sfnew.c revision 7c2fbfb345896881c631598ee3852ce9ce33fb07
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2008 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"
/* Fundamental function to create a new stream.
** The argument flags defines the type of stream and the scheme
** of buffering.
**
** Written by Kiem-Phong Vo.
*/
#if __STD_C
Sfio_t* sfnew(Sfio_t* oldf, Void_t* buf, size_t size, int file, int flags)
#else
Sfio_t* sfnew(oldf,buf,size,file,flags)
Sfio_t* oldf; /* old stream to be reused */
Void_t* buf; /* a buffer to read/write, if NULL, will be allocated */
size_t size; /* buffer size if buf is given or desired buffer size */
int file; /* file descriptor to read/write from */
int flags; /* type of file stream */
#endif
{
reg Sfio_t* f;
reg int sflags;
SFONCE(); /* initialize mutexes */
if(!(flags&SF_RDWR))
return NIL(Sfio_t*);
sflags = 0;
if((f = oldf) )
{ if(flags&SF_EOF)
{ if(f != sfstdin && f != sfstdout && f != sfstderr)
f->mutex = NIL(Vtmutex_t*);
SFCLEAR(f, f->mutex);
oldf = NIL(Sfio_t*);
}
else if(f->mode&SF_AVAIL)
{ /* only allow SF_STATIC to be already closed */
if(!(f->flags&SF_STATIC) )
return NIL(Sfio_t*);
sflags = f->flags;
oldf = NIL(Sfio_t*);
}
else
{ /* reopening an open stream, close it first */
sflags = f->flags;
if(((f->mode&SF_RDWR) != f->mode && _sfmode(f,0,0) < 0) ||
SFCLOSE(f) < 0 )
return NIL(Sfio_t*);
if(f->data && ((flags&SF_STRING) || size != (size_t)SF_UNBOUND) )
{ if(sflags&SF_MALLOC)
free((Void_t*)f->data);
f->data = NIL(uchar*);
}
if(!f->data)
sflags &= ~SF_MALLOC;
}
}
if(!f)
{ /* reuse a standard stream structure if possible */
if(!(flags&SF_STRING) && file >= 0 && file <= 2)
{ f = file == 0 ? sfstdin : file == 1 ? sfstdout : sfstderr;
if(f)
{ if(f->mode&SF_AVAIL)
{ sflags = f->flags;
SFCLEAR(f, f->mutex);
}
else f = NIL(Sfio_t*);
}
}
if(!f)
{ if(!(f = (Sfio_t*)malloc(sizeof(Sfio_t))) )
return NIL(Sfio_t*);
SFCLEAR(f, NIL(Vtmutex_t*));
}
}
/* create a mutex */
if(!f->mutex)
f->mutex = vtmtxopen(NIL(Vtmutex_t*), VT_INIT);
/* stream type */
f->mode = (flags&SF_READ) ? SF_READ : SF_WRITE;
f->flags = (flags&SF_FLAGS) | (sflags&(SF_MALLOC|SF_STATIC));
f->bits = (flags&SF_RDWR) == SF_RDWR ? SF_BOTH : 0;
f->file = file;
f->here = f->extent = 0;
f->getr = f->tiny[0] = 0;
f->mode |= SF_INIT;
if(size != (size_t)SF_UNBOUND)
{ f->size = size;
f->data = size <= 0 ? NIL(uchar*) : (uchar*)buf;
}
f->endb = f->endr = f->endw = f->next = f->data;
if(_Sfnotify)
(*_Sfnotify)(f, SF_NEW, (void*)((long)f->file));
if(f->flags&SF_STRING)
(void)_sfmode(f,f->mode&SF_RDWR,0);
return f;
}