match.h

/*
Copyright 2013-present Barefoot Networks, Inc.
 
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.
*/
 
#ifndef LIB_MATCH_H_
#define LIB_MATCH_H_
 
#include <stdint.h>
 
#include <iostream>
 
#include "big_int_util.h"
 
struct match_t {
    big_int word0, word1;
    match_t() : word0(0), word1(0) {}
    match_t(big_int w0, big_int w1) : word0(w0), word1(w1) {}
    explicit operator bool() const { return (word0 | word1) != 0; }
    bool operator==(const match_t &a) const { return word0 == a.word0 && word1 == a.word1; }
    bool operator!=(const match_t &a) const { return word0 != a.word0 || word1 != a.word1; }
    bool matches(big_int v) const {
        return (v | word1) == word1 && ((~v & word1) | word0) == word0;
    }
    void setwidth(int bits) {
        big_int mask = (big_int(1) << bits) - 1;
        word0 &= mask;
        word1 &= mask;
        mask &= ~(word0 | word1);
        word0 |= mask;
        word1 |= mask;
    }
    match_t(int size, big_int val, big_int mask) : word0(~val & mask), word1(val & mask) {
        setwidth(size);
    }
    static match_t dont_care(int size) { return match_t(size, 0, 0); }
};
 
std::ostream &operator<<(std::ostream &, const match_t &);
bool operator>>(const char *, match_t &);
 
#endif /* LIB_MATCH_H_ */