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//
// Copyright (C) 2015 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 UPDATE_ENGINE_PAYLOAD_GENERATOR_EXTENT_UTILS_H_
#define UPDATE_ENGINE_PAYLOAD_GENERATOR_EXTENT_UTILS_H_
#include <string>
#include <vector>
#include <base/logging.h>
#include "update_engine/payload_consumer/payload_constants.h"
#include "update_engine/update_metadata.pb.h"
// Utility functions for manipulating Extents and lists of blocks.
namespace chromeos_update_engine {
// |block| must either be the next block in the last extent or a block
// in the next extent. This function will not handle inserting block
// into an arbitrary place in the extents.
void AppendBlockToExtents(std::vector<Extent>* extents, uint64_t block);
// Takes a collection (vector or RepeatedPtrField) of Extent and
// returns a vector of the blocks referenced, in order.
template <typename T>
std::vector<uint64_t> ExpandExtents(const T& extents) {
std::vector<uint64_t> ret;
for (const auto& extent : extents) {
if (extent.start_block() == kSparseHole) {
ret.resize(ret.size() + extent.num_blocks(), kSparseHole);
} else {
for (uint64_t block = extent.start_block();
block < (extent.start_block() + extent.num_blocks());
block++) {
ret.push_back(block);
}
}
}
return ret;
}
// Stores all Extents in 'extents' into 'out'.
void StoreExtents(const std::vector<Extent>& extents,
google::protobuf::RepeatedPtrField<Extent>* out);
// Stores all extents in |extents| into |out_vector|.
void ExtentsToVector(const google::protobuf::RepeatedPtrField<Extent>& extents,
std::vector<Extent>* out_vector);
// Returns a string representing all extents in |extents|.
std::string ExtentsToString(const std::vector<Extent>& extents);
// Takes a pointer to extents |extents| and extents |extents_to_add|, and
// merges them by adding |extents_to_add| to |extents| and normalizing.
void ExtendExtents(
google::protobuf::RepeatedPtrField<Extent>* extents,
const google::protobuf::RepeatedPtrField<Extent>& extents_to_add);
// Takes a vector of extents and normalizes those extents. Expects the extents
// to be sorted by start block. E.g. if |extents| is [(1, 2), (3, 5), (10, 2)]
// then |extents| will be changed to [(1, 7), (10, 2)].
void NormalizeExtents(std::vector<Extent>* extents);
// Return a subsequence of the list of blocks passed. Both the passed list of
// blocks |extents| and the return value are expressed as a list of Extent, not
// blocks. The returned list skips the first |block_offset| blocks from the
// |extents| and cotains |block_count| blocks (or less if |extents| is shorter).
std::vector<Extent> ExtentsSublist(const std::vector<Extent>& extents,
uint64_t block_offset,
uint64_t block_count);
bool operator==(const Extent& a, const Extent& b);
// TODO(zhangkelvin) This is ugly. Rewrite using C++20's coroutine once
// that's available. Unfortunately with C++17 this is the best I could do.
// An iterator that takes a sequence of extents, and iterate over blocks
// inside this sequence of extents.
// Example usage:
// BlockIterator it1{src_extents};
// while(!it1.is_end()) {
// auto block = *it1;
// Do stuff with |block|
// }
struct BlockIterator {
explicit BlockIterator(
const google::protobuf::RepeatedPtrField<Extent>& src_extents)
: src_extents_(src_extents) {}
BlockIterator& operator++() {
CHECK_LT(cur_extent_, src_extents_.size());
block_offset_++;
if (block_offset_ >= src_extents_[cur_extent_].num_blocks()) {
cur_extent_++;
block_offset_ = 0;
}
return *this;
}
[[nodiscard]] bool is_end() { return cur_extent_ >= src_extents_.size(); }
[[nodiscard]] uint64_t operator*() {
return src_extents_[cur_extent_].start_block() + block_offset_;
}
const google::protobuf::RepeatedPtrField<Extent>& src_extents_;
int cur_extent_ = 0;
size_t block_offset_ = 0;
};
std::ostream& operator<<(std::ostream& out, const Extent& extent);
} // namespace chromeos_update_engine
#endif // UPDATE_ENGINE_PAYLOAD_GENERATOR_EXTENT_UTILS_H_
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