[GRASS5] r.texture segfault

[Hamish]

> we found a bug in r.texture which I'm unable to resolve.
>
> To reproduce it in Spearfish, run
> 
>    g.region rast=spot.image -p
>    r.rescale spot.image to=0,255 out=spot.resc
>    r.texture in=spot.resc -v pref=spot.image size=10 distance=5
>    Segmentation fault
> 
> I found with the debugger following
> 
> (gdb) r in=spot.resc -v pref=spot.image size=10 distance=5
> Starting program: /hardmnt/thuille0/ssi/software/cvsgrass61/dist.i686-pc-linux-gnu/bin/r.texture in=spot.resc -v pref=spot.image size=10 distance=5
> Reading the raster map...done
>    0%
> Program received signal SIGSEGV, Segmentation fault.
> 0x08049574 in h_measure (grays=0x87798e0, rows=10, cols=10, t_m=12, t_d=5)
>     at h_measure.c:124
> 124               while (tone[y] != grays[row][col + d])
> (gdb) bt
> #0  0x08049574 in h_measure (grays=0x87798e0, rows=10, cols=10, t_m=12, t_d=5)
>     at h_measure.c:124
> #1  0x0804d657 in main (argc=6, argv=0xbfe19214) at main.c:309
> 
> 
> The 'ddd' tells me that tone[y] is unavailable. Probably y get's
> too large and then the crash occurs.
> 
> How to fix this?


a full back trace should show the value of y when it segfaults:

(gdb) bt full



r.texture/h_measure.c:

#define PGM_MAXMAXVAL 255
int tone[PGM_MAXMAXVAL];


That 255 should really be 256?

int tone[255];

allocates tone[0] -> tone[254], maybe it loops up the value of y trying 
to match a grey value of 255 and then kerplunk?



Hamish