ruby/yarp/missing.c

#include "yarp/missing.h"

const char *
yp_strnstr(const char *haystack, const char *needle, size_t length) {
    size_t needle_length = strlen(needle);
    if (needle_length > length) return NULL;

    const char *haystack_limit = haystack + length - needle_length + 1;

    while ((haystack = memchr(haystack, needle[0], (size_t) (haystack_limit - haystack))) != NULL) {
        if (!strncmp(haystack, needle, needle_length)) return haystack;
        haystack++;
    }

    return NULL;
}

int
yp_strncasecmp(const char *string1, const char *string2, size_t length) {
    size_t offset = 0;
    int difference = 0;

    while (offset < length && string1[offset] != '\0') {
        if (string2[offset] == '\0') return string1[offset];

        unsigned char left = (unsigned char) string1[offset];
        unsigned char right = (unsigned char) string2[offset];

        if ((difference = tolower(left) - tolower(right)) != 0) return difference;
        offset++;
    }

    return difference;
}