calamares/src/libcalamares/utils/NamedSuffix.h

109 lines
3.2 KiB
C
Raw Normal View History

/* === This file is part of Calamares - <https://github.com/calamares> ===
*
* Copyright 2019, Adriaan de Groot <groot@kde.org>
*
* Calamares 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 3 of the License, or
* (at your option) any later version.
*
* Calamares 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 Calamares. If not, see <http://www.gnu.org/licenses/>.
*/
/** @brief Support for unit-suffixed values.
*
* This combines a value with an (enum) unit indicating what kind
* of value it is, e.g. 10 meters, or 64 pixels. Includes simple
* parsing support for the values written as strings like <value><unit>,
* e.g. "10m" or "64px".
*
* When a suffixed unit value needs validation, define an isValid()
* method; similarly for simple construction from a string (with a fixed
* table of suffixes). Typical use then looks like:
*
* class MyUnit : public NamedSuffix<MyUnitEnum, MyUnitEnum::None>
* {
* public:
* using NamedSuffix::NamedSuffix; // Keep existing constructors
* MyUnit( const QString& s );
* bool isValid() const;
* } ;
*/
#ifndef LIBCALAMARES_NAMEDSUFFIX_H
#define LIBCALAMARES_NAMEDSUFFIX_H
#include "NamedEnum.h"
/** @brief Template that takes the enum type to work with and a special none-enum. */
template<typename T, T _none>
class NamedSuffix
{
public:
using unit_t = T;
static constexpr unit_t none = _none;
/** @brief Empty value. */
NamedSuffix()
: m_value(0)
, m_unit( none )
{
}
/** @brief Specific value and unit. */
NamedSuffix( int value, unit_t unit )
: m_value( value )
, m_unit( unit )
{
}
/** @brief Construct value and unit from string.
*
* This parses the given string @p s by comparing with the suffixes
* in @p table and uses the first matching suffix as the unit.
*/
NamedSuffix( const NamedEnumTable<T>& table, const QString& s )
: NamedSuffix()
{
for( const auto suffix : table.table )
if ( s.endsWith( suffix.first ) )
{
m_value = s.left( s.length() - suffix.first.length() + 1 ).toInt();
m_unit = suffix.second;
break;
}
}
/** @brief Construct value from string.
*
* This is not defined in the template, because it should probably
* delegate to the constructor above with a fixed table.
*/
NamedSuffix( const QString& s );
int value() const { return m_value; }
unit_t unit() const { return m_unit; }
/** @brief Check that a value-unit combination is valid.
*
* This is not defined in the template, because validity (e.g.
* range of acceptable values) depends on the kind of unit.
*/
bool isValid() const;
protected:
int m_value;
unit_t m_unit;
};
#endif