Fix Display Width with Unicode library

lib/sup/buffer.rb

@@ -126,14 +126,11 @@ def write y, x, s, opts={}
     @w.attrset Colormap.color_for(opts[:color] || :none, opts[:highlight])
     s ||= ""
     maxl = @width - x # maximum display width width
-    stringl = maxl    # string "length"
 
     # fill up the line with blanks to overwrite old screen contents
     @w.mvaddstr y, x, " " * maxl unless opts[:no_fill]
 
-    ## the next horribleness is thanks to ruby's lack of widechar support
-    stringl += 1 while stringl < s.length && s[0 ... stringl].display_length < maxl
-    @w.mvaddstr y, x, s[0 ... stringl]
+    @w.mvaddstr y, x, s.slice_by_display_length(maxl)
   end
 
   def clear

lib/sup/modes/thread_index_mode.rb

@@ -856,14 +856,14 @@ def text_for_thread_at line
 
       abbrev =
         if cur_width + name.display_length > from_width
-          name[0 ... (from_width - cur_width - 1)] + "."
+          name.slice_by_display_length(from_width - cur_width - 1) + "."
         elsif cur_width + name.display_length == from_width
-          name[0 ... (from_width - cur_width)]
+          name.slice_by_display_length(from_width - cur_width)
         else
           if last
-            name[0 ... (from_width - cur_width)]
+            name.slice_by_display_length(from_width - cur_width)
           else
-            name[0 ... (from_width - cur_width - 1)] + ","
+            name.slice_by_display_length(from_width - cur_width - 1) + ","
           end
         end
 

lib/sup/util.rb

@@ -7,6 +7,7 @@
 require 'set'
 require 'enumerator'
 require 'benchmark'
+require 'unicode'
 
 ## time for some monkeypatching!
 class Symbol
@@ -254,14 +255,14 @@ def benchmark s, &b
 end
 
 class String
-  ## nasty multibyte hack for ruby 1.8. if it's utf-8, split into chars using
-  ## the utf8 regex and count those. otherwise, use the byte length.
   def display_length
-    if RUBY_VERSION < '1.9.1' && ($encoding == "UTF-8" || $encoding == "utf8")
-      # scan hack is somewhat slow, worth trying to cache
-      @display_length ||= scan(/./u).size
-    else
-      size
+    @display_length ||= Unicode.width(self, false)
+  end
+
+  def slice_by_display_length len
+    each_char.each_with_object "" do |c, buffer|
+      len -= c.display_length
+      buffer << c if len >= 0
     end
   end
 
@@ -348,14 +349,14 @@ def split_on_commas_with_remainder
   def wrap len
     ret = []
     s = self
-    while s.length > len
-      cut = s[0 ... len].rindex(/\s/)
+    while s.display_length > len
+      cut = s.slice_by_display_length(len).rindex(/\s/)
       if cut
         ret << s[0 ... cut]
         s = s[(cut + 1) .. -1]
       else
-        ret << s[0 ... len]
-        s = s[len .. -1]
+        ret << s.slice_by_display_length(len)
+        s = s[ret.last.length .. -1]
       end
     end
     ret << s

sup.gemspec

@@ -52,6 +52,7 @@ SUP: Please run `sup-psych-ify-config-files` to migrate from 0.13 to 0.14
     s.add_runtime_dependency "mime-types", "~> 1.0"
     s.add_runtime_dependency "locale", "~> 2.0"
     s.add_runtime_dependency "chronic", "~> 0.9.1"
+    s.add_runtime_dependency "unicode", "~> 0.4.4"
 
     s.add_development_dependency "bundler", "~> 1.3"
     s.add_development_dependency "rake"

test/unit/util/test_string.rb

@@ -0,0 +1,57 @@
+# encoding: utf-8
+
+require "test_helper"
+
+require "sup/util"
+
+describe "Sup's String extension" do
+  describe "#display_length" do
+    let :data do
+      [
+        ['some words', 10,],
+        ['中文', 4,],
+        ['ä', 1,],
+      ]
+    end
+
+    it "calculates display length of a string" do
+      data.each do |(str, length)|
+        str.display_length.must_equal length
+      end
+    end
+  end
+
+  describe "#slice_by_display_length(len)" do
+    let :data do
+      [
+        ['some words', 6, 'some w'],
+        ['中文', 2, '中'],
+        ['älpha', 3, 'älp'],
+      ]
+    end
+
+    it "slices string by display length" do
+      data.each do |(str, length, sliced)|
+        str.slice_by_display_length(length).must_equal sliced
+      end
+    end
+  end
+
+  describe "#wrap" do
+    let :data do
+      [
+        ['some words', 6, ['some', 'words']],
+        ['some words', 80, ['some words']],
+        ['中文', 2, ['中', '文']],
+        ['中文', 5, ['中文']],
+        ['älpha', 3, ['älp', 'ha']],
+      ]
+    end
+
+    it "wraps string by display length" do
+      data.each do |(str, length, wrapped)|
+        str.wrap(length).must_equal wrapped
+      end
+    end
+  end
+end