Add support for clang intrinsic constexpr

[folly.git] / folly / Checksum.h

diff --git a/folly/Checksum.h b/folly/Checksum.h
index 1168badf3d2eeb7f14aa9ef2172961381639c861..a47a6804066912d5c1b733a491779ac09bdfec8c 100644 (file)
--- a/folly/Checksum.h
+++ b/folly/Checksum.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 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 +14,7 @@
  * limitations under the License.
  */
 
-#ifndef FOLLY_CHECKSUM_H_
-#define FOLLY_CHECKSUM_H_
+#pragma once
 
 #include <stdint.h>
 #include <cstddef>
@@ -38,6 +37,24 @@ namespace folly {
 uint32_t crc32c(const uint8_t* data, size_t nbytes,
     uint32_t startingChecksum = ~0U);
 
-} // folly
+/**
+ * Compute the CRC-32 checksum of a buffer, using a hardware-accelerated
+ * implementation if available or a portable software implementation as
+ * a default.
+ */
+uint32_t
+crc32(const uint8_t* data, size_t nbytes, uint32_t startingChecksum = ~0U);
+
+/**
+ * Compute the CRC-32 checksum of a buffer, using a hardware-accelerated
+ * implementation if available or a portable software implementation as
+ * a default.
+ *
+ * @note compared to crc32(), crc32_type() uses a different set of default
+ *       parameters to match the results returned by boost::crc_32_type and
+ *       php's built-in crc32 implementation
+ */
+uint32_t
+crc32_type(const uint8_t* data, size_t nbytes, uint32_t startingChecksum = ~0U);
 
-#endif /* FOLLY_CHECKSUM_H_ */
+} // namespace folly