miller/c/lib/netbsd_strptime.c
2017-04-07 23:39:21 -04:00

379 lines
9.7 KiB
C

// $Id$
// $NetBSD: strptime.c,v 1.18 1999/04/29 02:58:30 tv Exp $
// ================================================================
// Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
// All rights reserved.
//
// This code was contributed to The NetBSD Foundation by Klaus Klein.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// 3. All advertising materials mentioning features or use of this software
// must display the following acknowledgement:
// This product includes software developed by the NetBSD
// Foundation, Inc. and its contributors.
// 4. Neither the name of The NetBSD Foundation nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
// ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
// BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
// ================================================================
#include "string.h"
#include "ctype.h"
#include "time.h"
// ----------------------------------------------------------------
#define TM_YEAR_BASE 1900
// We do not implement alternate representations. However, we always
// check whether a given modifier is allowed for a certain conversion.
#define ALT_E 0x01
#define ALT_O 0x02
#define LEGAL_ALT(x) { if (alt_format & ~(x)) return (0); }
// ----------------------------------------------------------------
static int conv_num(const char **, int *, int, int);
// ----------------------------------------------------------------
static const char *day[7] = {
"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday",
"Friday", "Saturday"
};
static const char *abday[7] = {
"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
};
static const char *mon[12] = {
"January", "February", "March", "April", "May", "June", "July",
"August", "September", "October", "November", "December"
};
static const char *abmon[12] = {
"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
static const char *am_pm[2] = {
"AM", "PM"
};
// ================================================================
char* netbsd_strptime(const char *buf, const char *fmt, struct tm *tm) {
char c;
const char *bp;
size_t len = 0;
int alt_format, i, split_year = 0;
bp = buf;
while ((c = *fmt) != '\0') {
// Clear `alternate' modifier prior to new conversion.
alt_format = 0;
// Eat up white-space.
if (isspace(c)) {
while (isspace(*bp))
bp++;
fmt++;
continue;
}
if ((c = *fmt++) != '%')
goto literal;
again: switch (c = *fmt++) {
case '%': // "%%" is converted to "%".
literal:
if (c != *bp++)
return (0);
break;
// "Alternative" modifiers. Just set the appropriate flag
// and start over again.
case 'E': // "%E?" alternative conversion modifier.
LEGAL_ALT(0);
alt_format |= ALT_E;
goto again;
case 'O': // "%O?" alternative conversion modifier.
LEGAL_ALT(0);
alt_format |= ALT_O;
goto again;
// "Complex" conversion rules, implemented through recursion.
case 'c': // Date and time, using the locale's format.
LEGAL_ALT(ALT_E);
if (!(bp = netbsd_strptime(bp, "%x %X", tm)))
return (0);
break;
case 'D': // The date as "%m/%d/%y".
LEGAL_ALT(0);
if (!(bp = netbsd_strptime(bp, "%m/%d/%y", tm)))
return (0);
break;
case 'R': // The time as "%H:%M".
LEGAL_ALT(0);
if (!(bp = netbsd_strptime(bp, "%H:%M", tm)))
return (0);
break;
case 'r': // The time in 12-hour clock representation.
LEGAL_ALT(0);
if (!(bp = netbsd_strptime(bp, "%I:%M:%S %p", tm)))
return (0);
break;
case 'T': // The time as "%H:%M:%S".
LEGAL_ALT(0);
if (!(bp = netbsd_strptime(bp, "%H:%M:%S", tm)))
return (0);
break;
case 'X': // The time, using the locale's format.
LEGAL_ALT(ALT_E);
if (!(bp = netbsd_strptime(bp, "%H:%M:%S", tm)))
return (0);
break;
case 'x': // The date, using the locale's format.
LEGAL_ALT(ALT_E);
if (!(bp = netbsd_strptime(bp, "%m/%d/%y", tm)))
return (0);
break;
// "Elementary" conversion rules.
case 'A': // The day of week, using the locale's form.
case 'a':
LEGAL_ALT(0);
for (i = 0; i < 7; i++) {
// Full name.
len = strlen(day[i]);
if (strncasecmp(day[i], bp, len) == 0)
break;
// Abbreviated name.
len = strlen(abday[i]);
if (strncasecmp(abday[i], bp, len) == 0)
break;
}
// Nothing matched.
if (i == 7)
return (0);
tm->tm_wday = i;
bp += len;
break;
case 'B': // The month, using the locale's form.
case 'b':
case 'h':
LEGAL_ALT(0);
for (i = 0; i < 12; i++) {
// Full name.
len = strlen(mon[i]);
if (strncasecmp(mon[i], bp, len) == 0)
break;
// Abbreviated name.
len = strlen(abmon[i]);
if (strncasecmp(abmon[i], bp, len) == 0)
break;
}
// Nothing matched.
if (i == 12)
return (0);
tm->tm_mon = i;
bp += len;
break;
case 'C': // The century number.
LEGAL_ALT(ALT_E);
if (!(conv_num(&bp, &i, 0, 99)))
return (0);
if (split_year) {
tm->tm_year = (tm->tm_year % 100) + (i * 100);
} else {
tm->tm_year = i * 100;
split_year = 1;
}
break;
case 'd': // The day of month.
case 'e':
LEGAL_ALT(ALT_O);
if (!(conv_num(&bp, &tm->tm_mday, 1, 31)))
return (0);
break;
case 'k': // The hour (24-hour clock representation).
LEGAL_ALT(0);
// FALLTHROUGH
case 'H':
LEGAL_ALT(ALT_O);
if (!(conv_num(&bp, &tm->tm_hour, 0, 23)))
return (0);
break;
case 'l': // The hour (12-hour clock representation).
LEGAL_ALT(0);
// FALLTHROUGH
case 'I':
LEGAL_ALT(ALT_O);
if (!(conv_num(&bp, &tm->tm_hour, 1, 12)))
return (0);
if (tm->tm_hour == 12)
tm->tm_hour = 0;
break;
case 'j': // The day of year.
LEGAL_ALT(0);
if (!(conv_num(&bp, &i, 1, 366)))
return (0);
tm->tm_yday = i - 1;
break;
case 'M': // The minute.
LEGAL_ALT(ALT_O);
if (!(conv_num(&bp, &tm->tm_min, 0, 59)))
return (0);
break;
case 'm': // The month.
LEGAL_ALT(ALT_O);
if (!(conv_num(&bp, &i, 1, 12)))
return (0);
tm->tm_mon = i - 1;
break;
case 'p': // The locale's equivalent of AM/PM.
LEGAL_ALT(0);
// AM?
if (strcasecmp(am_pm[0], bp) == 0) {
if (tm->tm_hour > 11)
return (0);
bp += strlen(am_pm[0]);
break;
}
// PM?
else if (strcasecmp(am_pm[1], bp) == 0) {
if (tm->tm_hour > 11)
return (0);
tm->tm_hour += 12;
bp += strlen(am_pm[1]);
break;
}
// Nothing matched.
return (0);
case 'S': // The seconds.
LEGAL_ALT(ALT_O);
if (!(conv_num(&bp, &tm->tm_sec, 0, 61)))
return (0);
break;
case 'U': // The week of year, beginning on sunday.
case 'W': // The week of year, beginning on monday.
LEGAL_ALT(ALT_O);
// XXX This is bogus, as we can not assume any valid
// information present in the tm structure at this
// point to calculate a real value, so just check the
// range for now.
if (!(conv_num(&bp, &i, 0, 53)))
return (0);
break;
case 'w': // The day of week, beginning on sunday.
LEGAL_ALT(ALT_O);
if (!(conv_num(&bp, &tm->tm_wday, 0, 6)))
return (0);
break;
case 'Y': // The year.
LEGAL_ALT(ALT_E);
if (!(conv_num(&bp, &i, 0, 9999)))
return (0);
tm->tm_year = i - TM_YEAR_BASE;
break;
case 'y': // The year within 100 years of the epoch.
LEGAL_ALT(ALT_E | ALT_O);
if (!(conv_num(&bp, &i, 0, 99)))
return (0);
if (split_year) {
tm->tm_year = ((tm->tm_year / 100) * 100) + i;
break;
}
split_year = 1;
if (i <= 68)
tm->tm_year = i + 2000 - TM_YEAR_BASE;
else
tm->tm_year = i + 1900 - TM_YEAR_BASE;
break;
// Miscellaneous conversions.
case 'n': // Any kind of white-space.
case 't':
LEGAL_ALT(0);
while (isspace(*bp))
bp++;
break;
default: // Unknown/unsupported conversion.
return (0);
}
}
// LINTED functional specification
return ((char *)bp);
}
// ----------------------------------------------------------------
static int conv_num(const char **buf, int *dest, int llim, int ulim) {
int result = 0;
// The limit also determines the number of valid digits.
int rulim = ulim;
if (**buf < '0' || **buf > '9')
return (0);
do {
result *= 10;
result += *(*buf)++ - '0';
rulim /= 10;
} while ((result * 10 <= ulim) && rulim && **buf >= '0' && **buf <= '9');
if (result < llim || result > ulim)
return (0);
*dest = result;
return (1);
}