inetutils/libinetutils/snprintf.h

/*
 Unix snprintf implementation.
 Version 1.3

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   It can be redistribute also under the terms of GNU Library General
   Public Lincense.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

   Revision History:
                   see header of snprintf.c.

format:
  int snprintf(holder, sizeof_holder, format, ...)

Return values:
  (sizeof_holder - 1)


 THANKS(for the patches and ideas):
     Miles Bader
     Cyrille Rustom
     Jacek Slabocewiz
     Mike Parker(mouse)

Alain Magloire: alainm@rcsm.ee.mcgill.ca
*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#if defined(HAVE_STDARG_H) && defined(__STDC__) && __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif

#include <stdlib.h>    /* for atoi() */
#include <ctype.h>


/*
 * For the FLOATING POINT FORMAT :
 *  the challenge was finding a way to
 *  manipulate the Real numbers without having
 *  to resort to mathematical function(it
 *  would require to link with -lm) and not
 *  going down to the bit pattern(not portable)
 *
 *  so a number, a real is:

      real = integral + fraction

      integral = ... + a(2)*10^2 + a(1)*10^1 + a(0)*10^0
      fraction = b(1)*10^-1 + b(2)*10^-2 + ...

      where:
       0 <= a(i) => 9
       0 <= b(i) => 9

    from then it was simple math
 */

/*
 * size of the buffer for the integral part
 * and the fraction part
 */
#define MAX_INT  99 + 1 /* 1 for the null */
#define MAX_FRACT 29 + 1

/*
 * numtoa() uses PRIVATE buffers to store the results,
 * So this function is not reentrant
 */
#define itoa(n) numtoa(n, 10, 0, (char **)0)
#define otoa(n) numtoa(n, 8, 0, (char **)0)
#define htoa(n) numtoa(n, 16, 0, (char **)0)
#define dtoa(n, p, f) numtoa(n, 10, p, f)

#define SWAP_INT(a,b) {int t; t = (a); (a) = (b); (b) = t;}

/* this struct holds everything we need */
struct DATA {
  int length;
  char *holder;
  int counter;
#ifdef __STDC__
  const char *pf;
#else
  char *pf;
#endif
/* FLAGS */
  int width, precision;
  int justify; char pad;
  int square, space, star_w, star_p, a_long ;
};

#define PRIVATE static
#define PUBLIC
/* signature of the functions */
#ifdef __STDC__
/* the floating point stuff */
  PRIVATE double pow_10(int);
  PRIVATE int log_10(double);
  PRIVATE double integral(double, double *);
  PRIVATE char * numtoa(double, int, int, char **);

/* for the format */
  PRIVATE void conv_flag(char *, struct DATA *);
  PRIVATE void floating(struct DATA *, double);
  PRIVATE void exponent(struct DATA *, double);
  PRIVATE void decimal(struct DATA *, double);
  PRIVATE void octal(struct DATA *, double);
  PRIVATE void hexa(struct DATA *, double);
  PRIVATE void strings(struct DATA *, char *);

#else
/* the floating point stuff */
  PRIVATE double pow_10();
  PRIVATE int log_10();
  PRIVATE double integral();
  PRIVATE char * numtoa();

/* for the format */
  PRIVATE void conv_flag();
  PRIVATE void floating();
  PRIVATE void exponent();
  PRIVATE void decimal();
  PRIVATE void octal();
  PRIVATE void hexa();
  PRIVATE void strings();
#endif

/* those are defines specific to snprintf to hopefully
 * make the code clearer :-)
 */
#define RIGHT 1
#define LEFT  0
#define NOT_FOUND -1
#define FOUND 1
#define MAX_FIELD 15

/* the conversion flags */
#define isflag(c) ((c) == '#' || (c) == ' ' || \
                   (c) == '*' || (c) == '+' || \
                   (c) == '-' || (c) == '.' || \
                   isdigit(c))

/* round off to the precision */
#define ROUND(d, p) \
            (d < 0.) ? \
             d - pow_10(-(p)->precision) * 0.5 : \
             d + pow_10(-(p)->precision) * 0.5

/* set default precision */
#define DEF_PREC(p) \
            if ((p)->precision == NOT_FOUND) \
              (p)->precision = 6

/* put a char */
#define PUT_CHAR(c, p) \
            if ((p)->counter < (p)->length) { \
              *(p)->holder++ = (c); \
              (p)->counter++; \
            }

#define PUT_PLUS(d, p) \
            if ((d) > 0. && (p)->justify == RIGHT) \
              PUT_CHAR('+', p)

#define PUT_SPACE(d, p) \
            if ((p)->space == FOUND && (d) > 0.) \
              PUT_CHAR(' ', p)

/* pad right */
#define PAD_RIGHT(p) \
            if ((p)->width > 0 && (p)->justify != LEFT) \
              for (; (p)->width > 0; (p)->width--) \
                 PUT_CHAR((p)->pad, p)

/* pad left */
#define PAD_LEFT(p) \
            if ((p)->width > 0 && (p)->justify == LEFT) \
              for (; (p)->width > 0; (p)->width--) \
                 PUT_CHAR((p)->pad, p)

/* if width and prec. in the args */
#define STAR_ARGS(p) \
            if ((p)->star_w == FOUND) \
              (p)->width = va_arg(args, int); \
            if ((p)->star_p == FOUND) \
              (p)->precision = va_arg(args, int)