1 files changed, 41 insertions, 0 deletions
diff --git a/util/stringprintf.h b/util/stringprintf.h
new file mode 100644
index 00000000..93e5eb93
--- /dev/null
+++ b/util/stringprintf.h
@@ -0,0 +1,41 @@
+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UTIL_STRINGPRINTF_H_
+#define UTIL_STRINGPRINTF_H_
+
+#include <ostream>
+
+namespace openscreen {
+
+template <typename It>
+void PrettyPrintAsciiHex(std::ostream& os, It first, It last) {
+  auto it = first;
+  while (it != last) {
+    uint8_t c = *it++;
+    if (c >= ' ' && c <= '~') {
+      os.put(c);
+    } else {
+      // Output a hex escape sequence for non-printable values.
+      os.put('\\');
+      os.put('x');
+      char digit = (c >> 4) & 0xf;
+      if (digit >= 0 && digit <= 9) {
+        os.put(digit + '0');
+      } else {
+        os.put(digit - 10 + 'a');
+      }
+      digit = c & 0xf;
+      if (digit >= 0 && digit <= 9) {
+        os.put(digit + '0');
+      } else {
+        os.put(digit - 10 + 'a');
+      }
+    }
+  }
+}
+
+}  // namespace openscreen
+
+#endif  // UTIL_STRINGPRINTF_H_