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Fix `bytevector->nix-base32-string'.

* guix/utils.scm (bytevector-quintet-ref-right,
  bytevector-quintet-fold): New procedures.
  (bytevector-quintet-fold-right): Add `quintet-fold' parameter; use it
  instead of `bytevector-quintet-fold'.
  (bytevector->base32-string): Pass BYTEVECTOR-QUINTET-FOLD as the
  first parameter.
  (bytevector->nix-base32-string): Pass BYTEVECTOR-QUINTET-FOLD-RIGHT as
  the first parameter.

* tests/utils.scm ("sha256 & bytevector->nix-base32-string"): New test.
gn-latest-20200428
Ludovic Courtès 9 years ago
parent
commit
f9c7080aa3
2 changed files with 77 additions and 9 deletions
  1. +57
    -8
      guix/utils.scm
  2. +20
    -1
      tests/utils.scm

+ 57
- 8
guix/utils.scm View File

@ -60,6 +60,40 @@
(let ((p (vector-ref refs (modulo index 8))))
(p bv (quotient (* index 5) 8))))))
(define bytevector-quintet-ref-right
(let* ((ref bytevector-u8-ref)
(ref+ (lambda (bv offset)
(let ((o (+ 1 offset)))
(if (>= o (bytevector-length bv))
0
(bytevector-u8-ref bv o)))))
(ref0 (lambda (bv offset)
(bit-field (ref bv offset) 0 5)))
(ref1 (lambda (bv offset)
(logior (bit-field (ref bv offset) 5 8)
(ash (bit-field (ref+ bv offset) 0 2) 3))))
(ref2 (lambda (bv offset)
(bit-field (ref bv offset) 2 7)))
(ref3 (lambda (bv offset)
(logior (bit-field (ref bv offset) 7 8)
(ash (bit-field (ref+ bv offset) 0 4) 1))))
(ref4 (lambda (bv offset)
(logior (bit-field (ref bv offset) 4 8)
(ash (bit-field (ref+ bv offset) 0 1) 4))))
(ref5 (lambda (bv offset)
(bit-field (ref bv offset) 1 6)))
(ref6 (lambda (bv offset)
(logior (bit-field (ref bv offset) 6 8)
(ash (bit-field (ref+ bv offset) 0 3) 2))))
(ref7 (lambda (bv offset)
(bit-field (ref bv offset) 3 8)))
(refs (vector ref0 ref1 ref2 ref3 ref4 ref5 ref6 ref7)))
(lambda (bv index)
"Return the INDEXth quintet of BV, assuming quintets start from the
least-significant bits, contrary to what RFC 4648 describes."
(let ((p (vector-ref refs (modulo index 8))))
(p bv (quotient (* index 5) 8))))))
(define (bytevector-quintet-length bv)
"Return the number of quintets (including truncated ones) available in BV."
(ceiling (/ (* (bytevector-length bv) 8) 5)))
@ -76,14 +110,27 @@ the previous application or INIT."
r
(loop (1+ i) (proc (bytevector-quintet-ref bv i) r)))))
(define (make-bytevector->base32-string base32-chars)
(define (bytevector-quintet-fold-right proc init bv)
"Return the result of applying PROC to each quintet of BV and the result of
the previous application or INIT."
(define len
(bytevector-quintet-length bv))
(let loop ((i len)
(r init))
(if (zero? i)
r
(let ((j (- i 1)))
(loop j (proc (bytevector-quintet-ref-right bv j) r))))))
(define (make-bytevector->base32-string quintet-fold base32-chars)
(lambda (bv)
"Return a base32 encoding of BV using BASE32-CHARS as the alphabet."
(let ((chars (bytevector-quintet-fold (lambda (q r)
(cons (vector-ref base32-chars q)
r))
'()
bv)))
(let ((chars (quintet-fold (lambda (q r)
(cons (vector-ref base32-chars q)
r))
'()
bv)))
(list->string (reverse chars)))))
(define %nix-base32-chars
@ -98,10 +145,12 @@ the previous application or INIT."
#\2 #\3 #\4 #\5 #\6 #\7))
(define bytevector->base32-string
(make-bytevector->base32-string %rfc4648-base32-chars))
(make-bytevector->base32-string bytevector-quintet-fold
%rfc4648-base32-chars))
(define bytevector->nix-base32-string
(make-bytevector->base32-string %nix-base32-chars))
(make-bytevector->base32-string bytevector-quintet-fold-right
%nix-base32-chars))
;;;
;;; Hash.


+ 20
- 1
tests/utils.scm View File

@ -22,7 +22,10 @@
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
#:use-module (srfi srfi-64)
#:use-module (rnrs bytevectors))
#:use-module (rnrs bytevectors)
#:use-module (rnrs io ports)
#:use-module (ice-9 rdelim)
#:use-module (ice-9 popen))
(test-begin "utils")
@ -43,6 +46,22 @@
"mzxw6ytb"
"mzxw6ytboi")))
;; The following tests requires `nix-hash' in $PATH.
(test-skip (if (false-if-exception (system* "nix-hash" "--version"))
0
1))
(test-assert "sha256 & bytevector->nix-base32-string"
(let ((file (search-path %load-path "tests/test.drv")))
(equal? (bytevector->nix-base32-string
(sha256 (call-with-input-file file get-bytevector-all)))
(let* ((c (format #f "nix-hash --type sha256 --base32 --flat \"~a\""
file))
(p (open-input-pipe c))
(l (read-line p)))
(close-pipe p)
l))))
(test-end)


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