snprintf.c

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/*
   Unix snprintf implementation.
   Version 1.1
   
   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.
   
   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:

   sitecopy changes:
      renamed dtoa -> doubletoa to avoid dtoa conflict with cygwin.


   1.1:
      *  added changes from Miles Bader
      *  corrected a bug with %f
      *  added support for %#g
      *  added more comments :-)
   1.0:
      *  supporting must ANSI syntaxic_sugars
   0.0:
      *  suppot %s %c %d

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

*/

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

#include "snprintf.h"

#ifdef HAVE_STRING_H
#include <string.h>    /* for strlen() */
#endif
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>    /* for atoi() */
#endif
#include <ctype.h>


/*
 * Find the nth power of 10
 */
PRIVATE double
#ifdef __STDC__
pow_10(int n)
#else
pow_10(n)
int n;
#endif
{ 
  int i;
  double P;

  if (n < 0)
    for (i = 1, P = 1., n = -n ; i <= n ; i++) {P *= .1;}
  else
    for (i = 1, P = 1. ; i <= n ; i++) {P *= 10.0;}
  return P;
}

/*
 * Find the integral part of the log in base 10 
 * Note: this not a real log10()
         I just need and approximation(integerpart) of x in:
          10^x ~= r
 * log_10(200) = 2;
 * log_10(250) = 2;
 */
PRIVATE int
#ifdef __STDC__
log_10(double r)
#else
log_10(r)
double r;
#endif
{ 
  int i = 0;
  double result = 1.;

  if (r < 0.)
    r = -r;

  if (r < 1.) {
    while (result >= r) {result *= .1; i++;}
    return (-i);
  } else {
    while (result <= r) {result *= 10.; i++;}
    return (i - 1);
  }
}

/*
 * This function return the fraction part of a double
 * and set in ip the integral part.
 * In many ways it resemble the modf() found on most Un*x
 */
PRIVATE double
#ifdef __STDC__
integral(double real, double * ip)
#else
integral(real, ip)
double real;
double * ip;
#endif
{ 
  int j;
  double i, s, p;
  double real_integral = 0.;

/* take care of the obvious */
/* equal to zero ? */
  if (real == 0.) {
    *ip = 0.;
    return (0.);
  }

/* negative number ? */
  if (real < 0.)
    real = -real;

/* a fraction ? */
  if ( real < 1.) {
    *ip = 0.;
    return real;
  }
/* the real work :-) */
  for (j = log_10(real); j >= 0; j--) {
    p = pow_10(j);
    s = (real - real_integral)/p;
    i = 0.;
    while (i + 1. <= s) {i++;}
    real_integral += i*p;
  }
  *ip = real_integral;
  return (real - real_integral);
}

#define PRECISION 1.e-6
/* 
 * return an ascii representation of the integral part of the number
 * and set fract to be an ascii representation of the fraction part
 * the container for the fraction and the integral part or staticly
 * declare with fix size 
 */
PRIVATE char *
#ifdef __STDC__
numtoa(double number, int base, int precision, char ** fract)
#else
numtoa(number, base, precision, fract)
double number;
int base;
int precision;
char ** fract;
#endif
{
  register int i, j;
  double ip, fp; /* integer and fraction part */
  double fraction;
  int digits = MAX_INT - 1;
  static char integral_part[MAX_INT];
  static char fraction_part[MAX_FRACT];
  double sign;
  int ch;

/* taking care of the obvious case: 0.0 */
  if (number == 0.) { 
    integral_part[0] = '0';
    integral_part[1] = '\0';
    fraction_part[0] = '0';
    fraction_part[1] = '\0';
    return integral_part;
  }

/* for negative numbers */
  if ((sign = number) < 0.) {
    number = -number;
    digits--; /* sign consume one digit */
  } 

  fraction = integral(number, &ip);
  number = ip;
/* do the integral part */
  if ( ip == 0.) {
    integral_part[0] = '0';
    i = 1;
  } else {
    for ( i = 0; i < digits && number != 0.; ++i) {
      number /= base;
      fp = integral(number, &ip);
      ch = (int)((fp + PRECISION)*base); /* force to round */
      integral_part[i] = (ch <= 9) ? ch + '0' : ch + 'a' - 10;
      if (! isxdigit(integral_part[i])) /* bail out overflow !! */
        break; 
      number = ip;
     }
  }
     
/* Oh No !! out of bound, ho well fill it up ! */
  if (number != 0.)
    for (i = 0; i < digits; ++i)
      integral_part[i] = '9';

/* put the sign ? */
  if (sign < 0.)
    integral_part[i++] = '-';

  integral_part[i] = '\0';

/* reverse every thing */
  for ( i--, j = 0; j < i; j++, i--)
    SWAP_INT(integral_part[i], integral_part[j]);  

/* the fractionnal part */
  for (i=0, fp=fraction; precision > 0 && i < MAX_FRACT ; i++, precision--	) {
    fraction_part[i] = (int)((fp + PRECISION)*10. + '0');
    if (! isdigit(fraction_part[i])) /* underflow ? */
      break;
    fp = (fp*10.0) - (double)(long)((fp + PRECISION)*10.);
  }
  fraction_part[i] = '\0';

  if (fract != (char **)0)
    *fract = fraction_part;

  return integral_part;

}

/* for %d and friends, it puts in holder
 * the representation with the right padding
 */
PRIVATE void
#ifdef __STDC__
decimal(struct DATA *p, double d)
#else
decimal(p, d)
struct DATA *p;
double d;
#endif
{
  char *tmp;

  tmp = itoa(d);
  p->width -= strlen(tmp);
  PAD_RIGHT(p);
  PUT_PLUS(d, p);
  PUT_SPACE(d, p);
  while (*tmp) { /* the integral */
    PUT_CHAR(*tmp, p);
    tmp++;
  }
  PAD_LEFT(p);
}

/* for %o octal representation */
PRIVATE void
#ifdef __STDC__
octal(struct DATA *p, double d)
#else
octal(p, d)
struct DATA *p;
double d;
#endif
{
  char *tmp;

  tmp = otoa(d);
  p->width -= strlen(tmp);
  PAD_RIGHT(p);
  if (p->square == FOUND) /* had prefix '0' for octal */
    PUT_CHAR('0', p);
  while (*tmp) { /* octal */
    PUT_CHAR(*tmp, p);
    tmp++;
  }
  PAD_LEFT(p);
}

/* for %x %X hexadecimal representation */
PRIVATE void
#ifdef __STDC__
hexa(struct DATA *p, double d)
#else
hexa(p, d)
struct DATA *p;
double d;
#endif
{
  char *tmp;

  tmp = htoa(d);
  p->width -= strlen(tmp);
  PAD_RIGHT(p);
  if (p->square == FOUND) { /* prefix '0x' for hexa */
    PUT_CHAR('0', p); PUT_CHAR(*p->pf, p);
  }
  while (*tmp) { /* hexa */
    PUT_CHAR((*p->pf == 'X' ? toupper(*tmp) : *tmp), p);
    tmp++;
  }
  PAD_LEFT(p);
}

/* %s strings */
PRIVATE void
#ifdef __STDC__
strings(struct DATA *p, char *tmp)
#else
strings(p, tmp)
struct DATA *p;
char *tmp;
#endif
{
  int i;

  i = strlen(tmp);
  if (p->precision != NOT_FOUND) /* the smallest number */
    i = (i < p->precision ? i : p->precision);
  p->width -= i;
  PAD_RIGHT(p);
  while (i-- > 0) { /* put the sting */
    PUT_CHAR(*tmp, p);
    tmp++;
  }
  PAD_LEFT(p);
}

/* %f or %g  floating point representation */
PRIVATE void
#ifdef __STDC__
floating(struct DATA *p, double d)
#else
floating(p, d)
struct DATA *p;
double d;
#endif
{
  char *tmp, *tmp2;
  int i;

  DEF_PREC(p);
  d = ROUND(d, p);
  tmp = doubletoa(d, p->precision, &tmp2);
  /* calculate the padding. 1 for the dot */
  p->width = p->width -
            ((d > 0. && p->justify == RIGHT) ? 1:0) -
            ((p->space == FOUND) ? 1:0) -
            strlen(tmp) - p->precision - 1;
  PAD_RIGHT(p);  
  PUT_PLUS(d, p);
  PUT_SPACE(d, p);
  while (*tmp) { /* the integral */
    PUT_CHAR(*tmp, p);
    tmp++;
  }
  if (p->precision != 0 || p->square == FOUND)
    PUT_CHAR('.', p);  /* put the '.' */
  if (*p->pf == 'g' || *p->pf == 'G') /* smash the trailing zeros */
    for (i = strlen(tmp2) - 1; i >= 0 && tmp2[i] == '0'; i--)
       tmp2[i] = '\0'; 
  for (; *tmp2; tmp2++)
    PUT_CHAR(*tmp2, p); /* the fraction */
  
  PAD_LEFT(p);
} 

/* %e %E %g exponent representation */
PRIVATE void
#ifdef __STDC__
exponent(struct DATA *p, double d)
#else
exponent(p, d)
struct DATA *p;
double d;
#endif
{
  char *tmp, *tmp2;
  int j, i;

  DEF_PREC(p);
  j = log_10(d);
  d = d / pow_10(j);  /* get the Mantissa */
  d = ROUND(d, p);                  
  tmp = doubletoa(d, p->precision, &tmp2);
  /* 1 for unit, 1 for the '.', 1 for 'e|E',
   * 1 for '+|-', 3 for 'exp' */
  /* calculate how much padding need */
  p->width = p->width - 
             ((d > 0. && p->justify == RIGHT) ? 1:0) -
             ((p->space == FOUND) ? 1:0) - p->precision - 7;
  PAD_RIGHT(p);
  PUT_PLUS(d, p);
  PUT_SPACE(d, p);
  while (*tmp) {/* the integral */
    PUT_CHAR(*tmp, p);
    tmp++;