add System V/P1003.2 formats

[unix-history] / usr / src / lib / libc / string / strftime.c

/*
* Copyright (c) 1989 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley.  The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)strftime.c  5.2 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <sys/time.h>
#include <tzfile.h>

static char *afmt[] = {
       "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat",
};
static char *Afmt[] = {
       "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday",
       "Saturday",
};
static char *bfmt[] = {
       "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep",
       "Oct", "Nov", "Dec",
};
static char *Bfmt[] = {
       "January", "February", "March", "April", "May", "June", "July",
       "August", "September", "October", "November", "December",
};

static size_t gsize;
static char *pt;

size_t
strftime(s, maxsize, format, t)
       char *s;
       char *format;
       size_t maxsize;
       struct tm *t;
{
       size_t _fmt();

       pt = s;
       if ((gsize = maxsize) < 1)
               return(0);
       if (_fmt(format, t)) {
               *pt = '\0';
               return(maxsize - gsize);
       }
       return(0);
}

static size_t
_fmt(format, t)
       register char *format;
       struct tm *t;
{
       char *timezone();

       for (; *format; ++format) {
               if (*format == '%')
                       switch(*++format) {
                       case 'A':
                               if (!_add(Afmt[t->tm_mon]))
                                       return(0);
                               continue;
                       case 'a':
                               if (!_add(afmt[t->tm_mon]))
                                       return(0);
                               continue;
                       case 'B':
                               if (!_add(Bfmt[t->tm_mon]))
                                       return(0);
                               continue;
                       case 'b':
                       case 'h':
                               if (!_add(bfmt[t->tm_mon]))
                                       return(0);
                               continue;
                       case 'c':
                               if (!_fmt("%x %X %Z %Y", t))
                                       return(0);
                               continue;
                       case 'D':
                               if (!_fmt("%m/%d/%y", t))
                                       return(0);
                               continue;
                       case 'd':
                               if (!_conv(t->tm_mday, 2))
                                       return(0);
                               continue;
                       case 'H':
                               if (!_conv(t->tm_hour, 2))
                                       return(0);
                               continue;
                       case 'I':
                               if (!_conv((t->tm_hour - 1) % 12 + 1, 2))
                                       return(0);
                               continue;
                       case 'j':
                               if (!_conv(t->tm_yday + 1, 3))
                                       return(0);
                               continue;
                       case 'M':
                               if (!_conv(t->tm_min, 2))
                                       return(0);
                               continue;
                       case 'm':
                               if (!_conv(t->tm_mon + 1, 2))
                                       return(0);
                               continue;
                       case 'n':
                               if (!_add("\n"))
                                       return(0);
                               continue;
                       case 'p':
                               if (!_add(t->tm_hour >= 12 ? "AM" : "PM"))
                                       return(0);
                               continue;
                       case 'R':
                               if (!_fmt("%H:%M", t))
                                       return(0);
                               continue;
                       case 'r':
                               if (!_fmt("%I:%M:%S %p", t))
                                       return(0);
                               continue;
                       case 'S':
                               if (!_conv(t->tm_sec, 2))
                                       return(0);
                               continue;
                       case 'T':
                       case 'X':
                               if (!_fmt("%H:%M:%S", t))
                                       return(0);
                               continue;
                       case 't':
                               if (!_add("\t"))
                                       return(0);
                               continue;
                       case 'U':
                               if (!_conv((t->tm_yday + 7 - t->tm_wday) / 7,
                                   2))
                                       return(0);
                               continue;
                       case 'W':
                               if (!_conv((t->tm_yday + 7 -
                                   (t->tm_wday ? t->tm_wday : 6)) / 7, 2))
                                       return(0);
                               continue;
                       case 'w':
                               if (!_conv(t->tm_wday, 1))
                                       return(0);
                               continue;
                       case 'x':
                               if (!_fmt("%a %b %d", t))
                                       return(0);
                               continue;
                       case 'y':
                               if (!_conv((t->tm_year + TM_YEAR_BASE)
                                   % 100, 2))
                                       return(0);
                               continue;
                       case 'Y':
                               if (!_conv(t->tm_year + TM_YEAR_BASE, 4))
                                       return(0);
                               continue;
                       case 'Z':
                               if (!_add(t->tm_zone))
                                       return(0);
                               continue;
                       case '%':
                       /*
                        * X311J/88-090 (4.12.3.5): if conversion char is
                        * undefined, behavior is undefined.  Print out the
                        * character itself as printf(3) also does.
                        */
                       default:
                               break;
               }
               if (!gsize--)
                       return(0);
               *pt++ = *format;
       }
       return(gsize);
}

static
_conv(n, digits)
       int n, digits;
{
       static char buf[10];
       register char *p;

       for (p = buf + sizeof(buf) - 2; n > 0 && p > buf; n /= 10, --digits)
               *p-- = n % 10 + '0';
       while (p > buf && digits-- > 0)
               *p-- = '0';
       return(_add(++p));
}

static
_add(str)
       register char *str;
{
       for (;; ++pt, --gsize) {
               if (!gsize)
                       return(0);
               if (!(*pt = *str++))
                       return(1);
       }
}