Merge branch 'kitagawa_jfm_opt'

diff --combined src/luatexja/jfont.lua
index cfb071e,782c2f7..0106dbb
--- 1/src/luatexja/jfont.lua
--- 2/src/luatexja/jfont.lua
+++ b/src/luatexja/jfont.lua
@@@ -126,18 -126,24 +126,24 @@@ local function update_jfm_cache(j,sz
     metrics[j].size_cache[sz].zh = round(metrics[j].zh*sz)
  end
  
+ luatexbase.create_callback("ltj.find_char_class", "data", 
+                          function (arg, fmtable, char)
+                             return 0
+                          end)
+ 
  function find_char_class(c,m)
- -- c: character code, m
-    if not metrics[m] then return 0 end
-    return metrics[m].chars[c] or 0
+ -- c: character code, m: index in font_metric table
+    if not metrics[m.jfm] then return 0 end
+    return metrics[m.jfm].chars[c] or 
+       luatexbase.call_callback("ltj.find_char_class", 0, m, c)
  end
  
  local function load_jfont_metric()
     if jfm_file_name=='' then 
        ltjb.package_error('luatexja',
                         'no JFM specified',
 -                       {'To load and define a Japanese font, a JFM must be specified.',
 -                        "The JFM 'ujis' will be  used for now."})
 +                       'To load and define a Japanese font, a JFM must be specified.'..
 +                        "The JFM 'ujis' will be  used for now.")
        jfm_file_name='ujis'
     end
     for j,v in ipairs(metrics) do 
@@@ -168,6 -174,8 +174,8 @@@ function jfontdefX(g
  end
  
  -- EXT
+ luatexbase.create_callback("ltj.define_jfont", "data", function (ft, fn) return ft end)
+ 
  function jfontdefY() -- for horizontal font
     local j = load_jfont_metric()
     local fn = font.id(cstemp)
@@@ -181,11 -189,10 +189,10 @@@
               .. '\\endcsname=\\relax')
       return 
     end
-    font_metric_table[fn]={}
-    font_metric_table[fn].jfm=j
-    font_metric_table[fn].size=f.size
-    font_metric_table[fn].var=jfm_var
     update_jfm_cache(j, f.size)
+    local fmtable = { jfm = j, size = f.size, var = jfm_var }
+    fmtable = luatexbase.call_callback("ltj.define_jfont", fmtable, fn)
+    font_metric_table[fn]=fmtable
     tex.sprint(cat_lp, ltj.is_global .. '\\protected\\expandafter\\def\\csname ' 
            .. cstemp  .. '\\endcsname{\\ltj@curjfnt=' .. fn .. '\\relax}')
  end
@@@ -258,7 -265,7 +265,7 @@@ function append_italic(
        if ltjc.is_ucs_in_japanese_char(p) then
         f = has_attr(p, attr_curjfnt)
         local j = font_metric_table[f]
-        local c = find_char_class(p.char, j.jfm)
+        local c = find_char_class(p.char, j)
         g.kern = metrics[j.jfm].size_cache[j.size].char_type[c].italic
        else
         g.kern = font.fonts[f].characters[p.char].italic