mirror of
https://github.com/fish-shell/fish-shell
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173 lines
3.3 KiB
C
173 lines
3.3 KiB
C
/** \file halloc.c
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A hierarchical memory allocation system. Works just like talloc
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used in Samba, except that an arbitrary block allocated with
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malloc() can be registered to be freed by halloc_free.
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*/
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#include "config.h"
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#include <stdlib.h>
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#include <unistd.h>
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#include "fallback.h"
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#include "util.h"
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#include "common.h"
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#include "halloc.h"
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#define HALLOC_BLOCK_SIZE 128
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#define HALLOC_SCRAP_SIZE 16
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#ifdef HALLOC_DEBUG
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static int child_count=0;
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static int child_size=0;
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static int alloc_count =0;
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static int alloc_spill = 0;
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static pid_t pid=0;
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static int parent_count=0;
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#endif
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typedef struct halloc
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{
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array_list_t children;
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void *scratch;
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size_t scratch_free;
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long long data[0];
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}
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halloc_t;
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static halloc_t *halloc_from_data( void *data )
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{
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return (halloc_t *)(((char *)data) - sizeof( halloc_t ) );
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}
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static void late_free( void *data)
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{
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}
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#ifdef HALLOC_DEBUG
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static void woot()
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{
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if( getpid() == pid )
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{
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debug( 1, L"%d parents, %d children with average child size of %.2f bytes caused %d allocs, average spill of %.2f bytes",
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parent_count, child_count, (double)child_size/child_count,
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parent_count+alloc_count, (double)alloc_spill/(parent_count+alloc_count) );
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}
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}
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#endif
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void *halloc( void *context, size_t size )
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{
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halloc_t *me, *parent;
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if( context )
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{
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void *res;
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#ifdef HALLOC_DEBUG
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if( !child_count )
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{
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pid = getpid();
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atexit( woot );
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}
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child_count++;
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child_size += size;
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#endif
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parent = halloc_from_data( context );
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if( size <= parent->scratch_free )
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{
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res = parent->scratch;
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parent->scratch_free -= size;
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parent->scratch = ((char *)parent->scratch)+size;
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}
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else
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{
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#ifdef HALLOC_DEBUG
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alloc_count++;
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#endif
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if( parent->scratch_free < HALLOC_SCRAP_SIZE )
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{
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#ifdef HALLOC_DEBUG
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alloc_spill += parent->scratch_free;
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#endif
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res = calloc( 1, size + HALLOC_BLOCK_SIZE );
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parent->scratch = (char *)res + size;
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parent->scratch_free = HALLOC_BLOCK_SIZE;
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}
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else
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{
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res = calloc( 1, size );
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}
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al_push( &parent->children, &late_free );
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al_push( &parent->children, res );
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}
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return res;
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}
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else
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{
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me = (halloc_t *)calloc( 1, sizeof(halloc_t) + size + HALLOC_BLOCK_SIZE );
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if( !me )
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return 0;
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#ifdef HALLOC_DEBUG
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parent_count++;
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#endif
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me->scratch = ((char *)me) + sizeof(halloc_t) + size;
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me->scratch_free = HALLOC_BLOCK_SIZE;
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al_init( &me->children );
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return &me->data;
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}
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}
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void halloc_register_function( void *context, void (*func)(void *), void *data )
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{
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halloc_t *me;
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if( !context )
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return;
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me = halloc_from_data( context );
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al_push( &me->children, func );
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al_push( &me->children, data );
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}
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void halloc_free( void *context )
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{
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halloc_t *me;
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int i;
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if( !context )
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return;
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me = halloc_from_data( context );
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#ifdef HALLOC_DEBUG
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alloc_spill += me->scratch_free;
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#endif
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for( i=0; i<al_get_count(&me->children); i+=2 )
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{
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void (*func)(void *) = (void (*)(void *))al_get( &me->children, i );
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void * data = (void *)al_get( &me->children, i+1 );
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if( func != &late_free )
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func( data );
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}
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for( i=0; i<al_get_count(&me->children); i+=2 )
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{
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void (*func)(void *) = (void (*)(void *))al_get( &me->children, i );
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void * data = (void *)al_get( &me->children, i+1 );
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if( func == &late_free )
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free( data );
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}
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al_destroy( &me->children );
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free(me);
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}
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