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authorxunchang <xunchang@google.com>2019-03-22 16:54:35 +0100
committerTianjie Xu <xunchang@google.com>2019-05-01 21:09:38 +0200
commit311e6ca7b609e578c0ec132440a4ad981db70a9e (patch)
tree206a8c1268e4664cb06890f9835d86e83014ae8a /otautil
parentMerge changes I2d42f55a,Ic1b5dbf7 (diff)
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Diffstat (limited to '')
-rw-r--r--otautil/include/otautil/rangeset.h7
-rw-r--r--otautil/rangeset.cpp52
-rw-r--r--otautil/sysutil.cpp5
3 files changed, 64 insertions, 0 deletions
diff --git a/otautil/include/otautil/rangeset.h b/otautil/include/otautil/rangeset.h
index e91d02ca6..a18c30e29 100644
--- a/otautil/include/otautil/rangeset.h
+++ b/otautil/include/otautil/rangeset.h
@@ -18,6 +18,7 @@
#include <stddef.h>
+#include <optional>
#include <string>
#include <utility>
#include <vector>
@@ -49,6 +50,12 @@ class RangeSet {
// bounds. For example, "3,5" contains blocks 3 and 4. So "3,5" and "5,7" are not overlapped.
bool Overlaps(const RangeSet& other) const;
+ // Returns a subset of ranges starting from |start_index| with respect to the original range. The
+ // output range will have |num_of_blocks| blocks in size. Returns std::nullopt if the input is
+ // invalid. e.g. RangeSet({{0, 5}, {10, 15}}).GetSubRanges(1, 5) returns
+ // RangeSet({{1, 5}, {10, 11}}).
+ std::optional<RangeSet> GetSubRanges(size_t start_index, size_t num_of_blocks) const;
+
// Returns a vector of RangeSets that contain the same set of blocks represented by the current
// RangeSet. The RangeSets in the vector contain similar number of blocks, with a maximum delta
// of 1-block between any two of them. For example, 14 blocks would be split into 4 + 4 + 3 + 3,
diff --git a/otautil/rangeset.cpp b/otautil/rangeset.cpp
index 5ab8e08fe..8ee99dd7a 100644
--- a/otautil/rangeset.cpp
+++ b/otautil/rangeset.cpp
@@ -184,6 +184,58 @@ bool RangeSet::Overlaps(const RangeSet& other) const {
return false;
}
+std::optional<RangeSet> RangeSet::GetSubRanges(size_t start_index, size_t num_of_blocks) const {
+ size_t end_index = start_index + num_of_blocks; // The index of final block to read plus one
+ if (start_index > end_index || end_index > blocks_) {
+ LOG(ERROR) << "Failed to get the sub ranges for start_index " << start_index
+ << " num_of_blocks " << num_of_blocks
+ << " total number of blocks the range contains is " << blocks_;
+ return std::nullopt;
+ }
+
+ if (num_of_blocks == 0) {
+ LOG(WARNING) << "num_of_blocks is zero when calling GetSubRanges()";
+ return RangeSet();
+ }
+
+ RangeSet result;
+ size_t current_index = 0;
+ for (const auto& [range_start, range_end] : ranges_) {
+ CHECK_LT(range_start, range_end);
+ size_t blocks_in_range = range_end - range_start;
+ // Linear search to skip the ranges until we reach start_block.
+ if (current_index + blocks_in_range <= start_index) {
+ current_index += blocks_in_range;
+ continue;
+ }
+
+ size_t trimmed_range_start = range_start;
+ // We have found the first block range to read, trim the heading blocks.
+ if (current_index < start_index) {
+ trimmed_range_start += start_index - current_index;
+ }
+ // Trim the trailing blocks if the last range has more blocks than desired; also return the
+ // result.
+ if (current_index + blocks_in_range >= end_index) {
+ size_t trimmed_range_end = range_end - (current_index + blocks_in_range - end_index);
+ if (!result.PushBack({ trimmed_range_start, trimmed_range_end })) {
+ return std::nullopt;
+ }
+
+ return result;
+ }
+
+ if (!result.PushBack({ trimmed_range_start, range_end })) {
+ return std::nullopt;
+ }
+ current_index += blocks_in_range;
+ }
+
+ LOG(ERROR) << "Failed to construct byte ranges to read, start_block: " << start_index
+ << ", num_of_blocks: " << num_of_blocks << " total number of blocks: " << blocks_;
+ return std::nullopt;
+}
+
// Ranges in the the set should be mutually exclusive; and they're sorted by the start block.
SortedRangeSet::SortedRangeSet(std::vector<Range>&& pairs) : RangeSet(std::move(pairs)) {
std::sort(ranges_.begin(), ranges_.end());
diff --git a/otautil/sysutil.cpp b/otautil/sysutil.cpp
index 2b4861809..420db4cac 100644
--- a/otautil/sysutil.cpp
+++ b/otautil/sysutil.cpp
@@ -94,6 +94,11 @@ BlockMapData BlockMapData::ParseBlockMapFile(const std::string& block_map_path)
remaining_blocks -= range_blocks;
}
+ if (remaining_blocks != 0) {
+ LOG(ERROR) << "Invalid ranges: remaining blocks " << remaining_blocks;
+ return {};
+ }
+
return BlockMapData(block_dev, file_size, blksize, std::move(ranges));
}