[PATCH 1/1] move LCS table away from the stack

[Eric Wong]

Lars Hjemli <hjemli at gmail.com> wrote:
> On Sun, Sep 18, 2011 at 00:25, Jamie Couture <jamie.couture at gmail.com> wrote:
> > - limit LCS table size: 128x128.
> > - move LCS table to global context: avoid allocating/freeing memory
> >  for every deferred line change.
> 
> Thanks, finally applied (to stable).

Hi, I got new segfaults with this patch, the following should
fix them.

>From 2d9ae9c3369d537259822a6dd64a13963cc4fdbf Mon Sep 17 00:00:00 2001
From: Eric Wong <normalperson at yhbt.net>
Date: Wed, 04 Jan 2012 08:57:43 +0000
Subject: [PATCH 2/2] correct length check for LCS table

Each individual string may be too long for its respective
dimension of the LCS table.

Signed-off-by: Eric Wong <normalperson at yhbt.net>
---
 ui-ssdiff.c |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/ui-ssdiff.c b/ui-ssdiff.c
index 9fb5b11..45770b1 100644
--- a/ui-ssdiff.c
+++ b/ui-ssdiff.c
@@ -42,14 +42,12 @@ static char *longest_common_subsequence(char *A, char *B)
 	int i, j, ri;
 	int m = strlen(A);
 	int n = strlen(B);
-	int tmp1, tmp2, length;
+	int tmp1, tmp2;
 	int lcs_length;
 	char *result;
 
-	length = (m + 1) * (n + 1);
-
 	// We bail if the lines are too long
-	if (length > MAX_SSDIFF_SIZE)
+	if (m >= MAX_SSDIFF_M || n >= MAX_SSDIFF_N)
 		return NULL;
 
 	create_or_reset_lcs_table();
-- 
Eric Wong