case-folding.rb: perfect hash for case folding

* enc/unicode/case-folding.rb (lookup_hash): make perfect hash to
  lookup case folding table.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46269 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

enc/unicode/case-folding.rb

@@ -13,21 +13,23 @@ class CaseFolding
     end
 
     def print_table_1(dest, data)
-      for k, v in data.sort
+      for k, v in data = data.sort
         sk = (Array === k and k.length > 1) ? "{#{hex_seq(k)}}" : ("0x%04x" % k)
         dest.print("  {#{sk}, {#{v.length}, {#{hex_seq(v)}}}},\n")
       end
+      data
     end
 
     def print_table(dest, type, data)
       dest.print("static const #{type}_Type #{type}_Table[] = {\n")
       i = 0
-      data.each do |n, d|
+      ret = data.inject([]) do |a, (n, d)|
         dest.print("#define #{n} (*(#{type}_Type (*)[#{d.size}])(#{type}_Table+#{i}))\n")
         i += d.size
-        print_table_1(dest, d)
+        a.concat(print_table_1(dest, d))
       end
       dest.print("};\n\n")
+      ret
     end
   end
 
@@ -76,6 +78,55 @@ class CaseFolding
     self
   end
 
+  def lookup_hash(key, type, data)
+    hash = "onigenc_unicode_#{key}_hash"
+    lookup = "onigenc_unicode_#{key}_lookup"
+    gperf = %W"gperf -7 -k1,2,3 -F,-1 -c -j1 -i1 -t -T -E -C -H #{hash} -N #{lookup}"
+    argname = "code"
+    argdecl = "const OnigCodePoint #{argname}"
+    n = 7
+    m = (1 << n) - 1
+    min, max = data.map {|c, *|c}.minmax
+    src = IO.popen(gperf, "r+") {|f|
+      f << "short\n%%\n"
+      data.each_with_index {|(k, _), i|
+        ks = [(k >> n*2) & m, (k >> n) & m, (k) & m].map {|c| "\\x%.2x" % c}.join("")
+        f.printf "\"%s\", ::::/*0x%.4x*/ %d\n", ks, k, i
+      }
+      f << "%%\n"
+      f.close_write
+      f.read
+    }
+    src.sub!(/^(#{hash})\s*\(.*?\).*?\n\{\n(.*)^\}/m) {
+      name = $1
+      body = $2
+      body.gsub!(/\(unsigned char\)str\[(\d+)\]/, "bits_of(#{argname}, \\1)")
+      "#{name}(#{argdecl})\n{\n#{body}}"
+    }
+    src.sub!(/const short *\*\n^(#{lookup})\s*\(.*?\).*?\n\{\n(.*)^\}/m) {
+      name = $1
+      body = $2
+      body.sub!(/\benum\s+\{(\n[ \t]+)/, "\\&MIN_CODE_VALUE = 0x#{min.to_s(16)},\\1""MAX_CODE_VALUE = 0x#{max.to_s(16)},\\1")
+      body.gsub!(/(#{hash})\s*\(.*?\)/, '\1(code)')
+      body.gsub!(/\{"",-1}/, "-1")
+      body.gsub!(/\{"(?:[^"]|\\")+", *::::(.*)\}/, '\1')
+      body.sub!(/(\s+if\s)\(len\b.*\)/) {"#$1(code <= MAX_CODE_VALUE && code >= MIN_CODE_VALUE)"}
+      v = nil
+      body.sub!(/(if\s*\(.*MAX_HASH_VALUE.*\)\n([ \t]*))\{(.*?)\n\2\}/m) {
+        pre = $1
+        indent = $2
+        s = $3
+        s.sub!(/const char *\* *(\w+)( *= *wordlist\[\w+\]).\w+/, 'short \1 = wordlist[key]')
+        v = $1
+        s.sub!(/\bif *\(.*\)/, "if (#{v} >= 0 && code1_equal(#{argname}, #{key}_Table[#{v}].from))")
+        "#{pre}{#{s}\n#{indent}}"
+      }
+      body.sub!(/\b(return\s+&)([^;]+);/, '\1'"#{key}_Table[#{v}].to;")
+      "static const #{type} *\n#{name}(#{argdecl})\n{\n#{body}}"
+    }
+    src
+  end
+
   def display(dest)
     # print the header
     dest.print("/* DO NOT EDIT THIS FILE. */\n")
@@ -85,7 +136,8 @@ class CaseFolding
 
     # CaseFold + CaseFold_Locale
     name = "CaseFold_11"
-    print_table(dest, name, "CaseFold"=>fold, "CaseFold_Locale"=>fold_locale)
+    data = print_table(dest, name, "CaseFold"=>fold, "CaseFold_Locale"=>fold_locale)
+    dest.print lookup_hash(name, "CodePointList3", data)
 
     # print unfolding data
 
@@ -102,8 +154,6 @@ class CaseFolding
     print_table(dest, name, name=>unfold[2])
 
     # table sizes
-    fold_table_size = fold.size + fold_locale.size
-    dest.printf("#define FOLD_TABLE_SIZE\t\t%d\n", (fold_table_size * 1.2))
     unfold1_table_size = unfold[0].size + unfold_locale[0].size
     dest.printf("#define UNFOLD1_TABLE_SIZE\t%d\n", (unfold1_table_size * 1.2))
     unfold2_table_size = unfold[1].size + unfold_locale[1].size