utils: Move base16 procedures to (guix base16).

* guix/utils.scm (bytevector->base16-string, base16-string->bytevector):
Move to...
* guix/base16.scm: ... here.  New file.
* tests/utils.scm ("bytevector->base16-string->bytevector"): Move to...
* tests/base16.scm: ... here.  New file.
* Makefile.am (MODULES): Add guix/base16.scm.
(SCM_TESTS): Add tests/base16.scm.
* build-aux/download.scm, guix/derivations.scm,
guix/docker.scm, guix/import/snix.scm, guix/pk-crypto.scm,
guix/scripts/authenticate.scm, guix/scripts/download.scm,
guix/scripts/hash.scm, guix/store.scm, tests/hash.scm,
tests/pk-crypto.scm: Adjust imports accordingly.

10 files changed, 96 insertions, 74 deletions

diff --git a/guix/base16.scm b/guix/base16.scm
new file mode 100644
index 0000000000..6c15a9f588
--- /dev/null
+++ b/guix/base16.scm
@@ -0,0 +1,83 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2012, 2014, 2017 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU 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.
+;;;
+;;; GNU 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 GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix base16)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-26)
+  #:use-module (srfi srfi-60)
+  #:use-module (rnrs bytevectors)
+  #:use-module (ice-9 vlist)
+  #:use-module (ice-9 format)
+  #:export (bytevector->base16-string
+            base16-string->bytevector))
+
+;;;
+;;; Base 16.
+;;;
+
+(define (bytevector->base16-string bv)
+  "Return the hexadecimal representation of BV's contents."
+  (define len
+    (bytevector-length bv))
+
+  (let-syntax ((base16-chars (lambda (s)
+                               (syntax-case s ()
+                                 (_
+                                  (let ((v (list->vector
+                                            (unfold (cut > <> 255)
+                                                    (lambda (n)
+                                                      (format #f "~2,'0x" n))
+                                                    1+
+                                                    0))))
+                                    v))))))
+    (define chars base16-chars)
+    (let loop ((i len)
+               (r '()))
+      (if (zero? i)
+          (string-concatenate r)
+          (let ((i (- i 1)))
+            (loop i
+                  (cons (vector-ref chars (bytevector-u8-ref bv i)) r)))))))
+
+(define base16-string->bytevector
+  (let ((chars->value (fold (lambda (i r)
+                              (vhash-consv (string-ref (number->string i 16)
+                                                       0)
+                                           i r))
+                            vlist-null
+                            (iota 16))))
+    (lambda (s)
+      "Return the bytevector whose hexadecimal representation is string S."
+      (define bv
+        (make-bytevector (quotient (string-length s) 2) 0))
+
+      (string-fold (lambda (chr i)
+                     (let ((j (quotient i 2))
+                           (v (and=> (vhash-assv chr chars->value) cdr)))
+                       (if v
+                           (if (zero? (logand i 1))
+                               (bytevector-u8-set! bv j
+                                                   (arithmetic-shift v 4))
+                               (let ((w (bytevector-u8-ref bv j)))
+                                 (bytevector-u8-set! bv j (logior v w))))
+                           (error "invalid hexadecimal character" chr)))
+                     (+ i 1))
+                   0
+                   s)
+      bv)))
+
diff --git a/guix/derivations.scm b/guix/derivations.scm
index 47a783f42f..e02d1ee036 100644
--- a/guix/derivations.scm
+++ b/guix/derivations.scm
@@ -31,6 +31,7 @@
   #:use-module (ice-9 vlist)
   #:use-module (guix store)
   #:use-module (guix utils)
+  #:use-module (guix base16)
   #:use-module (guix memoization)
   #:use-module (guix combinators)
   #:use-module (guix monads)
diff --git a/guix/docker.scm b/guix/docker.scm
index dbe1e5351c..6dabaf25b0 100644
--- a/guix/docker.scm
+++ b/guix/docker.scm
@@ -19,6 +19,7 @@
 (define-module (guix docker)
   #:use-module (guix hash)
   #:use-module (guix store)
+  #:use-module (guix base16)
   #:use-module (guix utils)
   #:use-module ((guix build utils)
                 #:select (delete-file-recursively
diff --git a/guix/import/snix.scm b/guix/import/snix.scm
index bc75cbfda5..778768ff2d 100644
--- a/guix/import/snix.scm
+++ b/guix/import/snix.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -39,6 +39,7 @@
   #:use-module ((guix build utils) #:select (package-name->name+version))
 
   #:use-module (guix import utils)
+  #:use-module (guix base16)
   #:use-module (guix base32)
   #:use-module (guix config)
   #:use-module (guix gnu-maintenance)
diff --git a/guix/pk-crypto.scm b/guix/pk-crypto.scm
index f90c2e61d5..7017006a71 100644
--- a/guix/pk-crypto.scm
+++ b/guix/pk-crypto.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013, 2014, 2015 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2013, 2014, 2015, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -17,9 +17,7 @@
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
 (define-module (guix pk-crypto)
-  #:use-module ((guix utils)
-                #:select (bytevector->base16-string
-                          base16-string->bytevector))
+  #:use-module (guix base16)
   #:use-module (guix gcrypt)
 
   #:use-module (system foreign)
diff --git a/guix/scripts/authenticate.scm b/guix/scripts/authenticate.scm
index d9f799df26..d9a312f1da 100644
--- a/guix/scripts/authenticate.scm
+++ b/guix/scripts/authenticate.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -18,7 +18,7 @@
 
 (define-module (guix scripts authenticate)
   #:use-module (guix config)
-  #:use-module (guix utils)
+  #:use-module (guix base16)
   #:use-module (guix pk-crypto)
   #:use-module (guix pki)
   #:use-module (guix ui)
diff --git a/guix/scripts/download.scm b/guix/scripts/download.scm
index dffff79729..1ddfd648cd 100644
--- a/guix/scripts/download.scm
+++ b/guix/scripts/download.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2012, 2013, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2012, 2013, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -21,7 +21,7 @@
   #:use-module (guix scripts)
   #:use-module (guix store)
   #:use-module (guix hash)
-  #:use-module (guix utils)
+  #:use-module (guix base16)
   #:use-module (guix base32)
   #:use-module ((guix download) #:hide (url-fetch))
   #:use-module ((guix build download)
diff --git a/guix/scripts/hash.scm b/guix/scripts/hash.scm
index 640b2417d2..a048b53461 100644
--- a/guix/scripts/hash.scm
+++ b/guix/scripts/hash.scm
@@ -24,7 +24,7 @@
   #:use-module (guix serialization)
   #:use-module (guix ui)
   #:use-module (guix scripts)
-  #:use-module (guix utils)
+  #:use-module (guix base16)
   #:use-module (ice-9 binary-ports)
   #:use-module (rnrs files)
   #:use-module (ice-9 match)
diff --git a/guix/store.scm b/guix/store.scm
index cce460f3ce..2f05351767 100644
--- a/guix/store.scm
+++ b/guix/store.scm
@@ -22,6 +22,7 @@
   #:use-module (guix memoization)
   #:use-module (guix serialization)
   #:use-module (guix monads)
+  #:use-module (guix base16)
   #:autoload   (guix base32) (bytevector->base32-string)
   #:autoload   (guix build syscalls) (terminal-columns)
   #:use-module (rnrs bytevectors)
diff --git a/guix/utils.scm b/guix/utils.scm
index b72e3f233f..bc90686de0 100644
--- a/guix/utils.scm
+++ b/guix/utils.scm
@@ -28,15 +28,12 @@
   #:use-module (srfi srfi-11)
   #:use-module (srfi srfi-26)
   #:use-module (srfi srfi-39)
-  #:use-module (srfi srfi-60)
-  #:use-module (rnrs bytevectors)
   #:use-module (ice-9 binary-ports)
   #:autoload   (rnrs io ports) (make-custom-binary-input-port)
   #:use-module ((rnrs bytevectors) #:select (bytevector-u8-set!))
   #:use-module (guix memoization)
   #:use-module ((guix build utils) #:select (dump-port))
   #:use-module ((guix build syscalls) #:select (mkdtemp! fdatasync))
-  #:use-module (ice-9 vlist)
   #:use-module (ice-9 format)
   #:autoload   (ice-9 popen)  (open-pipe*)
   #:autoload   (ice-9 rdelim) (read-line)
@@ -46,10 +43,7 @@
   #:use-module ((ice-9 iconv) #:prefix iconv:)
   #:use-module (system foreign)
   #:re-export (memoize)         ; for backwards compatibility
-  #:export (bytevector->base16-string
-            base16-string->bytevector
-
-            strip-keyword-arguments
+  #:export (strip-keyword-arguments
             default-keyword-arguments
             substitute-keyword-arguments
             ensure-keyword-arguments
@@ -100,63 +94,6 @@
 
 
 ;;;
-;;; Base 16.
-;;;
-
-(define (bytevector->base16-string bv)
-  "Return the hexadecimal representation of BV's contents."
-  (define len
-    (bytevector-length bv))
-
-  (let-syntax ((base16-chars (lambda (s)
-                               (syntax-case s ()
-                                 (_
-                                  (let ((v (list->vector
-                                            (unfold (cut > <> 255)
-                                                    (lambda (n)
-                                                      (format #f "~2,'0x" n))
-                                                    1+
-                                                    0))))
-                                    v))))))
-    (define chars base16-chars)
-    (let loop ((i len)
-               (r '()))
-      (if (zero? i)
-          (string-concatenate r)
-          (let ((i (- i 1)))
-            (loop i
-                  (cons (vector-ref chars (bytevector-u8-ref bv i)) r)))))))
-
-(define base16-string->bytevector
-  (let ((chars->value (fold (lambda (i r)
-                              (vhash-consv (string-ref (number->string i 16)
-                                                       0)
-                                           i r))
-                            vlist-null
-                            (iota 16))))
-    (lambda (s)
-      "Return the bytevector whose hexadecimal representation is string S."
-      (define bv
-        (make-bytevector (quotient (string-length s) 2) 0))
-
-      (string-fold (lambda (chr i)
-                     (let ((j (quotient i 2))
-                           (v (and=> (vhash-assv chr chars->value) cdr)))
-                       (if v
-                           (if (zero? (logand i 1))
-                               (bytevector-u8-set! bv j
-                                                   (arithmetic-shift v 4))
-                               (let ((w (bytevector-u8-ref bv j)))
-                                 (bytevector-u8-set! bv j (logior v w))))
-                           (error "invalid hexadecimal character" chr)))
-                     (+ i 1))
-                   0
-                   s)
-      bv)))
-
-
-
-;;;
 ;;; Filtering & pipes.
 ;;;