misc.cpp

#include "misc.hpp"

size_t strlen(const char *str)
{
    size_t len = 0;
    while (str[len])
        ++len;
    return len;
}

void *memcpy(void *dest, const void *src, size_t n)
{
    char *d = (char*)dest;
    const char *s = (char*)src;

    while (n)
    {
        *d = *s;
        ++d;
        ++s;
        --n;
    }
    return dest;
}

void *memset(void *s, int c, size_t n)
{
    char *p = (char*)s;
    while (n)
    {
        *p++ = c;
        --n;
    }
    return s;
}

char *strcpy(char *dest, const char *src)
{
    size_t i;

    for (i = 0; src[i]; ++i)
        dest[i] = src[i];
    dest[i] = '\0';
    return dest;
}

char *strncpy(char *dest, const char *src, size_t n)
{
    size_t i;

    for (i = 0; i < n && src[i]; ++i)
        dest[i] = src[i];
    dest[i] = '\0';
    return dest;
}

int strcmp(const char *s1, const char *s2)
{
    while (*s1 && *s2 && *s1 == *s2)
    {
        ++s1;
        ++s2;
    }
    return *s2 - *s1;
}

char *strchr(const char *s, int c)
{
    while (*s)
    {
        if (c == *s)
            return (char*)s;
        ++s;
    }
    return 0;
}

u32 atoi(const char *s, u32 base)
{
    static u32 (*is_digit_base[]) (char) = {NULL, NULL, is_bdigit, NULL, NULL, NULL, NULL, NULL, is_odigit, NULL, is_digit, NULL, NULL, NULL, NULL, NULL, is_xdigit};
    u32 out = 0;

    while (is_digit_base[base](*s))
    {
        out = out * base + (to_lower(*s) - (is_lower(*s) ? 'a' - 10 : '0'));
        ++s;
    }
    return out;
}

u32 atoi(const char *s)
{
    u32 base = 10;

    if (s[0] == '0')
    {
        if (to_lower(s[1]) == 'x')
            base = 16;
        else if (to_lower(s[1]) == 'b')
            base = 2;
        else
            base = 8;
    }
    switch (base)
    {
        case 16:
        case 2:
            s += 1;
        case 8:
            s += 1;
        default: break;
    }
    return atoi(s, base);
}