1 files changed, 74 insertions, 0 deletions
diff --git a/klm/util/stream/stream.hh b/klm/util/stream/stream.hh
new file mode 100644
index 00000000..6ff45b82
--- /dev/null
+++ b/klm/util/stream/stream.hh
@@ -0,0 +1,74 @@
+#ifndef UTIL_STREAM_STREAM__
+#define UTIL_STREAM_STREAM__
+
+#include "util/stream/chain.hh"
+
+#include <boost/noncopyable.hpp>
+
+#include <assert.h>
+#include <stdint.h>
+
+namespace util {
+namespace stream {
+
+class Stream : boost::noncopyable {
+  public:
+    Stream() : current_(NULL), end_(NULL) {}
+
+    void Init(const ChainPosition &position) {
+      entry_size_ = position.GetChain().EntrySize();
+      block_size_ = position.GetChain().BlockSize();
+      block_it_.Init(position);
+      StartBlock();
+    }
+
+    explicit Stream(const ChainPosition &position) {
+      Init(position);
+    }
+
+    operator bool() const { return current_ != NULL; }
+    bool operator!() const { return current_ == NULL; }
+
+    const void *Get() const { return current_; }
+    void *Get() { return current_; }
+
+    void Poison() {
+      block_it_->SetValidSize(current_ - static_cast<uint8_t*>(block_it_->Get()));
+      ++block_it_;
+      block_it_.Poison();
+    }
+    
+    Stream &operator++() {
+      assert(*this);
+      assert(current_ < end_);
+      current_ += entry_size_;
+      if (current_ == end_) {
+        ++block_it_;
+        StartBlock();
+      }
+      return *this;
+    }
+
+  private:
+    void StartBlock() {
+      for (; block_it_ && !block_it_->ValidSize(); ++block_it_) {}
+      current_ = static_cast<uint8_t*>(block_it_->Get());
+      end_ = current_ + block_it_->ValidSize();
+    }
+
+    uint8_t *current_, *end_;
+
+    std::size_t entry_size_;
+    std::size_t block_size_;
+
+    Link block_it_;
+};
+
+inline Chain &operator>>(Chain &chain, Stream &stream) {
+  stream.Init(chain.Add());
+  return chain;
+}
+
+} // namespace stream
+} // namespace util
+#endif // UTIL_STREAM_STREAM__