text: #ifndef CEPH_CRUSH_HASH_H
  #define CEPH_CRUSH_HASH_H
  
  #ifdef __KERNEL__
  # include <linux/types.h>
  #else
  # include "crush_compat.h"
  #endif
  
  #define CRUSH_HASH_RJENKINS1   0
  
  #define CRUSH_HASH_DEFAULT CRUSH_HASH_RJENKINS1
  
  extern const char *crush_hash_name(int type);
  
  extern __u32 crush_hash32(int type, __u32 a);
  extern __u32 crush_hash32_2(int type, __u32 a, __u32 b);
  extern __u32 crush_hash32_3(int type, __u32 a, __u32 b, __u32 c);
  extern __u32 crush_hash32_4(int type, __u32 a, __u32 b, __u32 c, __u32 d);
  extern __u32 crush_hash32_5(int type, __u32 a, __u32 b, __u32 c, __u32 d,
  			    __u32 e);
  
  #endif
  