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/*
* Copyright (c) 2016-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under both the BSD-style license (found in the
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
* in the COPYING file in the root directory of this source tree).
*/
/**
* A subset of `folly/Range.h`.
* All code copied verbatiam modulo formatting
*/
#pragma once
#include "utils/Likely.h"
#include <cstddef>
#include <cstring>
#include <stdexcept>
#include <string>
#include <type_traits>
namespace pzstd {
namespace detail {
/*
*Use IsCharPointer<T>::type to enable const char* or char*.
*Use IsCharPointer<T>::const_type to enable only const char*.
*/
template <class T>
struct IsCharPointer {};
template <>
struct IsCharPointer<char*> {
typedef int type;
};
template <>
struct IsCharPointer<const char*> {
typedef int const_type;
typedef int type;
};
} // namespace detail
template <typename Iter>
class Range {
Iter b_;
Iter e_;
public:
using size_type = std::size_t;
using iterator = Iter;
using const_iterator = Iter;
using value_type = typename std::remove_reference<
typename std::iterator_traits<Iter>::reference>::type;
using reference = typename std::iterator_traits<Iter>::reference;
constexpr Range() : b_(), e_() {}
constexpr Range(Iter begin, Iter end) : b_(begin), e_(end) {}
constexpr Range(Iter begin, size_type size) : b_(begin), e_(begin + size) {}
template <class T = Iter, typename detail::IsCharPointer<T>::type = 0>
/* implicit */ Range(Iter str) : b_(str), e_(str + std::strlen(str)) {}
template <class T = Iter, typename detail::IsCharPointer<T>::const_type = 0>
/* implicit */ Range(const std::string& str)
: b_(str.data()), e_(b_ + str.size()) {}
// Allow implicit conversion from Range<From> to Range<To> if From is
// implicitly convertible to To.
template <
class OtherIter,
typename std::enable_if<
(!std::is_same<Iter, OtherIter>::value &&
std::is_convertible<OtherIter, Iter>::value),
int>::type = 0>
constexpr /* implicit */ Range(const Range<OtherIter>& other)
: b_(other.begin()), e_(other.end()) {}
Range(const Range&) = default;
Range(Range&&) = default;
Range& operator=(const Range&) & = default;
Range& operator=(Range&&) & = default;
constexpr size_type size() const {
return e_ - b_;
}
bool empty() const {
return b_ == e_;
}
Iter data() const {
return b_;
}
Iter begin() const {
return b_;
}
Iter end() const {
return e_;
}
void advance(size_type n) {
if (UNLIKELY(n > size())) {
throw std::out_of_range("index out of range");
}
b_ += n;
}
void subtract(size_type n) {
if (UNLIKELY(n > size())) {
throw std::out_of_range("index out of range");
}
e_ -= n;
}
Range subpiece(size_type first, size_type length = std::string::npos) const {
if (UNLIKELY(first > size())) {
throw std::out_of_range("index out of range");
}
return Range(b_ + first, std::min(length, size() - first));
}
};
using ByteRange = Range<const unsigned char*>;
using MutableByteRange = Range<unsigned char*>;
using StringPiece = Range<const char*>;
}
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