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/** @file
* @brief Parse signed and unsigned type from string and check for trailing characters.
*/
/* Copyright (C) 2019 Olly Betts
* Copyright (C) 2019 Vaibhav Kansagara
*
* This program 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 of the License, or
* (at your option) any later version.
*
* This program 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 St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef XAPIAN_INCLUDED_PARSEINT_H
#define XAPIAN_INCLUDED_PARSEINT_H
#include "overflow.h"
#include <limits>
template<typename T>
bool parse_unsigned(const char* p, T& res)
{
res = 0;
do {
unsigned char digit = *p - '0';
if (digit > 9 ||
mul_overflows(res, unsigned(10), res) ||
add_overflows(res, digit, res)) {
return false;
}
} while (*++p);
return true;
}
template<typename T>
bool parse_signed(const char* p, T& res)
{
typedef typename std::make_unsigned<T>::type unsigned_type;
unsigned_type temp = 0;
if (*p == '-' && parse_unsigned(++p, temp) &&
// casting the min signed value to unsigned gives us its absolute value.
temp <= unsigned_type(std::numeric_limits<T>::min())) {
res = -temp;
return true;
} else if (parse_unsigned(p, temp) &&
temp <= unsigned_type(std::numeric_limits<T>::max())) {
res = temp;
return true;
}
return false;
}
#endif
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