diff -r 000000000000 -r 6474c204b198 intl/hyphenation/src/nsHyphenator.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/intl/hyphenation/src/nsHyphenator.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,122 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsHyphenator.h"
+#include "nsIFile.h"
+#include "nsUTF8Utils.h"
+#include "nsUnicodeProperties.h"
+#include "nsUnicharUtilCIID.h"
+#include "nsIURI.h"
+
+#include "hyphen.h"
+
+nsHyphenator::nsHyphenator(nsIURI *aURI)
+  : mDict(nullptr)
+{
+  nsCString uriSpec;
+  nsresult rv = aURI->GetSpec(uriSpec);
+  if (NS_FAILED(rv)) {
+    return;
+  }
+  mDict = hnj_hyphen_load(uriSpec.get());
+#ifdef DEBUG
+  if (mDict) {
+    printf("loaded hyphenation patterns from %s\n", uriSpec.get());
+  }
+#endif
+}
+
+nsHyphenator::~nsHyphenator()
+{
+  if (mDict != nullptr) {
+    hnj_hyphen_free((HyphenDict*)mDict);
+    mDict = nullptr;
+  }
+}
+
+bool
+nsHyphenator::IsValid()
+{
+  return (mDict != nullptr);
+}
+
+nsresult
+nsHyphenator::Hyphenate(const nsAString& aString,
+                        FallibleTArray<bool>& aHyphens)
+{
+  if (!aHyphens.SetLength(aString.Length())) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  memset(aHyphens.Elements(), false, aHyphens.Length());
+
+  bool inWord = false;
+  uint32_t wordStart = 0, wordLimit = 0;
+  uint32_t chLen;
+  for (uint32_t i = 0; i < aString.Length(); i += chLen) {
+    uint32_t ch = aString[i];
+    chLen = 1;
+
+    if (NS_IS_HIGH_SURROGATE(ch)) {
+      if (i + 1 < aString.Length() && NS_IS_LOW_SURROGATE(aString[i+1])) {
+        ch = SURROGATE_TO_UCS4(ch, aString[i+1]);
+        chLen = 2;
+      } else {
+        NS_WARNING("unpaired surrogate found during hyphenation");
+      }
+    }
+
+    nsIUGenCategory::nsUGenCategory cat = mozilla::unicode::GetGenCategory(ch);
+    if (cat == nsIUGenCategory::kLetter || cat == nsIUGenCategory::kMark) {
+      if (!inWord) {
+        inWord = true;
+        wordStart = i;
+      }
+      wordLimit = i + chLen;
+      if (i + chLen < aString.Length()) {
+        continue;
+      }
+    }
+
+    if (inWord) {
+      const char16_t *begin = aString.BeginReading();
+      NS_ConvertUTF16toUTF8 utf8(begin + wordStart,
+                                 wordLimit - wordStart);
+      nsAutoTArray<char,200> utf8hyphens;
+      utf8hyphens.SetLength(utf8.Length() + 5);
+      char **rep = nullptr;
+      int *pos = nullptr;
+      int *cut = nullptr;
+      int err = hnj_hyphen_hyphenate2((HyphenDict*)mDict,
+                                      utf8.BeginReading(), utf8.Length(),
+                                      utf8hyphens.Elements(), nullptr,
+                                      &rep, &pos, &cut);
+      if (!err) {
+        // Surprisingly, hnj_hyphen_hyphenate2 converts the 'hyphens' buffer
+        // from utf8 code unit indexing (which would match the utf8 input
+        // string directly) to Unicode character indexing.
+        // We then need to convert this to utf16 code unit offsets for Gecko.
+        const char *hyphPtr = utf8hyphens.Elements();
+        const char16_t *cur = begin + wordStart;
+        const char16_t *end = begin + wordLimit;
+        while (cur < end) {
+          if (*hyphPtr & 0x01) {
+            aHyphens[cur - begin] = true;
+          }
+          cur++;
+          if (cur < end && NS_IS_LOW_SURROGATE(*cur) &&
+              NS_IS_HIGH_SURROGATE(*(cur-1)))
+          {
+            cur++;
+          }
+          hyphPtr++;
+        }
+      }
+    }
+    
+    inWord = false;
+  }
+
+  return NS_OK;
+}