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

/*
* Copyright (c) 1989 The Regents of the University of California.
* All rights reserved.
*
* %sccs.include.redist.c%
*/

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)strftime.c  5.8 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <sys/time.h>
#include <tzfile.h>
#include <string.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;
{
       for (; *format; ++format) {
               if (*format == '%')
                       switch(*++format) {
                       case '\0':
                               --format;
                               break;
                       case 'A':
                               if (t->tm_wday < 0 || t->tm_wday > 6)
                                       return(0);
                               if (!_add(Afmt[t->tm_wday]))
                                       return(0);
                               continue;
                       case 'a':
                               if (t->tm_wday < 0 || t->tm_wday > 6)
                                       return(0);
                               if (!_add(afmt[t->tm_wday]))
                                       return(0);
                               continue;
                       case 'B':
                               if (t->tm_mon < 0 || t->tm_mon > 11)
                                       return(0);
                               if (!_add(Bfmt[t->tm_mon]))
                                       return(0);
                               continue;
                       case 'b':
                       case 'h':
                               if (t->tm_mon < 0 || t->tm_mon > 11)
                                       return(0);
                               if (!_add(bfmt[t->tm_mon]))
                                       return(0);
                               continue;
                       case 'C':
                               if (!_fmt("%a %b %e %H:%M:%S %Y", t))
                                       return(0);
                               continue;
                       case 'c':
                               if (!_fmt("%m/%d/%y %H:%M:%S", t))
                                       return(0);
                               continue;
                       case 'e':
                               if (!_conv(t->tm_mday, 2, ' '))
                                       return(0);
                               continue;
                       case 'D':
                               if (!_fmt("%m/%d/%y", t))
                                       return(0);
                               continue;
                       case 'd':
                               if (!_conv(t->tm_mday, 2, '0'))
                                       return(0);
                               continue;
                       case 'H':
                               if (!_conv(t->tm_hour, 2, '0'))
                                       return(0);
                               continue;
                       case 'I':
                               if (!_conv(t->tm_hour % 12 ?
                                   t->tm_hour % 12 : 12, 2, '0'))
                                       return(0);
                               continue;
                       case 'j':
                               if (!_conv(t->tm_yday + 1, 3, '0'))
                                       return(0);
                               continue;
                       case 'k':
                               if (!_conv(t->tm_hour, 2, ' '))
                                       return(0);
                               continue;
                       case 'l':
                               if (!_conv(t->tm_hour % 12 ?
                                   t->tm_hour % 12 : 12, 2, ' '))
                                       return(0);
                               continue;
                       case 'M':
                               if (!_conv(t->tm_min, 2, '0'))
                                       return(0);
                               continue;
                       case 'm':
                               if (!_conv(t->tm_mon + 1, 2, '0'))
                                       return(0);
                               continue;
                       case 'n':
                               if (!_add("\n"))
                                       return(0);
                               continue;
                       case 'p':
                               if (!_add(t->tm_hour >= 12 ? "PM" : "AM"))
                                       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, '0'))
                                       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, '0'))
                                       return(0);
                               continue;
                       case 'W':
                               if (!_conv((t->tm_yday + 7 -
                                   (t->tm_wday ? (t->tm_wday - 1) : 6))
                                   / 7, 2, '0'))
                                       return(0);
                               continue;
                       case 'w':
                               if (!_conv(t->tm_wday, 1, '0'))
                                       return(0);
                               continue;
                       case 'x':
                               if (!_fmt("%m/%d/%y", t))
                                       return(0);
                               continue;
                       case 'y':
                               if (!_conv((t->tm_year + TM_YEAR_BASE)
                                   % 100, 2, '0'))
                                       return(0);
                               continue;
                       case 'Y':
                               if (!_conv(t->tm_year + TM_YEAR_BASE, 4, '0'))
                                       return(0);
                               continue;
                       case 'Z':
                               if (!t->tm_zone || !_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) does.
                        */
                       default:
                               break;
               }
               if (!gsize--)
                       return(0);
               *pt++ = *format;
       }
       return(gsize);
}

static
_conv(n, digits, pad)
       int n, digits;
       char pad;
{
       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-- = pad;
       return(_add(++p));
}

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