From 8d4eb0847041a26377dc99b1c4fb5c22d4841d5e Mon Sep 17 00:00:00 2001
From: Cory Fields <cory-nospam-@coryfields.com>
Date: Fri, 16 Jun 2017 19:33:20 -0400
Subject: [PATCH] Add HasAcceleratedCRC32C to port_win.h

---
 port/port_win.cc | 11 +++++++++++
 port/port_win.h  |  1 +
 2 files changed, 12 insertions(+)

diff --git a/port/port_win.cc b/port/port_win.cc
index 1b0f060a19caab..62e19d41038831 100644
--- a/port/port_win.cc
+++ b/port/port_win.cc
@@ -32,6 +32,7 @@
 
 #include <windows.h>
 #include <cassert>
+#include <intrin.h>
 
 namespace leveldb {
 namespace port {
@@ -143,5 +144,15 @@ void AtomicPointer::NoBarrier_Store(void* v) {
   rep_ = v;
 }
 
+bool HasAcceleratedCRC32C() {
+#if (__x86_64__ || __i386__)
+  int cpu_info[4];
+  __cpuid(cpu_info, 1);
+  return (cpu_info[2] & (1 << 20)) != 0;
+#else
+  return false;
+#endif
+}
+
 }
 }
diff --git a/port/port_win.h b/port/port_win.h
index 50090048228389..e8bf46ef27cd68 100644
--- a/port/port_win.h
+++ b/port/port_win.h
@@ -168,6 +168,7 @@ inline bool GetHeapProfile(void (*func)(void*, const char*, int), void* arg) {
   return false;
 }
 
+bool HasAcceleratedCRC32C();
 uint32_t AcceleratedCRC32C(uint32_t crc, const char* buf, size_t size);
 
 }