Add hardware crc impl

[folly.git] / folly / detail / ChecksumDetail.h

diff --git a/folly/detail/ChecksumDetail.h b/folly/detail/ChecksumDetail.h
index 59ef402e55e7e03faa6b7da3a945f661ff174a39..97ad45193feff0c22ebbec9129651f4747458383 100644 (file)
--- a/folly/detail/ChecksumDetail.h
+++ b/folly/detail/ChecksumDetail.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2014 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,8 +14,11 @@
  * limitations under the License.
  */
 
-#ifndef FOLLY_DETAIL_CHECKSUMDETAIL_H_
-#define FOLLY_DETAIL_CHECKSUMDETAIL_H_
+#pragma once
+
+#include <immintrin.h>
+#include <stdint.h>
+#include <cstddef>
 
 namespace folly { namespace detail {
 
@@ -52,7 +55,39 @@ bool crc32c_hw_supported();
 uint32_t crc32c_sw(const uint8_t* data, size_t nbytes,
     uint32_t startingChecksum = ~0U);
 
+/**
+ * Compute a CRC-32 checksum of a buffer using a hardware-accelerated
+ * implementation.
+ *
+ * @note This function is exposed to support special cases where the
+ *       calling code is absolutely certain it ought to invoke a hardware-
+ *       accelerated CRC-32 implementation - unit tests, for example.  For
+ *       all other scenarios, please call crc32() and let it pick an
+ *       implementation based on the capabilities of the underlying CPU.
+ */
+uint32_t
+crc32_hw(const uint8_t* data, size_t nbytes, uint32_t startingChecksum = ~0U);
 
-}} // folly::detail
+uint32_t
+crc32_hw_aligned(uint32_t remainder, const __m128i* p, size_t vec_count);
 
-#endif /* FOLLY_DETAIL_CHECKSUMDETAIL_H_ */
+/**
+ * Check whether a hardware-accelerated CRC-32 implementation is
+ * supported on the current CPU.
+ */
+bool crc32_hw_supported();
+
+/**
+ * Compute a CRC-32 checksum of a buffer using a portable,
+ * software-only implementation.
+ *
+ * @note This function is exposed to support special cases where the
+ *       calling code is absolutely certain it wants to use the software
+ *       implementation instead of the hardware-accelerated code - unit
+ *       tests, for example.  For all other scenarios, please call crc32()
+ *       and let it pick an implementation based on the capabilities of
+ *       the underlying CPU.
+ */
+uint32_t
+crc32_sw(const uint8_t* data, size_t nbytes, uint32_t startingChecksum = ~0U);
+}} // folly::detail