1 files changed, 97 insertions, 28 deletions

diff --git a/updater/include/updater/rangeset.h b/updater/include/updater/rangeset.h
index afaa82dcd..fad038043 100644
--- a/updater/include/updater/rangeset.h
+++ b/updater/include/updater/rangeset.h
@@ -19,16 +19,35 @@
 #include <stddef.h>
 
 #include <string>
+#include <utility>
 #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.
+using Range = std::pair<size_t, size_t>;
+
+class RangeSet {
+ public:
+  RangeSet() : blocks_(0) {}
+
+  explicit RangeSet(std::vector<Range>&& pairs) {
+    CHECK_NE(pairs.size(), static_cast<size_t>(0)) << "Invalid number of tokens";
+
+    // Sanity check the input.
+    size_t result = 0;
+    for (const auto& range : pairs) {
+      CHECK_LT(range.first, range.second)
+          << "Empty or negative range: " << range.first << ", " << range.second;
+      size_t sz = range.second - range.first;
+      CHECK_LE(result, SIZE_MAX - sz) << "RangeSet size overflow";
+      result += sz;
+    }
+
+    ranges_ = pairs;
+    blocks_ = result;
+  }
 
   static RangeSet Parse(const std::string& range_text) {
     std::vector<std::string> pieces = android::base::Split(range_text, ",");
@@ -42,44 +61,43 @@ struct RangeSet {
     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;
+    std::vector<Range> pairs;
     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;
+      size_t first;
+      CHECK(android::base::ParseUint(pieces[i + 1], &first, static_cast<size_t>(INT_MAX)));
+      size_t second;
+      CHECK(android::base::ParseUint(pieces[i + 2], &second, static_cast<size_t>(INT_MAX)));
+
+      pairs.emplace_back(first, second);
     }
 
-    return RangeSet{ num / 2, size, std::move(pairs) };
+    return RangeSet(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;
+    CHECK_LT(idx, blocks_) << "Out of bound index " << idx << " (total blocks: " << blocks_ << ")";
+
+    for (const auto& range : ranges_) {
+      if (idx < range.second - range.first) {
+        return range.first + idx;
       }
-      idx -= (pos[i + 1] - pos[i]);
+      idx -= (range.second - range.first);
     }
-    CHECK(false);
+
+    CHECK(false) << "Failed to find block number for index " << idx;
     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];
+    for (const auto& range : ranges_) {
+      size_t start = range.first;
+      size_t end = range.second;
+      for (const auto& other_range : other.ranges_) {
+        size_t other_start = other_range.first;
+        size_t other_end = other_range.second;
         // [start, end) vs [other_start, other_end)
         if (!(other_start >= end || start >= other_end)) {
           return true;
@@ -89,7 +107,58 @@ struct RangeSet {
     return false;
   }
 
+  // size() gives the number of Range's in this RangeSet.
+  size_t size() const {
+    return ranges_.size();
+  }
+
+  // blocks() gives the number of all blocks in this RangeSet.
+  size_t blocks() const {
+    return blocks_;
+  }
+
+  // We provide const iterators only.
+  std::vector<Range>::const_iterator cbegin() const {
+    return ranges_.cbegin();
+  }
+
+  std::vector<Range>::const_iterator cend() const {
+    return ranges_.cend();
+  }
+
+  // Need to provide begin()/end() since range-based loop expects begin()/end().
+  std::vector<Range>::const_iterator begin() const {
+    return ranges_.cbegin();
+  }
+
+  std::vector<Range>::const_iterator end() const {
+    return ranges_.cend();
+  }
+
+  // Reverse const iterators for MoveRange().
+  std::vector<Range>::const_reverse_iterator crbegin() const {
+    return ranges_.crbegin();
+  }
+
+  std::vector<Range>::const_reverse_iterator crend() const {
+    return ranges_.crend();
+  }
+
+  const Range& operator[](size_t i) const {
+    return ranges_[i];
+  }
+
   bool operator==(const RangeSet& other) const {
-    return (count == other.count && size == other.size && pos == other.pos);
+    // The orders of Range's matter. "4,1,5,8,10" != "4,8,10,1,5".
+    return (ranges_ == other.ranges_);
   }
+
+  bool operator!=(const RangeSet& other) const {
+    return ranges_ != other.ranges_;
+  }
+
+ private:
+  // Actual limit for each value and the total number are both INT_MAX.
+  std::vector<Range> ranges_;
+  size_t blocks_;
 };