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From: fcaggian@kepler.com (Frank Caggiano)
Newsgroups: comp.lang.eiffel
Subject: formated string objects
Keywords: sprintf like routine
Message-ID: <457@kepler1.kepler.com>
Date: 4 Jan 91 21:51:03 GMT
Organization: Kepler Financial Mgmt., Setuket, NY
Lines: 154

The following c routine is something I've wanted to write for
a while now.  It makes creating formatted string objects 
easier.  

Its an sprintf like routine but it returns a string object.

The call and arguments are the same as for the [sf]printf c routines.

Declare it as 

	external format_obj: STRING language "C"

Usage colud then be something like :

	local
		s: STRING
	do
		s := format_obj("%2d %-5s%6d%8.3f%5d%7d%6d%4d",
				n,
				stock_list.item.ticker.to_c,
				stock_list.item.amount, 
				price / 256.0,
				ktotal / 1000,
				stock_list.item.position,
				stock_list.item.pending,
				stock_list.item.form
				);
This was written and tested on a space running 4.0.3.  It should
be poratable.  Please let me know of any problems especially with
the varargs stuff. 


********* BEGIN INCLUDED CODE

 /*
  -- Copyright (c) 1990 Kepler Financial Mgmt. 
  --
  -- Permission is granted to anyone to make or distribute
  -- copies of this software  provided that the
  -- copyright notice and this permission notice are preserved.
  -- Ownership remains with Kepler Financial Mgmt.
  */
#ifndef lint
    static char *sccsid = "@(#)_objformat.c:1.1	1/4/91";
#endif

#include <varargs.h>
#include <_eiffel.h>

#ifndef BUFSIZ
#define BUFSIZ 512
#endif BUFSIZ

OBJPTR format_obj(fmt, va_alist)
    char *fmt;
    va_dcl		/* the missing ; IS RIGHT see varargs */
{
    va_list ap;
    register int n;
    register char *cp, c, *buf_end;
    char buf[BUFSIZ], f[20];

    OBJPTR strobj;
    ROUT_PTR from_c;

    cp = buf;
    f[0] = '%';
  
    buf_end = buf+BUFSIZ;

    va_start (ap);

    while((c = *fmt++) != '\0' && cp < buf_end) {
	if(c == '%') {
	    for(c = *fmt++,n = 1; c; n++) {
		switch(c) {
		    
		  case '%':	/* its %% put out the % */
		    *cp++ = '%';
		    c = '\0';
		    break;
		    
		  case 's':	/* normal string */
		    f[n++] = c;
		    f[n] = '\0';
		    sprintf(cp, f, va_arg(ap,char *));
		    cp += strlen(cp);
		    c = '\0';
		    break;
		    
		  case '*':	/* variable field width */
		{
		    char varwidth[10];
		    int x = 0;
		    sprintf(varwidth,"%d",va_arg(ap, int));
		    while((f[n++] = varwidth[x++]))
			;
		}
		    n -= 2;
		    c = *fmt++;
		    break;
		    
		  case 'f':	/* floats etc. */
		  case 'g':
		  case 'e':
		    f[n++] = c;
		    f[n] = '\0';
		    sprintf(cp, f,va_arg(ap, double));
		    cp += strlen(cp);
		    c = '\0';
		    break;
		    
		  case 'd':	/* ints and such */
		  case 'o':
		  case 'c':
		  case 'x':
		  case 'u':
		    f[n++] = c;
		    f[n] = '\0';
		    sprintf(cp, f,va_arg(ap, int));
		    cp += strlen(cp);
		    c = '\0';
		    break;
		    
		  default:	/* none of the above */
		    f[n] = c;
		    c = *fmt++;
		    break;
		}
	    }
	} else		/* c wasn't '%'; just copy it into buf */
	    *cp++ = c;
    }
    
    va_end(ap);

    *cp = '\0';

    strobj = (OBJPTR) eif_create("string", 0)
    from_c = (ROUT_PTR) eif_rout(strobj, "from_c");
    (*from_c) (strobj, buf);
    return (strobj);
}
							
By the way has anyone had a chance to tryout the RESOURCE managment
stuf I posted some time back? Anyone doing anything with X/GUI's
and Eiffel.  I would like to hear from anyone doing work along those
lines.  (if they are free to talk.  Those on Double Secret Probation 
need not apply :-) ).
-- 
Frank Caggiano                      INTERNET: fcaggian@kepler.com  
Kepler Financial Management, Ltd.       UUCP: ..!uunet!kepler1!fcaggian
100 North Country Rd.                    fax: (516) 751-8678
Sekauket, NY 11733                     voice: (516) 689-6300