Various improvements to char_scanner

1 files changed, 32 insertions, 0 deletions

diff --git a/libbutl/char-scanner.ixx b/libbutl/char-scanner.ixx
new file mode 100644
index 0000000..2d96207
--- /dev/null
+++ b/libbutl/char-scanner.ixx
@@ -0,0 +1,32 @@
+// file      : libbutl/char-scanner.ixx -*- C++ -*-
+// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+namespace butl
+{
+  inline auto char_scanner::
+  get () -> xchar
+  {
+    if (unget_)
+    {
+      unget_ = false;
+      return ungetc_;
+    }
+    else
+    {
+      xchar c (peek ());
+      get (c);
+      return c;
+    }
+  }
+
+  inline void char_scanner::
+  unget (const xchar& c)
+  {
+    // Because iostream::unget cannot work once eos is reached, we have to
+    // provide our own implementation.
+    //
+    unget_ = true;
+    ungetc_ = c;
+  }
+}