lint_yymmd0.c File Reference

Purpose

The yymmd0 linter ensures that the data represents a meaningful date, in YYMMDD format, additionally permitting YYMM00 format indicating an unspecified day.

Macros
#define	CURRENT_YEAR   21
	20YY: For converting YY to 19YY, 20YY, 21YY, etc. for leap year validation

Functional Description

gs1_lint_yymmd0()

GS1_SYNTAX_DICTIONARY_API gs1_lint_err_t gs1_lint_yymmd0	(	const char *const	data,
		size_t *const	err_pos,
		size_t *const	err_len
	)

Used to ensure that an AI component conforms to the YYMMDD or YYMM00 formats.

Parameters

[in]	data	Pointer to the null-terminated data to be linted. Must not be NULL.
[out]	err_pos	To facilitate error highlighting, the start position of the bad data is written to this pointer, if not NULL.
[out]	err_len	The length of the bad data is written to this pointer, if not NULL.

Returns

GS1_LINTER_OK if okay.

GS1_LINTER_DATE_TOO_SHORT if the data is too short for YYMMDD format.

GS1_LINTER_DATE_TOO_LONG if the data is too long for YYMMDD format.

GS1_LINTER_NON_DIGIT_CHARACTER if the data contains a non-digit character.

GS1_LINTER_ILLEGAL_MONTH if the data contains an invalid month.

GS1_LINTER_ILLEGAL_DAY if the data contains an invalid day of the month.

{
 
/// \cond
#define XX(d) ( (data[d] - '0') * 10 + (data[d+1] - '0') )
#define YY XX(0)
#define MM XX(2)
#define DD XX(4)
/// \endcond
 
        static const int daysinmonth[] =
                { 31, -1, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
 
        size_t len, pos;
        int yyyy, maxdd;
 
        assert(data);
 
        len = strlen(data);
 
        /*
         * Data must be six characters.
         *
         */
        if (len != 6) {
                if (err_pos) *err_pos = 0;
                if (err_len) *err_len = len;
                return len < 6 ? GS1_LINTER_DATE_TOO_SHORT : GS1_LINTER_DATE_TOO_LONG;
        }
 
        /*
         * Data must consist of all digits.
         *
         */
        if ((pos = strspn(data, "0123456789")) != len) {
                if (err_pos) *err_pos = pos;
                if (err_len) *err_len = 1;
                return GS1_LINTER_NON_DIGIT_CHARACTER;
        }
 
        /*
         * Validate that the month is 01 to 12.
         *
         */
        if (MM < 1 || MM > 12) {
                if (err_pos) *err_pos = 2;
                if (err_len) *err_len = 2;
                return GS1_LINTER_ILLEGAL_MONTH;
        }
 
        /*
         * Convert YY to a year using a horizon based on CURRENT_YEAR.
         *
         */
        if (YY - CURRENT_YEAR >= 51)
                yyyy = 1900 + YY;
        else if (YY - CURRENT_YEAR > -50)
                yyyy = 2000 + YY;
        else
                yyyy = 2100 + YY;
 
        /*
         * Validate the day, accounting for leap years, and permitting "00".
         *
         */
        maxdd = daysinmonth[MM - 1];            /* Based at 0 */
        if (maxdd == -1)                        /* February; account for leap years */
                maxdd = ((yyyy % 4 == 0 && yyyy % 100 != 0) ||
                         yyyy % 400 == 0) ? 29 : 28;
 
        if (DD > maxdd) {
                if (err_pos) *err_pos = 4;
                if (err_len) *err_len = 2;
                return GS1_LINTER_ILLEGAL_DAY;
        }
 
        return GS1_LINTER_OK;
 
}