1 files changed, 90 insertions, 0 deletions
diff --git a/klm/util/stream/multi_progress.hh b/klm/util/stream/multi_progress.hh
new file mode 100644
index 00000000..c4dd45a9
--- /dev/null
+++ b/klm/util/stream/multi_progress.hh
@@ -0,0 +1,90 @@
+/* Progress bar suitable for chains of workers */
+#ifndef UTIL_MULTI_PROGRESS__
+#define UTIL_MULTI_PROGRESS__
+
+#include <boost/thread/mutex.hpp>
+
+#include <cstddef>
+
+#include <stdint.h>
+
+namespace util { namespace stream {
+
+class WorkerProgress;
+
+class MultiProgress {
+  public:
+    static const unsigned char kWidth = 100;
+
+    MultiProgress();
+
+    ~MultiProgress();
+
+    // Turns on showing (requires SetTarget too).
+    void Activate();
+
+    void SetTarget(uint64_t complete);
+
+    WorkerProgress Add();
+
+    void Finished();
+
+  private:
+    friend class WorkerProgress;
+    void Milestone(WorkerProgress &worker);
+
+    bool active_;
+
+    uint64_t complete_;
+
+    boost::mutex mutex_;
+
+    // \0 at the end.  
+    char display_[kWidth + 1];
+
+    std::size_t character_handout_;
+
+    MultiProgress(const MultiProgress &);
+    MultiProgress &operator=(const MultiProgress &);
+};
+
+class WorkerProgress {
+  public:
+    // Default contrutor must be initialized with operator= later.  
+    WorkerProgress() : parent_(NULL) {}
+
+    // Not threadsafe for the same worker by default.  
+    WorkerProgress &operator++() {
+      if (++current_ >= next_) {
+        parent_->Milestone(*this);
+      }
+      return *this;
+    }
+
+    WorkerProgress &operator+=(uint64_t amount) {
+      current_ += amount;
+      if (current_ >= next_) {
+        parent_->Milestone(*this);
+      }
+      return *this;
+    }
+
+  private:
+    friend class MultiProgress;
+    WorkerProgress(uint64_t next, MultiProgress &parent, char character) 
+      : current_(0), next_(next), parent_(&parent), stone_(0), character_(character) {}
+
+    uint64_t current_, next_;
+
+    MultiProgress *parent_;
+
+    // Previous milestone reached.  
+    unsigned char stone_;
+
+    // Character to display in bar.  
+    char character_;
+};
+
+}} // namespaces
+
+#endif // UTIL_MULTI_PROGRESS__