/* __gmp_doprnt_mpf -- mpf formatted output.

   THE FUNCTIONS IN THIS FILE ARE FOR INTERNAL USE ONLY.  THEY'RE ALMOST

   CERTAIN TO BE SUBJECT TO INCOMPATIBLE CHANGES OR DISAPPEAR COMPLETELY IN

   FUTURE GNU MP RELEASES.

Copyright 2001, 2002, 2011 Free Software Foundation, Inc.

This file is part of the GNU MP Library.

The GNU MP Library is free software; you can redistribute it and/or modify

it under the terms of either:

  * the GNU Lesser General Public License as published by the Free

    Software Foundation; either version 3 of the License, or (at your

    option) any later version.

or

  * 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.

or both in parallel, as here.

The GNU MP Library 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 copies of the GNU General Public License and the

GNU Lesser General Public License along with the GNU MP Library.  If not,

see https://www.gnu.org/licenses/.  */

#include <stdarg.h>    /* for va_list and hence doprnt_funs_t */

#include <ctype.h>

#include <string.h>

#include <stdio.h>

#include <stdlib.h>

#include "gmp.h"

#include "gmp-impl.h"

#include "longlong.h"

/* change this to "#define TRACE(x) x" for diagnostics */

#define TRACE(x)

/* The separate of __gmp_doprnt_float_digits and __gmp_doprnt_float is so

   some C++ can do the mpf_get_str and release it in case of an exception */

#define DIGIT_VALUE(c)                  \

  (isdigit (c)   ? (c) - '0'            \

   : islower (c) ? (c) - 'a' + 10       \

   :               (c) - 'A' + 10)

int

__gmp_doprnt_mpf (const struct doprnt_funs_t *funs,

		  void *data,

		  const struct doprnt_params_t *p,

		  const char *point,

		  mpf_srcptr f)

{

  int         prec, ndigits, free_size, len, newlen, justify, justlen, explen;

  int         showbaselen, sign, signlen, intlen, intzeros, pointlen;

  int         fraczeros, fraclen, preczeros;

  char        *s, *free_ptr;

  mp_exp_t    exp;

  char        exponent[GMP_LIMB_BITS + 10];

  const char  *showbase;

  int         retval = 0;

  TRACE (printf ("__gmp_doprnt_float\n");

	 printf ("  conv=%d prec=%d\n", p->conv, p->prec));

  prec = p->prec;

  if (prec <= -1)

    {

      /* all digits */

      ndigits = 0;

      /* arrange the fixed/scientific decision on a "prec" implied by how

	 many significant digits there are */

      if (p->conv == DOPRNT_CONV_GENERAL)

	MPF_SIGNIFICANT_DIGITS (prec, PREC(f), ABS(p->base));

    }

  else

    {

      switch (p->conv) {

      case DOPRNT_CONV_FIXED:

	/* Precision is digits after the radix point.  Try not to generate

	   too many more than will actually be required.  If f>=1 then

	   overestimate the integer part, and add prec.  If f<1 then

	   underestimate the zeros between the radix point and the first

	   digit and subtract that from prec.  In either case add 2 so the

	   round to nearest can be applied accurately.  Finally, we add 1 to

	   handle the case of 1-eps where EXP(f) = 0 but mpf_get_str returns

	   exp as 1.  */

	ndigits = prec + 2 + 1

	  + EXP(f) * (mp_bases[ABS(p->base)].chars_per_limb + (EXP(f)>=0));

	ndigits = MAX (ndigits, 1);

	break;

      case DOPRNT_CONV_SCIENTIFIC:

	/* precision is digits after the radix point, and there's one digit

	   before */

	ndigits = prec + 1;

	break;

      default:

	ASSERT (0);

	/*FALLTHRU*/

      case DOPRNT_CONV_GENERAL:

	/* precision is total digits, but be sure to ask mpf_get_str for at

	   least 1, not 0 */

	ndigits = MAX (prec, 1);

	break;

      }

    }

  TRACE (printf ("  ndigits %d\n", ndigits));

  s = mpf_get_str (NULL, &exp, p->base, ndigits, f);

  len = strlen (s);

  free_ptr = s;

  free_size = len + 1;

  TRACE (printf ("  s   %s\n", s);

	 printf ("  exp %ld\n", exp);

	 printf ("  len %d\n", len));

  /* For fixed mode check the ndigits formed above was in fact enough for

     the integer part plus p->prec after the radix point. */

  ASSERT ((p->conv == DOPRNT_CONV_FIXED && p->prec > -1)

	  ? ndigits >= MAX (1, exp + p->prec + 2) : 1);

  sign = p->sign;

  if (s[0] == '-')

    {

      sign = s[0];

      s++, len--;

    }

  signlen = (sign != '\0');

  TRACE (printf ("  sign %c  signlen %d\n", sign, signlen));

  switch (p->conv) {

  case DOPRNT_CONV_FIXED:

    if (prec <= -1)

      prec = MAX (0, len-exp);   /* retain all digits */

    /* Truncate if necessary so fraction will be at most prec digits. */

    ASSERT (prec >= 0);

    newlen = exp + prec;

    if (newlen < 0)

      {

	/* first non-zero digit is below target prec, and at least one zero

	   digit in between, so print zero */

	len = 0;

	exp = 0;

      }

    else if (len <= newlen)

      {

	/* already got few enough digits */

      }

    else

      {

	/* discard excess digits and round to nearest */

	const char  *num_to_text = (p->base >= 0

				    ? "0123456789abcdefghijklmnopqrstuvwxyz"

				    : "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ");

	int  base = ABS(p->base);

	int  n;

	ASSERT (base <= 36);

	len = newlen;

	n = DIGIT_VALUE (s[len]);

	TRACE (printf ("  rounding with %d\n", n));

	if (n >= (base + 1) / 2)

	  {

	    /* propagate a carry */

	    for (;;)

	      {

		if (len == 0)

		  {

		    s[0] = '1';

		    len = 1;

		    exp++;

		    break;

		  }

		n = DIGIT_VALUE (s[len-1]);

		ASSERT (n >= 0 && n < base);

		n++;

		if (n != base)

		  {

		    TRACE (printf ("  storing now %d\n", n));

		    s[len-1] = num_to_text[n];

		    break;

		  }

		len--;

	      }

	  }

	else

	  {

	    /* truncate only, strip any trailing zeros now exposed */

	    while (len > 0 && s[len-1] == '0')

	      len--;

	  }

	/* Can have newlen==0, in which case the truncate was just to check

	   for a carry turning it into "1".  If we're left with len==0 then

	   adjust exp to match.  */

	if (len == 0)

	  exp = 0;

      }

  fixed:

    ASSERT (len == 0 ? exp == 0 : 1);

    if (exp <= 0)

      {

	TRACE (printf ("  fixed 0.000sss\n"));

	intlen = 0;

	intzeros = 1;

	fraczeros = -exp;

	fraclen = len;

      }

    else

      {

	TRACE (printf ("  fixed sss.sss or sss000\n"));

	intlen = MIN (len, exp);

	intzeros = exp - intlen;

	fraczeros = 0;

	fraclen = len - intlen;

      }

    explen = 0;

    break;

  case DOPRNT_CONV_SCIENTIFIC:

    {

      long int expval;

      char  expsign;

      if (prec <= -1)

	prec = MAX (0, len-1);   /* retain all digits */

    scientific:

      TRACE (printf ("  scientific s.sss\n"));

      intlen = MIN (1, len);

      intzeros = (intlen == 0 ? 1 : 0);

      fraczeros = 0;

      fraclen = len - intlen;

      expval = (exp-intlen);

      if (p->exptimes4)

	expval <<= 2;

      /* Split out the sign since %o or %x in expfmt give negatives as twos

	 complement, not with a sign. */

      expsign = (expval >= 0 ? '+' : '-');

      expval = ABS (expval);

#if HAVE_VSNPRINTF

      explen = snprintf (exponent, sizeof(exponent),

			 p->expfmt, expsign, expval);

      /* test for < sizeof-1 since a glibc 2.0.x return of sizeof-1 might

	 mean truncation */

      ASSERT (explen >= 0 && explen < sizeof(exponent)-1);

#else

      sprintf (exponent, p->expfmt, expsign, expval);

      explen = strlen (exponent);

      ASSERT (explen < sizeof(exponent));

#endif

      TRACE (printf ("  expfmt %s gives %s\n", p->expfmt, exponent));

    }

    break;

  default:

    ASSERT (0);

    /*FALLTHRU*/  /* to stop variables looking uninitialized */

  case DOPRNT_CONV_GENERAL:

    /* The exponent for "scientific" will be exp-1, choose scientific if

       this is < -4 or >= prec (and minimum 1 for prec).  For f==0 will have

       exp==0 and get the desired "fixed".  This rule follows glibc.  For

       fixed there's no need to truncate, the desired ndigits will already

       be as required.  */

    if (exp-1 < -4 || exp-1 >= MAX (1, prec))

      goto scientific;

    else

      goto fixed;

  }

  TRACE (printf ("  intlen %d intzeros %d fraczeros %d fraclen %d\n",

		 intlen, intzeros, fraczeros, fraclen));

  ASSERT (p->prec <= -1

	  ? intlen + fraclen == strlen (s)

	  : intlen + fraclen <= strlen (s));

  if (p->showtrailing)

    {

      /* Pad to requested precision with trailing zeros, for general this is

	 all digits, for fixed and scientific just the fraction.  */

      preczeros = prec - (fraczeros + fraclen

			  + (p->conv == DOPRNT_CONV_GENERAL

			     ? intlen + intzeros : 0));

      preczeros = MAX (0, preczeros);

    }

  else

    preczeros = 0;

  TRACE (printf ("  prec=%d showtrailing=%d, pad with preczeros %d\n",

		 prec, p->showtrailing, preczeros));

  /* radix point if needed, or if forced */

  pointlen = ((fraczeros + fraclen + preczeros) != 0 || p->showpoint != 0)

    ? strlen (point) : 0;

  TRACE (printf ("  point |%s|  pointlen %d\n", point, pointlen));

  /* Notice the test for a non-zero value is done after any truncation for

     DOPRNT_CONV_FIXED. */

  showbase = NULL;

  showbaselen = 0;

  switch (p->showbase) {

  default:

    ASSERT (0);

    /*FALLTHRU*/

  case DOPRNT_SHOWBASE_NO:

    break;

  case DOPRNT_SHOWBASE_NONZERO:

    if (intlen == 0 && fraclen == 0)

      break;

    /*FALLTHRU*/

  case DOPRNT_SHOWBASE_YES:

    switch (p->base) {

    case 16:  showbase = "0x"; showbaselen = 2; break;

    case -16: showbase = "0X"; showbaselen = 2; break;

    case 8:   showbase = "0";  showbaselen = 1; break;

    }

    break;

  }

  TRACE (printf ("  showbase %s showbaselen %d\n",

		 showbase == NULL ? "" : showbase, showbaselen));

  /* left over field width */

  justlen = p->width - (signlen + showbaselen + intlen + intzeros + pointlen

			+ fraczeros + fraclen + preczeros + explen);

  TRACE (printf ("  justlen %d fill 0x%X\n", justlen, p->fill));

  justify = p->justify;

  if (justlen <= 0) /* no justifying if exceed width */

    justify = DOPRNT_JUSTIFY_NONE;

  TRACE (printf ("  justify type %d  intlen %d pointlen %d fraclen %d\n",

		 justify, intlen, pointlen, fraclen));

  if (justify == DOPRNT_JUSTIFY_RIGHT)         /* pad for right */

    DOPRNT_REPS (p->fill, justlen);

  if (signlen)                                 /* sign */

    DOPRNT_REPS (sign, 1);

  DOPRNT_MEMORY_MAYBE (showbase, showbaselen); /* base */

  if (justify == DOPRNT_JUSTIFY_INTERNAL)      /* pad for internal */

    DOPRNT_REPS (p->fill, justlen);

  DOPRNT_MEMORY (s, intlen);                   /* integer */

  DOPRNT_REPS_MAYBE ('0', intzeros);

  DOPRNT_MEMORY_MAYBE (point, pointlen);       /* point */

  DOPRNT_REPS_MAYBE ('0', fraczeros);          /* frac */

  DOPRNT_MEMORY_MAYBE (s+intlen, fraclen);

  DOPRNT_REPS_MAYBE ('0', preczeros);          /* prec */

  DOPRNT_MEMORY_MAYBE (exponent, explen);      /* exp */

  if (justify == DOPRNT_JUSTIFY_LEFT)          /* pad for left */

    DOPRNT_REPS (p->fill, justlen);

 done:

  (*__gmp_free_func) (free_ptr, free_size);

  return retval;

 error:

  retval = -1;

  goto done;

}