Correctly justify Unicode characters in terminal

Many Unicode characters take more spaces than one ASCII character. For
example, Chinese characters are two characters wide when using monospace
font in terminal. This patch use wcwidth of Markus Kuhn to count the
correct width for justification.

1 files changed, 11 insertions, 1 deletions

diff --git a/src/unistring.h b/src/unistring.h
index 8e963f37..7d78d134 100644
--- a/src/unistring.h
+++ b/src/unistring.h
@@ -44,6 +44,8 @@
 
 namespace ledger {
 
+int mk_wcwidth_cjk(boost::uint32_t ucs);
+
 /**
  * @class unistring
  *
@@ -81,6 +83,14 @@ public:
     return utf32chars.size();
   }
 
+  std::size_t width() const {
+    std::size_t width = 0;
+    foreach (const boost::uint32_t& ch, utf32chars) {
+      width += mk_wcwidth_cjk(ch);
+    }
+    return width;
+  }
+
   std::string extract(const std::string::size_type begin = 0,
                       const std::string::size_type len   = 0) const
   {
@@ -133,7 +143,7 @@ inline void justify(std::ostream&      out,
 
   unistring temp(str);
 
-  int spacing = width - int(temp.length());
+  int spacing = width - int(temp.width());
   while (spacing-- > 0)
     out << ' ';