From 6017de0314b5115183c04b81562bbe7fdb71959a Mon Sep 17 00:00:00 2001
From: duerst <duerst@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Sun, 19 Oct 2014 00:38:40 +0000
Subject: [PATCH] lib/unicode_normalize/normalize.rb: Importing from
 https://github.com/duerst/eprun/blob/master/lib/normalize.rb.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48005 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog                          |   5 +
 lib/unicode_normalize/normalize.rb | 176 +++++++++++++++++++++++++++++
 2 files changed, 181 insertions(+)
 create mode 100644 lib/unicode_normalize/normalize.rb

diff --git a/ChangeLog b/ChangeLog
index ddbc6e8b5a..df03a91453 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Oct 19 09:38:38 2014  Martin Duerst <duerst@it.aoyama.ac.jp>
+
+	* lib/unicode_normalize/normalize.rb: Importing from
+	  https://github.com/duerst/eprun/blob/master/lib/normalize.rb.
+
 Sat Oct 18 20:40:52 2014  Kazuki Tsujimoto  <kazuki@callcc.net>
 
 	* vm_core.h, proc.c, vm_backtrace.c, vm_trace.c:
diff --git a/lib/unicode_normalize/normalize.rb b/lib/unicode_normalize/normalize.rb
new file mode 100644
index 0000000000..4f0fdbc78a
--- /dev/null
+++ b/lib/unicode_normalize/normalize.rb
@@ -0,0 +1,176 @@
+# coding: utf-8
+
+# Copyright 2010-2013 Ayumu Nojima (野島 歩) and Martin J. Dürst (duerst@it.aoyama.ac.jp)
+# available under the same licence as Ruby itself
+# (see http://www.ruby-lang.org/en/LICENSE.txt)
+
+require_relative 'normalize_tables'
+
+
+module Normalize
+  ## Constant for max hash capacity to avoid DoS attack
+  MAX_HASH_LENGTH = 18000 # enough for all test cases, otherwise tests get slow
+  
+  ## Regular Expressions and Hash Constants
+  REGEXP_D = Regexp.compile(REGEXP_D_STRING, Regexp::EXTENDED)
+  REGEXP_C = Regexp.compile(REGEXP_C_STRING, Regexp::EXTENDED)
+  REGEXP_K = Regexp.compile(REGEXP_K_STRING, Regexp::EXTENDED)
+  NF_HASH_D = Hash.new do |hash, key|
+                         hash.delete hash.first[0] if hash.length>MAX_HASH_LENGTH # prevent DoS attack
+                         hash[key] = Normalize.nfd_one(key)
+                       end
+  NF_HASH_C = Hash.new do |hash, key|
+                         hash.delete hash.first[0] if hash.length>MAX_HASH_LENGTH # prevent DoS attack
+                         hash[key] = Normalize.nfc_one(key)
+                       end
+  NF_HASH_K = Hash.new do |hash, key|
+                         hash.delete hash.first[0] if hash.length>MAX_HASH_LENGTH # prevent DoS attack
+                         hash[key] = Normalize.nfkd_one(key)
+                       end
+  
+  ## Constants For Hangul
+  SBASE = 0xAC00
+  LBASE = 0x1100
+  VBASE = 0x1161
+  TBASE = 0x11A7
+  LCOUNT = 19
+  VCOUNT = 21
+  TCOUNT = 28
+  NCOUNT = VCOUNT * TCOUNT
+  SCOUNT = LCOUNT * NCOUNT
+  
+  # Unicode-based encodings (except UTF-8)
+  UNICODE_ENCODINGS = [Encoding::UTF_16BE, Encoding::UTF_16LE, Encoding::UTF_32BE, Encoding::UTF_32LE,
+                       Encoding::GB18030, Encoding::UCS_2BE, Encoding::UCS_4BE]
+  
+  ## Hangul Algorithm
+  def Normalize.hangul_decomp_one(target)
+    sIndex = target.ord - SBASE
+    return target if sIndex < 0 || sIndex >= SCOUNT
+    l = LBASE + sIndex / NCOUNT
+    v = VBASE + (sIndex % NCOUNT) / TCOUNT
+    t = TBASE + sIndex % TCOUNT
+    (t==TBASE ? [l, v] : [l, v, t]).pack('U*') + target[1..-1]
+  end
+  
+  def Normalize.hangul_comp_one(string)
+    length = string.length
+    if length>1 and 0 <= (lead =string[0].ord-LBASE) and lead  < LCOUNT and
+                    0 <= (vowel=string[1].ord-VBASE) and vowel < VCOUNT
+      lead_vowel = SBASE + (lead * VCOUNT + vowel) * TCOUNT
+      if length>2 and 0 <= (trail=string[2].ord-TBASE) and trail < TCOUNT
+        (lead_vowel + trail).chr(Encoding::UTF_8) + string[3..-1]
+      else
+        lead_vowel.chr(Encoding::UTF_8) + string[2..-1]
+      end
+    else
+      string
+    end
+  end
+  
+  ## Canonical Ordering
+  def Normalize.canonical_ordering_one(string)
+    sorting = string.each_char.collect { |c| [c, CLASS_TABLE[c]] }
+    (sorting.length-2).downto(0) do |i| # bubble sort
+      (0..i).each do |j|
+        later_class = sorting[j+1].last
+        if 0<later_class and later_class<sorting[j].last
+          sorting[j], sorting[j+1] = sorting[j+1], sorting[j]
+        end
+      end
+    end
+    return sorting.collect(&:first).join
+  end
+  
+  ## Normalization Forms for Patterns (not whole Strings)
+  def Normalize.nfd_one(string)
+    string = string.dup
+    (0...string.length).each do |position|
+      if decomposition = DECOMPOSITION_TABLE[string[position]]
+        string[position] = decomposition
+      end
+    end
+    canonical_ordering_one(hangul_decomp_one(string))
+  end
+  
+  def Normalize.nfkd_one(string)
+    string = string.dup
+    position = 0
+    while position < string.length
+      if decomposition = KOMPATIBLE_TABLE[string[position]]
+        string[position] = decomposition
+      else
+        position += 1
+      end
+    end
+    string
+  end
+  
+  def Normalize.nfc_one (string)
+    nfd_string = nfd_one string
+    start = nfd_string[0]
+    last_class = CLASS_TABLE[start]-1
+    accents = ''
+    nfd_string[1..-1].each_char do |accent|
+      accent_class = CLASS_TABLE[accent]
+      if last_class<accent_class and composite = COMPOSITION_TABLE[start+accent]
+        start = composite
+      else
+        accents += accent
+        last_class = accent_class
+      end
+    end
+    hangul_comp_one(start+accents)
+  end
+  
+  def Normalize.normalize(string, form = :nfc)
+    encoding = string.encoding
+    if encoding == Encoding::UTF_8
+      case form
+      when :nfc then
+        string.gsub REGEXP_C, NF_HASH_C
+      when :nfd then
+        string.gsub REGEXP_D, NF_HASH_D
+      when :nfkc then
+        string.gsub(REGEXP_K, NF_HASH_K).gsub REGEXP_C, NF_HASH_C
+      when :nfkd then
+        string.gsub(REGEXP_K, NF_HASH_K).gsub REGEXP_D, NF_HASH_D
+      else
+        raise ArgumentError, "Invalid normalization form #{form}."
+      end
+    elsif  UNICODE_ENCODINGS.include? encoding
+      normalize(string.encode(Encoding::UTF_8), form).encode(encoding)
+    else
+      raise Encoding::CompatibilityError, "Unicode Normalization not appropriate for #{encoding}"
+    end
+  end
+  
+  def Normalize.normalized?(string, form = :nfc)
+    encoding = string.encoding
+    if encoding == Encoding::UTF_8
+      case form
+      when :nfc then
+        string.scan REGEXP_C do |match|
+          return false  if NF_HASH_C[match] != match
+        end
+        true
+      when :nfd then
+        string.scan REGEXP_D do |match|
+          return false  if NF_HASH_D[match] != match
+        end
+        true
+      when :nfkc then
+        normalized?(string, :nfc) and string !~ REGEXP_K
+      when :nfkd then
+        normalized?(string, :nfd) and string !~ REGEXP_K
+      else
+        raise ArgumentError, "Invalid normalization form #{form}."
+      end
+    elsif  UNICODE_ENCODINGS.include? encoding
+      normalized? string.encode(Encoding::UTF_8), form
+    else
+      raise Encoding::CompatibilityError, "Unicode Normalization not appropriate for #{encoding}"
+    end
+  end
+  
+end # module