lint_posinseqslash.c File Reference

Purpose

The posinseqslash linter ensures that the data represents a meaningful position in a sequence in the format "`<pos>/<end>`".

Functional Description

gs1_lint_posinseqslash()

GS1_SYNTAX_DICTIONARY_API gs1_lint_err_t gs1_lint_posinseqslash	(	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 "`<pos>/<end>`" format for variable width <pos> and <end>.

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_POSITION_IN_SEQUENCE_MALFORMED if the data does not conform to "`<pos>/<end>`" format.

GS1_LINTER_ILLEGAL_ZERO_PREFIX if either the position number or the end number are zero or contain a zero prefix.

GS1_LINTER_POSITION_EXCEEDS_END if the data contains a position number that is larger than the end position.

{
 
/// \cond
#define P(i)    data[i]
#define E(i)    data[i + pos + 1]
/// \endcond
 
        size_t pos, slash_pos;
 
        assert(data);
 
        /*
         * First non-digit should be '/'
         *
         */
        for (pos = 0; pos < data_len && data[pos] >= '0' && data[pos] <= '9'; pos++);
 
        /*
         * Format so far must be digits + '/'
         *
         */
        if (GS1_LINTER_UNLIKELY(pos == 0 || pos >= data_len || data[pos] != '/')) {
                GS1_LINTER_RETURN_ERROR(
                        GS1_LINTER_POSITION_IN_SEQUENCE_MALFORMED,
                        0,
                        data_len
                );
        }
 
        slash_pos = pos;
 
        /*
         * Validate that remaining characters are digits and measure length
         *
         */
        for (pos++; pos < data_len; pos++)
                if (GS1_LINTER_UNLIKELY(data[pos] < '0' || data[pos] > '9')) {
                        GS1_LINTER_RETURN_ERROR(
                                GS1_LINTER_POSITION_IN_SEQUENCE_MALFORMED,
                                0,
                                data_len
                        );
                }
 
        /*
         * Must have digits after slash
         */
        if (GS1_LINTER_UNLIKELY(slash_pos >= data_len - 1))
                GS1_LINTER_RETURN_ERROR(
                        GS1_LINTER_POSITION_IN_SEQUENCE_MALFORMED,
                        0,
                        data_len
                );
 
        pos = slash_pos;
 
        /*
         * Ensure position number is non-zero and does not have zero prefix.
         *
         */
        if (GS1_LINTER_UNLIKELY(P(0) == '0'))
                GS1_LINTER_RETURN_ERROR(
                        GS1_LINTER_ILLEGAL_ZERO_PREFIX,
                        0,
                        pos
                );
 
        /*
         * Ensure end number is non-zero and does not have zero prefix.
         *
         */
        if (GS1_LINTER_UNLIKELY(E(0) == '0'))
                GS1_LINTER_RETURN_ERROR(
                        GS1_LINTER_ILLEGAL_ZERO_PREFIX,
                        pos + 1,
                        data_len - pos - 1
                );
 
        /*
         * Determine whether the position exceeds the end.
         *
         */
        if (pos == data_len - pos - 1) {
                size_t i;
                int compare = 0;                /* -1:P<E ; 0:P==E ; 1:P>E */
                for (i = 0; i < pos && !compare; i++)
                        if (P(i) != E(i))
                                compare = P(i) < E(i) ? -1 : 1;
                if (GS1_LINTER_UNLIKELY(compare == 1))
                        GS1_LINTER_RETURN_ERROR(
                                GS1_LINTER_POSITION_EXCEEDS_END,
                                0,
                                data_len
                        );
        } else if (GS1_LINTER_UNLIKELY(pos > data_len - pos - 1))
                /* Non-zero prefix, so a length check is sufficient. */
                GS1_LINTER_RETURN_ERROR(
                        GS1_LINTER_POSITION_EXCEEDS_END,
                        0,
                        data_len
                );
 
        GS1_LINTER_RETURN_OK;
 
}