//===--- CharUnits.h - Character units for sizes and offsets ----*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines the CharUnits class
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_AST_CHARUNITS_H
#define LLVM_CLANG_AST_CHARUNITS_H
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/Support/Alignment.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/MathExtras.h"
namespace clang {
/// CharUnits - This is an opaque type for sizes expressed in character units.
/// Instances of this type represent a quantity as a multiple of the size
/// of the standard C type, char, on the target architecture. As an opaque
/// type, CharUnits protects you from accidentally combining operations on
/// quantities in bit units and character units.
///
/// In both C and C++, an object of type 'char', 'signed char', or 'unsigned
/// char' occupies exactly one byte, so 'character unit' and 'byte' refer to
/// the same quantity of storage. However, we use the term 'character unit'
/// rather than 'byte' to avoid an implication that a character unit is
/// exactly 8 bits.
///
/// For portability, never assume that a target character is 8 bits wide. Use
/// CharUnit values wherever you calculate sizes, offsets, or alignments
/// in character units.
class CharUnits {
public:
typedef int64_t QuantityType;
private:
QuantityType Quantity = 0;
explicit CharUnits(QuantityType C) : Quantity(C) {}
public:
/// CharUnits - A default constructor.
CharUnits() = default;
/// Zero - Construct a CharUnits quantity of zero.
static CharUnits Zero() {
return CharUnits(0);
}
/// One - Construct a CharUnits quantity of one.
static CharUnits One() {
return CharUnits(1);
}
/// fromQuantity - Construct a CharUnits quantity from a raw integer type.
static CharUnits fromQuantity(QuantityType Quantity) {
return CharUnits(Quantity);
}
/// fromQuantity - Construct a CharUnits quantity from an llvm::Align
/// quantity.
static CharUnits fromQuantity(llvm::Align Quantity) {
return CharUnits(Quantity.value());
}
// Compound assignment.
CharUnits& operator+= (const CharUnits &Other) {
Quantity += Other.Quantity;
return *this;
}
CharUnits& operator++ () {
++Quantity;
return *this;
}
CharUnits operator++ (int) {
return CharUnits(Quantity++);
}
CharUnits& operator-= (const CharUnits &Other) {
Quantity -= Other.Quantity;
return *this;
}
CharUnits& operator-- () {
--Quantity;
return *this;
}
CharUnits operator-- (int) {
return CharUnits(Quantity--);
}
// Comparison operators.
bool operator== (const CharUnits &Other) const {
return Quantity == Other.Quantity;
}
bool operator!= (const CharUnits &Other) const {
return Quantity != Other.Quantity;
}
// Relational operators.
bool operator< (const CharUnits &Other) const {
return Quantity < Other.Quantity;
}
bool operator<= (const CharUnits &Other) const {
return Quantity <= Other.Quantity;
}
bool operator> (const CharUnits &Other) const {
return Quantity > Other.Quantity;
}
bool operator>= (const CharUnits &Other) const {
return Quantity >= Other.Quantity;
}
// Other predicates.
/// isZero - Test whether the quantity equals zero.
bool isZero() const { return Quantity == 0; }
/// isOne - Test whether the quantity equals one.
bool isOne() const { return Quantity == 1; }
/// isPositive - Test whether the quantity is greater than zero.
bool isPositive() const { return Quantity > 0; }
/// isNegative - Test whether the quantity is less than zero.
bool isNegative() const { return Quantity < 0; }
/// isPowerOfTwo - Test whether the quantity is a power of two.
/// Zero is not a power of two.
bool isPowerOfTwo() const {
return (Quantity & -Quantity) == Quantity;
}
/// Test whether this is a multiple of the other value.
///
/// Among other things, this promises that
/// self.alignTo(N) will just return self.
bool isMultipleOf(CharUnits N) const {
return (*this % N) == 0;
}
// Arithmetic operators.
CharUnits operator* (QuantityType N) const {
return CharUnits(Quantity * N);
}
CharUnits &operator*= (QuantityType N) {
Quantity *= N;
return *this;
}
CharUnits operator/ (QuantityType N) const {
return CharUnits(Quantity / N);
}
CharUnits &operator/= (QuantityType N) {
Quantity /= N;
return *this;
}
QuantityType operator/ (const CharUnits &Other) const {
return Quantity / Other.Quantity;
}
CharUnits operator% (QuantityType N) const {
return CharUnits(Quantity % N);
}
QuantityType operator% (const CharUnits &Other) const {
return Quantity % Other.Quantity;
}
CharUnits operator+ (const CharUnits &Other) const {
return CharUnits(Quantity + Other.Quantity);
}
CharUnits operator- (const CharUnits &Other) const {
return CharUnits(Quantity - Other.Quantity);
}
CharUnits operator- () const {
return CharUnits(-Quantity);
}
// Conversions.
/// getQuantity - Get the raw integer representation of this quantity.
QuantityType getQuantity() const { return Quantity; }
/// getAsAlign - Returns Quantity as a valid llvm::Align,
/// Beware llvm::Align assumes power of two 8-bit bytes.
llvm::Align getAsAlign() const { return llvm::Align(Quantity); }
/// getAsMaybeAlign - Returns Quantity as a valid llvm::Align or
/// std::nullopt, Beware llvm::MaybeAlign assumes power of two 8-bit
/// bytes.
llvm::MaybeAlign getAsMaybeAlign() const {
return llvm::MaybeAlign(Quantity);
}
/// alignTo - Returns the next integer (mod 2**64) that is
/// greater than or equal to this quantity and is a multiple of \p Align.
/// Align must be non-zero.
CharUnits alignTo(const CharUnits &Align) const {
return CharUnits(llvm::alignTo(Quantity, Align.Quantity));
}
/// Given that this is a non-zero alignment value, what is the
/// alignment at the given offset?
CharUnits alignmentAtOffset(CharUnits offset) const {
assert(Quantity != 0 && "offsetting from unknown alignment?");
return CharUnits(llvm::MinAlign(Quantity, offset.Quantity));
}
/// Given that this is the alignment of the first element of an
/// array, return the minimum alignment of any element in the array.
CharUnits alignmentOfArrayElement(CharUnits elementSize) const {
// Since we don't track offsetted alignments, the alignment of
// the second element (or any odd element) will be minimally
// aligned.
return alignmentAtOffset(elementSize);
}
}; // class CharUnit
} // namespace clang
inline clang::CharUnits operator* (clang::CharUnits::QuantityType Scale,
const clang::CharUnits &CU) {
return CU * Scale;
}
namespace llvm {
template<> struct DenseMapInfo<clang::CharUnits> {
static clang::CharUnits getEmptyKey() {
clang::CharUnits::QuantityType Quantity =
DenseMapInfo<clang::CharUnits::QuantityType>::getEmptyKey();
return clang::CharUnits::fromQuantity(Quantity);
}
static clang::CharUnits getTombstoneKey() {
clang::CharUnits::QuantityType Quantity =
DenseMapInfo<clang::CharUnits::QuantityType>::getTombstoneKey();
return clang::CharUnits::fromQuantity(Quantity);
}
static unsigned getHashValue(const clang::CharUnits &CU) {
clang::CharUnits::QuantityType Quantity = CU.getQuantity();
return DenseMapInfo<clang::CharUnits::QuantityType>::getHashValue(Quantity);
}
static bool isEqual(const clang::CharUnits &LHS,
const clang::CharUnits &RHS) {
return LHS == RHS;
}
};
} // end namespace llvm
#endif // LLVM_CLANG_AST_CHARUNITS_H