usr/src/lib/libtecla/common/strngmem.h

   1 #ifndef stringmem_h
   2 #define stringmem_h
   3 /*
   4  * Copyright (c) 2000, 2001, 2002, 2003, 2004 by Martin C. Shepherd.
   5  *
   6  * All rights reserved.
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the
  10  * "Software"), to deal in the Software without restriction, including
  11  * without limitation the rights to use, copy, modify, merge, publish,
  12  * distribute, and/or sell copies of the Software, and to permit persons
  13  * to whom the Software is furnished to do so, provided that the above
  14  * copyright notice(s) and this permission notice appear in all copies of
  15  * the Software and that both the above copyright notice(s) and this
  16  * permission notice appear in supporting documentation.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
  21  * OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
  22  * HOLDERS INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL
  23  * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING
  24  * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
  25  * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
  26  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  27  *
  28  * Except as contained in this notice, the name of a copyright holder
  29  * shall not be used in advertising or otherwise to promote the sale, use
  30  * or other dealings in this Software without prior written authorization
  31  * of the copyright holder.
  32  */
  33
  34 #pragma ident   "%Z%%M% %I%     %E% SMI"
  35
  36 typedef struct StringMem StringMem;
  37
  38 /*
  39  * Applications that dynamically allocate lots of small strings
  40  * run the risk of significantly fragmenting the heap. This module
  41  * aims to reduce this risk by allocating large arrays of small fixed
  42  * length strings, arranging them as a free-list and allowing
  43  * callers to allocate from the list. Strings that are too long
  44  * to be allocated from the free-list are allocated from the heap.
  45  * Since typical implementations of malloc() eat up a minimum of
  46  * 16 bytes per call to malloc() [because of alignment and space
  47  * management constraints] it makes sense to set the free-list
  48  * string size to 16 bytes. Note that unlike malloc() which typically
  49  * keeps 8 bytes per allocation for its own use, our allocator will
  50  * return all but one of the 16 bytes for use. One hidden byte of overhead
  51  * is reserved for flagging whether the string was allocated directly
  52  * from malloc or from the free-list.
  53  */
  54
  55 /*
  56  * Set the length of each free-list string. The longest string that
  57  * will be returned without calling malloc() will be one less than
  58  * this number.
  59  */
  60 #define SM_STRLEN 16
  61
  62 /*
  63  * Create a string free-list container and the first block of its free-list.
  64  */
  65 StringMem *_new_StringMem(unsigned blocking_factor);
  66
  67 /*
  68  * Delete a string free-list.
  69  */
  70 StringMem *_del_StringMem(StringMem *sm, int force);
  71
  72 /*
  73  * Allocate an array of 'length' chars.
  74  */
  75 char *_new_StringMemString(StringMem *sm, size_t size);
  76
  77 /*
  78  * Free a string that was previously returned by _new_StringMemString().
  79  */
  80 char *_del_StringMemString(StringMem *sm, char *s);
  81
  82 #endif