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Groups > comp.lang.c > #384296
| From | Tim Rentsch <tr.17687@z991.linuxsc.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: filling area by color atack safety - worst memory size |
| Date | 2024-04-11 21:06 -0700 |
| Organization | A noiseless patient Spider |
| Message-ID | <86zftzz0kx.fsf@linuxsc.com> (permalink) |
| References | (7 earlier) <20240324193352.000062e9@yahoo.com> <86jzlrk0f6.fsf@linuxsc.com> <20240405173033.00006145@yahoo.com> <868r1k1uq8.fsf@linuxsc.com> <20240411152033.00007173@yahoo.com> |
Michael S <already5chosen@yahoo.com> writes:
(I'm replying in pieces.)
> On Wed, 10 Apr 2024 19:47:11 -0700
> Tim Rentsch <tr.17687@z991.linuxsc.com> wrote:
>
>> Before I do anything else I should correct a bug in my earlier
>> FIFO algorithm. The initialization of the variable jx should
>> read
>>
>> Index const jx = used*3 < open ? k : j+open/3 &m;
>
> I lost track, sorry. I can not find your code that contains line
> similar to this.
> Can you point to specific post?
Easier for me just to repost the corrected algorithm. The
type UC is an unsigned char, the types Index and Count are
size_t (or maybe unsigned long long), the type U32 is a
32-bit unsigned type.
Please excuse any minor glitches, I have done some hand
editing to take out various bits of diagnostic code.
extern Count
fifo_fill( UC *field, Index w, Index h, Point p0, UC old, UC new ){
Index const xm = w-1;
Index const ym = h-1;
Index j = 0;
Index k = 0;
Index n = 1u << 10;
Index m = n-1;
U32 *todo = malloc( n * sizeof *todo );
Index x = p0.x;
Index y = p0.y;
if( !todo || x >= w || y >= h || field[ x+y*w ] != old ) return 0;
todo[ k++ ] = x<<16 | y;
while( j != k ){
Index used = j < k ? k-j : k+n-j;
Index open = n - used;
if( open < used/16 ){
Index new_n = n*2;
Index new_m = new_n-1;
Index new_j = j < k ? j : j+n;
U32 *t = realloc( todo, new_n * sizeof *t );
if( ! t ) break;
if( j != new_j ) memcpy( t+new_j, t+j, (n-j) * sizeof *t );
todo = t, n = new_n, m = new_m, j = new_j, open = n-used;
}
assert( (k-j&m) == used && open+used == n );
Index const jx = used*3 < open ? k : j+open/3 &m; // here it is!
while( j != jx ){
if( (k-j&m) > mm ) mm = k-j&m;
U32 p = todo[j]; j = j+1 &m;
x = p >> 16, y = p & 0xFFFF;
if( x > 0 && field[ x-1 + y*w ] == old ){
todo[k] = x-1<<16 | y, k = k+1&m, field[ x-1 + y*w ] = new;
}
if( y > 0 && field[ x + (y-1)*w ] == old ){
todo[k] = x<<16 | y-1, k = k+1&m, field[ x + (y-1)*w ] = new;
}
if( x < xm && field[ x+1 + y*w ] == old ){
todo[k] = x+1<<16 | y, k = k+1&m, field[ x+1 + y*w ] = new;
}
if( y < ym && field[ x + (y+1)*w ] == old ){
todo[k] = x<<16 | y+1, k = k+1&m, field[ x + (y+1)*w ] = new;
}
}
}
return free( todo ), 0;
}
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-20 10:01 -0700
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-24 19:33 +0300
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-24 10:24 -0700
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-25 01:04 +0300
Re: filling area by color atack safety - worst memory size Michael S <already5chosen@yahoo.com> - 2024-04-05 17:30 +0300
Re: filling area by color atack safety - worst memory size Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-10 19:47 -0700
Re: filling area by color atack safety - worst memory size Michael S <already5chosen@yahoo.com> - 2024-04-11 15:20 +0300
Re: filling area by color atack safety - worst memory size Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-11 21:06 -0700
Re: filling area by color atack safety - worst memory size Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-11 21:55 -0700
Re: filling area by color atack safety - worst memory size Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-11 22:09 -0700
Re: filling area by color atack safety - worst memory size Michael S <already5chosen@yahoo.com> - 2024-04-12 11:13 +0300
Re: filling area by color atack safety - worst memory size Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-13 08:30 -0700
Re: filling area by color atack safety - worst memory size Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-11 22:38 -0700
Re: filling area by color atack safety - worst memory size Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-11 22:43 -0700
Re: filling area by color atack safety - worst memory size Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-12 11:59 -0700
Re: filling area by color atack safety - worst memory size Michael S <already5chosen@yahoo.com> - 2024-04-13 20:26 +0300
Re: filling area by color atack safety - worst memory size Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-13 10:54 -0700
Re: filling area by color atack safety - worst memory size Michael S <already5chosen@yahoo.com> - 2024-04-13 23:11 +0300
Re: filling area by color atack safety - worst memory size Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-17 10:47 -0700
Re: filling area by color atack safety - worst memory size Michael S <already5chosen@yahoo.com> - 2024-04-17 22:41 +0300
Re: filling area by color atack safety - worst memory size Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-19 14:59 -0700
Re: filling area by color atack safety - worst memory size Michael S <already5chosen@yahoo.com> - 2024-04-20 21:10 +0300
Re: filling area by color atack safety - worst memory size Michael S <already5chosen@yahoo.com> - 2024-04-25 17:56 +0300
Re: filling area by color atack safety - worst memory size Michael S <already5chosen@yahoo.com> - 2024-05-03 18:33 +0300
Re: filling area by color atack safety - worst memory size Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-05-15 09:57 -0700
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