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Groups > comp.lang.c > #383763
| From | Tim Rentsch <tr.17687@z991.linuxsc.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: filling area by color atack safety |
| Date | 2024-03-19 21:40 -0700 |
| Organization | A noiseless patient Spider |
| Message-ID | <86o7b9ms7d.fsf@linuxsc.com> (permalink) |
| References | <ut3669$21eur$1@i2pn2.org> <86h6h3nvyz.fsf@linuxsc.com> <865xxiok09.fsf@linuxsc.com> <20240319131842.00002138@yahoo.com> |
Michael S <already5chosen@yahoo.com> writes:
> On Mon, 18 Mar 2024 22:42:14 -0700
> Tim Rentsch <tr.17687@z991.linuxsc.com> wrote:
>
>> Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
>>
>> [...]
>>
>> Here is the refinement that uses a resizing rather than
>> fixed-size buffer.
>>
>>
>> typedef unsigned char Color;
>> typedef unsigned int UI;
>> typedef struct { UI x, y; } Point;
>> typedef unsigned int Index;
>>
>> static _Bool change_it( UI w, UI h, Color [w][h], Point, Color,
>> Color );
>>
>> void
>> fill_area( UI w, UI h, Color pixels[w][h], Point p0, Color old, Color
>> new ){ static const Point deltas[4] = { {1,0}, {0,1}, {-1,0},
>> {0,-1}, }; UI k = 0;
>> UI n = 17;
>> Point *todo = malloc( n * sizeof *todo );
>>
>> if( todo && change_it( w, h, pixels, p0, old, new ) )
>> todo[k++] = p0;
>>
>> while( k > 0 ){
>> Index j = n-k;
>> memmove( todo + j, todo, k * sizeof *todo );
>> k = 0;
>>
>> while( j < n ){
>> Point p = todo[ j++ ];
>> for( Index i = 0; i < 4; i++ ){
>> Point q = { p.x + deltas[i].x, p.y + deltas[i].y };
>> if( ! change_it( w, h, pixels, q, old, new ) )
>> continue; todo[ k++ ] = q;
>> }
>>
>> if( j-k < 3 ){
>> Index new_n = n+n/4;
>> Index new_j = new_n - (n-j);
>> Point *t = realloc( todo, new_n * sizeof *t );
>> if( !t ){ k = 0; break; }
>> memmove( t + new_j, t + j, (n-j) * sizeof *t );
>> todo = t, n = new_n, j = new_j;
>> }
>> }
>> }
>>
>> free( todo );
>> }
>>
>> _Bool
>> change_it( UI w, UI h, Color pixels[w][h], Point p, Color old, Color
>> new ){ if( p.x >= w || p.y >= h || pixels[p.x][p.y] != old )
>> return 0; return pixels[p.x][p.y] = new, 1;
>> }
>
> This variant is significantly slower than Malcolm's.
> 2x slower for solid rectangle, 6x slower for snake shape.
Slower with some shapes, faster in others. In any case
the code was written for clarity of presentation, with
no attention paid to low-level performance.
> Is it the same algorithm?
Sorry, the same algorithm as what? The same as Malcolm's?
Definitely not. The same as my other posting that does
not do dynamic reallocation? Yes in the sense that if the
allocated array is large enough to begin with then no
reallocations are needed.
> Besides, I don't think that use of VLA in library code is a good idea.
> VLA is optional in latest C standards. And incompatible with C++.
The code uses a variably modified type, not a variable length
array. Again, the choice is for clarity of presentation. If
someone wants to get rid of the variably modified types, it's
very easy to do, literally a five minute task. Anyway the
interface is poorly designed to start with, there are bigger
problems than just whether a variably modified type is used.
(I chose the interface I did to approximate the interface
used in Malcolm's code.)
If someone wants to use the functionality from C++, it's
easy enough to write a C wrapper function to do that.
IMO C++ has diverged sufficiently from C so that there
is little to be gained by trying to make code interoperable
between the two languages.
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filling area by color atack safety fir <fir@grunge.pl> - 2024-03-16 05:11 +0100
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-16 11:33 +0000
Re: filling area by color atack safety Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-03-16 13:55 +0000
Re: filling area by color atack safety bart <bc@freeuk.com> - 2024-03-16 14:41 +0000
Re: filling area by color atack safety Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-03-17 10:42 +0000
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-18 03:00 -0700
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-18 14:23 +0200
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-18 14:13 -0700
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-19 16:05 +0100
Re: filling area by color atack safety bart <bc@freeuk.com> - 2024-03-19 17:16 +0000
Re: filling area by color atack safety bart <bc@freeuk.com> - 2024-03-19 17:33 +0000
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-19 23:07 +0100
Re: filling area by color atack safety David Brown <david.brown@hesbynett.no> - 2024-03-20 09:29 +0100
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-18 03:04 -0700
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-16 14:45 +0000
Re: filling area by color atack safety scott@slp53.sl.home (Scott Lurndal) - 2024-03-16 18:21 +0000
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-16 20:02 +0000
Re: filling area by color atack safety "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-16 13:29 -0700
Re: filling area by color atack safety "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-17 13:19 -0700
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-18 14:40 +0200
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-19 23:23 +0100
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-17 15:32 +0200
Re: filling area by color atack safety Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-03-17 11:25 +0000
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-17 12:37 +0000
Re: filling area by color atack safety Kaz Kylheku <433-929-6894@kylheku.com> - 2024-03-17 17:11 +0000
Re: filling area by color atack safety Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-03-23 00:21 +0000
Re: filling area by color atack safety scott@slp53.sl.home (Scott Lurndal) - 2024-03-23 14:43 +0000
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-23 11:48 -0700
Re: filling area by color atack safety scott@slp53.sl.home (Scott Lurndal) - 2024-03-24 20:48 +0000
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-28 22:51 -0700
Re: filling area by color atack safety David Brown <david.brown@hesbynett.no> - 2024-03-16 15:40 +0100
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-16 15:09 +0000
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-17 14:56 +0000
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-17 17:42 +0200
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-17 18:25 +0200
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-17 19:39 +0200
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-18 11:36 -0700
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-18 18:51 +0000
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-18 23:10 -0700
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-19 12:06 +0000
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-20 00:03 +0100
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-20 01:17 +0200
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-20 00:30 +0100
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-20 12:06 +0200
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-20 13:44 +0100
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-20 15:44 +0200
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-20 15:17 +0100
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-20 02:15 +0100
Re: filling area by color atack safety David Brown <david.brown@hesbynett.no> - 2024-03-17 17:45 +0100
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-17 18:28 +0000
Re: filling area by color atack safety David Brown <david.brown@hesbynett.no> - 2024-03-18 07:58 +0100
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-18 09:26 +0000
Re: filling area by color atack safety David Brown <david.brown@hesbynett.no> - 2024-03-18 17:28 +0100
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-18 17:25 +0000
Re: filling area by color atack safety scott@slp53.sl.home (Scott Lurndal) - 2024-03-18 17:42 +0000
Re: filling area by color atack safety bart <bc@freeuk.com> - 2024-03-18 18:50 +0000
Re: filling area by color atack safety David Brown <david.brown@hesbynett.no> - 2024-03-19 11:41 +0100
Re: filling area by color atack safety Richard Harnden <richard.nospam@gmail.invalid> - 2024-03-19 12:19 +0000
Re: filling area by color atack safety Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-03-18 11:10 -0700
Keith-world (Was: filling area by color atack safety) gazelle@shell.xmission.com (Kenny McCormack) - 2024-03-18 22:42 +0000
Re: filling area by color atack safety David Brown <david.brown@hesbynett.no> - 2024-03-19 12:31 +0100
Re: filling area by color atack safety "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-18 16:18 -0700
Re: filling area by color atack safety David Brown <david.brown@hesbynett.no> - 2024-03-19 11:32 +0100
Re: filling area by color atack safety scott@slp53.sl.home (Scott Lurndal) - 2024-03-16 18:25 +0000
Re: filling area by color atack safety Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-03-17 10:31 +0000
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-17 12:28 +0000
Re: filling area by color atack safety bart <bc@freeuk.com> - 2024-03-17 12:49 +0000
Re: filling area by color atack safety David Brown <david.brown@hesbynett.no> - 2024-03-17 17:59 +0100
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-19 23:52 +0100
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-20 01:36 +0100
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-17 14:46 +0200
Re: filling area by color atack safety bart <bc@freeuk.com> - 2024-03-17 12:54 +0000
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-17 15:15 +0200
Re: filling area by color atack safety bart <bc@freeuk.com> - 2024-03-17 13:23 +0000
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-17 15:37 +0200
Re: filling area by color atack safety David Brown <david.brown@hesbynett.no> - 2024-03-17 18:05 +0100
Re: filling area by color atack safety Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-03-17 14:10 +0000
Re: filling area by color atack safety Spiros Bousbouras <spibou@gmail.com> - 2024-03-17 16:58 +0000
Re: filling area by color atack safety Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-03-17 22:14 +0000
Re: filling area by color atack safety bart <bc@freeuk.com> - 2024-03-17 22:21 +0000
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-18 02:30 -0700
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-18 11:08 +0000
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-18 22:54 -0700
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-19 11:41 +0000
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-19 21:19 -0700
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-20 01:13 +0100
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-20 10:41 +0200
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-20 15:20 +0100
Re: filling area by color atack safety Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2024-03-17 14:27 +0000
Re: filling area by color atack safety bart <bc@freeuk.com> - 2024-03-17 15:13 +0000
Re: filling area by color atack safety Peter 'Shaggy' Haywood <phaywood@alphalink.com.au> - 2024-03-19 10:57 +1100
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-20 01:26 +0100
Re: filling area by color atack safety bart <bc@freeuk.com> - 2024-03-16 19:13 +0000
Re: filling area by color atack safety bart <bc@freeuk.com> - 2024-03-16 20:23 +0000
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-16 20:29 +0000
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-20 01:48 +0100
Re: filling area by color atack safety Peter 'Shaggy' Haywood <phaywood@alphalink.com.au> - 2024-03-22 13:04 +1100
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-22 17:55 +0300
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-22 18:31 +0300
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-23 11:06 +0100
Re: filling area by color atack safety Peter 'Shaggy' Haywood <phaywood@alphalink.com.au> - 2024-03-17 18:03 +1100
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-18 13:09 -0700
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-18 22:42 -0700
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-19 13:18 +0200
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-19 11:57 +0000
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-19 15:49 +0200
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-19 21:43 -0700
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-20 10:56 +0200
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-20 06:51 -0700
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-19 19:18 +0200
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-20 09:27 +0100
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-20 09:39 +0100
Re: filling area by color atack safety fir <fir@grunge.pl> - 2024-03-20 09:51 +0100
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-20 07:27 -0700
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-24 20:27 +0300
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-24 13:26 -0700
Re: filling area by color atack safety "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-24 14:26 -0700
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-25 01:28 +0300
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-26 17:52 +0200
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-30 00:54 -0700
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-30 21:26 +0300
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-09 01:00 -0700
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-28 23:04 -0700
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-29 15:21 +0200
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-29 23:58 -0700
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-30 21:15 +0300
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-31 10:54 +0200
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-09 02:32 -0700
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-04-09 01:55 -0700
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-30 11:59 -0700
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-20 10:26 -0700
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-21 15:36 +0200
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-21 09:47 -0700
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-19 21:40 -0700
Re: filling area by color atack safety "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-19 21:43 -0700
Re: filling area by color atack safety "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-19 21:48 -0700
Re: filling area by color atack safety Michael S <already5chosen@yahoo.com> - 2024-03-20 11:54 +0200
Re: filling area by color atack safety Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-03-20 10:23 +0000
Re: filling area by color atack safety Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-20 12:06 +0000
Re: filling area by color atack safety Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-20 07:52 -0700
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
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