From 90e4f3c37b097d71176e20b530b83a5dc31e3d42 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 25 Jul 2017 17:45:00 +0200
Subject: Implement case-insensitive path hashing for Windows

---
 libbutl/path.hxx | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/libbutl/path.hxx b/libbutl/path.hxx
index 7e35ba5..26b076f 100644
--- a/libbutl/path.hxx
+++ b/libbutl/path.hxx
@@ -1133,7 +1133,23 @@ namespace std
     size_t
     operator() (const butl::basic_path<C, K>& p) const noexcept
     {
+#ifndef _WIN32
       return hash<basic_string<C>>::operator() (p.string ());
+#else
+      // Case-insensitive FNV hash.
+      //
+      const auto& s (p.string ());
+
+      size_t hash (static_cast<size_t> (2166136261UL));
+      for (size_t i (0), n (s.size ()); i != n; ++i)
+      {
+        hash ^= static_cast<size_t> (butl::lcase (s[i]));
+        hash *= sizeof (size_t) == 4
+          ? static_cast<size_t>(16777619UL)
+          : static_cast<size_t>(1099511628211ULL);
+      }
+      return hash;
+#endif
     }
   };
 }
-- 
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