extent_utils.h revision aea4c1cea20dda7ae7e85fc8924a2d784f70d806
1// 2// Copyright (C) 2015 The Android Open Source Project 3// 4// Licensed under the Apache License, Version 2.0 (the "License"); 5// you may not use this file except in compliance with the License. 6// You may obtain a copy of the License at 7// 8// http://www.apache.org/licenses/LICENSE-2.0 9// 10// Unless required by applicable law or agreed to in writing, software 11// distributed under the License is distributed on an "AS IS" BASIS, 12// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13// See the License for the specific language governing permissions and 14// limitations under the License. 15// 16 17#ifndef UPDATE_ENGINE_PAYLOAD_GENERATOR_EXTENT_UTILS_H_ 18#define UPDATE_ENGINE_PAYLOAD_GENERATOR_EXTENT_UTILS_H_ 19 20#include <vector> 21 22#include "update_engine/payload_constants.h" 23#include "update_engine/update_metadata.pb.h" 24 25// Utility functions for manipulating Extents and lists of blocks. 26 27namespace chromeos_update_engine { 28 29// |block| must either be the next block in the last extent or a block 30// in the next extent. This function will not handle inserting block 31// into an arbitrary place in the extents. 32void AppendBlockToExtents(std::vector<Extent>* extents, uint64_t block); 33 34// Get/SetElement are intentionally overloaded so that templated functions 35// can accept either type of collection of Extents. 36Extent GetElement(const std::vector<Extent>& collection, size_t index); 37Extent GetElement( 38 const google::protobuf::RepeatedPtrField<Extent>& collection, 39 size_t index); 40 41// Return the total number of blocks in a collection (vector or 42// RepeatedPtrField) of Extents. 43template<typename T> 44uint64_t BlocksInExtents(const T& collection) { 45 uint64_t ret = 0; 46 for (size_t i = 0; i < static_cast<size_t>(collection.size()); ++i) { 47 ret += GetElement(collection, i).num_blocks(); 48 } 49 return ret; 50} 51 52// Takes a collection (vector or RepeatedPtrField) of Extent and 53// returns a vector of the blocks referenced, in order. 54template<typename T> 55std::vector<uint64_t> ExpandExtents(const T& extents) { 56 std::vector<uint64_t> ret; 57 for (size_t i = 0, e = static_cast<size_t>(extents.size()); i != e; ++i) { 58 const Extent extent = GetElement(extents, i); 59 if (extent.start_block() == kSparseHole) { 60 ret.resize(ret.size() + extent.num_blocks(), kSparseHole); 61 } else { 62 for (uint64_t block = extent.start_block(); 63 block < (extent.start_block() + extent.num_blocks()); block++) { 64 ret.push_back(block); 65 } 66 } 67 } 68 return ret; 69} 70 71// Stores all Extents in 'extents' into 'out'. 72void StoreExtents(const std::vector<Extent>& extents, 73 google::protobuf::RepeatedPtrField<Extent>* out); 74 75// Stores all extents in |extents| into |out_vector|. 76void ExtentsToVector(const google::protobuf::RepeatedPtrField<Extent>& extents, 77 std::vector<Extent>* out_vector); 78 79// Takes a pointer to extents |extents| and extents |extents_to_add|, and 80// merges them by adding |extents_to_add| to |extents| and normalizing. 81void ExtendExtents( 82 google::protobuf::RepeatedPtrField<Extent>* extents, 83 const google::protobuf::RepeatedPtrField<Extent>& extents_to_add); 84 85// Takes a vector of extents and normalizes those extents. Expects the extents 86// to be sorted by start block. E.g. if |extents| is [(1, 2), (3, 5), (10, 2)] 87// then |extents| will be changed to [(1, 7), (10, 2)]. 88void NormalizeExtents(std::vector<Extent>* extents); 89 90// Return a subsequence of the list of blocks passed. Both the passed list of 91// blocks |extents| and the return value are expressed as a list of Extent, not 92// blocks. The returned list skips the first |block_offset| blocks from the 93// |extents| and cotains |block_count| blocks (or less if |extents| is shorter). 94std::vector<Extent> ExtentsSublist(const std::vector<Extent>& extents, 95 uint64_t block_offset, uint64_t block_count); 96 97bool operator==(const Extent& a, const Extent& b); 98 99} // namespace chromeos_update_engine 100 101#endif // UPDATE_ENGINE_PAYLOAD_GENERATOR_EXTENT_UTILS_H_ 102