noniso.c

/*
 noniso.cpp - replacements for non-ISO functions used by Arduino core
 Copyright © 2016 Ivan Grokhotkov

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.
*/

#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <stdint.h>
#include <math.h>
#include "stdlib_noniso.h"

void reverse(char* begin, char* end)
{
    char* is = begin;
    char* ie = end - 1;
    while (is < ie)
    {
        char tmp = *ie;
        *ie      = *is;
        *is      = tmp;
        ++is;
        --ie;
    }
}

char* utoa(unsigned value, char* result, int base)
{
    if (base < 2 || base > 16)
    {
        *result = 0;
        return result;
    }

    char*    out      = result;
    unsigned quotient = value;

    do
    {
        const unsigned tmp = quotient / base;
        *out               = "0123456789abcdef"[quotient - (tmp * base)];
        ++out;
        quotient = tmp;
    } while (quotient);

    reverse(result, out);
    *out = 0;
    return result;
}

char* itoa(int value, char* result, int base)
{
    if (base < 2 || base > 16)
    {
        *result = 0;
        return result;
    }

    unsigned uvalue;
    char*    out = result;

    // after this point we convert the value to unsigned and go to the utoa
    // only base10 gets minus sign in the front, adhering to the newlib implementation
    if ((base == 10) && (value < 0))
    {
        *result++ = '-';
        uvalue    = (unsigned)-value;
    }
    else
    {
        uvalue = (unsigned)value;
    }

    utoa(uvalue, result, base);
    return out;
}

int atoi(const char* s)
{
    return (int)atol(s);
}

long atol(const char* s)
{
    char* tmp;
    return strtol(s, &tmp, 10);
}

double atof(const char* s)
{
    char* tmp;
    return strtod(s, &tmp);
}