message-digest
Note: This is taken from the Chicken Wiki, where a more recent version could be available.
= message-digest
Message Digest provides support for message digest primitives. A message-digest is a function taking arbitrary-length byte-block binary input and returning a fixed-length hash.
(require-extension message-digest)
[procedure] (make-binary-message-digest OBJECT CONTEXT-INFO DIGEST-LENGTH INIT UPDATE FINAL [ID])
Returns the message-digest for OBJECT as a binary string. ID is the symbol for the calling context.
Acceptable objects are string, input-port, blob, or anything that can be converted into a blob. Lists, vectors, and homogeneous-vectors can be converted. Lists and vectors should only be composed of characters, fixnums, or booleans. A boolean is treated as #f = 0 and #t = 1.
An input-port is not closed, but is read to end-of-file.
CONTEXT-INFO is either a procedure that returns an object, or a positive fixnum. When a fixnum a block of memory of length CONTEXT-INFO is allocated (and automatically free'ed). The CONTEXT can be a pointer object or any other Scheme object.
DIGEST-LENGTH The fixnum count of bytes in the result string.
The phase procedures:
[procedure] (INIT CONTEXT)
Initialization phase procedure. Sets up the CONTEXT, if necessary. The result is ignored.
[procedure] (UPDATE CONTEXT BYTES COUNT)
Accumulation phase procedure. Must accumulate the COUNT BYTES. BYTES is a Scheme non-immediate object. Will be called one or more times. The result is ignored.
See message-digest-chunk-size to set the number of bytes read per update invocation.
[procedure] (FINAL CONTEXT RESULT)
Finalization phase procedure. Must build the resulting message-digest in the supplied RESULT string. The result is ignored.
The optional ID is for identification. If not supplied a unique id will be generated.
[procedure] (make-message-digest OBJECT CONTEXT-INFO DIGEST-LENGTH INIT UPDATE FINAL [ID])
Exactly as above but returns the message-digest for OBJECT as a hexadecimal encoded string of length 2 * DIGEST-LENGTH.
[record] (message-digest-primitive CONTEXT-INFO DIGEST-LENGTH INIT UPDATE FINAL ID)
The meaning of the fields are exactly as above.
[procedure] message-digest? [procedure] message-digest-context-info [procedure] message-digest-digest-length [procedure] message-digest-init [procedure] message-digest-update [procedure] message-digest-final [procedure] message-digest-name
[procedure] (message-digest-primitive-apply MESSAGE-DIGEST-PRIMITIVE OBJECT [ID])
Returns a binary-message-digest of OBJECT using MESSAGE-DIGEST-PRIMITIVE.
[parameter] (message-digest-chunk-size [SIZE])
The number of bytes to read during the message-digest update phase. SIZE is a positive fixnum, default 1024.
[procedure] (byte-string->substring-list STRING CHUNK-SIZE [START [END]])
Returns a list of CHUNK-SIZE substrings of STRING, on the interval [START END). Defaults are [0 string-length). Any remaining substring less than chunk-size is appended to the list.
[procedure] (byte-string->substring-list/shared STRING CHUNK-SIZE [START [END]])
Returns a list of CHUNK-SIZE substrings of STRING, on the interval [START END). Defaults are [0 string-length). Any remaining substring less than chunk-size is appended to the list.
The substrings share storage with the STRING!
[procedure] (string->hexadecimal STRING [LENGTH])
Returns the STRING as a hex-encoded string. When LENGTH missing string-length is used. The returned string is 2 * string-length.
[procedure] (string->substring-list STRING CHUNK-SIZE [START [END]])
Returns a list of CHUNK-SIZE substrings of STRING, on the interval [START END). Defaults are [0 string-length). Any remaining substring less than chunk-size is appended to the list.
Byte Oriented!
[procedure] (string->substring-list/shared STRING CHUNK-SIZE [START [END]])
Returns a list of CHUNK-SIZE substrings of STRING, on the interval [START END). Defaults are [0 string-length). Any remaining substring less than chunk-size is appended to the list.
The substrings share storage with the STRING!
Byte Oriented!
[procedure] (->byte-vector OBJECT)
Converts the OBJECT into a byte-vector.
[procedure] (->blob OBJECT)
Converts the OBJECT into a blob.
Kon Lovett
Copyright © 2006, 2007 Kon Lovett. All rights reserved.
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