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mysysy/antlr/antlr4-runtime-4.13.2/runtime/src/misc/Interval.h
2025-02-27 23:14:53 +08:00

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/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
* Use of this file is governed by the BSD 3-clause license that
* can be found in the LICENSE.txt file in the project root.
*/
#pragma once
#include "antlr4-common.h"
namespace antlr4 {
namespace misc {
// Helpers to convert certain unsigned symbols (e.g. Token::EOF) to their original numeric value (e.g. -1)
// and vice versa. This is needed mostly for intervals to keep their original order and for toString()
// methods to print the original numeric value (e.g. for tests).
constexpr size_t numericToSymbol(ssize_t v) { return static_cast<size_t>(v); }
constexpr ssize_t symbolToNumeric(size_t v) { return static_cast<ssize_t>(v); }
/// An immutable inclusive interval a..b
class ANTLR4CPP_PUBLIC Interval final {
public:
static const Interval INVALID;
// Must stay signed to guarantee the correct sort order.
ssize_t a;
ssize_t b;
constexpr Interval() : Interval(static_cast<ssize_t>(-1), static_cast<ssize_t>(-2)) {}
constexpr explicit Interval(size_t a_, size_t b_) : Interval(symbolToNumeric(a_), symbolToNumeric(b_)) {}
constexpr Interval(ssize_t a_, ssize_t b_) : a(a_), b(b_) {}
/// return number of elements between a and b inclusively. x..x is length 1.
/// if b < a, then length is 0. 9..10 has length 2.
constexpr size_t length() const { return b >= a ? static_cast<size_t>(b - a + 1) : 0; }
constexpr bool operator==(const Interval &other) const { return a == other.a && b == other.b; }
size_t hashCode() const;
/// <summary>
/// Does this start completely before other? Disjoint </summary>
bool startsBeforeDisjoint(const Interval &other) const;
/// <summary>
/// Does this start at or before other? Nondisjoint </summary>
bool startsBeforeNonDisjoint(const Interval &other) const;
/// <summary>
/// Does this.a start after other.b? May or may not be disjoint </summary>
bool startsAfter(const Interval &other) const;
/// <summary>
/// Does this start completely after other? Disjoint </summary>
bool startsAfterDisjoint(const Interval &other) const;
/// <summary>
/// Does this start after other? NonDisjoint </summary>
bool startsAfterNonDisjoint(const Interval &other) const;
/// <summary>
/// Are both ranges disjoint? I.e., no overlap? </summary>
bool disjoint(const Interval &other) const;
/// <summary>
/// Are two intervals adjacent such as 0..41 and 42..42? </summary>
bool adjacent(const Interval &other) const;
bool properlyContains(const Interval &other) const;
/// <summary>
/// Return the interval computed from combining this and other </summary>
Interval Union(const Interval &other) const;
/// <summary>
/// Return the interval in common between this and o </summary>
Interval intersection(const Interval &other) const;
std::string toString() const;
};
} // namespace atn
} // namespace antlr4