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#ifndef CEPH_CRC32C_H
#define CEPH_CRC32C_H
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
#endif
typedef uint32_t (*ceph_crc32c_func_t)(uint32_t crc, unsigned char const *data, unsigned length);
/*
* this is a static global with the chosen crc32c implementation for
* the given architecture.
*/
extern ceph_crc32c_func_t ceph_crc32c_func;
extern ceph_crc32c_func_t ceph_choose_crc32(void);
/**
* calculate crc32c for data that is entirely 0 (ZERO)
*
* Note: works the same as ceph_crc32c_func for data == nullptr,
* but faster than the optimized assembly on certain architectures.
* This is faster than intel optimized assembly, but not as fast as
* ppc64le optimized assembly.
*
* @param crc initial value
* @param length length of buffer
*/
uint32_t ceph_crc32c_zeros(uint32_t crc, unsigned length);
/**
* calculate crc32c
*
* Note: if the data pointer is NULL, we calculate a crc value as if
* it were zero-filled.
*
* @param crc initial value
* @param data pointer to data buffer
* @param length length of buffer
*/
static inline uint32_t ceph_crc32c(uint32_t crc, unsigned char const *data, unsigned length)
{
#ifndef HAVE_POWER8
if (!data && length > 16)
return ceph_crc32c_zeros(crc, length);
#endif /* HAVE_POWER8 */
return ceph_crc32c_func(crc, data, length);
}
#ifdef __cplusplus
}
#endif
#endif
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