xpcom/string/nsTStringComparator.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "nsString.h"
   8 #include "plstr.h"
   9
  10 template <typename T>
  11 int NS_FASTCALL Compare(const mozilla::detail::nsTStringRepr<T>& aLhs,
  12                         const mozilla::detail::nsTStringRepr<T>& aRhs,
  13                         const nsTStringComparator<T> comp) {
  14   typedef typename nsTSubstring<T>::size_type size_type;
  15   typedef typename nsTSubstring<T>::const_iterator const_iterator;
  16
  17   if (&aLhs == &aRhs) {
  18     return 0;
  19   }
  20
  21   const_iterator leftIter, rightIter;
  22   aLhs.BeginReading(leftIter);
  23   aRhs.BeginReading(rightIter);
  24
  25   size_type lLength = aLhs.Length();
  26   size_type rLength = aRhs.Length();
  27   size_type lengthToCompare = XPCOM_MIN(lLength, rLength);
  28
  29   int result;
  30   if ((result = comp(leftIter.get(), rightIter.get(), lengthToCompare,
  31                      lengthToCompare)) == 0) {
  32     if (lLength < rLength) {
  33       result = -1;
  34     } else if (rLength < lLength) {
  35       result = 1;
  36     } else {
  37       result = 0;
  38     }
  39   }
  40
  41   return result;
  42 }
  43
  44 template int NS_FASTCALL Compare<char>(
  45     mozilla::detail::nsTStringRepr<char> const&,
  46     mozilla::detail::nsTStringRepr<char> const&, nsTStringComparator<char>);
  47
  48 template int NS_FASTCALL
  49 Compare<char16_t>(mozilla::detail::nsTStringRepr<char16_t> const&,
  50                   mozilla::detail::nsTStringRepr<char16_t> const&,
  51                   nsTStringComparator<char16_t>);
  52
  53 template <typename T>
  54 int nsTDefaultStringComparator(const T* aLhs, const T* aRhs, size_t aLLength,
  55                                size_t aRLength) {
  56   return aLLength == aRLength ? nsCharTraits<T>::compare(aLhs, aRhs, aLLength)
  57          : (aLLength > aRLength) ? 1
  58                                  : -1;
  59 }
  60
  61 template int nsTDefaultStringComparator(const char*, const char*, size_t,
  62                                         size_t);
  63 template int nsTDefaultStringComparator(const char16_t*, const char16_t*,
  64                                         size_t, size_t);
  65
  66 int nsCaseInsensitiveCStringComparator(const char* aLhs, const char* aRhs,
  67                                        size_t aLhsLength, size_t aRhsLength) {
  68 #if defined(LIBFUZZER) && defined(LINUX)
  69   // Make sure libFuzzer can see this string compare by calling the POSIX
  70   // native function which is intercepted. We also call this if the lengths
  71   // don't match so libFuzzer can at least see a partial string, but we throw
  72   // away the result afterwards again.
  73   int32_t result =
  74       int32_t(strncasecmp(aLhs, aRhs, std::min(aLhsLength, aRhsLength)));
  75
  76   if (aLhsLength != aRhsLength) {
  77     return (aLhsLength > aRhsLength) ? 1 : -1;
  78   }
  79 #else
  80   if (aLhsLength != aRhsLength) {
  81     return (aLhsLength > aRhsLength) ? 1 : -1;
  82   }
  83   int32_t result = int32_t(PL_strncasecmp(aLhs, aRhs, aLhsLength));
  84 #endif
  85   // Egads. PL_strncasecmp is returning *very* negative numbers.
  86   // Some folks expect -1,0,1, so let's temper its enthusiasm.
  87   if (result < 0) {
  88     result = -1;
  89   }
  90   return result;
  91 }