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openpgp: Use Libgcrypt's crc24 implementation.

This gives an 18% speedup on the wall-clock time of:

  guile -c '(use-modules (git) (guix git-authenticate)) (load-keyring-from-reference (repository-open ".") "keyring")'

* guix/openpgp.scm (crc24): Rewrite by calling out to 'bytevector-hash'.
gn-latest-20200725
Ludovic Courtès 1 year ago
parent
commit
6f233040d3
No known key found for this signature in database GPG Key ID: 90B11993D9AEBB5
1 changed files with 4 additions and 17 deletions
  1. +4
    -17
      guix/openpgp.scm

+ 4
- 17
guix/openpgp.scm View File

@ -1029,23 +1029,10 @@ there is no limit."
(define (crc24 bv)
"Compute a CRC24 as described in RFC4880, Section 6.1."
(define poly #x1864cfb)
(let loop ((crc #xb704ce)
(index 0))
(if (= index (bytevector-length bv))
(logand crc #xffffff)
(let ((crc (logxor (ash (bytevector-u8-ref bv index) 16)
crc)))
(let inner ((i 0)
(crc crc))
(if (< i 8)
(let ((crc (ash crc 1)))
(inner (+ i 1)
(if (zero? (logand crc #x1000000))
crc
(logxor crc poly))))
(loop crc (+ index 1))))))))
;; We used to have it implemented in Scheme but the C version here makes
;; 'load-keyring-from-reference' 18% faster when loading the 72
;; ASCII-armored files of today's Guix keyring.
(bytevector->uint (bytevector-hash bv (hash-algorithm crc24-rfc2440))))
(define %begin-block-prefix "-----BEGIN ")
(define %begin-block-suffix "-----")


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