Add support for clang intrinsic constexpr

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

diff --git a/folly/detail/ChecksumDetail.h b/folly/detail/ChecksumDetail.h
index c018c1c815a9c272555dc1226d3131b86955eb3f..05a6f22c8310dfbf275941e83ec20b19e9e9f4cf 100644 (file)
--- a/folly/detail/ChecksumDetail.h
+++ b/folly/detail/ChecksumDetail.h
@@ -16,6 +16,15 @@
 
 #pragma once
 
+#include <folly/Portability.h>
+
+#if FOLLY_SSE_PREREQ(4, 2)
+#include <immintrin.h>
+#endif
+
+#include <stdint.h>
+#include <cstddef>
+
 namespace folly { namespace detail {
 
 /**
@@ -51,5 +60,41 @@ 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);
+
+#if FOLLY_SSE_PREREQ(4, 2)
+uint32_t
+crc32_hw_aligned(uint32_t remainder, const __m128i* p, size_t vec_count);
+#endif
+
+/**
+ * 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