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-rw-r--r--updater/include/updater/rangeset.h95
1 files changed, 95 insertions, 0 deletions
diff --git a/updater/include/updater/rangeset.h b/updater/include/updater/rangeset.h
new file mode 100644
index 000000000..afaa82dcd
--- /dev/null
+++ b/updater/include/updater/rangeset.h
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <stddef.h>
+
+#include <string>
+#include <vector>
+
+#include <android-base/logging.h>
+#include <android-base/parseint.h>
+#include <android-base/strings.h>
+
+struct RangeSet {
+ size_t count; // Limit is INT_MAX.
+ size_t size; // The number of blocks in the RangeSet.
+ std::vector<size_t> pos; // Actual limit is INT_MAX.
+
+ static RangeSet Parse(const std::string& range_text) {
+ std::vector<std::string> pieces = android::base::Split(range_text, ",");
+ CHECK_GE(pieces.size(), static_cast<size_t>(3)) << "Invalid range text: " << range_text;
+
+ size_t num;
+ CHECK(android::base::ParseUint(pieces[0], &num, static_cast<size_t>(INT_MAX)))
+ << "Failed to parse the number of tokens: " << range_text;
+
+ CHECK_NE(num, static_cast<size_t>(0)) << "Invalid number of tokens: " << range_text;
+ CHECK_EQ(num % 2, static_cast<size_t>(0)) << "Number of tokens must be even: " << range_text;
+ CHECK_EQ(num, pieces.size() - 1) << "Mismatching number of tokens: " << range_text;
+
+ std::vector<size_t> pairs(num);
+ size_t size = 0;
+ for (size_t i = 0; i < num; i += 2) {
+ CHECK(android::base::ParseUint(pieces[i + 1], &pairs[i], static_cast<size_t>(INT_MAX)));
+ CHECK(android::base::ParseUint(pieces[i + 2], &pairs[i + 1], static_cast<size_t>(INT_MAX)));
+ CHECK_LT(pairs[i], pairs[i + 1])
+ << "Empty or negative range: " << pairs[i] << ", " << pairs[i + 1];
+
+ size_t sz = pairs[i + 1] - pairs[i];
+ CHECK_LE(size, SIZE_MAX - sz) << "RangeSet size overflow";
+ size += sz;
+ }
+
+ return RangeSet{ num / 2, size, std::move(pairs) };
+ }
+
+ // Get the block number for the i-th (starting from 0) block in the RangeSet.
+ size_t GetBlockNumber(size_t idx) const {
+ CHECK_LT(idx, size) << "Index " << idx << " is greater than RangeSet size " << size;
+ for (size_t i = 0; i < pos.size(); i += 2) {
+ if (idx < pos[i + 1] - pos[i]) {
+ return pos[i] + idx;
+ }
+ idx -= (pos[i + 1] - pos[i]);
+ }
+ CHECK(false);
+ return 0; // Unreachable, but to make compiler happy.
+ }
+
+ // RangeSet has half-closed half-open 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 {
+ for (size_t i = 0; i < count; ++i) {
+ size_t start = pos[i * 2];
+ size_t end = pos[i * 2 + 1];
+ for (size_t j = 0; j < other.count; ++j) {
+ size_t other_start = other.pos[j * 2];
+ size_t other_end = other.pos[j * 2 + 1];
+ // [start, end) vs [other_start, other_end)
+ if (!(other_start >= end || start >= other_end)) {
+ return true;
+ }
+ }
+ }
+ return false;
+ }
+
+ bool operator==(const RangeSet& other) const {
+ return (count == other.count && size == other.size && pos == other.pos);
+ }
+};