summaryrefslogtreecommitdiffstats
path: root/otautil/rangeset.cpp
diff options
context:
space:
mode:
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/rangeset.cpp
parentMerge changes I2d42f55a,Ic1b5dbf7 (diff)
downloadandroid_bootable_recovery-311e6ca7b609e578c0ec132440a4ad981db70a9e.tar
android_bootable_recovery-311e6ca7b609e578c0ec132440a4ad981db70a9e.tar.gz
android_bootable_recovery-311e6ca7b609e578c0ec132440a4ad981db70a9e.tar.bz2
android_bootable_recovery-311e6ca7b609e578c0ec132440a4ad981db70a9e.tar.lz
android_bootable_recovery-311e6ca7b609e578c0ec132440a4ad981db70a9e.tar.xz
android_bootable_recovery-311e6ca7b609e578c0ec132440a4ad981db70a9e.tar.zst
android_bootable_recovery-311e6ca7b609e578c0ec132440a4ad981db70a9e.zip
Diffstat (limited to 'otautil/rangeset.cpp')
-rw-r--r--otautil/rangeset.cpp52
1 files changed, 52 insertions, 0 deletions
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());