usr/src/lib/libast/common/sfio/sfresize.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                  David Korn <dgk@research.att.com>                   *
  19 *                   Phong Vo <kpv@research.att.com>                    *
  20 *                                                                      *
  21 ***********************************************************************/
  22 #include        "sfhdr.h"
  23
  24 /*      Resize a stream.
  25         Written by Kiem-Phong Vo.
  26 */
  27
  28 #if __STD_C
  29 int sfresize(Sfio_t* f, Sfoff_t size)
  30 #else
  31 int sfresize(f, size)
  32 Sfio_t*         f;
  33 Sfoff_t         size;
  34 #endif
  35 {
  36         SFMTXDECL(f);
  37
  38         SFMTXENTER(f, -1);
  39
  40         if(size < 0 || f->extent < 0 ||
  41            (f->mode != SF_WRITE && _sfmode(f,SF_WRITE,0) < 0) )
  42                 SFMTXRETURN(f, -1);
  43
  44         SFLOCK(f,0);
  45
  46         if(f->flags&SF_STRING)
  47         {       SFSTRSIZE(f);
  48
  49                 if(f->extent >= size)
  50                 {       if((f->flags&SF_MALLOC) && (f->next - f->data) <= size)
  51                         {       size_t  s = (((size_t)size + 1023)/1024)*1024;
  52                                 Void_t* d;
  53                                 if(s < f->size && (d = realloc(f->data, s)) )
  54                                 {       f->data = d;
  55                                         f->size = s;
  56                                         f->extent = s;
  57                                 }
  58                         }
  59                         memclear((char*)(f->data+size), (int)(f->extent-size));
  60                 }
  61                 else
  62                 {       if(SFSK(f, size, SEEK_SET, f->disc) != size)
  63                                 SFMTXRETURN(f, -1);
  64                         memclear((char*)(f->data+f->extent), (int)(size-f->extent));
  65                 }
  66         }
  67         else
  68         {       if(f->next > f->data)
  69                         SFSYNC(f);
  70 #if _lib_ftruncate
  71                 if(ftruncate(f->file, (sfoff_t)size) < 0)
  72                         SFMTXRETURN(f, -1);
  73 #else
  74                 SFMTXRETURN(f, -1);
  75 #endif
  76         }
  77
  78         f->extent = size;
  79
  80         SFOPEN(f, 0);
  81
  82         SFMTXRETURN(f, 0);
  83 }