matos/core/klibc.c

#include "klibc.h"

void *memcpy(void *dst, const void *src, size_t n)
{
        char *dstChar       = dst;
        const char *srcChar = src;
        for (size_t i = 0; i < n; i++) {
                *(dstChar++) = *(srcChar++);
        }
        return dst;
}

void *memset(void *src, int c, size_t n)
{
        for (char *ptr = (char *)src; n > 0; n--, ptr++) {
                *ptr = (char)c;
        }
        return src;
}

char * itoa( int value, char * str, int base )
{
    char * rc;
    char * ptr;
    char * low;
    // Check for supported base.
    if ( base < 2 || base > 36 )
    {
        *str = '\0';
        return str;
    }
    rc = ptr = str;
    // Set '-' for negative decimals.
    if ( value < 0 && base == 10 )
    {
        *ptr++ = '-';
    }
    // Remember where the numbers start.
    low = ptr;
    // The actual conversion.
    do
    {
        // Modulo is negative for negative value. This trick makes abs() unnecessary.
        *ptr++ = "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz"[35 + value % base];
        value /= base;
    } while ( value );
    // Terminating the string.
    *ptr-- = '\0';
    // Invert the numbers.
    while ( low < ptr )
    {
        char tmp = *low;
        *low++ = *ptr;
        *ptr-- = tmp;
    }
    return rc;
}

/* K&R */
void reverse(char s[])
{
    int c, i, j;
    for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
        c    = s[i];
        s[i] = s[j];
        s[j] = c;
    }
}

/* K&R */
int strlen(char s[])
{
    int i = 0;
    while (s[i] != '\0')
        ++i;
    return i;
}

/* K&R
 * Returns <0 if s1<s2, 0 if s1==s2, >0 if s1>s2 */
int strcmp(char s1[], char s2[])
{
    int i;
    for (i = 0; s1[i] == s2[i]; i++) {
        if (s1[i] == '\0')
            return 0;
    }
    return s1[i] - s2[i];
}