Modules/selectmodule.c

/***********************************************************
Copyright 1991, 1992, 1993, 1994 by Stichting Mathematisch Centrum,
Amsterdam, The Netherlands.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
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STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

******************************************************************/

/* select - Module containing unix select(2) call */

#include "allobjects.h"
#include "modsupport.h"
#include "ceval.h"

#include <sys/types.h>
#include "myselect.h" /* Also includes mytime.h */

static object *SelectError;

static
list2set(list, set, fd2obj)
    object *list;
    fd_set *set;
    object *fd2obj[FD_SETSIZE];
{
    int i, len, v, max = -1;
    object *o, *filenomethod, *fno;
    
    FD_ZERO(set);
    len = getlistsize(list);
    for( i=0; i<len; i++ ) {
	o = getlistitem(list, i);
	if ( is_intobject(o) ) {
	    v = getintvalue(o);
	} else if ( (filenomethod = getattr(o, "fileno")) != NULL ) {
	    fno = call_object(filenomethod, NULL);
	    DECREF(filenomethod);
	    if ( fno == NULL )
		return -1;
	    if ( !is_intobject(fno) ) {
		err_badarg();
		DECREF(fno);
		return -1;
	    }
	    v = getintvalue(fno);
	    DECREF(fno);
	} else {
	    err_badarg();
	    return -1;
	}
	if ( v < 0 || v >= FD_SETSIZE ) {
	    err_setstr(ValueError, "filedescriptor out of range in select()");
	    return -1;
	}
	if ( v > max ) max = v;
	FD_SET(v, set);
	XDECREF(fd2obj[v]);
	fd2obj[v] = o;
    }
    return max+1;
}

static object *
set2list(set, max, fd2obj)
    fd_set *set;
    int max;
    object *fd2obj[FD_SETSIZE];
{
    int i, num=0;
    object *list, *o;

    for(i=0; i<max; i++)
      if ( FD_ISSET(i,set) )
	num++;
    list = newlistobject(num);
    num = 0;
    for(i=0; i<max; i++)
      if ( FD_ISSET(i,set) ) {
	  if ( i > FD_SETSIZE ) {
	      err_setstr(SystemError,
			 "filedescriptor out of range returned in select()");
	      return NULL;
	  }
	  o = fd2obj[i];
	  if ( o == NULL ) {
	      err_setstr(SystemError,
			 "Bad filedescriptor returned from select()");
	      return NULL;
	  }
	  INCREF(o);
	  setlistitem(list, num, o);
	  num++;
    }
    return list;
}
    
static object *
select_select(self, args)
    object *self;
    object *args;
{
    object *fd2obj[FD_SETSIZE];
    object *ifdlist, *ofdlist, *efdlist;
    object *ret, *tout;
    fd_set ifdset, ofdset, efdset;
    double timeout;
    struct timeval tv, *tvp;
    int seconds;
    int imax, omax, emax, max;
    int n;


    /* Get args. Looks funny because of optional timeout argument */
    if ( getargs(args, "(OOOO)", &ifdlist, &ofdlist, &efdlist, &tout) ) {
	if (tout == None)
	    tvp = (struct timeval *)0;
	else {
	    if (!getargs(tout, "d;timeout must be float or None", &timeout))
		    return NULL;
	    seconds = (int)timeout;
	    timeout = timeout - (double)seconds;
	    tv.tv_sec = seconds;
	    tv.tv_usec = (int)(timeout*1000000.0);
	    tvp = &tv;
	}
    } else {
	/* Doesn't have 4 args, that means no timeout */
	err_clear();
	if (!getargs(args, "(OOO)", &ifdlist, &ofdlist, &efdlist) )
	  return 0;
	tvp = (struct timeval *)0;
    }
    if ( !is_listobject(ifdlist) || !is_listobject(ofdlist) ||
	!is_listobject(efdlist) ) {
	err_badarg();
	return 0;
    }

    memset((char *)fd2obj, '\0', sizeof(fd2obj));
    
    /* Convert lists to fd_sets, and get maximum fd number */
    if( (imax=list2set(ifdlist, &ifdset, fd2obj)) < 0 )
      return 0;
    if( (omax=list2set(ofdlist, &ofdset, fd2obj)) < 0 )
      return 0;
    if( (emax=list2set(efdlist, &efdset, fd2obj)) < 0 )
      return 0;
    max = imax;
    if ( omax > max ) max = omax;
    if ( emax > max ) max = emax;

    BGN_SAVE
    n = select(max, &ifdset, &ofdset, &efdset, tvp);
    END_SAVE

    if ( n < 0 ) {
	err_errno(SelectError);
	return 0;
    }

    if ( n == 0 )
      imax = omax = emax = 0; /* Speedup hack */

    ifdlist = set2list(&ifdset, imax, fd2obj);
    ofdlist = set2list(&ofdset, omax, fd2obj);
    efdlist = set2list(&efdset, emax, fd2obj);
    ret = mkvalue("OOO", ifdlist, ofdlist, efdlist);
    XDECREF(ifdlist);
    XDECREF(ofdlist);
    XDECREF(efdlist);
    return ret;
}


static struct methodlist select_methods[] = {
    { "select",	select_select },
    { 0,	0 },
};


void
initselect()
{
	object *m, *d;
	m = initmodule("select", select_methods);
	d = getmoduledict(m);
	SelectError = newstringobject("select.error");
	if ( SelectError == NULL || dictinsert(d, "error", SelectError) )
	  fatal("Cannot define select.error");
}