extent_utils.h revision d8b67f49d7f8ae291cd4fa901b2d3767137704e7 
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 <string>
21#include <vector>
22
23#include "update_engine/payload_consumer/payload_constants.h"
24#include "update_engine/update_metadata.pb.h"
25
26// Utility functions for manipulating Extents and lists of blocks.
27
28namespace chromeos_update_engine {
29
30// |block| must either be the next block in the last extent or a block
31// in the next extent. This function will not handle inserting block
32// into an arbitrary place in the extents.
33void AppendBlockToExtents(std::vector<Extent>* extents, uint64_t block);
34
35// Takes a collection (vector or RepeatedPtrField) of Extent and
36// returns a vector of the blocks referenced, in order.
37template<typename T>
38std::vector<uint64_t> ExpandExtents(const T& extents) {
39  std::vector<uint64_t> ret;
40  for (const auto& extent : extents) {
41    if (extent.start_block() == kSparseHole) {
42      ret.resize(ret.size() + extent.num_blocks(), kSparseHole);
43    } else {
44      for (uint64_t block = extent.start_block();
45           block < (extent.start_block() + extent.num_blocks()); block++) {
46        ret.push_back(block);
47      }
48    }
49  }
50  return ret;
51}
52
53// Stores all Extents in 'extents' into 'out'.
54void StoreExtents(const std::vector<Extent>& extents,
55                  google::protobuf::RepeatedPtrField<Extent>* out);
56
57// Stores all extents in |extents| into |out_vector|.
58void ExtentsToVector(const google::protobuf::RepeatedPtrField<Extent>& extents,
59                     std::vector<Extent>* out_vector);
60
61// Returns a string representing all extents in |extents|.
62std::string ExtentsToString(const std::vector<Extent>& extents);
63
64// Takes a pointer to extents |extents| and extents |extents_to_add|, and
65// merges them by adding |extents_to_add| to |extents| and normalizing.
66void ExtendExtents(
67  google::protobuf::RepeatedPtrField<Extent>* extents,
68  const google::protobuf::RepeatedPtrField<Extent>& extents_to_add);
69
70// Takes a vector of extents and normalizes those extents. Expects the extents
71// to be sorted by start block. E.g. if |extents| is [(1, 2), (3, 5), (10, 2)]
72// then |extents| will be changed to [(1, 7), (10, 2)].
73void NormalizeExtents(std::vector<Extent>* extents);
74
75// Return a subsequence of the list of blocks passed. Both the passed list of
76// blocks |extents| and the return value are expressed as a list of Extent, not
77// blocks. The returned list skips the first |block_offset| blocks from the
78// |extents| and cotains |block_count| blocks (or less if |extents| is shorter).
79std::vector<Extent> ExtentsSublist(const std::vector<Extent>& extents,
80                                   uint64_t block_offset, uint64_t block_count);
81
82bool operator==(const Extent& a, const Extent& b);
83
84}  // namespace chromeos_update_engine
85
86#endif  // UPDATE_ENGINE_PAYLOAD_GENERATOR_EXTENT_UTILS_H_
87