snprintf.c

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  for (strln = 0; value[strln]; ++strln); /* strlen */
  if (max >= 0 && max < strln)
    strln = max;
  padlen = min - strln;
  if (padlen < 0) 
    padlen = 0;
  if (flags & DP_F_MINUS) 
    padlen = -padlen; /* Left Justify */

  while (padlen > 0)
  {
    total += dopr_outch (buffer, currlen, maxlen, ' ');
    --padlen;
  }
  while (*value && ((max < 0) || (cnt < max)))
  {
    total += dopr_outch (buffer, currlen, maxlen, *value++);
    ++cnt;
  }
  while (padlen < 0)
  {
    total += dopr_outch (buffer, currlen, maxlen, ' ');
    ++padlen;
  }
  return total;
}

/* Have to handle DP_F_NUM (ie 0x and 0 alternates) */

static int fmtint (char *buffer, size_t *currlen, size_t maxlen,
		   LLONG value, int base, int min, int max, int flags)
{
  int signvalue = 0;
  unsigned LLONG uvalue;
  char convert[24];
  int place = 0;
  int spadlen = 0; /* amount to space pad */
  int zpadlen = 0; /* amount to zero pad */
  const char *digits;
  int total = 0;
  
  if (max < 0)
    max = 0;

  uvalue = value;

  if(!(flags & DP_F_UNSIGNED))
  {
    if( value < 0 ) {
      signvalue = '-';
      uvalue = -value;
    }
    else
      if (flags & DP_F_PLUS)  /* Do a sign (+/i) */
	signvalue = '+';
    else
      if (flags & DP_F_SPACE)
	signvalue = ' ';
  }
  
  if (flags & DP_F_UP)
    /* Should characters be upper case? */
    digits = "0123456789ABCDEF";
  else
    digits = "0123456789abcdef";

  do {
    convert[place++] = digits[uvalue % (unsigned)base];
    uvalue = (uvalue / (unsigned)base );
  } while(uvalue && (place < sizeof (convert)));
  if (place == sizeof (convert)) place--;
  convert[place] = 0;

  zpadlen = max - place;
  spadlen = min - MAX (max, place) - (signvalue ? 1 : 0);
  if (zpadlen < 0) zpadlen = 0;
  if (spadlen < 0) spadlen = 0;
  if (flags & DP_F_ZERO)
  {
    zpadlen = MAX(zpadlen, spadlen);
    spadlen = 0;
  }
  if (flags & DP_F_MINUS) 
    spadlen = -spadlen; /* Left Justifty */

#ifdef DEBUG_SNPRINTF
  dprint (1, (debugfile, "zpad: %d, spad: %d, min: %d, max: %d, place: %d\n",
      zpadlen, spadlen, min, max, place));
#endif

  /* Spaces */
  while (spadlen > 0) 
  {
    total += dopr_outch (buffer, currlen, maxlen, ' ');
    --spadlen;
  }

  /* Sign */
  if (signvalue) 
    total += dopr_outch (buffer, currlen, maxlen, signvalue);

  /* Zeros */
  if (zpadlen > 0) 
  {
    while (zpadlen > 0)
    {
      total += dopr_outch (buffer, currlen, maxlen, '0');
      --zpadlen;
    }
  }

  /* Digits */
  while (place > 0) 
    total += dopr_outch (buffer, currlen, maxlen, convert[--place]);
  
  /* Left Justified spaces */
  while (spadlen < 0) {
    total += dopr_outch (buffer, currlen, maxlen, ' ');
    ++spadlen;
  }

  return total;
}

static LDOUBLE abs_val (LDOUBLE value)
{
  LDOUBLE result = value;

  if (value < 0)
    result = -value;

  return result;
}

static LDOUBLE pow10 (int exp)
{
  LDOUBLE result = 1;

  while (exp)
  {
    result *= 10;
    exp--;
  }
  
  return result;
}

static long round (LDOUBLE value)
{
  long intpart;

  intpart = value;
  value = value - intpart;
  if (value >= 0.5)
    intpart++;

  return intpart;
}

static int fmtfp (char *buffer, size_t *currlen, size_t maxlen,
		  LDOUBLE fvalue, int min, int max, int flags)
{
  int signvalue = 0;
  LDOUBLE ufvalue;
  char iconvert[20];
  char fconvert[20];
  int iplace = 0;
  int fplace = 0;
  int padlen = 0; /* amount to pad */
  int zpadlen = 0; 
  int caps = 0;
  int total = 0;
  long intpart;
  long fracpart;
  
  /* 
   * AIX manpage says the default is 0, but Solaris says the default
   * is 6, and sprintf on AIX defaults to 6
   */
  if (max < 0)
    max = 6;

  ufvalue = abs_val (fvalue);

  if (fvalue < 0)
    signvalue = '-';
  else
    if (flags & DP_F_PLUS)  /* Do a sign (+/i) */
      signvalue = '+';
    else
      if (flags & DP_F_SPACE)
	signvalue = ' ';

#if 0
  if (flags & DP_F_UP) caps = 1; /* Should characters be upper case? */
#endif

  intpart = ufvalue;

  /* 
   * Sorry, we only support 9 digits past the decimal because of our 
   * conversion method
   */
  if (max > 9)
    max = 9;

  /* We "cheat" by converting the fractional part to integer by
   * multiplying by a factor of 10
   */
  fracpart = round ((pow10 (max)) * (ufvalue - intpart));

  if (fracpart >= pow10 (max))
  {
    intpart++;
    fracpart -= pow10 (max);
  }

#ifdef DEBUG_SNPRINTF
  dprint (1, (debugfile, "fmtfp: %f =? %d.%d\n", fvalue, intpart, fracpart));
#endif

  /* Convert integer part */
  do {
    iconvert[iplace++] =
      (caps? "0123456789ABCDEF":"0123456789abcdef")[intpart % 10];
    intpart = (intpart / 10);
  } while(intpart && (iplace < 20));
  if (iplace == 20) iplace--;
  iconvert[iplace] = 0;

  /* Convert fractional part */
  do {
    fconvert[fplace++] =
      (caps? "0123456789ABCDEF":"0123456789abcdef")[fracpart % 10];
    fracpart = (fracpart / 10);
  } while(fracpart && (fplace < 20));
  if (fplace == 20) fplace--;
  fconvert[fplace] = 0;

  /* -1 for decimal point, another -1 if we are printing a sign */
  padlen = min - iplace - max - 1 - ((signvalue) ? 1 : 0); 
  zpadlen = max - fplace;
  if (zpadlen < 0)
    zpadlen = 0;
  if (padlen < 0) 
    padlen = 0;
  if (flags & DP_F_MINUS) 
    padlen = -padlen; /* Left Justifty */

  if ((flags & DP_F_ZERO) && (padlen > 0)) 
  {
    if (signvalue) 
    {
      total += dopr_outch (buffer, currlen, maxlen, signvalue);
      --padlen;
      signvalue = 0;
    }
    while (padlen > 0)
    {
      total += dopr_outch (buffer, currlen, maxlen, '0');
      --padlen;
    }
  }
  while (padlen > 0)
  {
    total += dopr_outch (buffer, currlen, maxlen, ' ');
    --padlen;
  }
  if (signvalue) 
    total += dopr_outch (buffer, currlen, maxlen, signvalue);

  while (iplace > 0) 
    total += dopr_outch (buffer, currlen, maxlen, iconvert[--iplace]);

  /*
   * Decimal point.  This should probably use locale to find the correct
   * char to print out.
   */
  if (max > 0)
  {
    total += dopr_outch (buffer, currlen, maxlen, '.');

    while (fplace > 0) 
      total += dopr_outch (buffer, currlen, maxlen, fconvert[--fplace]);
  }

  while (zpadlen > 0)
  {
    total += dopr_outch (buffer, currlen, maxlen, '0');
    --zpadlen;
  }

  while (padlen < 0) 
  {
    total += dopr_outch (buffer, currlen, maxlen, ' ');
    ++padlen;
  }

  return total;
}

static int dopr_outch (char *buffer, size_t *currlen, size_t maxlen, char c)
{
  if (*currlen + 1 < maxlen)
    buffer[(*currlen)++] = c;
  return 1;
}

#ifndef HAVE_VSNPRINTF
int vsnprintf (char *str, size_t count, const char *fmt, va_list args)
{
  if (str != NULL)
    str[0] = 0;
  return dopr(str, count, fmt, args);
}
#endif /* !HAVE_VSNPRINTF */

#ifndef HAVE_SNPRINTF
/* VARARGS3 */
#ifdef HAVE_STDARGS
int snprintf (char *str,size_t count,const char *fmt,...)
#else
int snprintf (va_alist) va_dcl
#endif
{
#ifndef HAVE_STDARGS
  char *str;
  size_t count;
  char *fmt;
#endif
  VA_LOCAL_DECL;
  int total;
    
  VA_START (fmt);
  VA_SHIFT (str, char *);
  VA_SHIFT (count, size_t );
  VA_SHIFT (fmt, char *);
  total = vsnprintf(str, count, fmt, ap);
  VA_END;
  return total;
}
#endif /* !HAVE_SNPRINTF */
#endif /* !HAVE_SNPRINTF || !HAVE_VSNPRINTF */

#ifdef TEST_SNPRINTF

#include <stdio.h>

#ifndef LONG_STRING
#define LONG_STRING 1024
#endif
int main (void)
{
  char buf1[LONG_STRING];
  char buf2[LONG_STRING];
  char *fp_fmt[] = {
    "%-1.5f",
    "%1.5f",
    "%123.9f",
    "%10.5f",
    "% 10.5f",
    "%+22.9f",
    "%+4.9f",
    "%01.3f",
    "%4f",
    "%3.1f",
    "%3.2f",
    "%.0f",
    "%.1f",
    NULL
  };
  double fp_nums[] = { -1.5, 134.21, 91340.2, 341.1234, 0203.9, 0.96, 0.996, 
    0.9996, 1.996, 4.136, 0};
  char *int_fmt[] = {
    "%-1.5d",
    "%1.5d",
    "%123.9d",
    "%5.5d",
    "%10.5d",
    "% 10.5d",
    "%+22.33d",
    "%01.3d",
    "%4d",
    NULL
  };
  long int_nums[] = { -1, 134, 91340, 341, 0203, 0};
#if SIZEOF_LONG_LONG != 0
  char *llong_fmt[] = {
    "%lld",		"%llu",
    "%-1.5lld",		"%-1.5llu",
    "%1.5lld",		"%1.5llu",
    "%123.9lld",	"%123.9llu",
    "%5.5lld",		"%5.5llu",
    "%10.5lld",		"%10.5llu",
    "% 10.5lld",	"% 10.5llu",
    "%+22.33lld",	"%+22.33llu",
    "%01.3lld",		"%01.3llu",
    "%4lld",		"%4llu",
    NULL
  };
  long long llong_nums[] = {
    ~(long long)0,		/* all-1 bit pattern */
    (~(unsigned long long)0) >> 1, /* largest signed long long */
    /* random... */
    -150, 134, 91340, 341,
    0
  };
#endif
  int x, y;
  int fail = 0;
  int num = 0;

  printf ("Testing snprintf format codes against system sprintf...\n");

  for (x = 0; fp_fmt[x] != NULL ; x++)
    for (y = 0; fp_nums[y] != 0 ; y++)
    {
      snprintf (buf1, sizeof (buf1), fp_fmt[x], fp_nums[y]);
      sprintf (buf2, fp_fmt[x], fp_nums[y]);
      if (strcmp (buf1, buf2))
      {
	printf("snprintf doesn't match Format: %s\n\tsnprintf = %s\n\tsprintf  = %s\n", 
	    fp_fmt[x], buf1, buf2);
	fail++;
      }
      num++;
    }

  for (x = 0; int_fmt[x] != NULL ; x++)
    for (y = 0; int_nums[y] != 0 ; y++)
    {
      snprintf (buf1, sizeof (buf1), int_fmt[x], int_nums[y]);
      sprintf (buf2, int_fmt[x], int_nums[y]);
      if (strcmp (buf1, buf2))
      {
	printf("snprintf doesn't match Format: %s\n\tsnprintf = %s\n\tsprintf  = %s\n", 
	    int_fmt[x], buf1, buf2);
	fail++;
      }
      num++;
    }

#if SIZEOF_LONG_LONG != 0
  for (x = 0; llong_fmt[x] != NULL ; x++)
    for (y = 0; llong_nums[y] != 0 ; y++)
    {
      snprintf (buf1, sizeof (buf1), llong_fmt[x], llong_nums[y]);
      sprintf (buf2, llong_fmt[x], llong_nums[y]);
      if (strcmp (buf1, buf2))
      {
	printf("snprintf doesn't match Format: %s\n\tsnprintf = %s\n\tsprintf  = %s\n", 
	    llong_fmt[x], buf1, buf2);
	fail++;
      }
      num++;
    }
#endif

  printf ("%d tests failed out of %d.\n", fail, num);
}
#endif /* SNPRINTF_TEST */