#include "string.h"

void *memset(void *s, int c, size_t n)
{
    for(size_t i = 0; i < n; i++) {
        ((char*)s)[i] = c;
    }
    return s;
}
void *memcpy(void *a, const void *b, size_t n)
{
    for(size_t i = 0; i < n; i++) {
        ((char*)a)[i] = ((const char*)b)[i];
    }
    return a;
}

int memcmp(const void *a, const void *b, size_t n)
{
    const char *ca = a;
    const char *cb = b;
    for(size_t i = 0; i < n; i++) {
        if(ca[i] != cb[i]) return ca[i] - cb[i];
    }
    return 0;
}

size_t strlen(const char *s)
{
    size_t i = 0;
    for(; s[i]; i++);
    return i;
}

char c_toupper(char c) {
    return (c > 0x60 && c < 0x7B) ? (c - 0x20) : c;
}

char *str_toupper(char *s, size_t n)
{
    for(size_t i = 0; i < n; i++) {
        s[i] = c_toupper(s[i]);
    }
    return s;
}

int strncmp(const char *s1, const char *s2, size_t n)
{
    size_t i = 0;
    for(; s1[i] && s2[i] && i < n; i++) {
        int diff = s1[i] - s2[i];
        if(diff) return diff;
    }
    return s1[i] - s2[i];
}

char *strncpy(size_t n, char *restrict s1, const char *restrict s2)
{
    for(size_t i = 0; s2[i] && i < n; i++) s1[i] = s2[i];
    return s1;
}