lint_pcenc.c File Reference

Purpose

The pcenc linter ensures that the data has correct percent-encoding.

Remarks

Percent-encoding is defined by RFC 3986: Uniform Resource Identifier (URI): Generic Syntax section "2.1. Percent-Encoding".

Functional Description

gs1_lint_pcenc()

GS1_SYNTAX_DICTIONARY_API gs1_lint_err_t gs1_lint_pcenc	(	const char *const	data,
		size_t *const	err_pos,
		size_t *const	err_len
	)

Used to ensure that an AI component conforms with correct percent encoding.

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_INVALID_PERCENT_SEQUENCE if the data contains an invalid percent sequence.

{
 
        const char *p, *q;
        char pct[3] = {0};
 
        assert(data);
 
        p = data;
        q = data + strlen(data);
 
        /*
         * Find each instance of "%" in the data and ensure that there are at
         * least two following characters and that these two characters
         * represent a hex value.
         *
         */
        while (p != q && (p = strchr(p, '%')) != NULL) {
 
                if (q - p < 3)
                        GS1_LINTER_RETURN_ERROR(
                                GS1_LINTER_INVALID_PERCENT_SEQUENCE,
                                (size_t)(p - data),
                                (size_t)(q - p)
                        );
 
                memcpy(pct, p + 1, 2);
                if (strspn(pct, "0123456789ABCDEFabcdef") != 2)
                        GS1_LINTER_RETURN_ERROR(
                                GS1_LINTER_INVALID_PERCENT_SEQUENCE,
                                (size_t)(p - data),
                                3
                        );
 
                p += 3;
 
        }
 
        GS1_LINTER_RETURN_OK;
 
}