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z3/lib/expr_offset.h
Leonardo de Moura e9eab22e5c Z3 sources
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2012-10-02 11:35:25 -07:00

54 lines
1.4 KiB
C++

/*++
Copyright (c) 2006 Microsoft Corporation
Module Name:
expr_offset.h
Abstract:
Expressions + Offsets.
In order to avoid creating variants of terms, we use a pair (expression, offset),
where offset is just a small integer.
Non ground terms with different offsets are always considered
disequal. For example, (f x):1 is different from (f x):2, and
(f x):1 is unifiable with x:2.
Author:
Leonardo de Moura (leonardo) 2008-01-28.
Revision History:
--*/
#ifndef _EXPR_OFFSET_H_
#define _EXPR_OFFSET_H_
#include"ast.h"
class expr_offset {
expr * m_expr;
unsigned m_offset;
public:
expr_offset():m_expr(0), m_offset(0) {}
expr_offset(expr * e, unsigned o):m_expr(e), m_offset(o) {}
expr * get_expr() const { return m_expr; }
unsigned get_offset() const { return m_offset; }
bool operator==(expr_offset const & other) const { return m_expr == other.m_expr && m_offset == other.m_offset; }
bool operator!=(expr_offset const & other) const { return !operator==(other); }
unsigned hash() const {
unsigned a = m_expr->get_id();
unsigned b = m_offset;
unsigned c = 17;
mix(a, b, c);
return c;
}
};
typedef std::pair<expr_offset, expr_offset> expr_offset_pair;
typedef pair_hash<obj_hash<expr_offset>, obj_hash<expr_offset> > expr_offset_pair_hash;
#endif /* _EXPR_OFFSET_H_ */