On 01/02/2012 03:53 PM, Seth Arnold wrote:
Oh yes, I like that very much. :) thanks John!
So can I count that as an ACK?
------Original Message------
From: John Johansen
To: Seth Arnold
Cc: [email protected]
Subject: Re: [apparmor] [PATCH 1/5] Add basic string matching to the hfa
Sent: Jan 2, 2012 3:21 PM
On 12/27/2011 08:13 PM, Seth Arnold wrote:
Yay! I love patches. :)
<< snip>>
It seems unfortunate to me that this walks the string _twice_ -- once for
strlen, once for the match_len call. Is this me prematurely optimizing? Or
is this a potential performance problem?
And how do you find this for a solution
---
From 8f391bbc7e522d798a69809f3d40b7a6d6cdb8a1 Mon Sep 17 00:00:00 2001
From: John Johansen<[email protected]>
Date: Fri, 30 Dec 2011 17:36:05 -0800
Subject: [PATCH] Make hfa::match not need to walk a string twice
Currently hfa::match calls hfa::match_len to do matching. However this
requires walking the input string twice. Instead provide a match routine for
input that is supposed to terminate at a given input character.
Signed-off-by: John Johansen<[email protected]>
---
parser/libapparmor_re/hfa.cc | 10 +++++++++-
parser/libapparmor_re/hfa.h | 1 +
2 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/parser/libapparmor_re/hfa.cc b/parser/libapparmor_re/hfa.cc
index 86e5bd5..dca9304 100644
--- a/parser/libapparmor_re/hfa.cc
+++ b/parser/libapparmor_re/hfa.cc
@@ -276,9 +276,17 @@ State *DFA::match_len(State *state, const char *str,
size_t len)
return state;
}
+State *DFA::match_until(State *state, const char *str, const char term)
+{
+ while (*str != term)
+ state = state->next(*str++);
+
+ return state;
+}
+
State *DFA::match(const char *str)
{
- return match_len(start, str, strlen(str));
+ return match_until(start, str, 0);
}
void DFA::dump_uniq_perms(const char *s)
diff --git a/parser/libapparmor_re/hfa.h b/parser/libapparmor_re/hfa.h
index 3e8d99b..66f0a70 100644
--- a/parser/libapparmor_re/hfa.h
+++ b/parser/libapparmor_re/hfa.h
@@ -349,6 +349,7 @@ public:
virtual ~DFA();
State *match_len(State *state, const char *str, size_t len);
+ State *match_until(State *state, const char *str, const char term);
State *match(const char *str);
void remove_unreachable(dfaflags_t flags);
--
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