From clamav-devel-bounces@lists.clamav.net Wed Sep 5 04:39:27 2007 Return-Path: X-Original-To: list@tad.clamav.net Delivered-To: list@tad.clamav.net X-Virus-Scanned: Debian amavisd-new at tad.clamav.net Received: from tad.clamav.net ([127.0.0.1]) by localhost (tad.clamav.net [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 2ClbGVPLUUg7; Wed, 5 Sep 2007 04:39:26 +0200 (CEST) Received: from tad.clamav.net (localhost.localdomain [127.0.0.1]) by tad.clamav.net (Postfix) with ESMTP id 2CC2F354066; Wed, 5 Sep 2007 04:39:26 +0200 (CEST) X-Original-To: clamav-devel@tad.clamav.net Delivered-To: clamav-devel@tad.clamav.net X-Virus-Scanned: Debian amavisd-new at tad.clamav.net Received: from tad.clamav.net ([127.0.0.1]) by localhost (tad.clamav.net [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id WBtgC3x58yqA for ; Wed, 5 Sep 2007 04:39:21 +0200 (CEST) Received: from rv-out-0910.google.com (rv-out-0910.google.com [209.85.198.186]) by tad.clamav.net (Postfix) with ESMTP id DE41A354064 for ; Wed, 5 Sep 2007 04:39:20 +0200 (CEST) Received: by rv-out-0910.google.com with SMTP id k20so1320698rvb for ; Tue, 04 Sep 2007 19:39:20 -0700 (PDT) Received: by 10.141.202.12 with SMTP id e12mr2600979rvq.1188959959818; Tue, 04 Sep 2007 19:39:19 -0700 (PDT) Received: from db-jiangfengbin ( [219.131.196.66]) by mx.google.com with ESMTPS id k19sm8504282rvb.2007.09.04.19.39.17 (version=SSLv3 cipher=OTHER); Tue, 04 Sep 2007 19:39:18 -0700 (PDT) Date: Wed, 5 Sep 2007 10:39:02 +0800 From: "Leo Jiang" To: "clamav-devel" Message-ID: <200709051038584075531@trojan-shield.com> Organization: Leo Labs X-mailer: Foxmail 6, 8, 105, 25 [cn] Mime-Version: 1.0 Subject: [Clamav-devel] About BM_MIN_LENGTH and BM_BLOCK_SIZE in mater-bm.c X-BeenThere: clamav-devel@lists.clamav.net X-Mailman-Version: 2.1.9 Precedence: list Reply-To: ClamAV Development List-Id: ClamAV Development List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: clamav-devel-bounces@lists.clamav.net Errors-To: clamav-devel-bounces@lists.clamav.net Hi, Now in codes both of BM_MIN_LENGTH and BM_BLOCK_SIZE is zero. (In file "matcher-bm.c") So in function "cli_bm_addpatt" These codes: for (i = BM_MIN_LENGTH - BM_BLOCK_SIZE; i >= 0; i--) { idx = HASH(pt[i], pt[i + 1], pt[i + 2]); root->bm_shift[idx] = MIN(root->bm_shift[idx], BM_MIN_LENGTH - BM_BLOCK_SIZE - i); } i = BM_MIN_LENGTH - BM_BLOCK_SIZE; idx = HASH(pt[i], pt[i + 1], pt[i + 2]); equals: idx = HASH(pt[0], pt[1], pt[2]); root->bm_shift[idx] = 0; In my option one BM virus signature was load will using more instructions. More big the database is, more slow while loading it. And now bm_shift[] only have 2 value, one is 1 and another is 0. But in codes it using a int32_t type. I think it should using a unsigned char instead of int32_t. This will reduce a lot of memory, and it's very useful in a embedded system. Best regards, Leo Jiang _______________________________________________ http://lurker.clamav.net/list/clamav-devel.html Please submit your patches to our Bugzilla: http://bugs.clamav.net