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sfresize.c

/***********************************************************************
*                                                                      *
*               This software is part of the ast package               *
*          Copyright (c) 1985-2010 AT&T Intellectual Property          *
*                      and is licensed under the                       *
*                  Common Public License, Version 1.0                  *
*                    by AT&T Intellectual Property                     *
*                                                                      *
*                A copy of the License is available at                 *
*            http://www.opensource.org/licenses/cpl1.0.txt             *
*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
*                                                                      *
*              Information and Software Systems Research               *
*                            AT&T Research                             *
*                           Florham Park NJ                            *
*                                                                      *
*                 Glenn Fowler <gsf@research.att.com>                  *
*                  David Korn <dgk@research.att.com>                   *
*                   Phong Vo <kpv@research.att.com>                    *
*                                                                      *
***********************************************************************/
#include    "sfhdr.h"

/*    Resize a stream.
      Written by Kiem-Phong Vo.
*/

#if __STD_C
int sfresize(Sfio_t* f, Sfoff_t size)
#else
int sfresize(f, size)
Sfio_t*           f;
Sfoff_t           size;
#endif
{
      SFMTXDECL(f);

      SFMTXENTER(f, -1);

      if(size < 0 || f->extent < 0 ||
         (f->mode != SF_WRITE && _sfmode(f,SF_WRITE,0) < 0) )
            SFMTXRETURN(f, -1);

      SFLOCK(f,0);

      if(f->flags&SF_STRING)
      {     SFSTRSIZE(f);

            if(f->extent >= size)
            {     if((f->flags&SF_MALLOC) && (f->next - f->data) <= size)
                  {     size_t      s = (((size_t)size + 1023)/1024)*1024;
                        Void_t*     d;
                        if(s < f->size && (d = realloc(f->data, s)) )
                        {     f->data = d;
                              f->size = s;
                              f->extent = s;
                        }
                  }
                  memclear((char*)(f->data+size), (int)(f->extent-size));
            }
            else
            {     if(SFSK(f, size, SEEK_SET, f->disc) != size)
                        SFMTXRETURN(f, -1);
                  memclear((char*)(f->data+f->extent), (int)(size-f->extent));
            }
      }
      else
      {     if(f->next > f->data)
                  SFSYNC(f);
#if _lib_ftruncate
            if(ftruncate(f->file, (sfoff_t)size) < 0)
                  SFMTXRETURN(f, -1);
#else
            SFMTXRETURN(f, -1);
#endif
      }

      f->extent = size;

      SFOPEN(f, 0);

      SFMTXRETURN(f, 0);
}

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