Noissue - add SplitString and TrimSpaces helpers

compiled/String.cpp

+/*
+* This file is part of Adblock Plus <https://adblockplus.org/>,
+* Copyright (C) 2006-present eyeo GmbH
+*
+* Adblock Plus is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License version 3 as
+* published by the Free Software Foundation.
+*
+* Adblock Plus is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "String.h"
+
+ABP_NS_BEGIN
+
+DependentString TrimSpaces(const String& value)
+{
+  String::size_type start = 0;
+  auto end = value.length();
+  for (; start < end; ++start)
+  {
+    if (value[start] > u' ')

[hub, 2018/03/01 18:40:07]

we could write this loop as `for (; start < end && value[start] <= u' ';
++start)`

Even though I'm not sure if the compiler would generate more efficient code.

[sergei, 2018/03/01 21:14:12]

Yes, but I rather wanted to separate that comparison in order to improve the
readability (pretty subjective though) and because I thought that perhaps that
condition could be changed, so it will be easier to do it. If you want I can
change it of course.

[hub, 2018/03/01 22:15:44]

Acknowledged.

+      break;
+  }
+  for (; end > start; --end)
+  {
+    if (value[end - 1] > u' ')
+      break;
+  }
+  return DependentString(value, start, end - start);
+}
+
+std::pair<DependentString, DependentString> SplitString(const String& value, String::size_type separatorPos)
+{
+  const auto secondBeginPos = separatorPos < String::npos ? separatorPos + 1 : String::npos;
+  return {
+    DependentString{value, 0, separatorPos},
+    DependentString{value, secondBeginPos, value.length() - secondBeginPos}
+  };

[hub, 2018/03/01 18:40:07]

what if secondBeginPos > value.length() ? since size_type is unsigned, it would
lead to undefined behaviour

[sergei, 2018/03/01 21:14:12]

value.length(), secondBeginPos and len (the third arg of DependentString ctr)
are all unsigned integers which can represent the values, AFAIR (I googled,
https://stackoverflow.com/questions/28779803/is-subtracting-larger-unsigned-v...,
it's the same in C++14, the footnote is 48, though) the result of len should be
defined.

[hub, 2018/03/01 22:15:44]

Acknowledged.

+}
+
+ABP_NS_END