/*
Copyright 2022 Mattia Giambirtone & Contributors

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

#include "kernel/types.h"
#include "kernel/util.h"


void copystr(const char* restrict source, char* restrict dest, i32 n) {
    /*
    Copies n bytes from source to dest. The two memory locations may
    not overlap: if they do, the behavior is undefined. This function's
    behavior is also undefined if:
    - n is larger than source's or dest's actual size
    - dest is smaller than source
    The caller should make sure these conditions are checked for before
    calling this function 
    */
    int i;
    for (i = 0; i < n; i++) {
        *(dest + i) = *(source + i);
    }
}


void memset(u8* dest, u8 val, u32 len) {
    /*
    Implementation for memset
    */
    u8* temp = (u8*)dest;
    while (len) {
        *temp++ = val;
        len--;
    }
}


i32 countDigits(i32 n) {
    /*
    Returns the number of digits
    of n
    */
    i32 result = 0;
    while (n) {
        n /= 10;
        result++;
    }
    return result;

}


void itoa(i32 n, char* a) {
    /*
    Converts the integer n to
    a string. The result is written
    to a, which is assumed to be large
    enough to accomodate an optional
    negative sign, the number itself
    and a null byte at the end (if the
    buffer is not large enough, the 
    behavior is undefined)
    */
    int i, sign;
    if ((sign = n) < 0) n = -n;
    i = countDigits(n);
    do {
        a[--i] = n % 10 + '0';
    } while ((n /= 10) > 0);

    if (sign < 0) a[--i] = '-';
    a[--i] = '\0';
}