SHA-256: Difference between revisions

=={{header|Racket}}==

<lang Racket>#lang racket/base

(require ffi/unsafe

openssl/libcrypto

(only-in file/sha1 bytes->hex-string))

;; define a quick SH256 FFI interface, similar to the Racket's default

;; SHA1 interface

(define _SHA256_CTX-pointer _pointer)

(define SHA256_Init

(and libcrypto

(get-ffi-obj 'SHA256_Init libcrypto

(_fun _SHA256_CTX-pointer -> _int)

(lambda () #f))))

(define SHA256_Update

(and libcrypto

(get-ffi-obj 'SHA256_Update libcrypto

(_fun _SHA256_CTX-pointer _pointer _long -> _int)

(lambda () #f))))

(define SHA256_Final

(and libcrypto

(get-ffi-obj 'SHA256_Final libcrypto

(_fun _pointer _SHA256_CTX-pointer -> _int)

(lambda () #f))))

(define (sha256-bytes in)

(if SHA256_Init

(let ([ctx (malloc 128)]

[tmp (make-bytes 4096)]

[result (make-bytes 32)])

(SHA256_Init ctx)

(let loop ()

(let ([n (read-bytes-avail! tmp in)])

(unless (eof-object? n)

(SHA256_Update ctx tmp n)

(loop))))

(SHA256_Final result ctx)

result)

(error 'sha256-bytes "ffi SHA256 functionality not available")))

(define (sha256 in)

(bytes->hex-string (sha256-bytes in)))

;; use the defined wrapper to solve the task

(printf "~a\n" (sha256 (open-input-string "Rosetta code")))</lang>

{{out}}

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