#include <stdlib.h>
#include <string.h>

char* concat(const char *s1, const char *s2){
    const size_t len1 = strlen(s1);
    const size_t len2 = strlen(s2);
    char *result = malloc(len1 + len2 + 1);
    memcpy(result, s1, len1);
    memcpy(result + len1, s2, len2 + 1);
    return result;
}
char* smartstrcasestr(char *haystack, const char *needle){
	char smart = 0;
	char *ret;
	char passes = 0;
	while (*needle) {
		if (*needle >= 'A' && *needle <= 'Z') {
			smart = 1;
			break;
		}
		passes++;
		needle++;
	}
	needle -= passes;
	if (smart == 0) {
		char *needle_case = malloc(strlen(needle)+1);
		strcpy(needle_case, needle);
		passes = 0;
		while (*needle_case) {
			*needle_case = *needle_case | ' ';
			needle_case++;
			passes++;
		}
		needle_case -= passes;

		char *haystack_case = malloc(strlen(haystack)+1);
		strcpy(haystack_case, haystack);
		passes = 0;
		while (*haystack_case) {
			*haystack_case = *haystack_case | ' ';
			haystack_case++;
			passes++;
		}
		haystack_case -= passes;

		ret = strstr(haystack_case, needle_case);
		free(needle_case);
		free(haystack_case);
	} else {
		ret = strstr(haystack, needle);
	}
	return ret;
}