/* Test program for mktime().
 
Crude in that it assumes TZ=EST, but it is purposely avoided being set to
stop from messing up PC environments.  (Time was not spent to see if this
was a real problem or not.)  */
 
#include <stdio.h>
#include <string.h>
#include <time.h>

void pr_tm(struct tm *set, struct tm *work);
 
int
//test_mktime(void)
main(void)
{
const char *name=__func__;
const char *exp;
char  buf[80];
/* Include time zone in printout */
const char  *fmt="%a %b %e %H:%M:%S %Z %Y";
const char  pass[]="\t(PASS)", fail[]="\t(FAIL)";
int  err=0, p=0, f=0;
struct tm  tm_set, tm_work, *tm_p;
time_t  t;
 
/* Set up values in tm_set */
tm_set.tm_mon	= 3-1;	/* 3 for March */
tm_set.tm_mday	= 1;	/* 1 won't be DST */
tm_set.tm_hour	= 12;
tm_set.tm_min	= 34;
tm_set.tm_sec	= 0;
tm_set.tm_year	= 2008-1900;
tm_set.tm_wday	= -2;	/* mktime() ignores */
tm_set.tm_yday	= -3;	/* mktime() ignores */
 
/* Copy base set to working, run first test */
tm_set.tm_isdst	= -1;	/* -1=have mktime() decide DST|ST */
exp = "Sat Mar  1 12:34:00 EST 2008";
tm_work = tm_set;
t = mktime(&tm_work);
if(t == (time_t)-1)  {
    puts("mktime() failed on given data\007");
    err++;
    }
  else  {
    tm_p = localtime(&t);
    strftime(buf, sizeof(buf), fmt, tm_p);
    printf("For set => mktime(), ");
	puts("tm_isdst <0=mktime() figure out if is DST:");
    pr_tm(&tm_set, &tm_work);
    printf("strftime(localtime()) gives:  ");
    fputs(buf, stdout);
    if(strcmp(buf, exp))  { f++; puts(fail); }
      else  { p++; puts(pass); }
    }
 
/* Copy base set to working, run next test */
tm_set.tm_isdst = 0;	/* 0=specify not DST */
// exp is same, as working date is not DST
tm_work = tm_set;
t = mktime(&tm_work);
if(t == (time_t)-1)  {
    puts("mktime() failed on given data\007");
    err++;
    }
  else  {
    tm_p = localtime(&t);
    strftime(buf, sizeof(buf), fmt, tm_p);
    printf("For set => mktime(), ");
	puts("tm_isdst 0=specify not DST:");
    pr_tm(&tm_set, &tm_work);
    printf("strftime(localtime()) gives:  ");
    fputs(buf, stdout);
    if(strcmp(buf, exp))  { f++; puts(fail); }
      else  { p++; puts(pass); }
    }
 
/* Copy base set to working, run next test */
tm_set.tm_isdst = 2;	/* 1=specify is DST */
// Expect adjustment, since working date is not DST
exp = "Sat Mar  1 11:34:00 EST 2008";
tm_work = tm_set;
t = mktime(&tm_work);
if(t == (time_t)-1)  {
    puts("mktime() failed on given data\007");
    err++;
    }
  else  {
    tm_p = localtime(&t);
    strftime(buf, sizeof(buf), fmt, tm_p);
    printf("For set => mktime(), ");
	puts("tm_isdst 2=specify is DST:");
    pr_tm(&tm_set, &tm_work);
    printf("strftime(localtime()) gives:  ");
    fputs(buf, stdout);
    if(strcmp(buf, exp))  { f++; puts(fail); }
      else  { p++; puts(pass); }
    }
/*** HOW COME THIS WORKS OK ON CYGWIN, WHICH APPEARS TO USE 1.14.0? ***/
 
/******************************************************************************/
/* Repeat same basic calls, except use date that is DST */
tm_set.tm_mon	= 5-1;	/* 5 for May */
exp = "Thu May  1 12:34:00 EDT 2008";
 
/* Copy base set to working, run first test */
tm_set.tm_isdst	= -1;	/* -1=have mktime() decide DST|ST */
tm_work = tm_set;
t = mktime(&tm_work);
if(t == (time_t)-1)  {
    puts("mktime() failed on given data\007");
    err++;
    }
  else  {
    tm_p = localtime(&t);
    strftime(buf, sizeof(buf), fmt, tm_p);
    printf("For set => mktime(), ");
	puts("tm_isdst <0=mktime() figure out if is DST:");
    pr_tm(&tm_set, &tm_work);
    printf("strftime(localtime()) gives:  ");
    fputs(buf, stdout);
    if(strcmp(buf, exp))  { f++; puts(fail); }
      else  { p++; puts(pass); }
    }
 
/* Copy base set to working, run next test */
tm_set.tm_isdst = 0;	/* 0=specify not DST */
// Expect adjustment, since working date is DST
exp = "Thu May  1 13:34:00 EDT 2008";
tm_work = tm_set;
t = mktime(&tm_work);
if(t == (time_t)-1)  {
    puts("mktime() failed on given data\007");
    err++;
    }
  else  {
    tm_p = localtime(&t);
    strftime(buf, sizeof(buf), fmt, tm_p);
    printf("For set => mktime(), ");
	puts("tm_isdst 0=specify not DST:");
    pr_tm(&tm_set, &tm_work);
    printf("strftime(localtime()) gives:  ");
    fputs(buf, stdout);
    if(strcmp(buf, exp))  { f++; puts(fail); }
      else  { p++; puts(pass); }
    }
 
/* Copy base set to working, run next test */
tm_set.tm_isdst = 4;	/* 1=specify is DST */
// exp is unaltered, as working date is DST
exp = "Thu May  1 12:34:00 EDT 2008";
tm_work = tm_set;
t = mktime(&tm_work);
if(t == (time_t)-1)  {
    puts("mktime() failed on given data\007");
    err++;
    }
  else  {
    tm_p = localtime(&t);
    strftime(buf, sizeof(buf), fmt, tm_p);
    printf("For set => mktime(), ");
	puts("tm_isdst 4=specify is DST:");
    pr_tm(&tm_set, &tm_work);
    printf("strftime(localtime()) gives:  ");
    fputs(buf, stdout);
    if(strcmp(buf, exp))  { f++; puts(fail); }
      else  { p++; puts(pass); }
    }
 
printf("\nPassed %d cases, failed %d cases.\n", p, f);
printf("mktime() indicated failure %d times\n", err);
 
return(f || err);
}
 
#define PR(mem)  printf(#mem": \t%d => %d\n", set->mem, work->mem)
#define PRx(mem)  printf("("#mem": \t%d => %d)\n", set->mem, work->mem)
void
pr_tm(struct tm *set, struct tm *work)
{
PR(tm_mon);
PR(tm_mday);
PR(tm_hour);
PR(tm_min);
PR(tm_sec);
PR(tm_year);
PR(tm_isdst);
PRx(tm_wday);
PRx(tm_yday);
}