com32/menu/refstr.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2008 H. Peter Anvin - All Rights Reserved
   4  *
   5  *   This program is free software; you can redistribute it and/or modify
   6  *   it under the terms of the GNU General Public License as published by
   7  *   the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
   8  *   Boston MA 02110-1301, USA; either version 2 of the License, or
   9  *   (at your option) any later version; incorporated herein by reference.
  10  *
  11  * ----------------------------------------------------------------------- */
  12
  13 /*
  14  * refstr.c
  15  *
  16  * Simple reference-counted strings
  17  */
  18
  19 #include <stdlib.h>
  20 #include <string.h>
  21 #include "refstr.h"
  22
  23 const char *refstr_mkn(const char *str, size_t len)
  24 {
  25   char *r;
  26
  27   len = strnlen(str, len);
  28   r = malloc(sizeof(unsigned int)+len+1);
  29   *(unsigned int *)r = 1;
  30   r += sizeof(unsigned int);
  31   memcpy(r, str, len);
  32   r[len] = '\0';
  33   return r;
  34 }
  35
  36 const char *refstr_mk(const char *str)
  37 {
  38   refstr *r;
  39   size_t len;
  40
  41   len = strlen(str);
  42   r = malloc(sizeof(unsigned int)+len+1);
  43   *(unsigned int *)r = 1;
  44   r += sizeof(unsigned int);
  45   memcpy(r, str, len);
  46   r[len] = '\0';
  47   return r;
  48 }
  49
  50 void refstr_put(const char *r)
  51 {
  52   unsigned int *ref = (unsigned int *)r - 1;
  53
  54   if (!--*ref)
  55     free(ref);
  56 }