New module 'parse-duration'.

ChangeLog

@@ -1,3 +1,10 @@
+2008-11-17  Bruce Korb  <bkorb@gnu.org>
+
+	New module 'parse-duration'.
+	* lib/parse-duration.h: New file.
+	* lib/parse-duration.c: New file.
+	* modules/parse-duration: New file.
+
 2008-11-17  Bruno Haible  <bruno@clisp.org>
 
 	* tests/test-select-out.sh: Comment out the first pipe test.

lib/parse-duration.c

@@ -0,0 +1,582 @@
+/* Parse a time duration and return a seconds count
+   Copyright (C) 2008 Free Software Foundation, Inc.
+   Written by Bruce Korb <bkorb@gnu.org>, 2008.
+
+   This program 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 3 of the License, or
+   (at your option) any later version.
+
+   This program 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, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "parse-duration.h"
+
+#ifndef _
+#define _(_s)  _s
+#endif
+
+#ifndef NUL
+#define NUL '\0'
+#endif
+
+#define cch_t char const
+
+typedef enum {
+  NOTHING_IS_DONE,
+  YEAR_IS_DONE,
+  MONTH_IS_DONE,
+  WEEK_IS_DONE,
+  DAY_IS_DONE,
+  HOUR_IS_DONE,
+  MINUTE_IS_DONE,
+  SECOND_IS_DONE
+} whats_done_t;
+
+#define SEC_PER_MIN     60
+#define SEC_PER_HR      (SEC_PER_MIN * 60)
+#define SEC_PER_DAY     (SEC_PER_HR  * 24)
+#define SEC_PER_WEEK    (SEC_PER_DAY * 7)
+#define SEC_PER_MONTH   (SEC_PER_DAY * 30)
+#define SEC_PER_YEAR    (SEC_PER_DAY * 365)
+
+#define TIME_MAX        0x7FFFFFFF
+
+static unsigned long inline
+str_const_to_ul (cch_t * str, cch_t ** ppz, int base)
+{
+  return strtoul (str, (char **)ppz, base);
+}
+
+static long inline
+str_const_to_l (cch_t * str, cch_t ** ppz, int base)
+{
+  return strtol (str, (char **)ppz, base);
+}
+
+static time_t inline
+scale_n_add (time_t base, time_t val, int scale)
+{
+  if (base == BAD_TIME)
+    {
+      if (errno == 0)
+        errno = EINVAL;
+      return BAD_TIME;
+    }
+
+  if (val > TIME_MAX / scale)
+    {
+      errno = ERANGE;
+      return BAD_TIME;
+    }
+
+  val *= scale;
+  if (base > TIME_MAX - val)
+    {
+      errno = ERANGE;
+      return BAD_TIME;
+    }
+
+  return base + val;
+}
+
+static time_t
+parse_hr_min_sec (time_t start, cch_t * pz)
+{
+  int lpct = 0;
+
+  errno = 0;
+
+  /* For as long as our scanner pointer points to a colon *AND*
+     we've not looped before, then keep looping.  (two iterations max) */
+  while ((*pz == ':') && (lpct++ <= 1))
+    {
+      unsigned long v = str_const_to_ul (pz+1, &pz, 10);
+
+      if (errno != 0)
+        return BAD_TIME;
+
+      start = scale_n_add (v, start, 60);
+
+      if (errno != 0)
+        return BAD_TIME;
+    }
+
+  /* allow for trailing spaces */
+  while (isspace ((unsigned char)*pz))   pz++;
+  if (*pz != NUL)
+    {
+      errno = EINVAL;
+      return BAD_TIME;
+    }
+
+  return start;
+}
+
+static time_t
+parse_scaled_value (time_t base, cch_t ** ppz, cch_t * endp, int scale)
+{
+  cch_t * pz = *ppz;
+  time_t val;
+
+  if (base == BAD_TIME)
+    return base;
+
+  errno = 0;
+  val = str_const_to_ul (pz, &pz, 10);
+  if (errno != 0)
+    return BAD_TIME;
+  while (isspace ((unsigned char)*pz))   pz++;
+  if (pz != endp)
+    {
+      errno = EINVAL;
+      return BAD_TIME;
+    }
+
+  *ppz =  pz;
+  return scale_n_add (base, val, scale);
+}
+
+static time_t
+parse_year_month_day (cch_t * pz, cch_t * ps)
+{
+  time_t res = 0;
+
+  res = parse_scaled_value (0, &pz, ps, SEC_PER_YEAR);
+
+  ps = strchr (++pz, '-');
+  if (ps == NULL)
+    {
+      errno = EINVAL;
+      return BAD_TIME;
+    }
+  res = parse_scaled_value (res, &pz, ps, SEC_PER_MONTH);
+
+  pz++;
+  ps = pz + strlen (pz);
+  return parse_scaled_value (res, &pz, ps, SEC_PER_DAY);
+}
+
+static time_t
+parse_yearmonthday (cch_t * in_pz)
+{
+  time_t res = 0;
+  char   buf[8];
+  cch_t * pz;
+
+  if (strlen (in_pz) != 8)
+    {
+      errno = EINVAL;
+      return BAD_TIME;
+    }
+
+  memcpy (buf, in_pz, 4);
+  buf[4] = NUL;
+  pz = buf;
+  res = parse_scaled_value (0, &pz, buf + 4, SEC_PER_YEAR);
+
+  memcpy (buf, in_pz + 4, 2);
+  buf[2] = NUL;
+  pz =   buf;
+  res = parse_scaled_value (res, &pz, buf + 2, SEC_PER_MONTH);
+
+  memcpy (buf, in_pz + 6, 2);
+  buf[2] = NUL;
+  pz =   buf;
+  return parse_scaled_value (res, &pz, buf + 2, SEC_PER_DAY);
+}
+
+static time_t
+parse_YMWD (cch_t * pz)
+{
+  time_t res = 0;
+  cch_t * ps = strchr (pz, 'Y');
+  if (ps != NULL)
+    {
+      res = parse_scaled_value (0, &pz, ps, SEC_PER_YEAR);
+      pz++;
+    }
+
+  ps = strchr (pz, 'M');
+  if (ps != NULL)
+    {
+      res = parse_scaled_value (res, &pz, ps, SEC_PER_MONTH);
+      pz++;
+    }
+
+  ps = strchr (pz, 'W');
+  if (ps != NULL)
+    {
+      res = parse_scaled_value (res, &pz, ps, SEC_PER_WEEK);
+      pz++;
+    }
+
+  ps = strchr (pz, 'D');
+  if (ps != NULL)
+    {
+      res = parse_scaled_value (res, &pz, ps, SEC_PER_DAY);
+      pz++;
+    }
+
+  while (isspace ((unsigned char)*pz))   pz++;
+  if (*pz != NUL)
+    {
+      errno = EINVAL;
+      return BAD_TIME;
+    }
+
+  return res;
+}
+
+static time_t
+parse_hour_minute_second (cch_t * pz, cch_t * ps)
+{
+  time_t res = 0;
+
+  res = parse_scaled_value (0, &pz, ps, SEC_PER_HR);
+
+  ps = strchr (++pz, ':');
+  if (ps == NULL)
+    {
+      errno = EINVAL;
+      return BAD_TIME;
+    }
+
+  res = parse_scaled_value (res, &pz, ps, SEC_PER_MIN);
+
+  pz++;
+  ps = pz + strlen (pz);
+  return parse_scaled_value (res, &pz, ps, 1);
+}
+
+static time_t
+parse_hourminutesecond (cch_t * in_pz)
+{
+  time_t res = 0;
+  char   buf[4];
+  cch_t * pz;
+
+  if (strlen (in_pz) != 6)
+    {
+      errno = EINVAL;
+      return BAD_TIME;
+    }
+
+  memcpy (buf, in_pz, 2);
+  buf[2] = NUL;
+  pz = buf;
+  res = parse_scaled_value (0, &pz, buf + 2, SEC_PER_HR);
+
+  memcpy (buf, in_pz + 2, 2);
+  buf[2] = NUL;
+  pz =   buf;
+  res = parse_scaled_value (res, &pz, buf + 2, SEC_PER_MIN);
+
+  memcpy (buf, in_pz + 4, 2);
+  buf[2] = NUL;
+  pz =   buf;
+  return parse_scaled_value (res, &pz, buf + 2, 1);
+}
+
+static time_t
+parse_HMS (cch_t * pz)
+{
+  time_t res = 0;
+  cch_t * ps = strchr (pz, 'H');
+  if (ps != NULL)
+    {
+      res = parse_scaled_value (0, &pz, ps, SEC_PER_HR);
+      pz++;
+    }
+
+  ps = strchr (pz, 'M');
+  if (ps != NULL)
+    {
+      res = parse_scaled_value (res, &pz, ps, SEC_PER_MIN);
+      pz++;
+    }
+
+  ps = strchr (pz, 'S');
+  if (ps != NULL)
+    {
+      res = parse_scaled_value (res, &pz, ps, 1);
+      pz++;
+    }
+
+  while (isspace ((unsigned char)*pz))   pz++;
+  if (*pz != NUL)
+    {
+      errno = EINVAL;
+      return BAD_TIME;
+    }
+
+  return res;
+}
+
+static time_t
+parse_time (cch_t * pz)
+{
+  cch_t * ps;
+  time_t  res = 0;
+
+  /*
+   *  Scan for a hyphen
+   */
+  ps = strchr (pz, ':');
+  if (ps != NULL)
+    {
+      res = parse_hour_minute_second (pz, ps);
+    }
+
+  /*
+   *  Try for a 'H', 'M' or 'S' suffix
+   */
+  else if (ps = strpbrk (pz, "HMS"),
+           ps == NULL)
+    {
+      /* Its a YYYYMMDD format: */
+      res = parse_hourminutesecond (pz);
+    }
+
+  else
+    res = parse_HMS (pz);
+
+  return res;
+}
+
+static char *
+trim(char * pz)
+{
+  /* trim leading white space */
+  while (isspace ((unsigned char)*pz))  pz++;
+
+  /* trim trailing white space */
+  {
+    char * pe = pz + strlen (pz);
+    while ((pe > pz) && isspace ((unsigned char)pe[-1])) pe--;
+    *pe = NUL;
+  }
+
+  return pz;
+}
+
+/*
+ *  Parse the year/months/days of a time period
+ */
+static time_t
+parse_period (cch_t * in_pz)
+{
+  char * pz   = xstrdup (in_pz);
+  char * pT   = strchr (pz, 'T');
+  char * ps;
+  void * fptr = pz;
+  time_t res  = 0;
+
+  if (pT != NUL)
+    {
+      *(pT++) = NUL;
+      pz = trim (pz);
+      pT = trim (pT);
+    }
+
+  /*
+   *  Scan for a hyphen
+   */
+  ps = strchr (pz, '-');
+  if (ps != NULL)
+    {
+      res = parse_year_month_day (pz, ps);
+    }
+
+  /*
+   *  Try for a 'Y', 'M' or 'D' suffix
+   */
+  else if (ps = strpbrk (pz, "YMWD"),
+           ps == NULL)
+    {
+      /* Its a YYYYMMDD format: */
+      res = parse_yearmonthday (pz);
+    }
+
+  else
+    res = parse_YMWD (pz);
+
+  if ((errno == 0) && (pT != NULL))
+    {
+      time_t val = parse_time (pT);
+      res = scale_n_add (res, val, 1);
+    }
+
+  free (fptr);
+  return res;
+}
+
+static time_t
+parse_non_iso8601(cch_t * pz)
+{
+  whats_done_t whatd_we_do = NOTHING_IS_DONE;
+
+  time_t res = 0;
+
+  do  {
+    time_t val;
+
+    errno = 0;
+    val = str_const_to_l (pz, &pz, 10);
+    if (errno != 0)
+      goto bad_time;
+
+    /*  IF we find a colon, then we're going to have a seconds value.
+        We will not loop here any more.  We cannot already have parsed
+        a minute value and if we've parsed an hour value, then the result
+        value has to be less than an hour. */
+    if (*pz == ':')
+      {
+        if (whatd_we_do >= MINUTE_IS_DONE)
+          break;
+
+        val = parse_hr_min_sec (val, pz);
+
+        if ((whatd_we_do == HOUR_IS_DONE) && (val >= SEC_PER_HR))
+          break;
+
+        return scale_n_add (res, val, 1);
+      }
+
+    {
+      unsigned int mult;
+
+      /*  Skip over white space following the number we just parsed. */
+      while (isspace ((unsigned char)*pz))   pz++;
+
+      switch (*pz)
+        {
+        default:  goto bad_time;
+        case NUL:
+          return scale_n_add (res, val, 1);
+
+        case 'y': case 'Y':
+          if (whatd_we_do >= YEAR_IS_DONE)
+            goto bad_time;
+          mult = SEC_PER_YEAR;
+          whatd_we_do = YEAR_IS_DONE;
+          break;
+
+        case 'M':
+          if (whatd_we_do >= MONTH_IS_DONE)
+            goto bad_time;
+          mult = SEC_PER_MONTH;
+          whatd_we_do = MONTH_IS_DONE;
+          break;
+
+        case 'W':
+          if (whatd_we_do >= WEEK_IS_DONE)
+            goto bad_time;
+          mult = SEC_PER_WEEK;
+          whatd_we_do = WEEK_IS_DONE;
+          break;
+
+        case 'd': case 'D':
+          if (whatd_we_do >= DAY_IS_DONE)
+            goto bad_time;
+          mult = SEC_PER_DAY;
+          whatd_we_do = DAY_IS_DONE;
+          break;
+
+        case 'h':
+          if (whatd_we_do >= HOUR_IS_DONE)
+            goto bad_time;
+          mult = SEC_PER_HR;
+          whatd_we_do = HOUR_IS_DONE;
+          break;
+
+        case 'm':
+          if (whatd_we_do >= MINUTE_IS_DONE)
+            goto bad_time;
+          mult = SEC_PER_MIN;
+          whatd_we_do = MINUTE_IS_DONE;
+          break;
+
+        case 's':
+          mult = 1;
+          whatd_we_do = SECOND_IS_DONE;
+          break;
+        }
+
+      res = scale_n_add (res, val, mult);
+
+      while (isspace ((unsigned char)*++pz))   ;
+      if (*pz == NUL)
+        return res;
+
+      if (! isdigit ((unsigned char)*pz))
+        break;
+    }
+
+  } while (whatd_we_do < SECOND_IS_DONE);
+
+ bad_time:
+  errno = EINVAL;
+  return BAD_TIME;
+}
+
+time_t
+parse_duration (char const * pz)
+{
+  time_t res = 0;
+
+  while (isspace ((unsigned char)*pz)) pz++;
+
+  do {
+    if (*pz == 'P')
+      {
+        res = parse_period (pz + 1);
+        if ((errno != 0) || (res == BAD_TIME))
+          break;
+        return res;
+      }
+
+    if (*pz == 'T')
+      {
+        res = parse_time (pz + 1);
+        if ((errno != 0) || (res == BAD_TIME))
+          break;
+        return res;
+      }
+
+    if (! isdigit ((unsigned char)*pz))
+      break;
+
+    res = parse_non_iso8601 (pz);
+    if ((errno == 0) && (res != BAD_TIME))
+      return res;
+
+  } while (0);
+
+  fprintf (stderr, _("Invalid time duration:  %s\n"), pz);
+  if (errno == 0)
+    errno = EINVAL;
+  return BAD_TIME;
+}
+
+/*
+ * Local Variables:
+ * mode: C
+ * c-file-style: "gnu"
+ * indent-tabs-mode: nil
+ * End:
+ * end of parse-duration.c */

lib/parse-duration.h

@@ -0,0 +1,82 @@
+/* Parse a time duration and return a seconds count
+   Copyright (C) 2008 Free Software Foundation, Inc.
+   Written by Bruce Korb <bkorb@gnu.org>, 2008.
+
+   This program 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 3 of the License, or
+   (at your option) any later version.
+
+   This program 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, see <http://www.gnu.org/licenses/>.  */
+
+/*
+
+  Readers and users of this function are referred to the ISO-8601
+  specification, with particular attention to "Durations".
+
+  At the time of writing, this worked:
+
+  http://en.wikipedia.org/wiki/ISO_8601#Durations
+
+  The string must start with a 'P', 'T' or a digit.
+
+  ==== if it is a digit
+
+  the string may contain:  NNN d NNN h NNN m NNN s
+  This represents NNN days, NNN hours, NNN minutes and NNN seconds.
+  The embeded white space is optional.
+  These terms must appear in this order.
+  The final "s" is optional.
+  All of the terms ("NNN" plus designator) are optional.
+  Minutes and seconds may optionally be represented as NNN:NNN.
+  Also, hours, minute and seconds may be represented as NNN:NNN:NNN.
+  There is no limitation on the value of any of the terms, except
+  that the final result must fit in a time_t value.
+
+  ==== if it is a 'P' or 'T', please see ISO-8601 for a rigorous definition.
+
+  The 'P' term may be followed by any of three formats:
+    yyyymmdd
+    yy-mm-dd
+    yy Y mm M ww W dd D
+
+  or it may be empty and followed by a 'T'.  The "yyyymmdd" must be eight
+  digits long.  Note:  months are always 30 days and years are always 365
+  days long.  5 years is always 1825, not 1826 or 1827 depending on leap
+  year considerations.  3 months is always 90 days.  There is no consideration
+  for how many days are in the current, next or previous months.
+
+  For the final format:
+  *  Embedded white space is allowed, but it is optional.
+  *  All of the terms are optional.  Any or all-but-one may be omitted.
+  *  The meanings are yy years, mm months, ww weeks and dd days.
+  *  The terms must appear in this order.
+
+  ==== The 'T' term may be followed by any of these formats:
+
+    hhmmss
+    hh:mm:ss
+    hh H mm M ss S
+
+  For the final format:
+  *  Embedded white space is allowed, but it is optional.
+  *  All of the terms are optional.  Any or all-but-one may be omitted.
+  *  The terms must appear in this order.
+
+ */
+#ifndef GNULIB_PARSE_DURATION_H
+#define GNULIB_PARSE_DURATION_H
+
+#include <time.h>
+
+#define BAD_TIME        ((time_t)~0)
+
+extern time_t parse_duration(char const * in_pz);
+
+#endif /* GNULIB_PARSE_DURATION_H */

modules/parse-duration

@@ -0,0 +1,24 @@
+Description:
+Parse a duration given as string.
+
+Files:
+lib/parse-duration.h
+lib/parse-duration.c
+
+Depends-on:
+
+configure.ac:
+AC_REQUIRE([AC_C_INLINE])
+
+Makefile.am:
+lib_SOURCES += parse-duration.c
+
+Include:
+"parse-duration.h"
+
+License:
+GPL
+
+Maintainer:
+Bruce Korb
+