lint_pieceoftotal.c File Reference

Purpose

The pieceoftotal linter ensures that the data represents a meaningful piece of total, i.e. a concatenation of non-zero piece number follow by an equal-width, non-zero total number of pieces.

Functional Description

gs1_lint_pieceoftotal()

GS1_SYNTAX_DICTIONARY_API gs1_lint_err_t gs1_lint_pieceoftotal	(	const char *const	data,
		size_t	data_len,
		size_t *const	err_pos,
		size_t *const	err_len
	)

Used to ensure that an AI component conforms to a PPTT format, where PP and TT have equal width.

Parameters

[in]	data	Pointer to the data to be linted. Must not be NULL.
[in]	data_len	Length of the data to be linted.
[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_INVALID_LENGTH_FOR_PIECE_OF_TOTAL if the data is not an even length.

GS1_LINTER_NON_DIGIT_CHARACTER if the data contains a non-digit character.

GS1_LINTER_ZERO_PIECE_NUMBER if the data contains a piece number with a zero value.

GS1_LINTER_ZERO_TOTAL_PIECES if the data contains a total piece count with a zero value.

GS1_LINTER_PIECE_NUMBER_EXCEEDS_TOTAL if the data contains a piece number that is larger than the total piece count.

{
 
/// \cond
#define P(i)    data[i]
#define T(i)    data[data_len / 2 + i]
/// \endcond
 
        size_t pos, i;
        int pieceiszero, totaliszero, compare;
 
        assert(data);
 
        /*
         * Data must consist of all digits.
         *
         */
        for (pos = 0; pos < data_len; pos++)
                if (GS1_LINTER_UNLIKELY(data[pos] < '0' || data[pos] > '9'))
                        GS1_LINTER_RETURN_ERROR(
                                GS1_LINTER_NON_DIGIT_CHARACTER,
                                pos,
                                1
                        );
 
        /*
         * Data must be a non-zero, even number of characters.
         *
         */
        if (GS1_LINTER_UNLIKELY(data_len == 0 || data_len % 2 != 0))
                GS1_LINTER_RETURN_ERROR(
                        GS1_LINTER_INVALID_LENGTH_FOR_PIECE_OF_TOTAL,
                        0,
                        data_len
                );
 
        /*
         * Determine whether either the piece number or total piece count is
         * zero and whether the piece number exceeds the total piece count.
         *
         */
        pieceiszero = totaliszero = 1;
        compare = 0;                            /* -1:P<T ; 0:P==T ; 1:P>T */
        for (i = 0; i < data_len / 2; i++) {
                if (pieceiszero && P(i) != '0') pieceiszero = 0;
                if (totaliszero && T(i) != '0') totaliszero = 0;
                if (!compare && P(i) != T(i)) compare = P(i) < T(i) ? -1 : 1;
        }
 
        /*
         * Neither piece nor total may be zero.
         *
         */
        if (GS1_LINTER_UNLIKELY(pieceiszero || totaliszero))
                GS1_LINTER_RETURN_ERROR(
                        pieceiszero ? GS1_LINTER_ZERO_PIECE_NUMBER : GS1_LINTER_ZERO_TOTAL_PIECES,
                        pieceiszero ? 0 : data_len / 2,
                        data_len / 2
                );
 
        /*
         * The piece number must not exceed the total piece count.
         *
         */
        if (GS1_LINTER_UNLIKELY(compare == 1))
                GS1_LINTER_RETURN_ERROR(
                        GS1_LINTER_PIECE_NUMBER_EXCEEDS_TOTAL,
                        0,
                        data_len
                );
 
        GS1_LINTER_RETURN_OK;
 
}