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/* "True" vs "False" vs "Unknown".
Copyright (C) 2019-2020 Free Software Foundation, Inc.
Contributed by David Malcolm <dmalcolm@redhat.com>.
This file is part of GCC.
GCC 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, or (at your option)
any later version.
GCC 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 GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#ifndef GCC_TRISTATE_H
#define GCC_TRISTATE_H
/* "True" vs "False" vs "Unknown". */
class tristate {
public:
enum value {
TS_UNKNOWN,
TS_TRUE,
TS_FALSE
};
tristate (enum value val) : m_value (val) {}
tristate (bool val) : m_value (val ? TS_TRUE : TS_FALSE) {}
static tristate unknown () { return tristate (TS_UNKNOWN); }
const char *as_string () const;
bool is_known () const { return m_value != TS_UNKNOWN; }
bool is_true () const { return m_value == TS_TRUE; }
bool is_false () const { return m_value == TS_FALSE; }
tristate not_ () const;
tristate or_ (tristate other) const;
tristate and_ (tristate other) const;
bool operator== (const tristate &other) const
{
return m_value == other.m_value;
}
bool operator!= (const tristate &other) const
{
return m_value != other.m_value;
}
private:
enum value m_value;
};
/* Overloaded boolean operators on tristates. */
inline tristate
operator ! (tristate t)
{
return t.not_ ();
}
inline tristate
operator || (tristate a, tristate b)
{
return a.or_ (b);
}
inline tristate
operator && (tristate a, tristate b)
{
return a.and_ (b);
}
#endif /* GCC_TRISTATE_H */
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