To: Vladimir.Marek@oracle.com
Subject: Re: [PATCH 4/4] timegm: add portable implementation (Solaris support)
In-Reply-To: Your message of "Tue, 20 Aug 2013 11:28:55 +0200."
	<1376990935-12411-1-git-send-email-Vladimir.Marek@oracle.com> 
Date: Tue, 20 Aug 2013 08:33:19 -0700
Message-ID: <14321.1377012799@foo.net>
From: Blake Jones <blakej@foo.net>
Cc: notmuch@notmuchmail.org, Vladimir Marek <vlmarek@volny.cz>
Precedence: list

> From: Blake Jones <blakej@foo.net>
> 
> The timegm(3) function is a non-standard extension to libc which is
> available in GNU libc and on some BSDs.  Although SunOS had this
> function in its libc, Solaris (unfortunately) removed it.  This patch
> implements a very simple version of timegm() which is good enough for
> parse-time-string.c.

LGTM.

Blake

> Signed-off-by: Vladimir Marek <vlmarek@volny.cz>
> ---
>  compat/Makefile.local                 |    4 +++
>  compat/compat.h                       |    5 +++
>  compat/have_timegm.c                  |    7 ++++
>  compat/timegm.c                       |   57 +++++++++++++++++++++++++++++++++
>  configure                             |   11 +++++++
>  parse-time-string/parse-time-string.c |    1 +
>  6 files changed, 85 insertions(+)
>  create mode 100644 compat/have_timegm.c
>  create mode 100644 compat/timegm.c
> 
> diff --git a/compat/Makefile.local b/compat/Makefile.local
> index 2c4f65f..b0d5417 100644
> --- a/compat/Makefile.local
> +++ b/compat/Makefile.local
> @@ -17,4 +17,8 @@ ifneq ($(HAVE_STRSEP),1)
>  notmuch_compat_srcs += $(dir)/strsep.c
>  endif
>  
> +ifneq ($(HAVE_TIMEGM),1)
> +notmuch_compat_srcs += $(dir)/timegm.c
> +endif
> +
>  SRCS := $(SRCS) $(notmuch_compat_srcs)
> diff --git a/compat/compat.h b/compat/compat.h
> index ae762c3..5a402d5 100644
> --- a/compat/compat.h
> +++ b/compat/compat.h
> @@ -57,6 +57,11 @@ char* strcasestr(const char *haystack, const char *needle);
>  char *strsep(char **stringp, const char *delim);
>  #endif /* !HAVE_STRSEP */
>  
> +#if !HAVE_TIMEGM
> +#include <time.h>
> +time_t timegm (struct tm *tm);
> +#endif /* !HAVE_TIMEGM */
> +
>  /* Silence gcc warnings about unused results.  These warnings exist
>   * for a reason; any use of this needs to be justified. */
>  #ifdef __GNUC__
> diff --git a/compat/have_timegm.c b/compat/have_timegm.c
> new file mode 100644
> index 0000000..b62b793
> --- /dev/null
> +++ b/compat/have_timegm.c
> @@ -0,0 +1,7 @@
> +#include <time.h>
> +#include "compat.h"
> +
> +int main()
> +{
> +    return (int) timegm((struct tm *)0);
> +}
> diff --git a/compat/timegm.c b/compat/timegm.c
> new file mode 100644
> index 0000000..213963b
> --- /dev/null
> +++ b/compat/timegm.c
> @@ -0,0 +1,57 @@
> +/* timegm.c --- Implementation of replacement timegm function.
> +   Copyright (C) 2012 Free Software Foundation, Inc.
> +
> +   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, 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, write to the Free Software
> +   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> +   02110-1301, USA.  */
> +
> +/* Written by Blake Jones. */
> +
> +#include <time.h>
> +#include "compat.h"
> +
> +static int
> +leapyear (int year)
> +{
> +    return ((year % 4) == 0 && ((year % 100) != 0 || (year % 400) == 0));
> +}
> +
> +/*
> + * This is a simple implementation of timegm() which does what is needed
> + * by create_output() -- just turns the "struct tm" into a GMT time_t.
> + * It does not normalize any of the fields of the "struct tm", nor does
> + * it set tm_wday or tm_yday.
> + */
> +time_t
> +timegm (struct tm *tm)
> +{
> +    int	monthlen[2][12] = {
> +	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
> +	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
> +    };
> +    int	year, month, days;
> +
> +    days = 365 * (tm->tm_year - 70);
> +    for (year = 70; year < tm->tm_year; year++) {
> +	if (leapyear(1900 + year)) {
> +	    days++;
> +	}
> +    }
> +    for (month = 0; month < tm->tm_mon; month++) {
> +	days += monthlen[leapyear(1900 + year)][month];
> +    }
> +    days += tm->tm_mday - 1;
> +
> +    return ((((days * 24) + tm->tm_hour) * 60 + tm->tm_min) * 60 + tm->tm_sec);
> +}
> diff --git a/configure b/configure
> index ac44857..6166917 100755
> --- a/configure
> +++ b/configure
> @@ -530,6 +530,17 @@ else
>  fi
>  rm -f compat/have_strsep
>  
> +printf "Checking for timegm... "
> +if ${CC} -o compat/have_timegm "$srcdir"/compat/have_timegm.c > /dev/null 2>&1
> +then
> +    printf "Yes.\n"
> +    have_timegm="1"
> +else
> +    printf "No (will use our own instead).\n"
> +    have_timegm="0"
> +fi
> +rm -f compat/have_timegm
> +
>  printf "Checking for standard version of getpwuid_r... "
>  if ${CC} -o compat/check_getpwuid "$srcdir"/compat/check_getpwuid.c > /dev/null 2>&1
>  then
> diff --git a/parse-time-string/parse-time-string.c b/parse-time-string/parse-time-string.c
> index 584067d..ccad422 100644
> --- a/parse-time-string/parse-time-string.c
> +++ b/parse-time-string/parse-time-string.c
> @@ -32,6 +32,7 @@
>  #include <sys/time.h>
>  #include <sys/types.h>
>  
> +#include "compat.h"
>  #include "parse-time-string.h"
>  
>  /*
> -- 
> 1.7.9.2
> 
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