Added SegList<T>, replacement of Sequence<T>

1 files changed, 118 insertions, 0 deletions

diff --git a/src/SegList.h b/src/SegList.h
new file mode 100644
index 00000000..8115d038
--- /dev/null
+++ b/src/SegList.h
@@ -0,0 +1,118 @@
+/* <!-- copyright */
+/*
+ * aria2 - The high speed download utility
+ *
+ * Copyright (C) 2011 Tatsuhiro Tsujikawa
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to link the code of portions of this program with the
+ * OpenSSL library under certain conditions as described in each
+ * individual source file, and distribute linked combinations
+ * including the two.
+ * You must obey the GNU General Public License in all respects
+ * for all of the code used other than OpenSSL.  If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so.  If you
+ * do not wish to do so, delete this exception statement from your
+ * version.  If you delete this exception statement from all source
+ * files in the program, then also delete it here.
+ */
+/* copyright --> */
+#ifndef D_SEG_LIST_H
+#define D_SEG_LIST_H
+
+#include <cstdlib>
+#include <vector>
+#include <limits>
+#include <algorithm>
+
+namespace aria2 {
+
+template<typename T>
+class SegList {
+public:
+  SegList()
+    : index_(0), val_(std::numeric_limits<T>::min())
+  {}
+
+  // Transforms list of segments so that they are sorted ascending
+  // order of starting value and intersecting and touching segments
+  // are all merged into one. This function resets current position.
+  void normalize()
+  {
+    if(!seg_.empty()) {
+      std::sort(seg_.begin(), seg_.end());
+      std::vector<std::pair<T, T> > s;
+      s.push_back(seg_.front());
+      for(size_t i = 1, len = seg_.size(); i < len; ++i) {
+        const std::pair<T, T>& x = seg_[i];
+        if(x.first <= s.back().second) {
+          if(s.back().second < x.second) {
+            s.back().second = x.second;
+          }
+        } else {
+          s.push_back(x);
+        }
+      }
+      s.swap(seg_);
+      index_ = 0;
+      val_ = seg_.front().first;
+    }
+  }
+
+  // Add segment [a, b). If a >= b, do nothing.
+  void add(T a, T b)
+  {
+    if(a < b) {
+      if(seg_.empty()) {
+        val_ = std::max(val_, a);
+      }
+      seg_.push_back(std::make_pair(a, b));
+    }
+  }
+
+  // Returns true if next value is available. Otherwise returns false.
+  bool hasNext() const
+  {
+    return index_ < seg_.size() && val_ < seg_[index_].second;
+  }
+
+  // Returns next value. Advance current position to the next.  If
+  // this fuction is called when hasNext() returns false, returns 0.
+  T next()
+  {
+    T res;
+    if(index_ < seg_.size()) {
+      res = val_++;
+      if(val_ == seg_[index_].second) {
+        ++index_;
+        val_ = seg_[index_].first;
+      }
+    } else {
+      res = 0;
+    }
+    return res;
+  }
+private:
+  std::vector<std::pair<T, T> > seg_;
+  size_t index_;
+  T val_;
+};
+
+} // namespace aria2
+
+#endif // D_SEG_LIST_H