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Groups > comp.lang.c++ > #69094

Re: alloca()-support

From "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com>
Newsgroups comp.lang.c++, comp.lang.c
Subject Re: alloca()-support
Date 2019-10-05 14:08 -0700
Organization Aioe.org NNTP Server
Message-ID <qnb0nj$odf$1@gioia.aioe.org> (permalink)
References <qmsqs0$472$1@news.albasani.net> <qn1r0n$b77$1@gioia.aioe.org> <20191002162609.52a3f122331a7c7dd7040fe6@gmail.com> <qn2u1n$1m5p$1@gioia.aioe.org> <20191003014754.39250b808212c3b7c3a755b3@gmail.com>

Cross-posted to 2 groups.

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On 10/2/2019 3:47 PM, Anton Shepelev wrote:
> Chris M. Thomasson:
> 
>> Will have more time to get back to you later on tonight.
>> However, take a deep look at reaps:
>> https://people.cs.umass.edu/~emery/pubs/berger-oopsla2002.pdf
[...]

I was using it for systems that did not have malloc. Here is a example 
usage:

This region allocator does not force all allocations to be aligned up to 
a so-called maximum alignment like `malloc' and friends are required to 
do. For instance, allocations for a single char will not be forced to 
waste the extra alignment space. This can have benefits in space 
constrained environments (e.g., embedded devices). Also, its static in 
nature and can be fed with a buffer residing on the stack. There are no 
underlying calls to `malloc'. This can be useful in free standing 
environments that do not support heap allocation. One other thing. Its a 
pure region allocator which means you do not need to free individual 
objects. You can free the entire region. This is more efficient than 
calling `malloc()/free()' for each object. For instance, you can destroy 
all the nodes in a linked list just by freeing the region(s) in which 
the nodes were allocated from. There is no need to traverse the list to 
free its nodes. Its a sort of "manual" garbage collection... ;^)


You can use it like:
_________________________________________________________________
#include <ralloc.h>


struct foo {
   struct foo* next;
};


#include <stdio.h>


void crunch() {
   char local_buffer[1024];
   struct region local_region;
   struct foo* head1 = NULL;
   struct foo* head2 = NULL;
   size_t i, r;

   rinit(&local_region, local_buffer, sizeof(local_buffer));

   for (r = 0; r < 1024; ++r) {
     size_t c = 0;

     for (i = 0; i < 64; ++i) {
       struct foo* foo = ralloct(&local_region, 2, struct foo);
       if (foo) {
         foo->next = head1;
         head1 = foo;
         ++foo;
         foo->next = head2;
         head2 = foo;
         c += 2;
       }
     }

     while (head1) {
       head1 = head1->next;
       --c;
     }

     while (head2) {
       head2 = head2->next;
       --c;
     }

     assert(! c);

     rflush(&local_region);
   }
}


int main(void) {
   crunch();
   crunch();
   crunch();
   return 0;
}
_________________________________________________________________

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Thread

alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-09-30 14:02 +0200
  Re: alloca()-support Frederick Gotham <cauldwell.thomas@gmail.com> - 2019-09-30 07:02 -0700
    Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-09-30 16:09 +0200
      Re: alloca()-support Bo Persson <bo@bo-persson.se> - 2019-09-30 17:29 +0200
        Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-09-30 17:33 +0200
    Re: alloca()-support gazelle@shell.xmission.com (Kenny McCormack) - 2019-09-30 16:26 +0000
  Re: alloca()-support Anton Shepelev <anton.txt@g{oogle}mail.com> - 2019-09-30 17:12 +0300
    Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-09-30 16:16 +0200
      Re: alloca()-support Anton Shepelev <anton.txt@g{oogle}mail.com> - 2019-09-30 17:30 +0300
        Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-09-30 16:44 +0200
          Re: alloca()-support Anton Shepelev <anton.txt@gmail.com> - 2019-10-02 00:36 +0300
            Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-02 06:28 +0200
              Re: alloca()-support Anton Shepelev <anton.txt@gmail.com> - 2019-10-02 16:08 +0300
                Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-02 15:42 +0200
    Re: alloca()-support scott@slp53.sl.home (Scott Lurndal) - 2019-09-30 14:30 +0000
      Re: alloca()-support Anton Shepelev <anton.txt@g{oogle}mail.com> - 2019-09-30 17:33 +0300
        Re: alloca()-support David Brown <david.brown@hesbynett.no> - 2019-09-30 16:56 +0200
    Re: alloca()-support Melzzzzz <Melzzzzz@zzzzz.com> - 2019-09-30 15:29 +0000
      Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-09-30 17:31 +0200
        Re: alloca()-support Melzzzzz <Melzzzzz@zzzzz.com> - 2019-10-01 07:03 +0000
          Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-01 10:57 +0200
            Re: alloca()-support Melzzzzz <Melzzzzz@zzzzz.com> - 2019-10-01 18:49 +0000
              Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-01 21:20 +0200
                Re: alloca()-support scott@slp53.sl.home (Scott Lurndal) - 2019-10-01 20:39 +0000
                Re: alloca()-support Melzzzzz <Melzzzzz@zzzzz.com> - 2019-10-02 04:15 +0000
                Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-02 06:28 +0200
                Re: alloca()-support Melzzzzz <Melzzzzz@zzzzz.com> - 2019-10-02 04:29 +0000
    Re: alloca()-support Keith Thompson <kst-u@mib.org> - 2019-09-30 11:14 -0700
  Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-09-30 18:04 +0200
    Re: alloca()-support William Ahern <william@25thandClement.com> - 2019-09-30 11:01 -0700
      Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-01 07:19 +0200
    Re: alloca()-support Paavo Helde <myfirstname@osa.pri.ee> - 2019-09-30 22:26 +0300
      Re: alloca()-support scott@slp53.sl.home (Scott Lurndal) - 2019-09-30 19:46 +0000
    Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-01 07:32 +0200
      Re: alloca()-support Paavo Helde <myfirstname@osa.pri.ee> - 2019-10-01 09:08 +0300
        Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-01 08:35 +0200
  Re: alloca()-support Soviet_Mario <SovietMario@CCCP.MIR> - 2019-09-30 18:48 +0200
    Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-09-30 18:51 +0200
      Re: alloca()-support Soviet_Mario <SovietMario@CCCP.MIR> - 2019-09-30 18:55 +0200
        Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-09-30 18:58 +0200
          Re: alloca()-support Soviet_Mario <SovietMario@CCCP.MIR> - 2019-09-30 19:53 +0200
            Re: alloca()-support Keith Thompson <kst-u@mib.org> - 2019-09-30 11:13 -0700
            Re: alloca()-support scott@slp53.sl.home (Scott Lurndal) - 2019-09-30 19:38 +0000
              Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-01 07:41 +0200
                Re: alloca()-support scott@slp53.sl.home (Scott Lurndal) - 2019-10-01 15:19 +0000
                Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-01 17:31 +0200
                Re: alloca()-support Melzzzzz <Melzzzzz@zzzzz.com> - 2019-10-01 18:58 +0000
                Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-01 21:24 +0200
                Re: alloca()-support Melzzzzz <Melzzzzz@zzzzz.com> - 2019-10-02 04:28 +0000
                Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-02 06:30 +0200
                Re: alloca()-support Melzzzzz <Melzzzzz@zzzzz.com> - 2019-10-02 04:36 +0000
                Re: alloca()-support David Brown <david.brown@hesbynett.no> - 2019-10-02 10:01 +0200
                Re: alloca()-support Melzzzzz <Melzzzzz@zzzzz.com> - 2019-10-02 04:42 +0000
                Re: alloca()-support David Brown <david.brown@hesbynett.no> - 2019-10-02 10:10 +0200
                Re: alloca()-support Mel <mel@zzzzz.com> - 2019-10-02 15:13 +0200
                Re: alloca()-support David Brown <david.brown@hesbynett.no> - 2019-10-01 21:10 +0200
                Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-01 21:25 +0200
                Re: alloca()-support scott@slp53.sl.home (Scott Lurndal) - 2019-10-01 20:44 +0000
                Re: alloca()-support David Brown <david.brown@hesbynett.no> - 2019-10-01 23:26 +0200
                Re: alloca()-support Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2019-10-01 21:08 -0600
                Re: alloca()-support David Brown <david.brown@hesbynett.no> - 2019-10-02 10:19 +0200
                Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-02 06:39 +0200
                Re: alloca()-support David Brown <david.brown@hesbynett.no> - 2019-10-02 10:34 +0200
                Re: alloca()-support Mel <mel@zzzzz.com> - 2019-10-02 15:14 +0200
                Re: alloca()-support Mel <mel@zzzzz.com> - 2019-10-02 15:18 +0200
                Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-02 15:21 +0200
                Re: alloca()-support Melzzzzz <Melzzzzz@zzzzz.com> - 2019-10-03 04:09 +0000
                Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-03 07:48 +0200
                Re: alloca()-support Melzzzzz <Melzzzzz@zzzzz.com> - 2019-10-03 05:49 +0000
                Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-03 07:52 +0200
                Re: alloca()-support Melzzzzz <Melzzzzz@zzzzz.com> - 2019-10-03 06:46 +0000
                Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-03 10:59 +0200
              Re: alloca()-support Soviet_Mario <SovietMario@CCCP.MIR> - 2019-10-03 13:39 +0200
                Re: alloca()-support scott@slp53.sl.home (Scott Lurndal) - 2019-10-03 13:23 +0000
                Re: alloca()-support David Brown <david.brown@hesbynett.no> - 2019-10-03 15:38 +0200
                Re: alloca()-support scott@slp53.sl.home (Scott Lurndal) - 2019-10-03 14:51 +0000
                Re: alloca()-support David Brown <david.brown@hesbynett.no> - 2019-10-04 09:49 +0200
                Re: alloca()-support Soviet_Mario <SovietMario@CCCP.MIR> - 2019-10-03 21:47 +0200
                Re: alloca()-support David Brown <david.brown@hesbynett.no> - 2019-10-04 09:53 +0200
                Re: alloca()-support Soviet_Mario <SovietMario@CCCP.MIR> - 2019-10-03 21:52 +0200
            Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-01 07:39 +0200
        Re: alloca()-support James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-09-30 21:36 -0400
      Re: alloca()-support Philipp Klaus Krause <pkk@spth.de> - 2019-09-30 19:14 +0200
        Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-09-30 19:16 +0200
          Re: alloca()-support Robert Wessel <robertwessel2@yahoo.com> - 2019-10-01 00:18 -0500
            Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-01 07:43 +0200
            Re: alloca()-support Keith Thompson <kst-u@mib.org> - 2019-10-01 02:42 -0700
              Re: alloca()-support James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-10-01 08:11 -0400
              Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-10-01 14:53 +0200
      Re: alloca()-support scott@slp53.sl.home (Scott Lurndal) - 2019-09-30 17:52 +0000
    Re: alloca()-support Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2019-09-30 11:20 -0600
      Re: alloca()-support Bonita Montero <Bonita.Montero@gmail.com> - 2019-09-30 19:42 +0200
        Re: alloca()-support Soviet_Mario <SovietMario@CCCP.MIR> - 2019-09-30 20:02 +0200
      Re: alloca()-support Soviet_Mario <SovietMario@CCCP.MIR> - 2019-09-30 19:54 +0200
        Re: alloca()-support Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2019-09-30 14:28 -0600
          Re: alloca()-support David Brown <david.brown@hesbynett.no> - 2019-10-01 09:38 +0200
      Re: alloca()-support Soviet_Mario <SovietMario@CCCP.MIR> - 2019-09-30 20:01 +0200
        Re: alloca()-support Manfred <noname@add.invalid> - 2019-10-01 17:45 +0200
  Re: alloca()-support Frederick Gotham <cauldwell.thomas@gmail.com> - 2019-10-02 00:03 -0700
    Re: alloca()-support Paavo Helde <myfirstname@osa.pri.ee> - 2019-10-02 11:30 +0300
    Re: alloca()-support Ian Collins <ian-news@hotmail.com> - 2019-10-02 21:34 +1300
      Re: alloca()-support Frederick Gotham <cauldwell.thomas@gmail.com> - 2019-10-02 01:36 -0700
        Re: alloca()-support Ian Collins <ian-news@hotmail.com> - 2019-10-02 21:41 +1300
          Re: alloca()-support Frederick Gotham <cauldwell.thomas@gmail.com> - 2019-10-02 02:28 -0700
  Re: alloca()-support "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2019-10-02 02:35 -0700
    Re: alloca()-support Frederick Gotham <cauldwell.thomas@gmail.com> - 2019-10-02 02:43 -0700
    Re: alloca()-support Anton Shepelev <anton.txt@gmail.com> - 2019-10-02 16:26 +0300
      Re: alloca()-support "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2019-10-02 12:33 -0700
        Re: alloca()-support Anton Shepelev <anton.txt@gmail.com> - 2019-10-03 01:47 +0300
          Re: alloca()-support "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2019-10-05 14:08 -0700

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