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

[Jamie Couture]

On Wed, Jan 4, 2012 at 3:59 AM, Eric Wong <normalperson at yhbt.net> wrote:

> 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
>

Tested and confirmed segfault fix

Thanks, Eric