/* 
 core_esp8266_noniso.c - nonstandard (but usefull) conversion functions

 Copyright (c) 2014 Ivan Grokhotkov. All rights reserved.
 This file is part of the esp8266 core for Arduino environment.
 
 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License as published by the Free Software Foundation; either
 version 2.1 of the License, or (at your option) any later version.

 This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public
 License along with this library; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 Modified 03 April 2015 by Markus Sattler

 */

#include <stdlib.h>
#include "stdlib_noniso.h"
#include "ets_sys.h"

#define sprintf ets_sprintf
#define strcpy ets_strcpy

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);
}

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

    char* out = result;
    int quotient = abs(value);

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

    // Apply negative sign
    if(value < 0)
        *out++ = '-';

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

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

    char* out = result;
    long quotient = abs(value);

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

    // Apply negative sign
    if(value < 0)
        *out++ = '-';

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

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

    char* out = result;
    unsigned long quotient = value;

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

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

char * dtostrf(double number, signed char width, unsigned char prec, char *s) {

    if(isnan(number)) {
        strcpy(s, "nan");
        return s;
    }
    if(isinf(number)) {
        strcpy(s, "inf");
        return s;
    }

    if(number > 4294967040.0 || number < -4294967040.0) {
        strcpy(s, "ovf");
        return s;
    }
    char* out = s;
    // Handle negative numbers
    if(number < 0.0) {
        *out = '-';
        ++out;
        number = -number;
    }

    // Round correctly so that print(1.999, 2) prints as "2.00"
    double rounding = 0.5;
    for(uint8_t i = 0; i < prec; ++i)
        rounding /= 10.0;

    number += rounding;

    // Extract the integer part of the number and print it
    unsigned long int_part = (unsigned long) number;
    double remainder = number - (double) int_part;
    out += sprintf(out, "%ld", int_part);

    // Print the decimal point, but only if there are digits beyond
    if(prec > 0) {
        *out = '.';
        ++out;
    }

    for (unsigned char decShift = prec; decShift > 0; decShift--) {
        remainder *= 10.0;
    }
    sprintf(out, "%0*d", prec, (int)remainder);

    return s;
}