/*----------------------------------------------------------------------  File    : memsys.c  Contents: memory management system for equally sized (small) objects  Author  : Christian Borgelt  History : 10.12.2004 file created from fpgrowth.c----------------------------------------------------------------------*/#include <stdio.h>#include <stdlib.h>#include <assert.h>#include "memsys.h"#ifdef STORAGE#include "storage.h"#endif/*----------------------------------------------------------------------  Main Functions----------------------------------------------------------------------*/MEMSYS* ms_create (int size, int cnt){                               /* --- create a memory system */  MEMSYS *ms;                   /* created memory system */  assert((cnt > 0)              /* check the function arguments */      && (size > 0) && (size % sizeof(void*) == 0));  ms = malloc(sizeof(MEMSYS));  /* create a memory management system */  if (!ms) return NULL;         /* with no free objects and */  ms->cnt   = cnt;              /* initialize the variables */  ms->size  = size /sizeof(void*);  ms->blksz = sizeof(MSBLOCK) +ms->cnt *size;  ms->free  = ms->blocks = NULL;  return ms;                    /* return the created memory system */}  /* ms_create() *//*--------------------------------------------------------------------*/void ms_delete (MEMSYS *ms){                               /* --- delete a memory system */  MSBLOCK *block;               /* to traverse the memory blocks */  assert(ms);                   /* check the function argument */  while (ms->blocks) {          /* while there is another block */    block = ms->blocks;         /* note the memory block and */    ms->blocks = block->succ;   /* remove it from the block list */    free(block);                /* delete the memory block */  }  free(ms);                     /* delete the base structure */}  /* ms_delete() *//*--------------------------------------------------------------------*/void* ms_alloc (MEMSYS *ms){                               /* --- allocate an object */  int     i;                    /* loop variable */  void    **obj, **tmp;         /* allocated object, buffer */  MSBLOCK *block;               /* new block */  assert(ms);                   /* check the function argument */  obj = ms->free;               /* get the head of the free list */  if (!obj) {                   /* if there is no free node, */    block = (MSBLOCK*)malloc(ms->blksz);    if (!block) return NULL;    /* allocate a new memory block */    block->succ = ms->blocks;   /* and add it at the head */    ms->blocks  = block;        /* of the block list */    ms->free    = obj = (void*)(block +1);    for (i = ms->cnt; --i > 0; ) {      tmp = obj; *tmp = obj += ms->size; }    *obj = NULL;                /* traverse the object vector */    obj  = ms->free;            /* and link the objects together, */  }                             /* then get the next free object */  ms->free = *obj;              /* remove object from the free list */  return (void*)obj;            /* and return the retrieved object */}  /* ms_alloc() *//*--------------------------------------------------------------------*/void ms_free (MEMSYS *ms, void *obj){                              /* --- deallocate an f.p. tree node */  assert(ms && obj);           /* check the function arguments */  *(void**)obj = ms->free;     /* insert the freed object */  ms->free     = obj;          /* at the head of the free list */}  /* ms_free() */