libcruft-util/parse.cpp

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/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2017 Danny Robson <danny@nerdcruft.net>
*/
#include "parse.hpp"
#include "cast.hpp"
#include <cstdlib>
#include <stdexcept>
using util::parse;
///////////////////////////////////////////////////////////////////////////////
template <typename T> struct c_traits;
template <> struct c_traits<long> { static constexpr auto func = strtol; };
template <> struct c_traits<long long> { static constexpr auto func = strtoll; };
template <> struct c_traits<unsigned long> { static constexpr auto func = strtoul; };
template <> struct c_traits<unsigned long long> { static constexpr auto func = strtoull; };
template <> struct c_traits<float> { static constexpr auto func = strtof; };
template <> struct c_traits<double> { static constexpr auto func = strtod; };
template <> struct c_traits<long double> { static constexpr auto func = strtold; };
//-----------------------------------------------------------------------------
template <typename T>
T
c_iparse (const char *first, const char *last)
{
auto tail = const_cast<char *> (last);
auto val = c_traits<T>::func (first, &tail, 0);
if (tail != last)
throw std::invalid_argument ("unable to parse");
return val;
}
//-----------------------------------------------------------------------------
template <typename T>
T
c_fparse (const char *first, const char *last)
{
auto tail = const_cast<char *> (last);
auto val = c_traits<T>::func (first, &tail);
if (tail != last)
throw std::invalid_argument ("unable to parse");
return val;
}
///////////////////////////////////////////////////////////////////////////////
#define C_PARSE(T, KLASS) \
template <> \
T \
util::parse<T> (util::view<const char *> str) \
{ \
return c_ ## KLASS ## parse<T> (std::cbegin (str), std::cend (str)); \
}
//-----------------------------------------------------------------------------
C_PARSE(long, i)
C_PARSE(long long, i)
C_PARSE(unsigned long, i)
C_PARSE(unsigned long long, i)
C_PARSE(float, f)
C_PARSE(double, f)
C_PARSE(long double, f)
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template <>
int
util::parse<int> (util::view<const char*> str)
{
auto intermediate = util::parse<long> (str);
return util::cast::lossless<int> (intermediate);
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}
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template <>
unsigned
util::parse<unsigned> (util::view<const char*> str)
{
return util::cast::narrow<unsigned> (parse<unsigned long> (str));
}
template <>
unsigned short
util::parse<unsigned short> (util::view<const char*> str)
{
return util::cast::narrow<unsigned short> (parse<unsigned long> (str));
}