From 6f233040d34706879a9ac490668a7132be4f1e13 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ludovic=20Court=C3=A8s?= Date: Tue, 23 Jun 2020 18:11:35 +0200 Subject: [PATCH] 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'. --- guix/openpgp.scm | 21 ++++----------------- 1 file changed, 4 insertions(+), 17 deletions(-) diff --git a/guix/openpgp.scm b/guix/openpgp.scm index b74f8ff5bf..33c851255b 100644 --- a/guix/openpgp.scm +++ b/guix/openpgp.scm @@ -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 "-----")