Add PZstandard to contrib/

contrib/pzstd/utils/FileSystem.h

@@ -0,0 +1,61 @@
+/**
+ * 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 "utils/Range.h"
+
+#include <sys/stat.h>
+#include <cstdint>
+#include <system_error>
+
+// A small subset of `std::filesystem`.
+// `std::filesystem` should be a drop in replacement.
+// See http://en.cppreference.com/w/cpp/filesystem for documentation.
+
+namespace pzstd {
+
+using file_status = struct stat;
+
+/// http://en.cppreference.com/w/cpp/filesystem/status
+inline file_status status(StringPiece path, std::error_code& ec) noexcept {
+  file_status status;
+  if (stat(path.data(), &status)) {
+    ec.assign(errno, std::generic_category());
+  } else {
+    ec.clear();
+  }
+  return status;
+}
+
+/// http://en.cppreference.com/w/cpp/filesystem/is_regular_file
+inline bool is_regular_file(file_status status) noexcept {
+  return S_ISREG(status.st_mode);
+}
+
+/// http://en.cppreference.com/w/cpp/filesystem/is_regular_file
+inline bool is_regular_file(StringPiece path, std::error_code& ec) noexcept {
+  return is_regular_file(status(path, ec));
+}
+
+/// http://en.cppreference.com/w/cpp/filesystem/file_size
+inline std::uintmax_t file_size(
+    StringPiece path,
+    std::error_code& ec) noexcept {
+  auto stat = status(path, ec);
+  if (ec) {
+    return -1;
+  }
+  if (!is_regular_file(stat)) {
+    ec.assign(ENOTSUP, std::generic_category());
+    return -1;
+  }
+  ec.clear();
+  return stat.st_size;
+}
+}