cvs: /php4/ext/standard datetime.c

verdy_p Sat Aug 28 12:19:44 1999 EDT Modified files: /php4/ext/standard datetime.c Log: Bug in gmmktime(): it produced wrong results in New Foundland, Central Australia, India, Iran, and Java, with half-hour timezones. Index: php4/ext/standard/datetime.c diff -u php4/ext/standard/datetime.c:1.19 php4/ext/standard/datetime.c:1.20 --- php4/ext/standard/datetime.c:1.19 Mon Aug 2 15:16:50 1999 +++ php4/ext/standard/datetime.c Sat Aug 28 12:19:14 1999 @@ -19,7 +19,7 @@ */ -/* $Id: datetime.c,v 1.19 1999/08/02 19:16:50 zeev Exp $ */ +/* $Id: datetime.c,v 1.20 1999/08/28 16:19:14 verdy_p Exp $ */ #include "php.h" @@ -88,18 +88,53 @@ for (i = 0; i < arg_count; i++) { convert_to_long(arguments[i]); } - t=time(NULL); + t = time(NULL); #ifdef HAVE_TZSET tzset(); #endif + /* + ** Set default time parameters with local time values, + ** EVEN when some GMT time parameters are specified! + ** This may give strange result, with PHP gmmktime(0,0,0), + ** which is assumed to return GMT midnight time + ** for today (in localtime), so that the result time may be + ** AFTER or BEFORE the current time. + ** May be we should initialize tn using gmtime(), so that + ** default parameters for PHP gmmktime would be the current + ** GMT time values... + */ tn = localtime(&t); - memcpy(&ta,tn,sizeof(struct tm)); - ta.tm_isdst = arg_count > 6 ? arguments[6]->value.lval : gm ? 0 : -1; + memcpy(&ta, tn, sizeof(struct tm)); + if (gm) { + ta.tm_isdst = 0 /* force winter time if UTC flag is true */ + /* unless the UTC flag is specified after GMT date parameters. */ + } + else { + ta.tm_isdst = -1; /* let DST unknown */ + /* this will recompute the DST status for the */ + /* given date, based on localtime rules. */ + /* Most often, this will return the same value */ + } + /* + ** Now change date values with supplied parameters. + */ switch(arg_count) { case 7: + ta.tm_isdst = arguments[6]->value.lval; + /* fall-through */ case 6: - ta.tm_year = arguments[5]->value.lval - ((arguments[5]->value.lval > 1000) ? 1900 : 0); + /* + ** Accept parameter in range 0..1000 interpreted as 1900..2900 + ** (if 100 is given, it means year 2000) + ** or in range 1001..9999 interpreted as is (this will store + ** negative tm_year for years in range 1001..1899) + ** This function is then Y2K ready, and accepts a wide range of + ** dates including the whole gregorian calendar. + ** But it cannot represent ancestral dates prior to year 1001. + */ + ta.tm_year = arguments[5]->value.lval + - ((arguments[5]->value.lval > 1000) ? 1900 : 0); /* fall-through */ case 5: ta.tm_mday = arguments[4]->value.lval; @@ -115,20 +150,51 @@ /* fall-through */ case 1: ta.tm_hour = arguments[0]->value.lval; + /* fall-through */ case 0: break; } - t=mktime(&ta); /* Need to do this because of Daylight savings */ - tn = localtime(&t); if (gm) { #if HAVE_TM_GMTOFF - gmadjust=tn->tm_gmtoff; + /* + ** If GMT parameters were given, mktime() will + ** use the forced winter time local convention + ** and the structure will be adjusted to compute + ** the effective localtime GMT offset in seconds. + ** This value depends on date parameters in ta. + ** So this compute the Winter GMT offset. + */ + t = mktime(&ta); /* Need to do this because of Daylight savings */ + tn = localtime(&t); + /* + ** Note: despite locatime() returns a global structure, + ** structure, this structure is supposed to be thread-unique, + ** (this is true with MS Visual compiler for Windows) + ** so the localtime() function will be MT-safe. + ** On other systems, localtime() may not return thread-unique + ** structure, and won't be MT-safe. For now MT is supported + ** only on Windows for the DLL versions of PHP. + */ + gmadjust = tn->tm_gmtoff; #else - gmadjust=timezone; + /* + ** Without tm_gmtoff, the non-ANSI C run-time global 'timezone' + ** variable simply returns the current Winter GMT offset + ** in the current locale (defined in DOS/Windows compilers). + */ + gmadjust = timezone; #endif - ta.tm_hour += gmadjust / 3600; - ta.tm_min += gmadjust % 3600; + /* + ** Adjust parameters, to void the GMT offset in seconds + ** in the supplied parameters, because mktime() below + ** computes a local time instead of GMT time. + */ + ta.tm_hour += gmadjust / 3600; + /* bug here: gmadjust % 3600 gives seconds, not minutes!!! */ + ta.tm_min += (gmadjust % 3600) / 60; + /* is there any timezone with seconds ? */ + ta.tm_sec += gmadjust % 60; } RETURN_LONG(mktime(&ta));