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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#ifndef frontend_BytecodeOffset_h
#define frontend_BytecodeOffset_h
#include "mozilla/Assertions.h" // MOZ_ASSERT
#include "mozilla/CheckedInt.h" // mozilla::CheckedInt
#include <stddef.h> // ptrdiff_t
namespace js {
namespace frontend {
class BytecodeOffsetDiff;
// The offset inside bytecode.
class BytecodeOffset {
private:
static const ptrdiff_t INVALID_OFFSET = -1;
ptrdiff_t value_ = 0;
struct Invalid {};
explicit constexpr BytecodeOffset(Invalid) : value_(INVALID_OFFSET) {}
public:
constexpr BytecodeOffset() = default;
explicit BytecodeOffset(ptrdiff_t value) : value_(value) {
MOZ_ASSERT(value >= 0);
}
static constexpr BytecodeOffset invalidOffset() {
return BytecodeOffset(Invalid());
}
bool operator==(const BytecodeOffset& rhs) const {
return value_ == rhs.value_;
}
bool operator!=(const BytecodeOffset& rhs) const { return !(*this == rhs); }
inline BytecodeOffsetDiff operator-(const BytecodeOffset& rhs) const;
inline BytecodeOffset operator+(const BytecodeOffsetDiff& diff) const;
inline BytecodeOffset& operator+=(const BytecodeOffsetDiff& diff);
inline BytecodeOffset& operator-=(const BytecodeOffsetDiff& diff);
bool operator<(const BytecodeOffset& rhs) const {
MOZ_ASSERT(valid());
MOZ_ASSERT(rhs.valid());
return value_ < rhs.value_;
}
bool operator<=(const BytecodeOffset& rhs) const {
MOZ_ASSERT(valid());
MOZ_ASSERT(rhs.valid());
return value_ <= rhs.value_;
}
bool operator>(const BytecodeOffset& rhs) const {
MOZ_ASSERT(valid());
MOZ_ASSERT(rhs.valid());
return value_ > rhs.value_;
}
bool operator>=(const BytecodeOffset& rhs) const {
MOZ_ASSERT(valid());
MOZ_ASSERT(rhs.valid());
return value_ >= rhs.value_;
}
ptrdiff_t value() const { return value_; }
uint32_t toUint32() const {
MOZ_ASSERT(size_t(uint32_t(value_)) == size_t(value_));
return uint32_t(value_);
}
bool valid() const { return value_ != INVALID_OFFSET; }
};
class BytecodeOffsetDiff {
private:
friend class BytecodeOffset;
ptrdiff_t value_ = 0;
public:
constexpr BytecodeOffsetDiff() = default;
explicit constexpr BytecodeOffsetDiff(ptrdiff_t value_) : value_(value_) {}
bool operator==(const BytecodeOffsetDiff& rhs) const {
return value_ == rhs.value_;
}
bool operator!=(const BytecodeOffsetDiff& rhs) const {
return !(*this == rhs);
}
BytecodeOffsetDiff operator+(const BytecodeOffsetDiff& rhs) const {
mozilla::CheckedInt<ptrdiff_t> result = value_;
result += rhs.value_;
return BytecodeOffsetDiff(result.value());
}
ptrdiff_t value() const { return value_; }
uint32_t toUint32() const {
MOZ_ASSERT(size_t(uint32_t(value_)) == size_t(value_));
return uint32_t(value_);
}
};
inline BytecodeOffsetDiff BytecodeOffset::operator-(
const BytecodeOffset& rhs) const {
MOZ_ASSERT(valid());
MOZ_ASSERT(rhs.valid());
mozilla::CheckedInt<ptrdiff_t> result = value_;
result -= rhs.value_;
return BytecodeOffsetDiff(result.value());
}
inline BytecodeOffset BytecodeOffset::operator+(
const BytecodeOffsetDiff& diff) const {
MOZ_ASSERT(valid());
mozilla::CheckedInt<ptrdiff_t> result = value_;
result += diff.value_;
return BytecodeOffset(result.value());
}
inline BytecodeOffset& BytecodeOffset::operator+=(
const BytecodeOffsetDiff& diff) {
MOZ_ASSERT(valid());
mozilla::CheckedInt<ptrdiff_t> result = value_;
result += diff.value_;
value_ = result.value();
return *this;
}
inline BytecodeOffset& BytecodeOffset::operator-=(
const BytecodeOffsetDiff& diff) {
MOZ_ASSERT(valid());
mozilla::CheckedInt<ptrdiff_t> result = value_;
result -= diff.value_;
value_ = result.value();
return *this;
}
} /* namespace frontend */
} /* namespace js */
#endif /* frontend_BytecodeOffset_h */