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-rw-r--r--guix/utils.scm100
-rw-r--r--tests/utils.scm53
2 files changed, 153 insertions, 0 deletions
diff --git a/guix/utils.scm b/guix/utils.scm
new file mode 100644
index 0000000000..69abcb4b55
--- /dev/null
+++ b/guix/utils.scm
@@ -0,0 +1,100 @@
+;;; Guix --- Nix package management from Guile. -*- coding: utf-8 -*-
+;;; Copyright (C) 2012 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of Guix.
+;;;
+;;; Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with Guix. If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix utils)
+ #:use-module (srfi srfi-60)
+ #:use-module (rnrs bytevectors)
+ #:export (bytevector-quintet-length
+ bytevector->base32-string
+ bytevector->nix-base32-string))
+
+(define bytevector-quintet-ref
+ (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) 3 8)))
+ (ref1 (lambda (bv offset)
+ (logior (ash (bit-field (ref bv offset) 0 3) 2)
+ (bit-field (ref+ bv offset) 6 8))))
+ (ref2 (lambda (bv offset)
+ (bit-field (ref bv offset) 1 6)))
+ (ref3 (lambda (bv offset)
+ (logior (ash (bit-field (ref bv offset) 0 1) 4)
+ (bit-field (ref+ bv offset) 4 8))))
+ (ref4 (lambda (bv offset)
+ (logior (ash (bit-field (ref bv offset) 0 4) 1)
+ (bit-field (ref+ bv offset) 7 8))))
+ (ref5 (lambda (bv offset)
+ (bit-field (ref bv offset) 2 7)))
+ (ref6 (lambda (bv offset)
+ (logior (ash (bit-field (ref bv offset) 0 2) 3)
+ (bit-field (ref+ bv offset) 5 8))))
+ (ref7 (lambda (bv offset)
+ (bit-field (ref bv offset) 0 5)))
+ (refs (vector ref0 ref1 ref2 ref3 ref4 ref5 ref6 ref7)))
+ (lambda (bv index)
+ "Return the INDEXth quintet of BV."
+ (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)))
+
+(define (bytevector-quintet-fold 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 0)
+ (r init))
+ (if (= i len)
+ r
+ (loop (1+ i) (proc (bytevector-quintet-ref bv i) r)))))
+
+(define (make-bytevector->base32-string 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)))
+ (list->string (reverse chars)))))
+
+(define %nix-base32-chars
+ ;; See `libutil/hash.cc'.
+ #(#\0 #\1 #\2 #\3 #\4 #\5 #\6 #\7 #\8 #\9
+ #\a #\b #\c #\d #\f #\g #\h #\i #\j #\k #\l #\m #\n
+ #\p #\q #\r #\s #\v #\w #\x #\y #\z))
+
+(define %rfc4648-base32-chars
+ #(#\a #\b #\c #\d #\e #\f #\g #\h #\i #\j #\k #\l #\m
+ #\n #\o #\p #\q #\r #\s #\t #\u #\v #\w #\x #\y #\z
+ #\2 #\3 #\4 #\5 #\6 #\7))
+
+(define bytevector->base32-string
+ (make-bytevector->base32-string %rfc4648-base32-chars))
+
+(define bytevector->nix-base32-string
+ (make-bytevector->base32-string %nix-base32-chars))
diff --git a/tests/utils.scm b/tests/utils.scm
new file mode 100644
index 0000000000..57705e6f48
--- /dev/null
+++ b/tests/utils.scm
@@ -0,0 +1,53 @@
+;;; Guix --- Nix package management from Guile. -*- coding: utf-8 -*-
+;;; Copyright (C) 2012 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of Guix.
+;;;
+;;; Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with Guix. If not, see <http://www.gnu.org/licenses/>.
+
+
+(define-module (test-utils)
+ #:use-module (guix utils)
+ #:use-module (srfi srfi-1)
+ #:use-module (srfi srfi-26)
+ #:use-module (srfi srfi-64)
+ #:use-module (rnrs bytevectors))
+
+(test-begin "utils")
+
+(test-assert "bytevector->base32-string"
+ (fold (lambda (bv expected result)
+ (and result
+ (string=? (bytevector->base32-string bv)
+ expected)))
+ #t
+
+ ;; Examples from RFC 4648.
+ (map string->utf8 '("" "f" "fo" "foo" "foob" "fooba" "foobar"))
+ '(""
+ "my"
+ "mzxq"
+ "mzxw6"
+ "mzxw6yq"
+ "mzxw6ytb"
+ "mzxw6ytboi")))
+
+(test-end)
+
+
+(exit (= (test-runner-fail-count (test-runner-current)) 0))
+
+;;; Local Variables:
+;;; eval: (put 'test-assert 'scheme-indent-function 1)
+;;; End: