#include <string.h>

char *itoa(int value, char *str, int base) {
    char        *p = str;
    char        *p1, *p2;
    unsigned int uvalue = value;
    int          negative = 0;

    if (base < 2 || base > 36) {
        *str = '\0';
        return str;
    }

    if (value < 0 && base == 10) {
        negative = 1;
        uvalue = -value;
    }

    // Convert to string
    do {
        int digit = uvalue % base;
        *p++ = (digit < 10) ? '0' + digit : 'a' + (digit - 10);
        uvalue /= base;
    } while (uvalue);

    if (negative)
        *p++ = '-';

    *p = '\0';

    // Reverse string
    p1 = str;
    p2 = p - 1;
    while (p1 < p2) {
        char tmp = *p1;
        *p1++ = *p2;
        *p2-- = tmp;
    }

    return str;
}

void *memset(void *dst, int c, size_t length) {
    u8      *ptr = (u8 *)dst;
    const u8 value = (u8)c;

    while (length--) *(ptr++) = value;

    return dst;
}

void *memcpy(void *dst, const void *src, size_t len) {
    u8       *d = (u8 *)dst;
    const u8 *s = (const u8 *)src;
    for (size_t i = 0; i < len; i++) {
        d[i] = s[i];
    }
    return dst;
}

void *memmove(void *dst, const void *src, size_t len) {
    u8       *d = (u8 *)dst;
    const u8 *s = (const u8 *)src;
    if (d < s) {
        for (size_t i = 0; i < len; i++) {
            d[i] = s[i];
        }
    } else if (d > s) {
        for (size_t i = len; i > 0; i--) {
            d[i - 1] = s[i - 1];
        }
    }
    return dst;
}

int memcmp(const void *s1, const void *s2, size_t len) {
    const u8 *a = (const u8 *)s1;
    const u8 *b = (const u8 *)s2;
    for (size_t i = 0; i < len; i++) {
        if (a[i] != b[i]) {
            return (int)a[i] - (int)b[i];
        }
    }
    return 0;
}

size_t strlen(const char *s) {
    const char *p = s;
    while (*p) ++p;
    return (size_t)(p - s);
}

size_t strnlen(const char *s, size_t maxlen) {
    size_t len = 0;
    while (len < maxlen && s[len] != '\0') {
        len++;
    }
    return len;
}