Add StrInStrNoCase, a StringRef version of CStrInCStrNoCase.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93174 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/Support/StringExtras.cpp b/lib/Support/StringExtras.cpp
index 2363ad6..7fd840b 100644
--- a/lib/Support/StringExtras.cpp
+++ b/lib/Support/StringExtras.cpp
@@ -16,6 +16,19 @@
 #include "llvm/ADT/StringExtras.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