From fc0493d2ca87710c037ecc12fc38f9b55efa125e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?T=C3=B6r=C3=B6k=20Edvin?= <edwin@clamav.net>
Date: Mon, 10 Nov 2008 10:46:24 +0000
Subject: [PATCH] reduce memory usage of AC nodes

git-svn: trunk@4363
---
 ChangeLog              |  5 +++++
 libclamav/matcher-ac.c | 23 ++++++++---------------
 libclamav/matcher-ac.h |  4 +++-
 3 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index ade23af14..90597f1a0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Nov 10 11:46:14 EET 2008 (edwin)
+------------------------------------
+ * libclamav/matcher-ac.c, libclamav/matcher-ac.h: reduce memory
+ usage of AC nodes
+
 Sun Nov  9 22:37:29 EET 2008 (edwin)
 ------------------------------------
  * contrib/clamdtop/Makefile, contrib/clamdtop/clamdtop.c: clamdtop:
diff --git a/libclamav/matcher-ac.c b/libclamav/matcher-ac.c
index f43cffba9..ec50dce60 100644
--- a/libclamav/matcher-ac.c
+++ b/libclamav/matcher-ac.c
@@ -93,8 +93,6 @@ int cli_ac_addpatt(struct cli_matcher *root, struct cli_ac_patt *pattern)
 		    mp_free(root->mempool, next);
 		    return CL_EMEM;
 		}
-	    } else {
-		next->leaf = 1;
 	    }
 
 	    root->ac_nodes++;
@@ -111,7 +109,6 @@ int cli_ac_addpatt(struct cli_matcher *root, struct cli_ac_patt *pattern)
 	    root->ac_nodetable[root->ac_nodes - 1] = next;
 
 	    pt->trans[(unsigned char) (pattern->pattern[i] & 0xff)] = next;
-	    pt->leaf = 0;
 	}
 
 	pt = next;
@@ -127,7 +124,6 @@ int cli_ac_addpatt(struct cli_matcher *root, struct cli_ac_patt *pattern)
     root->ac_pattable = (struct cli_ac_patt **) newtable;
     root->ac_pattable[root->ac_patterns - 1] = pattern;
 
-    pt->final = 1;
     pattern->depth = i;
 
     ph = pt->list;
@@ -253,9 +249,9 @@ static int ac_maketrans(struct cli_matcher *root)
     }
 
     while((node = bfs_dequeue(&bfs, &bfs_last))) {
-	if(node->leaf) {
+	if(IS_LEAF(node)) {
 	    struct cli_ac_node *failtarget = node->fail;
-	    while(failtarget->leaf)
+	    while(IS_LEAF(failtarget))
 		failtarget = failtarget->fail;
 	    node->fail = failtarget;
 	    continue;
@@ -265,7 +261,7 @@ static int ac_maketrans(struct cli_matcher *root)
 	    child = node->trans[i];
 	    if(child) {
 		fail = node->fail;
-		while(fail->leaf || !fail->trans[i])
+		while(IS_LEAF(fail) || !fail->trans[i])
 		    fail = fail->fail;
 
 		child->fail = fail->trans[i];
@@ -280,9 +276,6 @@ static int ac_maketrans(struct cli_matcher *root)
 		    child->list = child->fail->list;
 		}
 
-		if(child->list)
-		    child->final = 1;
-
 		if((ret = bfs_enqueue(&bfs, &bfs_last, child)) != 0)
 		    return ret;
 	    }
@@ -298,13 +291,13 @@ static int ac_maketrans(struct cli_matcher *root)
 	}
     }
     while((node = bfs_dequeue(&bfs, &bfs_last))) {
-	if(node->leaf)
+	if(IS_LEAF(node))
 	    continue;
 	for(i = 0; i < 256; i++) {
 	    child = node->trans[i];
 	    if(!child) {
 		struct cli_ac_node *failtarget = node->fail;
-		while(failtarget->leaf || !failtarget->trans[i])
+		while(IS_LEAF(failtarget) || !failtarget->trans[i])
 		    failtarget = failtarget->fail;
 		node->trans[i] = failtarget->trans[i];
 	    } else {
@@ -403,7 +396,7 @@ void cli_ac_free(struct cli_matcher *root)
 	mp_free(root->mempool, root->ac_pattable);
 
     for(i = 0; i < root->ac_nodes; i++) {
-	if(!root->ac_nodetable[i]->leaf)
+	if(!IS_LEAF(root->ac_nodetable[i]))
 	    mp_free(root->mempool, root->ac_nodetable[i]->trans);
 	mp_free(root->mempool, root->ac_nodetable[i]);
     }
@@ -900,12 +893,12 @@ int cli_ac_scanbuff(const unsigned char *buffer, uint32_t length, const char **v
 
     for(i = 0; i < length; i++)  {
 
-	if(current->leaf)
+	if(IS_LEAF(current))
 	    current = current->fail;
 
 	current = current->trans[buffer[i]];
 
-	if(current->final) {
+	if(IS_FINAL(current)) {
 	    patt = current->list;
 	    while(patt) {
 		bp = i + 1 - patt->depth;
diff --git a/libclamav/matcher-ac.h b/libclamav/matcher-ac.h
index c0256cc17..33d9e0fc8 100644
--- a/libclamav/matcher-ac.h
+++ b/libclamav/matcher-ac.h
@@ -68,9 +68,11 @@ struct cli_ac_patt {
 struct cli_ac_node {
     struct cli_ac_patt *list;
     struct cli_ac_node **trans, *fail;
-    uint8_t leaf, final;
 };
 
+#define IS_LEAF(node) (!node->trans)
+#define IS_FINAL(node) (!!node->list)
+
 struct cli_ac_result {
     const char *virname;
     void *customdata;