/* mpz_get_str (string, base, mp_src) -- Convert the multiple precision

   number MP_SRC to a string STRING of base BASE.  If STRING is NULL

   allocate space for the result.  In any case, return a pointer to the

   result.  If STRING is not NULL, the caller must ensure enough space is

   available to store the result.

Copyright 1991, 1993, 1994, 1996, 2000-2002, 2005, 2012 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 <string.h> /* for strlen */

#include "gmp.h"

#include "gmp-impl.h"

#include "longlong.h"

char *

mpz_get_str (char *res_str, int base, mpz_srcptr x)

{

  mp_ptr xp;

  mp_size_t x_size = SIZ (x);

  char *return_str;

  size_t str_size;

  size_t alloc_size = 0;

  const char *num_to_text;

  int i;

  TMP_DECL;

  if (base >= 0)

    {

      num_to_text = "0123456789abcdefghijklmnopqrstuvwxyz";

      if (base <= 1)

	base = 10;

      else if (base > 36)

	{

	  num_to_text = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

	  if (base > 62)

	    return NULL;

	}

    }

  else

    {

      base = -base;

      if (base <= 1)

	base = 10;

      else if (base > 36)

	return NULL;

      num_to_text = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    }

  /* allocate string for the user if necessary */

  if (res_str == NULL)

    {

      /* digits, null terminator, possible minus sign */

      MPN_SIZEINBASE (alloc_size, PTR(x), ABS(x_size), base);

      alloc_size += 1 + (x_size<0);

      res_str = (char *) (*__gmp_allocate_func) (alloc_size);

    }

  return_str = res_str;

  if (x_size < 0)

    {

      *res_str++ = '-';

      x_size = -x_size;

    }

  /* mpn_get_str clobbers its input on non power-of-2 bases */

  TMP_MARK;

  xp = PTR (x);

  if (! POW2_P (base))

    {

      xp = TMP_ALLOC_LIMBS (x_size | 1);  /* |1 in case x_size==0 */

      MPN_COPY (xp, PTR (x), x_size);

    }

  str_size = mpn_get_str ((unsigned char *) res_str, base, xp, x_size);

  ASSERT (alloc_size == 0 || str_size <= alloc_size - (SIZ(x) < 0));

  /* Convert result to printable chars.  */

  for (i = 0; i < str_size; i++)

    res_str[i] = num_to_text[(int) res_str[i]];

  res_str[str_size] = 0;

  TMP_FREE;

  /* if allocated then resize down to the actual space required */

  if (alloc_size != 0)

    {

      size_t  actual_size = str_size + 1 + (res_str - return_str);

      ASSERT (actual_size == strlen (return_str) + 1);

      __GMP_REALLOCATE_FUNC_MAYBE_TYPE (return_str, alloc_size, actual_size,

					char);

    }

  return return_str;

}