PHP strtotime函数用法、实现原理和源码分析

源码位置：/ext/date/php_date.c
代码如下:
/* {{{ proto int strtotime(string time [, int now ])
   Convert string representation of date and time to a timestamp */
PHP_FUNCTION(strtotime)
{
    char *times, *initial_ts;
    int   time_len, error1, error2;
    struct timelib_error_container *error;
    long  preset_ts = 0, ts;

    timelib_time *t, *now;
    timelib_tzinfo *tzi;

    tzi = get_timezone_info(TSRMLS_C);

    if (zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS() TSRMLS_CC, “sl”, ×, &time_len, &preset_ts) != FAILURE) {
        /* We have an initial timestamp */
        now = timelib_time_ctor();

        initial_ts = emalloc(25);
        snprintf(initial_ts, 24, “@%ld UTC”, preset_ts);
        t = timelib_strtotime(initial_ts, strlen(initial_ts), NULL, DATE_TIMEZONEDB, php_date_parse_tzfile_wrapper); /* we ignore the error here, as this should never fail */
        timelib_update_ts(t, tzi);
        now->tz_info = tzi;
        now->zone_type = TIMELIB_ZONETYPE_ID;
        timelib_unixtime2local(now, t->sse);
        timelib_time_dtor(t);
        efree(initial_ts);
    } else if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, “s|l”, ×, &time_len, &preset_ts) != FAILURE) {
        /* We have no initial timestamp */
        now = timelib_time_ctor();
        now->tz_info = tzi;
        now->zone_type = TIMELIB_ZONETYPE_ID;
        timelib_unixtime2local(now, (timelib_sll) time(NULL));
    } else {
        RETURN_FALSE;
    }

    if (!time_len) {
        timelib_time_dtor(now);   
        RETURN_FALSE;
    }

    t = timelib_strtotime(times, time_len, &error, DATE_TIMEZONEDB, php_date_parse_tzfile_wrapper);
    error1 = error->error_count;
    timelib_error_container_dtor(error);
    timelib_fill_holes(t, now, TIMELIB_NO_CLONE);
    timelib_update_ts(t, tzi);