hash_key.h File Reference

Interface for map implementations. More...

#include "common.h"

Go to the source code of this file.

Data Structures
struct	cx_hash_key_s
	Internal structure for a key within a hash map. More...

Macros
#define	cx_hash_key_cxstr(str)   cx_hash_key((void*)(str).ptr, (str).length)
	Computes a hash key from a UCX string.

Typedefs
typedef struct cx_hash_key_s	CxHashKey
	Type for a hash key.

Functions
void	cx_hash_murmur (CxHashKey *key)
	Computes a murmur2 32 bit hash.
CxHashKey	cx_hash_key_str (char const *str)
	Computes a hash key from a string.
CxHashKey	cx_hash_key_bytes (unsigned char const *bytes, size_t len)
	Computes a hash key from a byte array.
CxHashKey	cx_hash_key (void const *obj, size_t len)
	Computes a hash key for an arbitrary object.

Detailed Description

Interface for map implementations.

Author

Mike Becker

Olaf Wintermann

Version

3.0

Copyright

2-Clause BSD License

Macro Definition Documentation

cx_hash_key_cxstr

#define cx_hash_key_cxstr

(

str

)

cx_hash_key((void*)(str).ptr, (str).length)

Computes a hash key from a UCX string.

Parameters

str	the string

Returns

the hash key

Function Documentation

cx_hash_key()

CxHashKey cx_hash_key	(	void const *	obj,
		size_t	len
	)

Computes a hash key for an arbitrary object.

The computation uses the in-memory representation that might not be the same on different platforms. Therefore, this hash should not be used for data exchange with different machines.

Parameters

obj	a pointer to an arbitrary object
len	the length of object in memory

Returns

the hash key

cx_hash_key_bytes()

CxHashKey cx_hash_key_bytes	(	unsigned char const *	bytes,
		size_t	len
	)

Computes a hash key from a byte array.

Parameters

bytes	the array
len	the length

Returns

the hash key

cx_hash_key_str()

CxHashKey cx_hash_key_str

(

char const *

str

)

Computes a hash key from a string.

The string needs to be zero-terminated.

Parameters

str	the string

Returns

the hash key

cx_hash_murmur()

void cx_hash_murmur

(

CxHashKey *

key

)

Computes a murmur2 32 bit hash.

You need to initialize data and len in the key struct. The hash is then directly written to that struct.

Note

If data is NULL, the hash is defined as 1574210520.

Parameters

key	the key, the hash shall be computed for