command
+    (const char *name, void (*function)(void *), void * parameter);
+
+extern struct cron_entry *allocate_cron_entry (void);
+extern struct cron_entry *get_cron_entry (size_t idx);
+extern void               free_cron_entry (struct cron_entry *e);
+extern void               cron (void);
+
+#endif /* _cron_h_ */