Ticket #17932: test.cpp

#include <cstdio>
#include <cstring>
#include <ctime>

// The formats used should be, in order of preference (according to RFC2616,
// section 3.3):
// RFC1123 / RFC822: "Sun, 06 Nov 1994 08:49:37 GMT"
// RFC1036 / RFC850: "Sunday, 06-Nov-94 08:49:37 GMT"
// asctime         : "Sun Nov  6 08:49:37 1994"
//
// RFC1123 is the preferred one because it has 4 digit years.
//
// But of course in real life, all possible mixes of the formats are used.
// Believe it or not, it's even possible to find some website that gets this
// right and use one of the 3 formats above.
// Often seen variants are:
// - RFC1036 but with 4 digit year,
// - Missing or different timezone indicator
// - Invalid weekday
static const char* kDateFormats[] = {
    // RFC1123
    "%a, %d %b %Y %H:%M:%S",     // without timezone
    "%a, %d %b %Y %H:%M:%S GMT", // canonical

    // RFC1036
    "%A, %d-%b-%y %H:%M:%S",     // without timezone
    "%A, %d-%b-%y %H:%M:%S GMT", // canonical

    // RFC1036 with 4 digit year
    "%a, %d-%b-%Y %H:%M:%S",     // without timezone
    "%a, %d-%b-%Y %H:%M:%S GMT", // with 4-digit year
    "%a, %d-%b-%Y %H:%M:%S UTC", // "UTC" timezone

    // asctime
    "%a %d %b %H:%M:%S %Y"
};

static const char* example = "Mon, 5 Sep 2022 14:14:14 GMT";

// Main function
int main(void)
{
    struct tm expireTime;
    
    memset(&expireTime, 0, sizeof(struct tm));
    
    int fDateFormat = -1;
    unsigned int i;
    for (i = 0; i < sizeof(kDateFormats) / sizeof(const char*);
        i++) {
        const char* result = strptime(example, kDateFormats[i],
            &expireTime);
        printf("Parsing %s\n", example);
        printf("Year %d, hour %d\n", expireTime.tm_year, expireTime.tm_hour);

        if (result != NULL) {
            printf("Match!\n");
            fDateFormat = i;
            break;
        }
    }

    if (fDateFormat == -1)
        printf("Did not match\n");
}