From 4ff3bb9d4fc5dcd38c4129b8e83b543212ee2a49 Mon Sep 17 00:00:00 2001
From: Lukas Fleischer <calcurse@cryptocrack.de>
Date: Wed, 5 Oct 2011 11:19:17 +0200
Subject: src/utils.c: Support more powerful duration strings
Add support for "1d23h42m"-like duration strings to parse_duration().
Also, switch to using a deterministic finite automaton to parse duration
strings, as things tend to get unclear.
Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>
---
src/utils.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++++------------
1 file changed, 100 insertions(+), 23 deletions(-)
(limited to 'src')
diff --git a/src/utils.c b/src/utils.c
index ce4b0f7..2501d9b 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -696,50 +696,127 @@ parse_time (const char *string, unsigned *hour, unsigned *minute)
}
/*
- * Converts a duration string into minutes. Both "hh:mm" (e.g. "23:42") and
- * "mmm" (e.g. "100") formats are accepted. Short forms like "23:" (23:00) or
- * ":45" (0:45) are allowed as well.
+ * Converts a duration string into minutes.
+ *
+ * Allowed formats (noted as regular expressions):
+ *
+ * - \d*:\d*
+ * - (\d*m|\d*h(|\d*m)|\d*d(|\d*m|\d*h(|\d*m)))
+ * - \d+
+ *
+ * "\d" is used as a placeholder for "(0|1|2|3|4|5|6|7|8|9)".
+ *
+ * Note that this function performs an additional range check on each token to
+ * ensure we do not accept semantically invalid strings such as "42:23".
*
* Returns 1 on success and 0 on failure.
*/
int
parse_duration (const char *string, unsigned *duration)
{
+ enum {
+ STATE_INITIAL,
+ STATE_HHMM_MM,
+ STATE_DDHHMM_HH,
+ STATE_DDHHMM_MM,
+ STATE_DONE
+ } state = STATE_INITIAL;
+
const char *p;
- unsigned in[2] = {0, 0}, n = 0;
+ unsigned in = 0;
+ unsigned dur = 0;
if (!string || *string == '\0')
return 0;
- /* parse string into in[], read up to two integers */
+ /* parse string using a simple state machine */
for (p = string; *p; p++)
{
- if (*p == ':')
+ if ((*p >= '0') && (*p <= '9'))
{
- if ((++n) > 1)
+ if (state == STATE_DONE)
return 0;
+ else
+ in = in * 10 + (int)(*p - '0');
}
- else if ((*p >= '0') && (*p <= '9'))
- in[n] = in[n] * 10 + (int)(*p - '0');
else
- return 0;
- }
+ {
+ switch (state)
+ {
+ case STATE_INITIAL:
+ if (*p == ':')
+ {
+ dur += in * HOURINMIN;
+ state = STATE_HHMM_MM;
+ }
+ else if (*p == 'd')
+ {
+ dur += in * DAYINMIN;
+ state = STATE_DDHHMM_HH;
+ }
+ else if (*p == 'h')
+ {
+ if (in >= DAYINHOURS)
+ return 0;
+ dur += in * HOURINMIN;
+ state = STATE_DDHHMM_MM;
+ }
+ else if (*p == 'm')
+ {
+ if (in >= HOURINMIN)
+ return 0;
+ dur += in;
+ state = STATE_DONE;
+ }
+ else
+ return 0;
+ break;
+ case STATE_DDHHMM_HH:
+ if (*p == 'h')
+ {
+ if (in >= DAYINHOURS)
+ return 0;
+ dur += in * HOURINMIN;
+ state = STATE_DDHHMM_MM;
+ }
+ else if (*p == 'm')
+ {
+ if (in >= HOURINMIN)
+ return 0;
+ dur += in;
+ state = STATE_DONE;
+ }
+ else
+ return 0;
+ break;
+ case STATE_DDHHMM_MM:
+ if (*p == 'm')
+ {
+ if (in >= HOURINMIN)
+ return 0;
+ dur += in;
+ state = STATE_DONE;
+ }
+ else
+ return 0;
+ break;
+ case STATE_HHMM_MM:
+ case STATE_DONE:
+ return 0;
+ break;
+ }
- if (n == 0)
- {
- if (in[0] > 999)
- return 0;
- *duration = in[0];
- }
- else if (n == 1)
- {
- if (in[0] > DAYINHOURS || in[1] >= HOURINMIN)
- return 0;
- *duration = in[0] * HOURINMIN + in[1];
+ in = 0;
+ }
}
- else
+
+ if ((state == STATE_HHMM_MM && in >= HOURINMIN) ||
+ ((state == STATE_DDHHMM_HH || state == STATE_DDHHMM_MM) && in > 0))
return 0;
+ dur += in;
+ *duration = dur;
+
return 1;
}
--
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