From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:37132) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hUAUO-00009A-VA for guix-patches@gnu.org; Fri, 24 May 2019 09:44:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hUAUN-0000YJ-UD for guix-patches@gnu.org; Fri, 24 May 2019 09:44:04 -0400 Received: from debbugs.gnu.org ([209.51.188.43]:32770) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hUAUN-0000Y8-Qx for guix-patches@gnu.org; Fri, 24 May 2019 09:44:03 -0400 Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1hUAUN-0002SA-MK for guix-patches@gnu.org; Fri, 24 May 2019 09:44:03 -0400 Subject: [bug#35880] [PATCH 7/7] lzlib: 'lzread!' never returns more than it was asked for. Resent-Message-ID: From: Ludovic =?UTF-8?Q?Court=C3=A8s?= Date: Fri, 24 May 2019 15:42:38 +0200 Message-Id: <20190524134238.22802-7-ludo@gnu.org> In-Reply-To: <20190524134238.22802-1-ludo@gnu.org> References: <20190524134238.22802-1-ludo@gnu.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-patches-bounces+kyle=kyleam.com@gnu.org Sender: "Guix-patches" To: 35880@debbugs.gnu.org Cc: Pierre Neidhardt Fixes a bug whereby 'lzread!' could return more than COUNT. * guix/lzlib.scm (lzread!): Rewrite in a semi-functional style. --- guix/lzlib.scm | 39 +++++++++++++++++++-------------------- 1 file changed, 19 insertions(+), 20 deletions(-) diff --git a/guix/lzlib.scm b/guix/lzlib.scm index 48927c6262..0e384f6cb8 100644 --- a/guix/lzlib.scm +++ b/guix/lzlib.scm @@ -494,29 +494,28 @@ perhaps not yet read." ;; High level functions. -(define* (lzread! decoder file-port bv + +(define* (lzread! decoder port bv #:optional (start 0) (count (bytevector-length bv))) - "Read up to COUNT bytes from FILE-PORT into BV at offset START. Return the + "Read up to COUNT bytes from PORT into BV at offset START. Return the number of uncompressed bytes actually read; it is zero if COUNT is zero or if the end-of-stream has been reached." - ;; WARNING: Because we don't alternate between lz-reads and lz-writes, we can't - ;; process more than lz-decompress-write-size from the file-port. - (when (> count (lz-decompress-write-size decoder)) - (set! count (lz-decompress-write-size decoder))) - (let ((file-bv (get-bytevector-n file-port count))) - (unless (eof-object? file-bv) - (lz-decompress-write decoder file-bv 0 (bytevector-length file-bv)))) - (let ((read 0)) - (let loop ((rd 0)) - (if (< start (bytevector-length bv)) - (begin - (set! rd (lz-decompress-read decoder bv start (- (bytevector-length bv) start))) - (set! start (+ start rd)) - (set! read (+ read rd))) - (set! rd 0)) - (unless (= rd 0) - (loop rd))) - read)) + (define (feed-decoder! decoder) + ;; Feed DECODER with data read from PORT. + (match (get-bytevector-n port (lz-decompress-write-size decoder)) + ((? eof-object? eof) eof) + (bv (lz-decompress-write decoder bv)))) + + (let loop ((read 0) + (start start)) + (cond ((< read count) + (match (lz-decompress-read decoder bv start (- count read)) + (0 (if (eof-object? (feed-decoder! decoder)) + read + (loop read start))) + (n (loop (+ read n) (+ start n))))) + (else + read)))) (define (lzwrite! encoder source source-offset source-count target target-offset target-count) -- 2.21.0