usr.bin/xlint/lint2/mem2.c

   1 /*      $NetBSD: mem2.c,v 1.8 2003/10/21 23:58:53 christos Exp $        */
   2
   3 /*
   4  * Copyright (c) 1994, 1995 Jochen Pohl
   5  * All Rights Reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by Jochen Pohl for
  18  *      The NetBSD Project.
  19  * 4. The name of the author may not be used to endorse or promote products
  20  *    derived from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #if HAVE_NBTOOL_CONFIG_H
  35 #include "nbtool_config.h"
  36 #endif
  37
  38 #include <sys/cdefs.h>
  39 #if defined(__RCSID) && !defined(lint)
  40 __RCSID("$NetBSD: mem2.c,v 1.8 2003/10/21 23:58:53 christos Exp $");
  41 #endif
  42
  43 #include <sys/param.h>
  44 #include <sys/types.h>
  45 #include <unistd.h>
  46 #include <string.h>
  47
  48 #include "lint2.h"
  49
  50 /* length of new allocated memory blocks */
  51 static size_t   mblklen;
  52
  53 /* offset of next free byte in mbuf */
  54 static size_t   nxtfree;
  55
  56 /* current buffer to server memory requests from */
  57 static void     *mbuf;
  58
  59 void
  60 initmem(void)
  61 {
  62         int     pgsz;
  63
  64         pgsz = getpagesize();
  65         mblklen = ((MBLKSIZ + pgsz - 1) / pgsz) * pgsz;
  66
  67         nxtfree = mblklen;
  68 }
  69
  70 /*
  71  * Allocate memory in large chunks to avoid space and time overhead of
  72  * malloc(). This is possible because memory allocated by xalloc()
  73  * need never to be freed.
  74  */
  75 void *
  76 xalloc(size_t sz)
  77 {
  78         void    *ptr;
  79
  80         /* Align to at least 8 bytes. */
  81         sz = (sz + 7) & ~7L;
  82         if (nxtfree + sz > mblklen) {
  83                 /* use mmap() instead of malloc() to avoid malloc overhead. */
  84                 mbuf = xmapalloc(mblklen);
  85                 (void)memset(mbuf, 0, mblklen);
  86                 nxtfree = 0;
  87         }
  88
  89         ptr = (char *)mbuf + nxtfree;
  90         nxtfree += sz;
  91
  92         return (ptr);
  93 }