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/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ART_LIBARTBASE_BASE_STL_UTIL_H_
#define ART_LIBARTBASE_BASE_STL_UTIL_H_
#include <algorithm>
#include <iterator>
#include <set>
#include <sstream>
#include <android-base/logging.h>
#include "base/iteration_range.h"
namespace art {
// STLDeleteContainerPointers()
// For a range within a container of pointers, calls delete
// (non-array version) on these pointers.
// NOTE: for these three functions, we could just implement a DeleteObject
// functor and then call for_each() on the range and functor, but this
// requires us to pull in all of algorithm.h, which seems expensive.
// For hash_[multi]set, it is important that this deletes behind the iterator
// because the hash_set may call the hash function on the iterator when it is
// advanced, which could result in the hash function trying to deference a
// stale pointer.
template <class ForwardIterator>
void STLDeleteContainerPointers(ForwardIterator begin,
ForwardIterator end) {
while (begin != end) {
ForwardIterator temp = begin;
++begin;
delete *temp;
}
}
// STLDeleteElements() deletes all the elements in an STL container and clears
// the container. This function is suitable for use with a vector, set,
// hash_set, or any other STL container which defines sensible begin(), end(),
// and clear() methods.
//
// If container is null, this function is a no-op.
//
// As an alternative to calling STLDeleteElements() directly, consider
// using a container of std::unique_ptr, which ensures that your container's
// elements are deleted when the container goes out of scope.
template <class T>
void STLDeleteElements(T *container) {
if (container != nullptr) {
STLDeleteContainerPointers(container->begin(), container->end());
container->clear();
}
}
// Given an STL container consisting of (key, value) pairs, STLDeleteValues
// deletes all the "value" components and clears the container. Does nothing
// in the case it's given a null pointer.
template <class T>
void STLDeleteValues(T *v) {
if (v != nullptr) {
for (typename T::iterator i = v->begin(); i != v->end(); ++i) {
delete i->second;
}
v->clear();
}
}
// Deleter using free() for use with std::unique_ptr<>. See also UniqueCPtr<> below.
struct FreeDelete {
// NOTE: Deleting a const object is valid but free() takes a non-const pointer.
void operator()(const void* ptr) const {
free(const_cast<void*>(ptr));
}
};
// Alias for std::unique_ptr<> that uses the C function free() to delete objects.
template <typename T>
using UniqueCPtr = std::unique_ptr<T, FreeDelete>;
// Find index of the first element with the specified value known to be in the container.
template <typename Container, typename T>
size_t IndexOfElement(const Container& container, const T& value) {
auto it = std::find(container.begin(), container.end(), value);
DCHECK(it != container.end()); // Must exist.
return std::distance(container.begin(), it);
}
// Remove the first element with the specified value known to be in the container.
template <typename Container, typename T>
void RemoveElement(Container& container, const T& value) {
auto it = std::find(container.begin(), container.end(), value);
DCHECK(it != container.end()); // Must exist.
container.erase(it);
}
// Replace the first element with the specified old_value known to be in the container.
template <typename Container, typename T>
void ReplaceElement(Container& container, const T& old_value, const T& new_value) {
auto it = std::find(container.begin(), container.end(), old_value);
DCHECK(it != container.end()); // Must exist.
*it = new_value;
}
// Search for an element with the specified value and return true if it was found, false otherwise.
template <typename Container, typename T>
bool ContainsElement(const Container& container, const T& value, size_t start_pos = 0u) {
DCHECK_LE(start_pos, container.size());
auto start = container.begin();
std::advance(start, start_pos);
auto it = std::find(start, container.end(), value);
return it != container.end();
}
template <typename T>
bool ContainsElement(const std::set<T>& container, const T& value) {
return container.count(value) != 0u;
}
// 32-bit FNV-1a hash function suitable for std::unordered_map.
// It can be used with any container which works with range-based for loop.
// See http://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function
template <typename Vector>
struct FNVHash {
size_t operator()(const Vector& vector) const {
uint32_t hash = 2166136261u;
for (const auto& value : vector) {
hash = (hash ^ value) * 16777619u;
}
return hash;
}
};
// Returns a copy of the passed vector that doesn't memory-own its entries.
template <typename T>
static inline std::vector<T*> MakeNonOwningPointerVector(const std::vector<std::unique_ptr<T>>& src) {
std::vector<T*> result;
result.reserve(src.size());
for (const std::unique_ptr<T>& t : src) {
result.push_back(t.get());
}
return result;
}
template <typename IterLeft, typename IterRight>
class ZipLeftIter {
public:
using iterator_category = std::forward_iterator_tag;
using value_type = std::pair<typename IterLeft::value_type, typename IterRight::value_type>;
using difference_type = std::ptrdiff_t;
using pointer = std::pair<typename IterLeft::value_type, typename IterRight::value_type>*;
using reference = std::pair<typename IterLeft::value_type, typename IterRight::value_type>&;
ZipLeftIter(IterLeft left, IterRight right) : left_iter_(left), right_iter_(right) {}
ZipLeftIter<IterLeft, IterRight>& operator++() {
++left_iter_;
++right_iter_;
return *this;
}
ZipLeftIter<IterLeft, IterRight> operator++(int) {
ZipLeftIter<IterLeft, IterRight> ret(left_iter_, right_iter_);
++(*this);
return ret;
}
bool operator==(const ZipLeftIter<IterLeft, IterRight>& other) const {
return left_iter_ == other.left_iter_;
}
bool operator!=(const ZipLeftIter<IterLeft, IterRight>& other) const {
return !(*this == other);
}
std::pair<typename IterLeft::value_type, typename IterRight::value_type> operator*() const {
return std::make_pair(*left_iter_, *right_iter_);
}
private:
IterLeft left_iter_;
IterRight right_iter_;
};
class CountIter {
public:
using iterator_category = std::forward_iterator_tag;
using value_type = size_t;
using difference_type = size_t;
using pointer = size_t;
using reference = size_t;
CountIter() : count_(0) {}
explicit CountIter(size_t count) : count_(count) {}
CountIter& operator++() {
++count_;
return *this;
}
CountIter operator++(int) {
size_t ret = count_;
++count_;
return CountIter(ret);
}
bool operator==(const CountIter& other) const {
return count_ == other.count_;
}
bool operator!=(const CountIter& other) const {
return !(*this == other);
}
size_t operator*() const {
return count_;
}
private:
size_t count_;
};
// Make an iteration range that returns a pair of the element and the index of the element.
template <typename Iter>
static inline IterationRange<ZipLeftIter<Iter, CountIter>> ZipCount(IterationRange<Iter> iter) {
return IterationRange(ZipLeftIter(iter.begin(), CountIter(0)),
ZipLeftIter(iter.end(), CountIter(-1)));
}
// Make an iteration range that returns a pair of the outputs of two iterators. Stops when the first
// (left) one is exhausted. The left iterator must be at least as long as the right one.
template <typename IterLeft, typename IterRight>
static inline IterationRange<ZipLeftIter<IterLeft, IterRight>> ZipLeft(
IterationRange<IterLeft> iter_left, IterationRange<IterRight> iter_right) {
return IterationRange(ZipLeftIter(iter_left.begin(), iter_right.begin()),
ZipLeftIter(iter_left.end(), iter_right.end()));
}
static inline IterationRange<CountIter> Range(size_t start, size_t end) {
return IterationRange(CountIter(start), CountIter(end));
}
static inline IterationRange<CountIter> Range(size_t end) {
return Range(0, end);
}
template <typename RealIter, typename Filter>
struct FilterIterator {
public:
using iterator_category = std::forward_iterator_tag;
using value_type = typename RealIter::value_type;
using difference_type = std::ptrdiff_t;
using pointer = typename RealIter::value_type*;
using reference = typename RealIter::value_type&;
FilterIterator(RealIter rl,
Filter cond,
std::optional<RealIter> end = std::nullopt)
: real_iter_(rl), cond_(cond), end_(end) {
DCHECK(std::make_optional(rl) == end_ || cond_(*real_iter_));
}
FilterIterator<RealIter, Filter>& operator++() {
DCHECK(std::make_optional(real_iter_) != end_);
do {
if (std::make_optional(++real_iter_) == end_) {
break;
}
} while (!cond_(*real_iter_));
return *this;
}
FilterIterator<RealIter, Filter> operator++(int) {
FilterIterator<RealIter, Filter> ret(real_iter_, cond_, end_);
++(*this);
return ret;
}
bool operator==(const FilterIterator<RealIter, Filter>& other) const {
return real_iter_ == other.real_iter_;
}
bool operator!=(const FilterIterator<RealIter, Filter>& other) const {
return !(*this == other);
}
typename RealIter::value_type operator*() const {
return *real_iter_;
}
private:
RealIter real_iter_;
Filter cond_;
std::optional<RealIter> end_;
};
template <typename Iter, typename Filter>
static inline IterationRange<FilterIterator<Iter, Filter>> Filter(
IterationRange<Iter> it, Filter cond) {
auto end = it.end();
auto start = std::find_if(it.begin(), end, cond);
return MakeIterationRange(FilterIterator(start, cond, std::make_optional(end)),
FilterIterator(end, cond, std::make_optional(end)));
}
template <typename Val>
struct NonNullFilter {
public:
static_assert(std::is_pointer_v<Val>, "Must be pointer type!");
constexpr bool operator()(Val v) const {
return v != nullptr;
}
};
template <typename InnerIter>
using FilterNull = FilterIterator<InnerIter, NonNullFilter<typename InnerIter::value_type>>;
template <typename InnerIter>
static inline IterationRange<FilterNull<InnerIter>> FilterOutNull(IterationRange<InnerIter> inner) {
return Filter(inner, NonNullFilter<typename InnerIter::value_type>());
}
template <typename Val>
struct SafePrinter {
const Val* val_;
};
template<typename Val>
std::ostream& operator<<(std::ostream& os, const SafePrinter<Val>& v) {
if (v.val_ == nullptr) {
return os << "NULL";
} else {
return os << *v.val_;
}
}
template<typename Val>
SafePrinter<Val> SafePrint(const Val* v) {
return SafePrinter<Val>{v};
}
// Helper struct for iterating a split-string without allocation.
struct SplitStringIter {
public:
using iterator_category = std::forward_iterator_tag;
using value_type = std::string_view;
using difference_type = std::ptrdiff_t;
using pointer = std::string_view*;
using reference = std::string_view&;
// Direct iterator constructor. The iteration state is only the current index.
// We use that with the split char and the full string to get the current and
// next segment.
SplitStringIter(size_t index, char split, std::string_view sv)
: cur_index_(index), split_on_(split), sv_(sv) {}
SplitStringIter(const SplitStringIter&) = default;
SplitStringIter(SplitStringIter&&) = default;
SplitStringIter& operator=(SplitStringIter&&) = default;
SplitStringIter& operator=(const SplitStringIter&) = default;
SplitStringIter& operator++() {
size_t nxt = sv_.find(split_on_, cur_index_);
if (nxt == std::string_view::npos) {
cur_index_ = std::string_view::npos;
} else {
cur_index_ = nxt + 1;
}
return *this;
}
SplitStringIter operator++(int) {
SplitStringIter ret(cur_index_, split_on_, sv_);
++(*this);
return ret;
}
bool operator==(const SplitStringIter& other) const {
return sv_ == other.sv_ && split_on_ == other.split_on_ && cur_index_== other.cur_index_;
}
bool operator!=(const SplitStringIter& other) const {
return !(*this == other);
}
typename std::string_view operator*() const {
return sv_.substr(cur_index_, sv_.substr(cur_index_).find(split_on_));
}
private:
size_t cur_index_;
char split_on_;
std::string_view sv_;
};
// Create an iteration range over the string 'sv' split at each 'target' occurrence.
// Eg: SplitString(":foo::bar") -> ["", "foo", "", "bar"]
inline IterationRange<SplitStringIter> SplitString(std::string_view sv, char target) {
return MakeIterationRange(SplitStringIter(0, target, sv),
SplitStringIter(std::string_view::npos, target, sv));
}
} // namespace art
#endif // ART_LIBARTBASE_BASE_STL_UTIL_H_