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/* |
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* Implementation of Free Store Module |
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* Kirk A. Abbott |
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* Created Dec 18, 1994 |
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* Version: $Revision: 1.8 $ |
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* Version control file: $RCSfile: freestore.c,v $ |
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* Date last modified: $Date: 1997/07/18 12:29:49 $ |
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* Last modified by: $Author: mthomas $ |
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* |
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* This file is part of the Ascend Language Interpreter. |
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* |
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* Copyright (C) 1994, 1995 Kirk Andre Abbott. |
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* |
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* The Ascend Language Interpreter is free software; you can redistribute |
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* it and/or modify it under the terms of the GNU General Public License |
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* as published by the Free Software Foundation; either version 2 of the |
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* License, or (at your option) any later version. |
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* |
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* The Ascend Language Interpreter is distributed in hope that it will be |
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* useful, but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program. If not, see <http://www.gnu.org/licenses/>. |
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*/ |
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|
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#include <limits.h> /* for INT_MAX */ |
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#include <ascend/utilities/config.h> |
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#include <ascend/general/platform.h> |
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|
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#include "freestore.h" |
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|
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#include <stdarg.h> |
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#include <ascend/general/platform.h> |
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|
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#include <ascend/general/panic.h> |
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#include <ascend/general/ascMalloc.h> |
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#include <ascend/general/stack.h> |
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|
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|
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#include "functype.h" |
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#include "expr_types.h" |
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#include "relation_type.h" |
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#include "freestore.h" |
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#include <ascend/general/mathmacros.h> |
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|
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/* |
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* This is an implementation of a *freestore* which is hoped to |
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* reduce the memory management difficulties associated with |
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* symbolic processing. This is algorithm 1 |
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* which does no *freeing* until a computation is done. |
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* In this way it acts as a *buffer*. The difficulty is that |
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* instantaneous size of the buffer may be large, depending upon |
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* the number of terms generated, as we dont *free* or mark nodes |
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* as unused until we are done. |
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* |
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* A second variation of this algorithm would be to call Copy |
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* and Destroy, which would play a reference count game. We would |
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* also maintain a stack of pointers to nodes, as they were requested |
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* to be destroyed. This stack would allow us to find free terms quickly |
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* as within the distribution of terms. |
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* |
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* |
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* -------------------------------------------------------- |
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* | | | | | | | | |
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* ------> | O | X | X | X | O | O | O | |
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* | | | | | | | | |
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* -------------------------------------------------------- |
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* ^ ^ |
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* | | |
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* | |--------------->------- |
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* -------------------------------------------------------- |
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* ------> | | | | | | | | |
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* -------------------------------------------------------- |
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*/ |
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|
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static struct FreeStore *g_free_store = NULL; |
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static long g_units_alloc = 0L; |
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|
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struct FreeStore *FreeStore_Create(int n_buffers,int buffer_length){ |
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struct FreeStore *result; |
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union RelationTermUnion **root; |
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int i; |
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|
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result = ASC_NEW(struct FreeStore); |
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/* |
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* Make and initialize the array of pointers to the buffers. |
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*/ |
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root = ASC_NEW_ARRAY_CLEAR(union RelationTermUnion *,n_buffers); |
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|
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/* |
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* Allocate all n_buffers of size buffer_length. |
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* Allocate the return stack at 30% of the buffer_length; |
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* The return stack is expanded by the stack module at a rate |
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* orig_capacity *(1.5)^n-1, where n is the number of times that the |
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* stack has to be reallocated. |
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*/ |
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for (i=0;i<n_buffers;i++) { |
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root[i] = ASC_NEW_ARRAY(union RelationTermUnion,buffer_length); |
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} |
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result->returned = gs_stack_create(MAX(8,(long)0.3*buffer_length)); |
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|
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/* |
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* Set the structures created to the result; Add the other |
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* information about the freestore. |
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*/ |
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result->root = root; |
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result->next_free = root[0]; /* start of first buffer */ |
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result->n_buffers = n_buffers; |
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result->buffer_length = buffer_length; |
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result->row = 0; |
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result->col = 0; |
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return result; |
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} |
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|
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void FreeStore_ReInit(struct FreeStore *store){ |
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if (store && store->root) { |
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gs_stack_destroy(store->returned,0); /* faster to destroy and rebuild */ |
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store->returned = gs_stack_create(MAX(8,(long)0.3*store->buffer_length)); |
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store->row = 0; |
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store->col = 0; |
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store->next_free = store->root[0]; |
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g_units_alloc = 0; |
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} |
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} |
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|
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static union RelationTermUnion *FreeStore__GetMem(struct FreeStore *store){ |
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union RelationTermUnion *result; |
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union RelationTermUnion *ptr; |
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union RelationTermUnion **root; |
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int i; |
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|
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root = store->root; |
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if (!root) { |
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FPRINTF(stderr,"FreeStore not initialized\n"); |
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return NULL; |
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} |
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|
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/* |
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* Try the returned list first. |
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*/ |
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ptr = (union RelationTermUnion *)gs_stack_pop(store->returned); |
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if (ptr!=NULL) { |
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return ptr; |
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} |
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else if (store->col == store->buffer_length) { |
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/* |
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* Nothing on the returned stack, and we are out of blocks |
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* on the current buffer, i.e, need to make a buffer. |
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*/ |
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i = store->n_buffers++; /* update buffer count */ |
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root = (union RelationTermUnion **) |
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realloc(root,store->n_buffers * sizeof(union RelationTermUnion*)); |
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root[i] = (union RelationTermUnion *) |
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malloc(store->buffer_length * sizeof(union RelationTermUnion)); |
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store->root = root; /* critical !! -- realloc could moved root */ |
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result = &root[i][0]; /* memory to be returned */ |
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store->col = 1; /* point to next free block */ |
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store->row = i; /* update the row counter */ |
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store->next_free = &root[i][1]; |
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return result; |
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} |
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else{ |
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ptr = store->next_free; |
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store->next_free++; |
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store->col++; |
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return ptr; |
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} |
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} |
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|
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|
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static union RelationTermUnion *FreeStore__FindMem( |
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struct FreeStore *store |
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,union RelationTermUnion *term |
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){ |
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union RelationTermUnion **root, *start, *end; |
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int i; |
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|
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if (store==NULL || term==NULL) |
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return NULL; |
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root = store->root; |
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for (i=0;i<store->n_buffers;i++) { |
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start = root[i] - 1; /* just before the start */ |
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end = root[i] + store->buffer_length; /* just beyond the end */ |
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if ((term > start ) && (term < end)) { |
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return term; |
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} |
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} |
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return NULL; /* term not found within range */ |
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} |
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|
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static int FreeStore__FreeMem(struct FreeStore *store |
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,union RelationTermUnion *term |
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){ |
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union RelationTermUnion *ptr; |
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|
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ptr = FreeStore__FindMem(store,term); /* check if we own the memory */ |
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if(ptr==NULL){ |
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FPRINTF(stderr,"This is not one of our pointers;"); |
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FPRINTF(stderr,"free it yourself.\n"); |
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return 1; |
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} |
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gs_stack_push(store->returned,ptr); |
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return 0; |
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} |
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|
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union RelationTermUnion *FreeStoreCheckMem(union RelationTermUnion *term){ |
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return FreeStore__FindMem(FreeStore_GetFreeStore(),term); |
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} |
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|
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void FreeStore__Statistics(FILE *fp, struct FreeStore *store){ |
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union RelationTermUnion *bufptr; |
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int n_allocated=0; |
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int n_maxused=0; |
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int n_destroyed=0; |
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int n_buffers, buffer_length; |
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int i,j; |
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|
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if (store==NULL) { |
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FPRINTF(stderr,"FreeStore is nonexistent\n"); |
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return; |
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} |
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n_buffers = store->n_buffers; |
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buffer_length = store->buffer_length; |
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n_allocated = n_buffers * buffer_length; |
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n_maxused = (store->row)*buffer_length + store->col; |
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for (i=0;i<n_buffers;i++) { |
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bufptr = store->root[i]; |
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for (j=0;j<buffer_length;j++) { |
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if (bufptr == store->next_free) |
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break; |
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bufptr++; |
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} |
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} |
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n_destroyed = (int)gs_stack_size(store->returned); |
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FPRINTF(fp,"Memory Allocated = %d or %ld bytes\n", |
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n_allocated,(long)n_allocated*sizeof(union RelationTermUnion)); |
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FPRINTF(fp,"Maximum Memory Used = %d or %ld bytes\n", |
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n_maxused,(long)n_maxused*sizeof(union RelationTermUnion)); |
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FPRINTF(fp,"Memory Destroyed = %d or %ld bytes\n", |
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n_destroyed,(long)n_destroyed*sizeof(union RelationTermUnion)); |
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} |
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|
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/* |
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* This is to be used as a high water counter |
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* over many invocations of the free strore. |
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*/ |
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long FreeStore_UnitsAllocated(){ |
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return g_units_alloc; |
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} |
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|
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void FreeStore__BlastMem(struct FreeStore *store){ |
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int i,n_buffers; |
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if (!store) |
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return; |
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n_buffers = store->n_buffers; |
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for (i=0;i<n_buffers;i++) { |
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ascfree((char *)store->root[i]); /* freeup each buffer */ |
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store->root[i] = NULL; /* unnecessary ... oh well*/ |
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} |
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ascfree((char *)store->root); |
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gs_stack_destroy(store->returned,0); |
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store->row = store->col = 0; |
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store->next_free = NULL; |
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ascfree((char *)store); |
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store = NULL; |
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g_units_alloc = 0; |
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} |
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|
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void FreeStore_SetFreeStore(struct FreeStore *store){ |
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g_free_store = store; |
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} |
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|
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struct FreeStore *FreeStore_GetFreeStore(void){ |
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return g_free_store; |
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} |
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|
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union RelationTermUnion *FreeStore_GetMem(){ |
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g_units_alloc++; |
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return FreeStore__GetMem(g_free_store); |
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} |
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|
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int FreeStore_FreeMem(union RelationTermUnion *term){ |
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return FreeStore__FreeMem(g_free_store,term); |
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} |
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