OpenEuphoria

8.31 Hashing Algorithms

8.31.1 Type Constants

8.31.1.1 HSIEH30

include std/hash.e
namespace stdhash
public enum HSIEH30

8.31.1.2 HSIEH32

include std/hash.e
namespace stdhash
public enum HSIEH32

8.31.1.3 ADLER32

include std/hash.e
namespace stdhash
public enum ADLER32

8.31.1.4 FLETCHER32

include std/hash.e
namespace stdhash
public enum FLETCHER32

8.31.1.5 MD5

include std/hash.e
namespace stdhash
public enum MD5

8.31.1.6 SHA256

include std/hash.e
namespace stdhash
public enum SHA256

8.31.2 Routines

8.31.2.1 hash

<built-in> function hash(object source, atom algo)

Calculates a hash value from key using the algorithm algo

Parameters:

1. source : Any Euphoria object
2. algo : A code indicating which algorithm to use.
   • HSIEH30 uses Hsieh. Returns a 30-bit (a Euphoria integer). Fast and good dispersion
   • HSIEH32 uses Hsieh. Returns a 32-bit value. Fast and very good dispersion
   • ADLER32 uses Adler. Very fast and reasonable dispersion, especially for small strings
   • FLETCHER32 uses Fletcher. Very fast and good dispersion
   • MD5 uses MD5 (not implemented yet) Slower but very good dispersion. Suitable for signatures.
   • SHA256 uses SHA256 (not implemented yet) Slow but excellent dispersion. Suitable for signatures. More secure than MD5.
   • 0 and above (integers and decimals) and non-integers less than zero use the cyclic variant (hash = hash * algo + c). This is a fast and good to excellent dispersion depending on the value of algo. Decimals give better dispersion but are slightly slower.

Returns:

An atom, Except for the HSIEH30, MD5 and SHA256 algorithms, this is a 32-bit integer.
An integer, Except for the HSIEH30 algorithms, this is a 30-bit integer.
A sequence, MD5 returns a 4-element sequence of integers
SHA256 returns a 8-element sequence of integers.

Comments:

• For algo values from zero to less than 1, that actual value used is (algo + 69096).

Example 1:

? hash("The quick brown fox jumps over the lazy dog", 0         ) --> 3071488335
? hash("The quick brown fox jumps over the lazy dog", 99        ) --> 4122557553
? hash("The quick brown fox jumps over the lazy dog", 99.94     ) -->   95918096
? hash("The quick brown fox jumps over the lazy dog", -99.94    ) --> 4175585990
? hash("The quick brown fox jumps over the lazy dog", HSIEH30   ) -->   96435427
? hash("The quick brown fox jumps over the lazy dog", HSIEH32   ) -->   96435427
? hash("The quick brown fox jumps over the lazy dog", ADLER32   ) --> 1541148634
? hash("The quick brown fox jumps over the lazy dog", FLETCHER32) --> 1730140417
? hash(123,                                           99        ) --> 1188623852
? hash(1.23,                                          99        ) --> 3808916725
? hash({1, {2,3, {4,5,6}, 7}, 8.9},                   99        ) -->  526266621