Move common utility classes to wpiutil library. (#79)

This is a breaking change to dependencies that use the static ntcore
library.  Unless the wpiutil library is also linked, linker errors will
result.  This does not affect the shared ntcore library.

src/llvm/StringExtras.cpp

@@ -0,0 +1,58 @@
+//===-- StringExtras.cpp - Implement the StringExtras header --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the StringExtras.h header
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/StringExtras.h"
+#include "llvm/SmallVector.h"
+using namespace llvm;
+
+/// StrInStrNoCase - Portable version of strcasestr.  Locates the first
+/// occurrence of string 's1' in string 's2', ignoring case.  Returns
+/// the offset of s2 in s1 or npos if s2 cannot be found.
+StringRef::size_type llvm::StrInStrNoCase(StringRef s1, StringRef s2) {
+  size_t N = s2.size(), M = s1.size();
+  if (N > M)
+    return StringRef::npos;
+  for (size_t i = 0, e = M - N + 1; i != e; ++i)
+    if (s1.substr(i, N).equals_lower(s2))
+      return i;
+  return StringRef::npos;
+}
+
+/// getToken - This function extracts one token from source, ignoring any
+/// leading characters that appear in the Delimiters string, and ending the
+/// token at any of the characters that appear in the Delimiters string.  If
+/// there are no tokens in the source string, an empty string is returned.
+/// The function returns a pair containing the extracted token and the
+/// remaining tail string.
+std::pair<StringRef, StringRef> llvm::getToken(StringRef Source,
+                                               StringRef Delimiters) {
+  // Figure out where the token starts.
+  StringRef::size_type Start = Source.find_first_not_of(Delimiters);
+
+  // Find the next occurrence of the delimiter.
+  StringRef::size_type End = Source.find_first_of(Delimiters, Start);
+
+  return std::make_pair(Source.slice(Start, End), Source.substr(End));
+}
+
+/// SplitString - Split up the specified string according to the specified
+/// delimiters, appending the result fragments to the output list.
+void llvm::SplitString(StringRef Source,
+                       SmallVectorImpl<StringRef> &OutFragments,
+                       StringRef Delimiters) {
+  std::pair<StringRef, StringRef> S = getToken(Source, Delimiters);
+  while (!S.first.empty()) {
+    OutFragments.push_back(S.first);
+    S = getToken(S.second, Delimiters);
+  }
+}