mdw@git.distorted.org.uk Git - mLib/blob - dspool.h

   1 /* -*-c-*-
   2  *
   3  * $Id: dspool.h,v 1.3 2004/04/08 01:36:11 mdw Exp $
   4  *
   5  * Provide pools of strings
   6  *
   7  * (c) 1999 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of the mLib utilities library.
  13  *
  14  * mLib is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * mLib is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with mLib; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 #ifndef MLIB_DSPOOL_H
  30 #define MLIB_DSPOOL_H
  31
  32 #ifdef __cplusplus
  33   extern "C" {
  34 #endif
  35
  36 /*----- Header files ------------------------------------------------------*/
  37
  38 #include "dstr.h"
  39 #include "sub.h"
  40
  41 /*----- Data structures ---------------------------------------------------*/
  42
  43 typedef struct dspoolstr {
  44   dstr ds;
  45   struct dspoolstr *next;
  46 } dspoolstr;
  47
  48 typedef struct dspool {
  49   dspoolstr *free;
  50   size_t isz;
  51 } dspool;
  52
  53 /*----- Functions provided ------------------------------------------------*/
  54
  55 /* --- @dspool_create@ --- *
  56  *
  57  * Arguments:   @dspool *p@ = address of pool to create
  58  *              @size_t isz@ = initial size of new strings
  59  *
  60  * Returns:     ---
  61  *
  62  * Use:         Initializes a dynamic string pool.
  63  */
  64
  65 extern void dspool_create(dspool */*p*/, size_t /*isz*/);
  66
  67 /* --- @dspool_destroy@ --- *
  68  *
  69  * Arguments:   @dspool *p@ = pool to destroy
  70  *
  71  * Returns:     ---
  72  *
  73  * Use:         Releases all of the strings left in the pool.  Any strings
  74  *              not put back into the pool aren't freed.  However, the pool
  75  *              is still valid, and the active strings can be put back and
  76  *              released later.
  77  */
  78
  79 extern void dspool_destroy(dspool */*p*/);
  80
  81 /* --- @dspool_get@ --- *
  82  *
  83  * Arguments:   @dspool *p@ = pointer to a string pool
  84  *
  85  * Returns:     Pointer to a dynamic string.
  86  *
  87  * Use:         Fetches a string from the pool.  The string has space for at
  88  *              least @isz@ characters (where @isz@ is the size passed to
  89  *              @dspool_create@ for the pool).
  90  */
  91
  92 extern dstr *dspool_get(dspool */*p*/);
  93
  94 #define DSGET(p, d) do {                                                \
  95   dspoolstr *_s;                                                        \
  96   dspool *_p = (p);                                                     \
  97   if (_p->free) {                                                       \
  98     _s = _p->free;                                                      \
  99     _p->free = _s->next;                                                \
 100   } else {                                                              \
 101     _s = CREATE(dspoolstr);                                             \
 102     DCREATE(&_s->ds);                                                   \
 103     if (_p->isz)                                                        \
 104       DENSURE(&_s->ds, _p->isz);                                        \
 105   }                                                                     \
 106   d = &_s->ds;                                                          \
 107 } while (0)
 108
 109 /* --- @dspool_put@ --- *
 110  *
 111  * Arguments:   @dspool *p@ = pointer to a string pool
 112  *              @dstr *d@ = pointer to a dynamic string from a string pool
 113  *
 114  * Returns:     ---
 115  *
 116  * Use:         Releases a dynamic string back into a string pool.  It
 117  *              doesn't have to be the same pool the string actually came
 118  *              from, although it does have to have come from some string
 119  *              pool.
 120  */
 121
 122 extern void dspool_put(dspool */*p*/, dstr */*d*/);
 123
 124 #define DSPUT(p, d) do {                                                \
 125   dspool *_p = (p);                                                     \
 126   dspoolstr *_s = (dspoolstr *)(d);                                     \
 127   DRESET(d);                                                            \
 128   _s->next = _p->free;                                                  \
 129   _p->free = _s;                                                        \
 130 } while (0)
 131
 132 /*----- That's all, folks -------------------------------------------------*/
 133
 134 #ifdef __cplusplus
 135   }
 136 #endif
 137
 138 #endif