/* -*- 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
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#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 */
