[pzstd] Add Logger class

contrib/pzstd/Logging.h

@@ -0,0 +1,72 @@
+/**
+ * Copyright (c) 2016-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#pragma once
+
+#include <cstdio>
+#include <mutex>
+
+namespace pzstd {
+
+constexpr int ERROR = 1;
+constexpr int INFO = 2;
+constexpr int DEBUG = 3;
+constexpr int VERBOSE = 4;
+
+class Logger {
+  std::mutex mutex_;
+  FILE* out_;
+  const int level_;
+
+  using Clock = std::chrono::system_clock;
+  Clock::time_point lastUpdate_;
+  std::chrono::milliseconds refreshRate_;
+
+ public:
+  explicit Logger(int level, FILE* out = stderr)
+      : out_(out), level_(level), lastUpdate_(Clock::now()),
+        refreshRate_(150) {}
+
+
+  bool logsAt(int level) {
+    return level <= level_;
+  }
+
+  template <typename... Args>
+  void operator()(int level, const char *fmt, Args... args) {
+    if (level > level_) {
+      return;
+    }
+    std::lock_guard<std::mutex> lock(mutex_);
+    std::fprintf(out_, fmt, args...);
+  }
+
+  template <typename... Args>
+  void update(int level, const char *fmt, Args... args) {
+    if (level > level_) {
+      return;
+    }
+    std::lock_guard<std::mutex> lock(mutex_);
+    auto now = Clock::now();
+    if (now - lastUpdate_ > refreshRate_) {
+      lastUpdate_ = now;
+      std::fprintf(out_, "\r");
+      std::fprintf(out_, fmt, args...);
+    }
+  }
+
+  void clear(int level) {
+    if (level > level_) {
+      return;
+    }
+    std::lock_guard<std::mutex> lock(mutex_);
+    std::fprintf(out_, "\r%79s\r", "");
+  }
+};
+
+}