extent_utils.h revision 39910dcd1d68987ccee7c3031dc269233a8490bb 
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_consumer/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