1 files changed, 84 insertions, 0 deletions
diff --git a/tool/jisx0208.rb b/tool/jisx0208.rb
new file mode 100644
index 0000000000..921f574816
--- /dev/null
+++ b/tool/jisx0208.rb
@@ -0,0 +1,84 @@
+module JISX0208
+  class Char
+    class << self
+      def from_sjis(sjis)
+        unless 0x8140 <= sjis && sjis <= 0xFCFC
+          raise ArgumentError, "out of the range of JIS X 0208: 0x#{sjis.to_s(16)}"
+        end
+        sjis_hi, sjis_lo = sjis >> 8, sjis & 0xFF
+        sjis_hi = (sjis_hi - ((sjis_hi <= 0x9F) ? 0x80 : 0xC0)) << 1
+        if sjis_lo <= 0x9E
+          sjis_hi -= 1
+          sjis_lo -= (sjis_lo <= 0x7E) ? 0x3F : 0x40
+        else
+          sjis_lo -= 0x9E
+        end
+        return self.new(sjis_hi, sjis_lo)
+      end
+    end
+
+    def initialize(row, cell=nil)
+      if cell
+        @code = row_cell_to_code(row, cell)
+      else
+        @code = row.to_int
+      end
+    end
+
+    def ==(other)
+      if self.class === other
+        return Integer(self) == Integer(other)
+      end
+      return super(other)
+    end
+
+    def to_int
+      return @code
+    end
+
+    def hi
+      Integer(self) >> 8
+    end
+
+    def lo
+      Integer(self) & 0xFF
+    end
+
+    def row
+      self.hi - 0x20
+    end
+
+    def cell
+      self.lo - 0x20
+    end
+
+    def succ
+      succ_hi, succ_lo = self.hi, self.lo + 1
+      if succ_lo > 0x7E
+        succ_lo = 0x21
+        succ_hi += 1
+      end
+      return self.class.new(succ_hi << 8 | succ_lo)
+    end
+
+    def to_sjis
+      h, l = self.hi, self.lo
+      h = (h + 1) / 2 + ((0x21..0x5E).include?(h) ? 0x70 : 0xB0)
+      l += self.hi.odd? ? 0x1F + ((l >= 0x60) ? 1 : 0) : 0x7E
+      return h << 8 | l
+    end
+
+    def inspect
+      "#<JISX0208::Char:#{self.object_id.to_s(16)} sjis=#{self.to_sjis.to_s(16)} jis=#{self.to_int.to_s(16)}>"
+    end
+
+    private
+
+    def row_cell_to_code(row, cell)
+      unless 0 < row && (1..94).include?(cell)
+        raise ArgumentError, "out of row-cell range: #{row}-#{cell}"
+      end
+      return (row + 0x20) << 8 | (cell + 0x20)
+    end
+  end
+end