1 files changed, 91 insertions, 0 deletions
diff --git a/xpcom/string/nsTStringComparator.cpp b/xpcom/string/nsTStringComparator.cpp
new file mode 100644
index 0000000000..801a3623b9
--- /dev/null
+++ b/xpcom/string/nsTStringComparator.cpp
@@ -0,0 +1,91 @@
+/* -*- 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 "nsString.h"
+#include "plstr.h"
+
+template <typename T>
+int NS_FASTCALL Compare(const mozilla::detail::nsTStringRepr<T>& aLhs,
+                        const mozilla::detail::nsTStringRepr<T>& aRhs,
+                        const nsTStringComparator<T> comp) {
+  typedef typename nsTSubstring<T>::size_type size_type;
+  typedef typename nsTSubstring<T>::const_iterator const_iterator;
+
+  if (&aLhs == &aRhs) {
+    return 0;
+  }
+
+  const_iterator leftIter, rightIter;
+  aLhs.BeginReading(leftIter);
+  aRhs.BeginReading(rightIter);
+
+  size_type lLength = aLhs.Length();
+  size_type rLength = aRhs.Length();
+  size_type lengthToCompare = XPCOM_MIN(lLength, rLength);
+
+  int result;
+  if ((result = comp(leftIter.get(), rightIter.get(), lengthToCompare,
+                     lengthToCompare)) == 0) {
+    if (lLength < rLength) {
+      result = -1;
+    } else if (rLength < lLength) {
+      result = 1;
+    } else {
+      result = 0;
+    }
+  }
+
+  return result;
+}
+
+template int NS_FASTCALL Compare<char>(
+    mozilla::detail::nsTStringRepr<char> const&,
+    mozilla::detail::nsTStringRepr<char> const&, nsTStringComparator<char>);
+
+template int NS_FASTCALL
+Compare<char16_t>(mozilla::detail::nsTStringRepr<char16_t> const&,
+                  mozilla::detail::nsTStringRepr<char16_t> const&,
+                  nsTStringComparator<char16_t>);
+
+template <typename T>
+int nsTDefaultStringComparator(const T* aLhs, const T* aRhs, size_t aLLength,
+                               size_t aRLength) {
+  return aLLength == aRLength ? nsCharTraits<T>::compare(aLhs, aRhs, aLLength)
+         : (aLLength > aRLength) ? 1
+                                 : -1;
+}
+
+template int nsTDefaultStringComparator(const char*, const char*, size_t,
+                                        size_t);
+template int nsTDefaultStringComparator(const char16_t*, const char16_t*,
+                                        size_t, size_t);
+
+int nsCaseInsensitiveCStringComparator(const char* aLhs, const char* aRhs,
+                                       size_t aLhsLength, size_t aRhsLength) {
+#if defined(LIBFUZZER) && defined(LINUX)
+  // Make sure libFuzzer can see this string compare by calling the POSIX
+  // native function which is intercepted. We also call this if the lengths
+  // don't match so libFuzzer can at least see a partial string, but we throw
+  // away the result afterwards again.
+  int32_t result =
+      int32_t(strncasecmp(aLhs, aRhs, std::min(aLhsLength, aRhsLength)));
+
+  if (aLhsLength != aRhsLength) {
+    return (aLhsLength > aRhsLength) ? 1 : -1;
+  }
+#else
+  if (aLhsLength != aRhsLength) {
+    return (aLhsLength > aRhsLength) ? 1 : -1;
+  }
+  int32_t result = int32_t(PL_strncasecmp(aLhs, aRhs, aLhsLength));
+#endif
+  // Egads. PL_strncasecmp is returning *very* negative numbers.
+  // Some folks expect -1,0,1, so let's temper its enthusiasm.
+  if (result < 0) {
+    result = -1;
+  }
+  return result;
+}