Add m-esr52 at 52.6.0

1 files changed, 1383 insertions, 0 deletions

diff --git a/xpcom/string/nsReadableUtils.cpp b/xpcom/string/nsReadableUtils.cpp
new file mode 100644
index 000000000..524b1d7fe
--- /dev/null
+++ b/xpcom/string/nsReadableUtils.cpp
@@ -0,0 +1,1383 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 "nsReadableUtils.h"
+#include "nsReadableUtilsImpl.h"
+
+#include <algorithm>
+
+#include "mozilla/CheckedInt.h"
+
+#include "nscore.h"
+#include "nsMemory.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "nsUTF8Utils.h"
+
+using mozilla::IsASCII;
+
+/**
+ * Fallback implementation for finding the first non-ASCII character in a
+ * UTF-16 string.
+ */
+static inline int32_t
+FirstNonASCIIUnvectorized(const char16_t* aBegin, const char16_t* aEnd)
+{
+  typedef mozilla::NonASCIIParameters<sizeof(size_t)> p;
+  const size_t kMask = p::mask();
+  const uintptr_t kAlignMask = p::alignMask();
+  const size_t kNumUnicharsPerWord = p::numUnicharsPerWord();
+
+  const char16_t* idx = aBegin;
+
+  // Align ourselves to a word boundary.
+  for (; idx != aEnd && ((uintptr_t(idx) & kAlignMask) != 0); idx++) {
+    if (!IsASCII(*idx)) {
+      return idx - aBegin;
+    }
+  }
+
+  // Check one word at a time.
+  const char16_t* wordWalkEnd = mozilla::aligned(aEnd, kAlignMask);
+  for (; idx != wordWalkEnd; idx += kNumUnicharsPerWord) {
+    const size_t word = *reinterpret_cast<const size_t*>(idx);
+    if (word & kMask) {
+      return idx - aBegin;
+    }
+  }
+
+  // Take care of the remainder one character at a time.
+  for (; idx != aEnd; idx++) {
+    if (!IsASCII(*idx)) {
+      return idx - aBegin;
+    }
+  }
+
+  return -1;
+}
+
+/*
+ * This function returns -1 if all characters in str are ASCII characters.
+ * Otherwise, it returns a value less than or equal to the index of the first
+ * ASCII character in str. For example, if first non-ASCII character is at
+ * position 25, it may return 25, 24, or 16. But it guarantees
+ * there are only ASCII characters before returned value.
+ */
+static inline int32_t
+FirstNonASCII(const char16_t* aBegin, const char16_t* aEnd)
+{
+#ifdef MOZILLA_MAY_SUPPORT_SSE2
+  if (mozilla::supports_sse2()) {
+    return mozilla::SSE2::FirstNonASCII(aBegin, aEnd);
+  }
+#endif
+
+  return FirstNonASCIIUnvectorized(aBegin, aEnd);
+}
+
+void
+LossyCopyUTF16toASCII(const nsAString& aSource, nsACString& aDest)
+{
+  aDest.Truncate();
+  LossyAppendUTF16toASCII(aSource, aDest);
+}
+
+void
+CopyASCIItoUTF16(const nsACString& aSource, nsAString& aDest)
+{
+  aDest.Truncate();
+  AppendASCIItoUTF16(aSource, aDest);
+}
+
+void
+LossyCopyUTF16toASCII(const char16ptr_t aSource, nsACString& aDest)
+{
+  aDest.Truncate();
+  if (aSource) {
+    LossyAppendUTF16toASCII(nsDependentString(aSource), aDest);
+  }
+}
+
+void
+CopyASCIItoUTF16(const char* aSource, nsAString& aDest)
+{
+  aDest.Truncate();
+  if (aSource) {
+    AppendASCIItoUTF16(nsDependentCString(aSource), aDest);
+  }
+}
+
+void
+CopyUTF16toUTF8(const nsAString& aSource, nsACString& aDest)
+{
+  if (!CopyUTF16toUTF8(aSource, aDest, mozilla::fallible)) {
+    // Note that this may wildly underestimate the allocation that failed, as
+    // we report the length of aSource as UTF-16 instead of UTF-8.
+    aDest.AllocFailed(aDest.Length() + aSource.Length());
+  }
+}
+
+bool
+CopyUTF16toUTF8(const nsAString& aSource, nsACString& aDest,
+                const mozilla::fallible_t& aFallible)
+{
+  aDest.Truncate();
+  if (!AppendUTF16toUTF8(aSource, aDest, aFallible)) {
+    return false;
+  }
+  return true;
+}
+
+void
+CopyUTF8toUTF16(const nsACString& aSource, nsAString& aDest)
+{
+  aDest.Truncate();
+  AppendUTF8toUTF16(aSource, aDest);
+}
+
+void
+CopyUTF16toUTF8(const char16ptr_t aSource, nsACString& aDest)
+{
+  aDest.Truncate();
+  AppendUTF16toUTF8(aSource, aDest);
+}
+
+void
+CopyUTF8toUTF16(const char* aSource, nsAString& aDest)
+{
+  aDest.Truncate();
+  AppendUTF8toUTF16(aSource, aDest);
+}
+
+void
+LossyAppendUTF16toASCII(const nsAString& aSource, nsACString& aDest)
+{
+  uint32_t old_dest_length = aDest.Length();
+  aDest.SetLength(old_dest_length + aSource.Length());
+
+  nsAString::const_iterator fromBegin, fromEnd;
+
+  nsACString::iterator dest;
+  aDest.BeginWriting(dest);
+
+  dest.advance(old_dest_length);
+
+  // right now, this won't work on multi-fragment destinations
+  LossyConvertEncoding16to8 converter(dest.get());
+
+  copy_string(aSource.BeginReading(fromBegin), aSource.EndReading(fromEnd),
+              converter);
+}
+
+void
+AppendASCIItoUTF16(const nsACString& aSource, nsAString& aDest)
+{
+  if (!AppendASCIItoUTF16(aSource, aDest, mozilla::fallible)) {
+    aDest.AllocFailed(aDest.Length() + aSource.Length());
+  }
+}
+
+bool
+AppendASCIItoUTF16(const nsACString& aSource, nsAString& aDest,
+                   const mozilla::fallible_t& aFallible)
+{
+  uint32_t old_dest_length = aDest.Length();
+  if (!aDest.SetLength(old_dest_length + aSource.Length(),
+                       aFallible)) {
+    return false;
+  }
+
+  nsACString::const_iterator fromBegin, fromEnd;
+
+  nsAString::iterator dest;
+  aDest.BeginWriting(dest);
+
+  dest.advance(old_dest_length);
+
+  // right now, this won't work on multi-fragment destinations
+  LossyConvertEncoding8to16 converter(dest.get());
+
+  copy_string(aSource.BeginReading(fromBegin), aSource.EndReading(fromEnd),
+              converter);
+  return true;
+}
+
+void
+LossyAppendUTF16toASCII(const char16ptr_t aSource, nsACString& aDest)
+{
+  if (aSource) {
+    LossyAppendUTF16toASCII(nsDependentString(aSource), aDest);
+  }
+}
+
+bool
+AppendASCIItoUTF16(const char* aSource, nsAString& aDest, const mozilla::fallible_t& aFallible)
+{
+  if (aSource) {
+    return AppendASCIItoUTF16(nsDependentCString(aSource), aDest, aFallible);
+  }
+
+  return true;
+}
+
+void
+AppendASCIItoUTF16(const char* aSource, nsAString& aDest)
+{
+  if (aSource) {
+    AppendASCIItoUTF16(nsDependentCString(aSource), aDest);
+  }
+}
+
+void
+AppendUTF16toUTF8(const nsAString& aSource, nsACString& aDest)
+{
+  if (!AppendUTF16toUTF8(aSource, aDest, mozilla::fallible)) {
+    // Note that this may wildly underestimate the allocation that failed, as
+    // we report the length of aSource as UTF-16 instead of UTF-8.
+    aDest.AllocFailed(aDest.Length() + aSource.Length());
+  }
+}
+
+bool
+AppendUTF16toUTF8(const nsAString& aSource, nsACString& aDest,
+                  const mozilla::fallible_t& aFallible)
+{
+  // At 16 characters analysis showed better performance of both the all ASCII
+  // and non-ASCII cases, so we limit calling |FirstNonASCII| to strings of
+  // that length.
+  const nsAString::size_type kFastPathMinLength = 16;
+
+  int32_t firstNonASCII = 0;
+  if (aSource.Length() >= kFastPathMinLength) {
+    firstNonASCII = FirstNonASCII(aSource.BeginReading(), aSource.EndReading());
+  }
+
+  if (firstNonASCII == -1) {
+    // This is all ASCII, we can use the more efficient lossy append.
+    mozilla::CheckedInt<nsACString::size_type> new_length(aSource.Length());
+    new_length += aDest.Length();
+
+    if (!new_length.isValid() ||
+        !aDest.SetCapacity(new_length.value(), aFallible)) {
+      return false;
+    }
+
+    LossyAppendUTF16toASCII(aSource, aDest);
+    return true;
+  }
+
+  nsAString::const_iterator source_start, source_end;
+  CalculateUTF8Size calculator;
+  aSource.BeginReading(source_start);
+  aSource.EndReading(source_end);
+
+  // Skip the characters that we know are single byte.
+  source_start.advance(firstNonASCII);
+
+  copy_string(source_start,
+              source_end, calculator);
+
+  // Include the ASCII characters that were skipped in the count.
+  size_t count = calculator.Size() + firstNonASCII;
+
+  if (count) {
+    auto old_dest_length = aDest.Length();
+    // Grow the buffer if we need to.
+    mozilla::CheckedInt<nsACString::size_type> new_length(count);
+    new_length += old_dest_length;
+
+    if (!new_length.isValid() ||
+        !aDest.SetLength(new_length.value(), aFallible)) {
+      return false;
+    }
+
+    // All ready? Time to convert
+
+    nsAString::const_iterator ascii_end;
+    aSource.BeginReading(ascii_end);
+
+    if (firstNonASCII >= static_cast<int32_t>(kFastPathMinLength)) {
+      // Use the more efficient lossy converter for the ASCII portion.
+      LossyConvertEncoding16to8 lossy_converter(
+          aDest.BeginWriting() + old_dest_length);
+      nsAString::const_iterator ascii_start;
+      aSource.BeginReading(ascii_start);
+      ascii_end.advance(firstNonASCII);
+
+      copy_string(ascii_start, ascii_end, lossy_converter);
+    } else {
+      // Not using the lossy shortcut, we need to include the leading ASCII
+      // chars.
+      firstNonASCII = 0;
+    }
+
+    ConvertUTF16toUTF8 converter(
+        aDest.BeginWriting() + old_dest_length + firstNonASCII);
+    copy_string(ascii_end,
+                aSource.EndReading(source_end), converter);
+
+    NS_ASSERTION(converter.Size() == count - firstNonASCII,
+                 "Unexpected disparity between CalculateUTF8Size and "
+                 "ConvertUTF16toUTF8");
+  }
+
+  return true;
+}
+
+void
+AppendUTF8toUTF16(const nsACString& aSource, nsAString& aDest)
+{
+  if (!AppendUTF8toUTF16(aSource, aDest, mozilla::fallible)) {
+    aDest.AllocFailed(aDest.Length() + aSource.Length());
+  }
+}
+
+bool
+AppendUTF8toUTF16(const nsACString& aSource, nsAString& aDest,
+                  const mozilla::fallible_t& aFallible)
+{
+  nsACString::const_iterator source_start, source_end;
+  CalculateUTF8Length calculator;
+  copy_string(aSource.BeginReading(source_start),
+              aSource.EndReading(source_end), calculator);
+
+  uint32_t count = calculator.Length();
+
+  // Avoid making the string mutable if we're appending an empty string
+  if (count) {
+    uint32_t old_dest_length = aDest.Length();
+
+    // Grow the buffer if we need to.
+    if (!aDest.SetLength(old_dest_length + count, aFallible)) {
+      return false;
+    }
+
+    // All ready? Time to convert
+
+    ConvertUTF8toUTF16 converter(aDest.BeginWriting() + old_dest_length);
+    copy_string(aSource.BeginReading(source_start),
+                aSource.EndReading(source_end), converter);
+
+    NS_ASSERTION(converter.ErrorEncountered() ||
+                 converter.Length() == count,
+                 "CalculateUTF8Length produced the wrong length");
+
+    if (converter.ErrorEncountered()) {
+      NS_ERROR("Input wasn't UTF8 or incorrect length was calculated");
+      aDest.SetLength(old_dest_length);
+    }
+  }
+
+  return true;
+}
+
+void
+AppendUTF16toUTF8(const char16ptr_t aSource, nsACString& aDest)
+{
+  if (aSource) {
+    AppendUTF16toUTF8(nsDependentString(aSource), aDest);
+  }
+}
+
+void
+AppendUTF8toUTF16(const char* aSource, nsAString& aDest)
+{
+  if (aSource) {
+    AppendUTF8toUTF16(nsDependentCString(aSource), aDest);
+  }
+}
+
+
+/**
+ * A helper function that allocates a buffer of the desired character type big enough to hold a copy of the supplied string (plus a zero terminator).
+ *
+ * @param aSource an string you will eventually be making a copy of
+ * @return a new buffer (of the type specified by the second parameter) which you must free with |free|.
+ *
+ */
+template <class FromStringT, class ToCharT>
+inline
+ToCharT*
+AllocateStringCopy(const FromStringT& aSource, ToCharT*)
+{
+  return static_cast<ToCharT*>(moz_xmalloc(
+    (aSource.Length() + 1) * sizeof(ToCharT)));
+}
+
+
+char*
+ToNewCString(const nsAString& aSource)
+{
+  char* result = AllocateStringCopy(aSource, (char*)0);
+  if (!result) {
+    return nullptr;
+  }
+
+  nsAString::const_iterator fromBegin, fromEnd;
+  LossyConvertEncoding16to8 converter(result);
+  copy_string(aSource.BeginReading(fromBegin), aSource.EndReading(fromEnd),
+              converter).write_terminator();
+  return result;
+}
+
+char*
+ToNewUTF8String(const nsAString& aSource, uint32_t* aUTF8Count)
+{
+  nsAString::const_iterator start, end;
+  CalculateUTF8Size calculator;
+  copy_string(aSource.BeginReading(start), aSource.EndReading(end),
+              calculator);
+
+  if (aUTF8Count) {
+    *aUTF8Count = calculator.Size();
+  }
+
+  char* result = static_cast<char*>
+                 (moz_xmalloc(calculator.Size() + 1));
+  if (!result) {
+    return nullptr;
+  }
+
+  ConvertUTF16toUTF8 converter(result);
+  copy_string(aSource.BeginReading(start), aSource.EndReading(end),
+              converter).write_terminator();
+  NS_ASSERTION(calculator.Size() == converter.Size(), "length mismatch");
+
+  return result;
+}
+
+char*
+ToNewCString(const nsACString& aSource)
+{
+  // no conversion needed, just allocate a buffer of the correct length and copy into it
+
+  char* result = AllocateStringCopy(aSource, (char*)0);
+  if (!result) {
+    return nullptr;
+  }
+
+  nsACString::const_iterator fromBegin, fromEnd;
+  char* toBegin = result;
+  *copy_string(aSource.BeginReading(fromBegin), aSource.EndReading(fromEnd),
+               toBegin) = char(0);
+  return result;
+}
+
+char16_t*
+ToNewUnicode(const nsAString& aSource)
+{
+  // no conversion needed, just allocate a buffer of the correct length and copy into it
+
+  char16_t* result = AllocateStringCopy(aSource, (char16_t*)0);
+  if (!result) {
+    return nullptr;
+  }
+
+  nsAString::const_iterator fromBegin, fromEnd;
+  char16_t* toBegin = result;
+  *copy_string(aSource.BeginReading(fromBegin), aSource.EndReading(fromEnd),
+               toBegin) = char16_t(0);
+  return result;
+}
+
+char16_t*
+ToNewUnicode(const nsACString& aSource)
+{
+  char16_t* result = AllocateStringCopy(aSource, (char16_t*)0);
+  if (!result) {
+    return nullptr;
+  }
+
+  nsACString::const_iterator fromBegin, fromEnd;
+  LossyConvertEncoding8to16 converter(result);
+  copy_string(aSource.BeginReading(fromBegin), aSource.EndReading(fromEnd),
+              converter).write_terminator();
+  return result;
+}
+
+uint32_t
+CalcUTF8ToUnicodeLength(const nsACString& aSource)
+{
+  nsACString::const_iterator start, end;
+  CalculateUTF8Length calculator;
+  copy_string(aSource.BeginReading(start), aSource.EndReading(end),
+              calculator);
+  return calculator.Length();
+}
+
+char16_t*
+UTF8ToUnicodeBuffer(const nsACString& aSource, char16_t* aBuffer,
+                    uint32_t* aUTF16Count)
+{
+  nsACString::const_iterator start, end;
+  ConvertUTF8toUTF16 converter(aBuffer);
+  copy_string(aSource.BeginReading(start),
+              aSource.EndReading(end),
+              converter).write_terminator();
+  if (aUTF16Count) {
+    *aUTF16Count = converter.Length();
+  }
+  return aBuffer;
+}
+
+char16_t*
+UTF8ToNewUnicode(const nsACString& aSource, uint32_t* aUTF16Count)
+{
+  const uint32_t length = CalcUTF8ToUnicodeLength(aSource);
+  const size_t buffer_size = (length + 1) * sizeof(char16_t);
+  char16_t* buffer = static_cast<char16_t*>(moz_xmalloc(buffer_size));
+  if (!buffer) {
+    return nullptr;
+  }
+
+  uint32_t copied;
+  UTF8ToUnicodeBuffer(aSource, buffer, &copied);
+  NS_ASSERTION(length == copied, "length mismatch");
+
+  if (aUTF16Count) {
+    *aUTF16Count = copied;
+  }
+  return buffer;
+}
+
+char16_t*
+CopyUnicodeTo(const nsAString& aSource, uint32_t aSrcOffset, char16_t* aDest,
+              uint32_t aLength)
+{
+  nsAString::const_iterator fromBegin, fromEnd;
+  char16_t* toBegin = aDest;
+  copy_string(aSource.BeginReading(fromBegin).advance(int32_t(aSrcOffset)),
+              aSource.BeginReading(fromEnd).advance(int32_t(aSrcOffset + aLength)),
+              toBegin);
+  return aDest;
+}
+
+void
+CopyUnicodeTo(const nsAString::const_iterator& aSrcStart,
+              const nsAString::const_iterator& aSrcEnd,
+              nsAString& aDest)
+{
+  aDest.SetLength(Distance(aSrcStart, aSrcEnd));
+
+  nsAString::char_iterator dest = aDest.BeginWriting();
+  nsAString::const_iterator fromBegin(aSrcStart);
+
+  copy_string(fromBegin, aSrcEnd, dest);
+}
+
+void
+AppendUnicodeTo(const nsAString::const_iterator& aSrcStart,
+                const nsAString::const_iterator& aSrcEnd,
+                nsAString& aDest)
+{
+  uint32_t oldLength = aDest.Length();
+  aDest.SetLength(oldLength + Distance(aSrcStart, aSrcEnd));
+
+  nsAString::char_iterator dest = aDest.BeginWriting() + oldLength;
+  nsAString::const_iterator fromBegin(aSrcStart);
+
+  copy_string(fromBegin, aSrcEnd, dest);
+}
+
+bool
+IsASCII(const nsAString& aString)
+{
+  static const char16_t NOT_ASCII = char16_t(~0x007F);
+
+
+  // Don't want to use |copy_string| for this task, since we can stop at the first non-ASCII character
+
+  nsAString::const_iterator iter, done_reading;
+  aString.BeginReading(iter);
+  aString.EndReading(done_reading);
+
+  const char16_t* c = iter.get();
+  const char16_t* end = done_reading.get();
+
+  while (c < end) {
+    if (*c++ & NOT_ASCII) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+bool
+IsASCII(const nsACString& aString)
+{
+  static const char NOT_ASCII = char(~0x7F);
+
+
+  // Don't want to use |copy_string| for this task, since we can stop at the first non-ASCII character
+
+  nsACString::const_iterator iter, done_reading;
+  aString.BeginReading(iter);
+  aString.EndReading(done_reading);
+
+  const char* c = iter.get();
+  const char* end = done_reading.get();
+
+  while (c < end) {
+    if (*c++ & NOT_ASCII) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+bool
+IsUTF8(const nsACString& aString, bool aRejectNonChar)
+{
+  nsReadingIterator<char> done_reading;
+  aString.EndReading(done_reading);
+
+  int32_t state = 0;
+  bool overlong = false;
+  bool surrogate = false;
+  bool nonchar = false;
+  uint16_t olupper = 0; // overlong byte upper bound.
+  uint16_t slower = 0;  // surrogate byte lower bound.
+
+  nsReadingIterator<char> iter;
+  aString.BeginReading(iter);
+
+  const char* ptr = iter.get();
+  const char* end = done_reading.get();
+  while (ptr < end) {
+    uint8_t c;
+
+    if (0 == state) {
+      c = *ptr++;
+
+      if (UTF8traits::isASCII(c)) {
+        continue;
+      }
+
+      if (c <= 0xC1) { // [80-BF] where not expected, [C0-C1] for overlong.
+        return false;
+      } else if (UTF8traits::is2byte(c)) {
+        state = 1;
+      } else if (UTF8traits::is3byte(c)) {
+        state = 2;
+        if (c == 0xE0) { // to exclude E0[80-9F][80-BF]
+          overlong = true;
+          olupper = 0x9F;
+        } else if (c == 0xED) { // ED[A0-BF][80-BF] : surrogate codepoint
+          surrogate = true;
+          slower = 0xA0;
+        } else if (c == 0xEF) { // EF BF [BE-BF] : non-character
+          nonchar = true;
+        }
+      } else if (c <= 0xF4) { // XXX replace /w UTF8traits::is4byte when it's updated to exclude [F5-F7].(bug 199090)
+        state = 3;
+        nonchar = true;
+        if (c == 0xF0) { // to exclude F0[80-8F][80-BF]{2}
+          overlong = true;
+          olupper = 0x8F;
+        } else if (c == 0xF4) { // to exclude F4[90-BF][80-BF]
+          // actually not surrogates but codepoints beyond 0x10FFFF
+          surrogate = true;
+          slower = 0x90;
+        }
+      } else {
+        return false;  // Not UTF-8 string
+      }
+    }
+
+    if (nonchar && !aRejectNonChar) {
+      nonchar = false;
+    }
+
+    while (ptr < end && state) {
+      c = *ptr++;
+      --state;
+
+      // non-character : EF BF [BE-BF] or F[0-7] [89AB]F BF [BE-BF]
+      if (nonchar &&
+          ((!state && c < 0xBE) ||
+           (state == 1 && c != 0xBF)  ||
+           (state == 2 && 0x0F != (0x0F & c)))) {
+        nonchar = false;
+      }
+
+      if (!UTF8traits::isInSeq(c) || (overlong && c <= olupper) ||
+          (surrogate && slower <= c) || (nonchar && !state)) {
+        return false;  // Not UTF-8 string
+      }
+
+      overlong = surrogate = false;
+    }
+  }
+  return !state; // state != 0 at the end indicates an invalid UTF-8 seq.
+}
+
+/**
+ * A character sink for in-place case conversion.
+ */
+class ConvertToUpperCase
+{
+public:
+  typedef char value_type;
+
+  uint32_t
+  write(const char* aSource, uint32_t aSourceLength)
+  {
+    char* cp = const_cast<char*>(aSource);
+    const char* end = aSource + aSourceLength;
+    while (cp != end) {
+      char ch = *cp;
+      if (ch >= 'a' && ch <= 'z') {
+        *cp = ch - ('a' - 'A');
+      }
+      ++cp;
+    }
+    return aSourceLength;
+  }
+};
+
+void
+ToUpperCase(nsCSubstring& aCString)
+{
+  ConvertToUpperCase converter;
+  char* start;
+  converter.write(aCString.BeginWriting(start), aCString.Length());
+}
+
+/**
+ * A character sink for copying with case conversion.
+ */
+class CopyToUpperCase
+{
+public:
+  typedef char value_type;
+
+  explicit CopyToUpperCase(nsACString::iterator& aDestIter,
+                           const nsACString::iterator& aEndIter)
+    : mIter(aDestIter)
+    , mEnd(aEndIter)
+  {
+  }
+
+  uint32_t
+  write(const char* aSource, uint32_t aSourceLength)
+  {
+    uint32_t len = XPCOM_MIN(uint32_t(mEnd - mIter), aSourceLength);
+    char* cp = mIter.get();
+    const char* end = aSource + len;
+    while (aSource != end) {
+      char ch = *aSource;
+      if ((ch >= 'a') && (ch <= 'z')) {
+        *cp = ch - ('a' - 'A');
+      } else {
+        *cp = ch;
+      }
+      ++aSource;
+      ++cp;
+    }
+    mIter.advance(len);
+    return len;
+  }
+
+protected:
+  nsACString::iterator& mIter;
+  const nsACString::iterator& mEnd;
+};
+
+void
+ToUpperCase(const nsACString& aSource, nsACString& aDest)
+{
+  nsACString::const_iterator fromBegin, fromEnd;
+  nsACString::iterator toBegin, toEnd;
+  aDest.SetLength(aSource.Length());
+
+  CopyToUpperCase converter(aDest.BeginWriting(toBegin), aDest.EndWriting(toEnd));
+  copy_string(aSource.BeginReading(fromBegin), aSource.EndReading(fromEnd),
+              converter);
+}
+
+/**
+ * A character sink for case conversion.
+ */
+class ConvertToLowerCase
+{
+public:
+  typedef char value_type;
+
+  uint32_t
+  write(const char* aSource, uint32_t aSourceLength)
+  {
+    char* cp = const_cast<char*>(aSource);
+    const char* end = aSource + aSourceLength;
+    while (cp != end) {
+      char ch = *cp;
+      if ((ch >= 'A') && (ch <= 'Z')) {
+        *cp = ch + ('a' - 'A');
+      }
+      ++cp;
+    }
+    return aSourceLength;
+  }
+};
+
+void
+ToLowerCase(nsCSubstring& aCString)
+{
+  ConvertToLowerCase converter;
+  char* start;
+  converter.write(aCString.BeginWriting(start), aCString.Length());
+}
+
+/**
+ * A character sink for copying with case conversion.
+ */
+class CopyToLowerCase
+{
+public:
+  typedef char value_type;
+
+  explicit CopyToLowerCase(nsACString::iterator& aDestIter,
+                           const nsACString::iterator& aEndIter)
+    : mIter(aDestIter)
+    , mEnd(aEndIter)
+  {
+  }
+
+  uint32_t
+  write(const char* aSource, uint32_t aSourceLength)
+  {
+    uint32_t len = XPCOM_MIN(uint32_t(mEnd - mIter), aSourceLength);
+    char* cp = mIter.get();
+    const char* end = aSource + len;
+    while (aSource != end) {
+      char ch = *aSource;
+      if ((ch >= 'A') && (ch <= 'Z')) {
+        *cp = ch + ('a' - 'A');
+      } else {
+        *cp = ch;
+      }
+      ++aSource;
+      ++cp;
+    }
+    mIter.advance(len);
+    return len;
+  }
+
+protected:
+  nsACString::iterator& mIter;
+  const nsACString::iterator& mEnd;
+};
+
+void
+ToLowerCase(const nsACString& aSource, nsACString& aDest)
+{
+  nsACString::const_iterator fromBegin, fromEnd;
+  nsACString::iterator toBegin, toEnd;
+  aDest.SetLength(aSource.Length());
+
+  CopyToLowerCase converter(aDest.BeginWriting(toBegin), aDest.EndWriting(toEnd));
+  copy_string(aSource.BeginReading(fromBegin), aSource.EndReading(fromEnd),
+              converter);
+}
+
+bool
+ParseString(const nsACString& aSource, char aDelimiter,
+            nsTArray<nsCString>& aArray)
+{
+  nsACString::const_iterator start, end;
+  aSource.BeginReading(start);
+  aSource.EndReading(end);
+
+  uint32_t oldLength = aArray.Length();
+
+  for (;;) {
+    nsACString::const_iterator delimiter = start;
+    FindCharInReadable(aDelimiter, delimiter, end);
+
+    if (delimiter != start) {
+      if (!aArray.AppendElement(Substring(start, delimiter))) {
+        aArray.RemoveElementsAt(oldLength, aArray.Length() - oldLength);
+        return false;
+      }
+    }
+
+    if (delimiter == end) {
+      break;
+    }
+    start = ++delimiter;
+    if (start == end) {
+      break;
+    }
+  }
+
+  return true;
+}
+
+template <class StringT, class IteratorT, class Comparator>
+bool
+FindInReadable_Impl(const StringT& aPattern, IteratorT& aSearchStart,
+                    IteratorT& aSearchEnd, const Comparator& aCompare)
+{
+  bool found_it = false;
+
+  // only bother searching at all if we're given a non-empty range to search
+  if (aSearchStart != aSearchEnd) {
+    IteratorT aPatternStart, aPatternEnd;
+    aPattern.BeginReading(aPatternStart);
+    aPattern.EndReading(aPatternEnd);
+
+    // outer loop keeps searching till we find it or run out of string to search
+    while (!found_it) {
+      // fast inner loop (that's what it's called, not what it is) looks for a potential match
+      while (aSearchStart != aSearchEnd &&
+             aCompare(aPatternStart.get(), aSearchStart.get(), 1, 1)) {
+        ++aSearchStart;
+      }
+
+      // if we broke out of the `fast' loop because we're out of string ... we're done: no match
+      if (aSearchStart == aSearchEnd) {
+        break;
+      }
+
+      // otherwise, we're at a potential match, let's see if we really hit one
+      IteratorT testPattern(aPatternStart);
+      IteratorT testSearch(aSearchStart);
+
+      // slow inner loop verifies the potential match (found by the `fast' loop) at the current position
+      for (;;) {
+        // we already compared the first character in the outer loop,
+        //  so we'll advance before the next comparison
+        ++testPattern;
+        ++testSearch;
+
+        // if we verified all the way to the end of the pattern, then we found it!
+        if (testPattern == aPatternEnd) {
+          found_it = true;
+          aSearchEnd = testSearch; // return the exact found range through the parameters
+          break;
+        }
+
+        // if we got to end of the string we're searching before we hit the end of the
+        //  pattern, we'll never find what we're looking for
+        if (testSearch == aSearchEnd) {
+          aSearchStart = aSearchEnd;
+          break;
+        }
+
+        // else if we mismatched ... it's time to advance to the next search position
+        //  and get back into the `fast' loop
+        if (aCompare(testPattern.get(), testSearch.get(), 1, 1)) {
+          ++aSearchStart;
+          break;
+        }
+      }
+    }
+  }
+
+  return found_it;
+}
+
+/**
+ * This searches the entire string from right to left, and returns the first match found, if any.
+ */
+template <class StringT, class IteratorT, class Comparator>
+bool
+RFindInReadable_Impl(const StringT& aPattern, IteratorT& aSearchStart,
+                     IteratorT& aSearchEnd, const Comparator& aCompare)
+{
+  IteratorT patternStart, patternEnd, searchEnd = aSearchEnd;
+  aPattern.BeginReading(patternStart);
+  aPattern.EndReading(patternEnd);
+
+  // Point to the last character in the pattern
+  --patternEnd;
+  // outer loop keeps searching till we run out of string to search
+  while (aSearchStart != searchEnd) {
+    // Point to the end position of the next possible match
+    --searchEnd;
+
+    // Check last character, if a match, explore further from here
+    if (aCompare(patternEnd.get(), searchEnd.get(), 1, 1) == 0) {
+      // We're at a potential match, let's see if we really hit one
+      IteratorT testPattern(patternEnd);
+      IteratorT testSearch(searchEnd);
+
+      // inner loop verifies the potential match at the current position
+      do {
+        // if we verified all the way to the end of the pattern, then we found it!
+        if (testPattern == patternStart) {
+          aSearchStart = testSearch;  // point to start of match
+          aSearchEnd = ++searchEnd;   // point to end of match
+          return true;
+        }
+
+        // if we got to end of the string we're searching before we hit the end of the
+        //  pattern, we'll never find what we're looking for
+        if (testSearch == aSearchStart) {
+          aSearchStart = aSearchEnd;
+          return false;
+        }
+
+        // test previous character for a match
+        --testPattern;
+        --testSearch;
+      } while (aCompare(testPattern.get(), testSearch.get(), 1, 1) == 0);
+    }
+  }
+
+  aSearchStart = aSearchEnd;
+  return false;
+}
+
+bool
+FindInReadable(const nsAString& aPattern,
+               nsAString::const_iterator& aSearchStart,
+               nsAString::const_iterator& aSearchEnd,
+               const nsStringComparator& aComparator)
+{
+  return FindInReadable_Impl(aPattern, aSearchStart, aSearchEnd, aComparator);
+}
+
+bool
+FindInReadable(const nsACString& aPattern,
+               nsACString::const_iterator& aSearchStart,
+               nsACString::const_iterator& aSearchEnd,
+               const nsCStringComparator& aComparator)
+{
+  return FindInReadable_Impl(aPattern, aSearchStart, aSearchEnd, aComparator);
+}
+
+bool
+CaseInsensitiveFindInReadable(const nsACString& aPattern,
+                              nsACString::const_iterator& aSearchStart,
+                              nsACString::const_iterator& aSearchEnd)
+{
+  return FindInReadable_Impl(aPattern, aSearchStart, aSearchEnd,
+                             nsCaseInsensitiveCStringComparator());
+}
+
+bool
+RFindInReadable(const nsAString& aPattern,
+                nsAString::const_iterator& aSearchStart,
+                nsAString::const_iterator& aSearchEnd,
+                const nsStringComparator& aComparator)
+{
+  return RFindInReadable_Impl(aPattern, aSearchStart, aSearchEnd, aComparator);
+}
+
+bool
+RFindInReadable(const nsACString& aPattern,
+                nsACString::const_iterator& aSearchStart,
+                nsACString::const_iterator& aSearchEnd,
+                const nsCStringComparator& aComparator)
+{
+  return RFindInReadable_Impl(aPattern, aSearchStart, aSearchEnd, aComparator);
+}
+
+bool
+FindCharInReadable(char16_t aChar, nsAString::const_iterator& aSearchStart,
+                   const nsAString::const_iterator& aSearchEnd)
+{
+  int32_t fragmentLength = aSearchEnd.get() - aSearchStart.get();
+
+  const char16_t* charFoundAt =
+    nsCharTraits<char16_t>::find(aSearchStart.get(), fragmentLength, aChar);
+  if (charFoundAt) {
+    aSearchStart.advance(charFoundAt - aSearchStart.get());
+    return true;
+  }
+
+  aSearchStart.advance(fragmentLength);
+  return false;
+}
+
+bool
+FindCharInReadable(char aChar, nsACString::const_iterator& aSearchStart,
+                   const nsACString::const_iterator& aSearchEnd)
+{
+  int32_t fragmentLength = aSearchEnd.get() - aSearchStart.get();
+
+  const char* charFoundAt =
+    nsCharTraits<char>::find(aSearchStart.get(), fragmentLength, aChar);
+  if (charFoundAt) {
+    aSearchStart.advance(charFoundAt - aSearchStart.get());
+    return true;
+  }
+
+  aSearchStart.advance(fragmentLength);
+  return false;
+}
+
+uint32_t
+CountCharInReadable(const nsAString& aStr, char16_t aChar)
+{
+  uint32_t count = 0;
+  nsAString::const_iterator begin, end;
+
+  aStr.BeginReading(begin);
+  aStr.EndReading(end);
+
+  while (begin != end) {
+    if (*begin == aChar) {
+      ++count;
+    }
+    ++begin;
+  }
+
+  return count;
+}
+
+uint32_t
+CountCharInReadable(const nsACString& aStr, char aChar)
+{
+  uint32_t count = 0;
+  nsACString::const_iterator begin, end;
+
+  aStr.BeginReading(begin);
+  aStr.EndReading(end);
+
+  while (begin != end) {
+    if (*begin == aChar) {
+      ++count;
+    }
+    ++begin;
+  }
+
+  return count;
+}
+
+bool
+StringBeginsWith(const nsAString& aSource, const nsAString& aSubstring)
+{
+  nsAString::size_type src_len = aSource.Length(),
+                       sub_len = aSubstring.Length();
+  if (sub_len > src_len) {
+    return false;
+  }
+  return Substring(aSource, 0, sub_len).Equals(aSubstring);
+}
+
+bool
+StringBeginsWith(const nsAString& aSource, const nsAString& aSubstring,
+                 const nsStringComparator& aComparator)
+{
+  nsAString::size_type src_len = aSource.Length(),
+                       sub_len = aSubstring.Length();
+  if (sub_len > src_len) {
+    return false;
+  }
+  return Substring(aSource, 0, sub_len).Equals(aSubstring, aComparator);
+}
+
+bool
+StringBeginsWith(const nsACString& aSource, const nsACString& aSubstring)
+{
+  nsACString::size_type src_len = aSource.Length(),
+                        sub_len = aSubstring.Length();
+  if (sub_len > src_len) {
+    return false;
+  }
+  return Substring(aSource, 0, sub_len).Equals(aSubstring);
+}
+
+bool
+StringBeginsWith(const nsACString& aSource, const nsACString& aSubstring,
+                 const nsCStringComparator& aComparator)
+{
+  nsACString::size_type src_len = aSource.Length(),
+                        sub_len = aSubstring.Length();
+  if (sub_len > src_len) {
+    return false;
+  }
+  return Substring(aSource, 0, sub_len).Equals(aSubstring, aComparator);
+}
+
+bool
+StringEndsWith(const nsAString& aSource, const nsAString& aSubstring)
+{
+  nsAString::size_type src_len = aSource.Length(),
+                       sub_len = aSubstring.Length();
+  if (sub_len > src_len) {
+    return false;
+  }
+  return Substring(aSource, src_len - sub_len, sub_len).Equals(aSubstring);
+}
+
+bool
+StringEndsWith(const nsAString& aSource, const nsAString& aSubstring,
+               const nsStringComparator& aComparator)
+{
+  nsAString::size_type src_len = aSource.Length(),
+                       sub_len = aSubstring.Length();
+  if (sub_len > src_len) {
+    return false;
+  }
+  return Substring(aSource, src_len - sub_len, sub_len).Equals(aSubstring,
+                                                               aComparator);
+}
+
+bool
+StringEndsWith(const nsACString& aSource, const nsACString& aSubstring)
+{
+  nsACString::size_type src_len = aSource.Length(),
+                        sub_len = aSubstring.Length();
+  if (sub_len > src_len) {
+    return false;
+  }
+  return Substring(aSource, src_len - sub_len, sub_len).Equals(aSubstring);
+}
+
+bool
+StringEndsWith(const nsACString& aSource, const nsACString& aSubstring,
+               const nsCStringComparator& aComparator)
+{
+  nsACString::size_type src_len = aSource.Length(),
+                        sub_len = aSubstring.Length();
+  if (sub_len > src_len) {
+    return false;
+  }
+  return Substring(aSource, src_len - sub_len, sub_len).Equals(aSubstring,
+                                                               aComparator);
+}
+
+
+
+static const char16_t empty_buffer[1] = { '\0' };
+
+const nsAFlatString&
+EmptyString()
+{
+  static const nsDependentString sEmpty(empty_buffer);
+
+  return sEmpty;
+}
+
+const nsAFlatCString&
+EmptyCString()
+{
+  static const nsDependentCString sEmpty((const char*)empty_buffer);
+
+  return sEmpty;
+}
+
+const nsAFlatString&
+NullString()
+{
+  static const nsXPIDLString sNull;
+
+  return sNull;
+}
+
+const nsAFlatCString&
+NullCString()
+{
+  static const nsXPIDLCString sNull;
+
+  return sNull;
+}
+
+int32_t
+CompareUTF8toUTF16(const nsASingleFragmentCString& aUTF8String,
+                   const nsASingleFragmentString& aUTF16String)
+{
+  static const uint32_t NOT_ASCII = uint32_t(~0x7F);
+
+  const char* u8;
+  const char* u8end;
+  aUTF8String.BeginReading(u8);
+  aUTF8String.EndReading(u8end);
+
+  const char16_t* u16;
+  const char16_t* u16end;
+  aUTF16String.BeginReading(u16);
+  aUTF16String.EndReading(u16end);
+
+  while (u8 != u8end && u16 != u16end) {
+    // Cast away the signedness of *u8 to prevent signextension when
+    // converting to uint32_t
+    uint32_t c8_32 = (uint8_t)*u8;
+
+    if (c8_32 & NOT_ASCII) {
+      bool err;
+      c8_32 = UTF8CharEnumerator::NextChar(&u8, u8end, &err);
+      if (err) {
+        return INT32_MIN;
+      }
+
+      uint32_t c16_32 = UTF16CharEnumerator::NextChar(&u16, u16end);
+      // The above UTF16CharEnumerator::NextChar() calls can
+      // fail, but if it does for anything other than no data to
+      // look at (which can't happen here), it returns the
+      // Unicode replacement character 0xFFFD for the invalid
+      // data they were fed. Ignore that error and treat invalid
+      // UTF16 as 0xFFFD.
+      //
+      // This matches what our UTF16 to UTF8 conversion code
+      // does, and thus a UTF8 string that came from an invalid
+      // UTF16 string will compare equal to the invalid UTF16
+      // string it came from. Same is true for any other UTF16
+      // string differs only in the invalid part of the string.
+
+      if (c8_32 != c16_32) {
+        return c8_32 < c16_32 ? -1 : 1;
+      }
+    } else {
+      if (c8_32 != *u16) {
+        return c8_32 > *u16 ? 1 : -1;
+      }
+
+      ++u8;
+      ++u16;
+    }
+  }
+
+  if (u8 != u8end) {
+    // We get to the end of the UTF16 string, but no to the end of
+    // the UTF8 string. The UTF8 string is longer than the UTF16
+    // string
+
+    return 1;
+  }
+
+  if (u16 != u16end) {
+    // We get to the end of the UTF8 string, but no to the end of
+    // the UTF16 string. The UTF16 string is longer than the UTF8
+    // string
+
+    return -1;
+  }
+
+  // The two strings match.
+
+  return 0;
+}
+
+void
+AppendUCS4ToUTF16(const uint32_t aSource, nsAString& aDest)
+{
+  NS_ASSERTION(IS_VALID_CHAR(aSource), "Invalid UCS4 char");
+  if (IS_IN_BMP(aSource)) {
+    aDest.Append(char16_t(aSource));
+  } else {
+    aDest.Append(H_SURROGATE(aSource));
+    aDest.Append(L_SURROGATE(aSource));
+  }
+}
+
+extern "C" {
+
+void Gecko_AppendUTF16toCString(nsACString* aThis, const nsAString* aOther)
+{
+  AppendUTF16toUTF8(*aOther, *aThis);
+}
+
+void Gecko_AppendUTF8toString(nsAString* aThis, const nsACString* aOther)
+{
+  AppendUTF8toUTF16(*aOther, *aThis);
+}
+
+}