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[master] / src / liblimb / bytestr.h / byte_istr.c

/* This file is part of limb                           https://lila.oss/limb
 * Copyright (C) 2023 Olivier Brunel                          jjk@jjacky.com */
/* SPDX-License-Identifier: GPL-2.0-only */
#include <ctype.h>
#include <limb/bytestr.h>

size_t
byte_istr(const char *haystack, size_t hlen, const char *needle, size_t nlen)
{
    if (!hlen || !nlen || nlen > hlen) return hlen;

    size_t from, n;
    for (from = 0, n = 0; from < hlen - nlen && n < nlen; ) {
        if (tolower(haystack[from + n]) != tolower(needle[n])) {
            n = 0;
            ++from;
        } else {
            ++n;
        }
    }

    return (n == nlen) ? from : hlen;
}