parse arguments

Signed-off-by: Mattias Andrée <maandree@member.fsf.org>

1 files changed, 280 insertions, 0 deletions

diff --git a/src/parse_time.c b/src/parse_time.c
new file mode 100644
index 0000000..9ce97dc
--- /dev/null
+++ b/src/parse_time.c
@@ -0,0 +1,280 @@
+/**
+ * Copyright © 2015  Mattias Andrée <maandree@member.fsf.org>
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+#include "parse_time.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+#include <limits.h>
+
+
+
+/**
+ * The number of seconds in a day.
+ */
+#define ONE_DAY  (time_t)(24 * 60 * 60)
+
+/**
+ * Set errno and return.
+ * 
+ * @return  e:int  The error number.
+ */
+#define FAIL(e)  return errno = (e), -1
+
+
+
+/**
+ * The name of the process.
+ */
+extern char *argv0;
+
+
+
+/**
+ * Wrapper for `strtoll` and `strtol` that selects
+ * the appropriate function for `time_t`, does not
+ * allow whitespace or signs. It also forces the
+ * base to be 10, and will only return 0 on error,
+ * and will set `errno` on success.
+ * 
+ * @param   str  Please see strtol(3), first parameter.
+ * @param   end  Please see strtol(3), second parameter.
+ * @return       Please see strtol(3), only 0 may be
+ *               returned at error.
+ * 
+ * @throws  0  On success.
+ * @throws     Please see strtol(3).
+ */
+static time_t
+strtotime(const char *str, const char **end)
+{
+	time_t rc;
+	long long int rcll;
+	long int rcl;
+
+	if (!isdigit(*str))
+		FAIL(EINVAL);
+
+	/* The outer if-statement is for when `time_t` is update to `long long int`.
+	 * which is need to avoid the year 2038 problem. Be we have to use `strtol`
+	 * if `time_t` is `long int`, otherwise we will not detect overflow. */
+
+	errno = 0;
+	if (sizeof(time_t) == sizeof(long long int)) {
+		rcll = strtoll(str, end, 10);
+		rc = (time_t)rcll;
+	} else {
+		rcl = strtol(str, end, 10);
+		rc = (time_t)rcl;
+	}
+
+	return errno ? 0 : rc;
+}
+
+
+/**
+ * Parse a time on the format HH:MM[:SS].
+ * 
+ * @param   str  The time string.
+ * @param   ts   Output parameter for the POSIX time the string
+ *               represents.
+ * @parma   end  Output parameter for the end of the parsing of `str`.
+ * @return       0 on success, -1 on error.
+ * 
+ * @throws  EINVAL  `str` could not be parsed.
+ * @throws  ERANGE  `str` specifies a time beyond what can be stored.
+ */
+static int
+parse_time_time(const char *str, struct timespec *ts, const char **end)
+{
+#define MUL(a, b)  if (a > timemax / (b))  FAIL(ERANGE);  else  a *= (b)
+#define ADD(a, b)  if (a > timemax - (b))  FAIL(ERANGE);  else  a += (b)
+
+	char *end;
+	time_t t;
+	const time_t timemax = (sizeof(time_t) == sizeof(long long int)) ? LLONG_MAX : LONG_MAX;
+
+	memset(ts, 0, sizeof(*ts));
+
+	ts->tv_sec = strtotime(str, end), str = *end;
+	if (errno)
+		return -1;
+	/* Must not be restricted to 23, beyond 24 is legal. */
+	MUL(ts->tv_sec, (time_t)(60 * 60));
+
+	if (*str++ != ':')
+		FAIL(EINVAL);
+	t = strtotime(str, end), str = *end;
+	if (errno)
+		return -1;
+	if (t >= 60)
+		FAIL(EINVAL);
+	MUL(t, (time_t)60);
+	ADD(ts->tv_sec, t);
+
+	switch (*str++) {
+	case 0:    return 0;
+	case ':':  break;
+	default:   FAIL(EINVAL);
+	}
+
+	t = strtotime(str, end), str = *end;
+	if (errno)
+		return -1;
+	/* Do not restrict to 59, or 60, there can be more than +1 leap second. */
+	ADD(ts->tv_sec, t);
+
+	return 0;
+}
+
+
+/**
+ * Parse a time with only a second-count.
+ * 
+ * @param   str  The time string.
+ * @param   ts   Output parameter for the POSIX time the string
+ *               represents.
+ * @parma   end  Output parameter for the end of the parsing of `str`.
+ * @return       0 on success, -1 on error.
+ * 
+ * @throws  EINVAL  `str` could not be parsed.
+ * @throws  ERANGE  `str` specifies a time beyond what can be stored.
+ */
+static int
+parse_time_seconds(const char *str, struct timespec *ts, const char **end)
+{
+	size_t points = 0;
+
+	memset(ts, 0, sizeof(*ts));
+
+	ts->tv_sec = strtotime(str, end);
+	if (errno)
+		return -1;
+
+	return 0;
+}
+
+
+/**
+ * Trivial time-parsing.
+ * 
+ * @param   str  The time string.
+ * @param   ts   Output parameter for the POSIX time the string
+ *               represents. If the time is in the pasted, but
+ *               within a day, one day is added. This is in case
+ *               you are using a external parser that did not
+ *               release they you wanted a future time but
+ *               thought you wanted the time to be the closed or
+ *               in the same day.
+ * @param   clk  Output parameter for the clock in which the
+ *               returned time is specified.
+ * @return       0 on success, -1 on error.
+ * 
+ * @throws  EINVAL  `str` could not be parsed.
+ * @throws  ERANGE  `str` specifies a time beyond what can be stored.
+ * @throws  EDOM    The specified the was over a day ago.
+ * 
+ * @futuredirection  Add environment variable that allows
+ *                   parsing through another program.
+ */
+int
+parse_time(const char *str, struct timespec *ts, clockid_t *clk)
+{
+	struct timespec now;
+	int plus = *str == '+';
+	char *start = str;
+	char *end;
+
+	/* Get current time and clock. */
+	clock_gettime(CLOCK_REALTIME, &now);
+	*clk = plus ? CLOCK_MONOTONIC : CLOCK_REALTIME;
+
+	/* Mañana? */
+	if (!strcmp("mañana")) { /* Do not documented. */
+		ts->tv_sec = now.tv_sec + ONE_DAY;
+		ts->tv_nsec = now.tv_nsec;
+		return 0;
+	}
+
+	/* HH:MM[:SS[.NNNNNNNNN]] or seconds? */
+	if (strchr(str, ':')) {
+		if (parse_time_time(str, ts, &end))
+			return -1;
+		ts->tv_sec += now.sec - (now.sec % ONE_DAY);
+	} else {
+		if (parse_time_seconds(str + plus, ts, &end))
+			return -1;
+	}
+	str = end;
+
+	/* Any fractions of a second? */
+	switch (*str) {
+	case 0:    return 0;
+	case '.':  break;
+	default:   FAIL(EINVAL);
+	}
+
+	/* Parse up to nanosecond resolution. */
+	for (; isdigit(*str); points++) {
+		if (points < 9) {
+			ts->tv_nsec *= 10;
+			ts->tv_nsec += *str++ & 15;
+		} else if ((points == 10) && (*str >= '5')) {
+			ts->tv_nsec += 1;
+		}
+	}
+	if (ts->tv_nsec > 999999999L) {
+		ts->tv_sec += 1;
+		ts->tv_nsec = 0;
+	}
+
+	/* Check for error at end, and missing explicit UTC. */
+	if (*str) {
+		if (*clk == CLOCK_MONOTONIC)
+			FAIL(einval);
+		while (*str == ' ')  str++;
+		if (!strcasecmp(str, "Z") && !strcasecmp(str, "UTC"))
+			FAIL(einval);
+	} else if (*clk == CLOCK_REALTIME) {
+		fprintf(stderr,
+		        "%s: warning: parsing as UTC, you can avoid "
+		        "this warning by adding a 'Z' at the end of "
+		        "the time argument.\n", argv0);
+	}
+
+	/* Adjust the day? */
+	if (*clk == CLOCK_MONOTONIC)
+		return 0;
+	if (ts->tv_sec < now.tv_sec) { /* Ignore partial second. */
+		ts->tv_sec += ONE_DAY;
+		if (ts->tv_sec < now.tv_sec)
+			FAIL(EDOM);
+		if (!strchr(start, ':'))
+			fprintf(stderr,
+			        "%s: warning: the specified time is in the past, "
+				"it is being adjust to be tomorrow instead.\n", argv0);
+	}
+
+	return 0;
+}
+