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//===--- ArrayRef.h - Array Reference Wrapper -------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_ARRAYREF_H
#define LLVM_ADT_ARRAYREF_H
#include "llvm/ADT/SmallVector.h"
#include <vector>
namespace llvm {
class APInt;
/// ArrayRef - Represent a constant reference to an array (0 or more elements
/// consecutively in memory), i.e. a start pointer and a length. It allows
/// various APIs to take consecutive elements easily and conveniently.
///
/// This class does not own the underlying data, it is expected to be used in
/// situations where the data resides in some other buffer, whose lifetime
/// extends past that of the ArrayRef. For this reason, it is not in general
/// safe to store an ArrayRef.
///
/// This is intended to be trivially copyable, so it should be passed by
/// value.
template<typename T>
class ArrayRef {
public:
typedef const T *iterator;
typedef const T *const_iterator;
typedef size_t size_type;
private:
/// The start of the array, in an external buffer.
const T *Data;
/// The number of elements.
size_type Length;
public:
/// @name Constructors
/// @{
/// Construct an empty ArrayRef.
/*implicit*/ ArrayRef() : Data(0), Length(0) {}
/// Construct an ArrayRef from a single element.
/*implicit*/ ArrayRef(const T &OneElt)
: Data(&OneElt), Length(1) {}
/// Construct an ArrayRef from a pointer and length.
/*implicit*/ ArrayRef(const T *data, size_t length)
: Data(data), Length(length) {}
/// Construct an ArrayRef from a range.
ArrayRef(const T *begin, const T *end)
: Data(begin), Length(end - begin) {}
/// Construct an ArrayRef from a SmallVector.
/*implicit*/ ArrayRef(const SmallVectorImpl<T> &Vec)
: Data(Vec.data()), Length(Vec.size()) {}
/// Construct an ArrayRef from a std::vector.
/*implicit*/ ArrayRef(const std::vector<T> &Vec)
: Data(Vec.empty() ? (T*)0 : &Vec[0]), Length(Vec.size()) {}
/// Construct an ArrayRef from a C array.
template <size_t N>
/*implicit*/ ArrayRef(const T (&Arr)[N])
: Data(Arr), Length(N) {}
/// @}
/// @name Simple Operations
/// @{
iterator begin() const { return Data; }
iterator end() const { return Data + Length; }
/// empty - Check if the array is empty.
bool empty() const { return Length == 0; }
const T *data() const { return Data; }
/// size - Get the array size.
size_t size() const { return Length; }
/// front - Get the first element.
const T &front() const {
assert(!empty());
return Data[0];
}
/// back - Get the last element.
const T &back() const {
assert(!empty());
return Data[Length-1];
}
/// equals - Check for element-wise equality.
bool equals(ArrayRef RHS) const {
if (Length != RHS.Length)
return false;
for (size_type i = 0; i != Length; i++)
if (Data[i] != RHS.Data[i])
return false;
return true;
}
/// slice(n) - Chop off the first N elements of the array.
ArrayRef<T> slice(unsigned N) {
assert(N <= size() && "Invalid specifier");
return ArrayRef<T>(data()+N, size()-N);
}
/// slice(n, m) - Chop off the first N elements of the array, and keep M
/// elements in the array.
ArrayRef<T> slice(unsigned N, unsigned M) {
assert(N+M <= size() && "Invalid specifier");
return ArrayRef<T>(data()+N, M);
}
/// @}
/// @name Operator Overloads
/// @{
const T &operator[](size_t Index) const {
assert(Index < Length && "Invalid index!");
return Data[Index];
}
/// @}
/// @name Expensive Operations
/// @{
std::vector<T> vec() const {
return std::vector<T>(Data, Data+Length);
}
/// @}
/// @name Conversion operators
/// @{
operator std::vector<T>() const {
return std::vector<T>(Data, Data+Length);
}
/// @}
};
/// @name ArrayRef Comparison Operators
/// @{
template<typename T>
inline bool operator==(ArrayRef<T> LHS, ArrayRef<T> RHS) {
return LHS.equals(RHS);
}
template<typename T>
inline bool operator!=(ArrayRef<T> LHS, ArrayRef<T> RHS) {
return !(LHS == RHS);
}
/// @}
// ArrayRefs can be treated like a POD type.
template <typename T> struct isPodLike;
template <typename T> struct isPodLike<ArrayRef<T> > {
static const bool value = true;
};
}
#endif
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