/* This file is part of Libspectre.

 *

 * Copyright (C) 2007, 2012 Albert Astals Cid <aacid@kde.org>

 * Copyright (C) 2007 Carlos Garcia Campos <carlosgc@gnome.org>

 *

 * Libspectre is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2, or (at your option)

 * any later version.

 *

 * Libspectre 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

 */

/* This function comes from spectre-utils from libspectre */

#include "gstrtod.h"

#include <clocale>

#include <cerrno>

#include <cstdlib>

#include <cstring>

#define ascii_isspace(c) ((c) == ' ' || (c) == '\f' || (c) == '\n' || (c) == '\r' || (c) == '\t' || (c) == '\v')

#define ascii_isdigit(c) ((c) >= '0' && (c) <= '9')

double gatof(const char *nptr)

{

    return gstrtod(nptr, nullptr);

}

double gstrtod(const char *nptr, char **endptr)

{

    char *fail_pos;

    double val;

    struct lconv *locale_data;

    const char *decimal_point;

    int decimal_point_len;

    const char *p, *decimal_point_pos;

    const char *end = nullptr; /* Silence gcc */

    int strtod_errno;

    fail_pos = nullptr;

    locale_data = localeconv();

    decimal_point = locale_data->decimal_point;

    decimal_point_len = strlen(decimal_point);

    decimal_point_pos = nullptr;

    end = nullptr;

    if (decimal_point[0] != '.' || decimal_point[1] != 0) {

        p = nptr;

        /* Skip leading space */

        while (ascii_isspace(*p)) {

            p++;

        }

        /* Skip leading optional sign */

        if (*p == '+' || *p == '-') {

            p++;

        }

        if (ascii_isdigit(*p) || *p == '.') {

            while (ascii_isdigit(*p)) {

                p++;

            }

            if (*p == '.') {

                decimal_point_pos = p++;

            }

            while (ascii_isdigit(*p)) {

                p++;

            }

            if (*p == 'e' || *p == 'E') {

                p++;

            }

            if (*p == '+' || *p == '-') {

                p++;

            }

            while (ascii_isdigit(*p)) {

                p++;

            }

            end = p;

        }

        /* For the other cases, we need not convert the decimal point */

    }

    if (decimal_point_pos) {

        char *copy, *c;

        /* We need to convert the '.' to the locale specific decimal point */

        copy = (char *)malloc(end - nptr + 1 + decimal_point_len);

        c = copy;

        memcpy(c, nptr, decimal_point_pos - nptr);

        c += decimal_point_pos - nptr;

        memcpy(c, decimal_point, decimal_point_len);

        c += decimal_point_len;

        memcpy(c, decimal_point_pos + 1, end - (decimal_point_pos + 1));

        c += end - (decimal_point_pos + 1);

        *c = 0;

        errno = 0;

        val = strtod(copy, &fail_pos);

        strtod_errno = errno;

        if (fail_pos) {

            if (fail_pos - copy > decimal_point_pos - nptr) {

                fail_pos = (char *)nptr + (fail_pos - copy) - (decimal_point_len - 1);

            } else {

                fail_pos = (char *)nptr + (fail_pos - copy);

            }

        }

        free(copy);

    } else if (end) {

        char *copy;

        copy = (char *)malloc(end - (char *)nptr + 1);

        memcpy(copy, nptr, end - nptr);

        *(copy + (end - (char *)nptr)) = 0;

        errno = 0;

        val = strtod(copy, &fail_pos);

        strtod_errno = errno;

        if (fail_pos) {

            fail_pos = (char *)nptr + (fail_pos - copy);

        }

        free(copy);

    } else {

        errno = 0;

        val = strtod(nptr, &fail_pos);

        strtod_errno = errno;

    }

    if (endptr) {

        *endptr = fail_pos;

    }

    errno = strtod_errno;

    return val;

}