hashes
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Miscellaneous Hash Functions
A suite of hash procedures. All have the same signature. All return hash values in a 32-bit range, so non-fixnum results possible! The {HASH} name refers to one of the hash algorithm symbols below.
Use of the 'hashes' extension will cause all the hash functions to load. Use the individual '{HASH}' extensions when the entire suite is not desired.
Though this egg is categorized as 'cryptographic' not a one of these is suitable for cryptographic work!
Returns the hash of STRING of LENGTH, using SEED.
Returns the hash of STRING. When LENGTH is missing (string-length STRING) is assumed. When SEED is missing 0 is assumed.
| RJMXHash |
Bob Jenkins' MIX Lookup 2 hash function. |
| RJL3Hash |
Bob Jenkins' MIX Lookup 3 hash function. |
| TWMXHash |
Thomas Wang's hash function with original MIX. |
| TWSHMXHash |
Thomas Wang's hash function with shift MIX. |
| TWSHMLMXHash |
Thomas Wang's hash function with shift-multiply MIX. |
| TWMGMXHash |
Thomas Wang's hash function with Magic MIX. |
| FNVHash |
Fowler/Noll/Vo 1 hash function. Substitutes the algorithm's initial value when the seed is non-zero. |
| FNVAHash |
Fowler/Noll/Vo 1a hash function. Substitutes the algorithm's initial value when the seed is non-zero. |
| PHSFHash |
Paul Hsieh's SuperFast hash function. Substitutes the algorithm's initial value when the seed is non-zero. |
| RSHash |
Robert Sedgwick's "Algorithms in C" hash function. |
| JSHash |
A bitwise hash function written by Justin Sobel. Ignores the seed when 0. |
| PJWHash |
Hash algorithm is based on work by Peter J. Weinberger of AT&T Bell Labs. |
| ELFHash |
Similar to the PJW Hash function, but tweaked for 32-bit processors. It's the hash function widely used on most UNIX systems. |
| BKDRHash |
This hash function comes from Brian Kernighan and Dennis Ritchie's book "The C Programming Language". It is a simple hash function using a strange set of possible seeds which all constitute a pattern of 31....31...31 etc, it seems to be very similar to the DJB hash function |
| SDBMHash |
This is the algorithm of choice which is used in the open source SDBM project. The hash function seems to have a good over-all distribution for many different data sets. It seems to work well in situations where there is a high variance in the MSBs of the elements in a data set. |
| DJBHash |
An algorithm produced by Professor Daniel J. Bernstein and shown first to the world on the usenet newsgroup comp.lang.c. It is one of the most efficient hash functions ever published. Substitutes the algorithm's initial value when the seed is non-zero. |
| NDJBHash |
Now favored by Bernstein. Substitutes the algorithm's initial value when the seed is non-zero. |
| DEKHash |
An algorithm proposed by Donald E. Knuth in "The Art Of Computer Programming, Volume 3", under the topic of sorting and search chapter 6.4. Substitutes the algorithm's initial value when the seed is non-zero. |
| APHash |
Arash Partow's hash function. A hybrid rotative and additive hash function algorithm based around four primes 3, 5, 7, and 11. |
| CRCHash |
The crc32 procedure wrapped as above. Ignores the seed when 0. |
| BRPHash |
A hash function by Bruno R. Preiss. |
| PYHash |
The Python String Object hash function. |
| ISPLHash |
The ISpell hash function. |
Thomas Wang's hash function with a user supplied MIX procedure.
Returns a hash primitive procedure, (scheme-object unsigned-integer32 unsigned-integer32 -> unsigned-integer32), for the procedure MIX, (unsigned-integer32 -> unsigned-integer32).
When UNSAFE no exception checking is performed.
Returns 5 values: HASH-PRIM, HASH, :binary-digest, :digest, and :primitive.
An acceptable input object for the digest procedures is a string, input-port, blob, vector, list, or homogeneous-vector. See message-digest for more information.
Returns the hash of OBJECT as a hexadecimal text string.
Returns the hash of OBJECT as a byte-string.
Returns the hash primitive object.
Note: The domain 'number' below means '(or flonum fixnum)', not the full Scheme 'number' domain.
Returns or sets the current default hash seed. The initial value is 0.
Returns a hash function with a SRFI-69 signature, but with a fixnum domain; i.e. (object #!optional (positive fixnum) -> fixnum). The GETLEN will be used to aquire the OBJECT length for the {HASH}. The GETINT will supply the initial hash value.
Returns a hash function with a SRFI-69 signature, but with a real domain; i.e. (object #!optional (positive number) -> number). The GETLEN will be used to aquire the OBJECT length for the {HASH}. The GETINT will supply the initial hash value.
Returns a curried {HASH} of 1 or 2 arguments with the supplied SEED. When the seed is missing the (current-hash-seed) is assumed.
Returns a {HASH} with the hash value bitwise and'ed with the supplied MASK.
Returns a {HASH} with the hash value restricted to the supplied exact interval, [LOWER UPPER]. When LOWER is missing 0 is assumed. The signature is that of the {HASH}.
Returns a {HASH} with the hash value restricted to the interval, [0.0 1.0]. The signature is that of the {HASH}.
Returns a hash procedure, (scheme-object #!optional unsigned-integer32 unsigned-integer32 -> unsigned-integer32), for the hash primitive procedure HASH-PRIM.
Returns a list of :binary-digest, :digest, and :primitivefor the hash primitive procedure HASH-PRIM.
Returns a procedure of 1 argument, (-> number number). The arguments will be swapped if necessary so the range is [LOWER UPPER]. When LOWER missing 0 is assumed.
Returns a procedure of 1 argument, (-> number fixnum). The arguments will be swapped if necessary so the range is [LOWER UPPER]. When LOWER missing 0 is assumed.
LOWER & UPPER must be fixnums.
Returns the first 32-bits of OBJECT as an unsigned-integer32.
Sets the first 32-bits of STRING to NUMBER.
Returns a procedure of one argument, the search string, and two optional arguments, the start and end positions within the string. The search procedure returns a list of the matched substring and a list of the start and end positions of the match in the search string. Returns #f when no match found. Similar to the regex unit string-match procedure.
SUBSTRINGS is a list of strings. TEST is an equivalence procedure. HASH is a SRFI-69 compliant hash procedure.
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