* tool/transcode-tblgen.rb: reject ambiguous mapping.

* enc/trans/single_byte.trans: remove ambiguous maping such as
  \xD6 -> U+05F2 and \xD6\xC7 -> U+FB1F in Windows-1255


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@26912 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 19 insertions, 0 deletions

diff --git a/tool/transcode-tblgen.rb b/tool/transcode-tblgen.rb
index dbd03e3028..14a09dbadf 100755
--- a/tool/transcode-tblgen.rb
+++ b/tool/transcode-tblgen.rb
@@ -133,6 +133,12 @@ class StrSet
     }
   end
 
+  def has_nonempty?
+    @pat.any? {|seq|
+      !seq.empty?
+    }
+  end
+
   def first_bytes
     result = {}
     @pat.each {|seq|
@@ -228,6 +234,18 @@ class ActionMap
     @map.keys.map {|k| k.max_length }.max
   end
 
+  def check_conflict
+    has_empty = false
+    has_nonempty = false
+    @map.each {|ss, action|
+      has_empty = true if ss.emptyable?
+      has_nonempty = true if ss.has_nonempty?
+    }
+    if has_empty && has_nonempty
+      raise "conflict between empty and nonempty sequence"
+    end
+  end
+
   def empty_action
     @map.each {|ss, action|
       return action if ss.emptyable?
@@ -440,6 +458,7 @@ End
 
     table = Array.new(0x100, :invalid)
     each_firstbyte(valid_encoding) {|byte, rest, rest_valid_encoding|
+      rest.check_conflict
       if a = rest.empty_action
         table[byte] = a
       else