/* Test file for mpfr_cmp2.

Copyright 1999, 2000, 2001, 2002, 2003, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
Contributed by the Arenaire and Cacao projects, INRIA.

This file is part of the GNU MPFR Library.

The GNU MPFR Library is free software; you can redistribute it and/or modify
it under the terms of 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.

The GNU MPFR 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 Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */

#include <stdio.h>
#include <stdlib.h>

#include "mpfr-test.h"

/* set bit n of x to b, where bit 0 is the most significant one */
static void
set_bit (mpfr_t x, unsigned int n, int b)
{
  unsigned l;
  mp_size_t xn;

  xn = (MPFR_PREC(x) - 1) / mp_bits_per_limb;
  l = n / mp_bits_per_limb;
  n %= mp_bits_per_limb;
  n = mp_bits_per_limb - 1 - n;
  if (b)
    MPFR_MANT(x)[xn - l] |= (mp_limb_t) 1 << n;
  else
    MPFR_MANT(x)[xn - l] &= ~((mp_limb_t) 1 << n);
}

/* check that for x = 1.u 1 v 0^k low(x)
                  y = 1.u 0 v 1^k low(y)
   mpfr_cmp2 (x, y) returns 1 + |u| + |v| + k for low(x) >= low(y),
                        and 1 + |u| + |v| + k + 1 otherwise */
static void
worst_cases (void)
{
  mpfr_t x, y;
  unsigned int i, j, k, b, expected;
  mpfr_prec_t l;

  mpfr_init2 (x, 200);
  mpfr_init2 (y, 200);

  mpfr_set_ui (y, 1, MPFR_RNDN);
  for (i = 1; i < MPFR_PREC(x); i++)
    {
      mpfr_set_ui (x, 1, MPFR_RNDN);
      mpfr_div_2exp (y, y, 1, MPFR_RNDN); /* y = 1/2^i */

      l = 0;
      if (mpfr_cmp2 (x, y, &l) <= 0 || l != 1)
        {
          printf ("Error in mpfr_cmp2:\nx=");
          mpfr_out_str (stdout, 2, 0, x, MPFR_RNDN);
          printf ("\ny=");
          mpfr_out_str (stdout, 2, 0, y, MPFR_RNDN);
          printf ("\ngot %lu instead of 1\n", l);
          exit (1);
        }

      mpfr_add (x, x, y, MPFR_RNDN); /* x = 1 + 1/2^i */
      l = 0;
      if (mpfr_cmp2 (x, y, &l) <= 0 || l != 0)
        {
          printf ("Error in mpfr_cmp2:\nx=");
          mpfr_out_str (stdout, 2, 0, x, MPFR_RNDN);
          printf ("\ny=");
          mpfr_out_str (stdout, 2, 0, y, MPFR_RNDN);
          printf ("\ngot %lu instead of 0\n", l);
          exit (1);
        }
    }

  for (i = 0; i < 64; i++) /* |u| = i */
    {
      mpfr_urandomb (x, RANDS);
      mpfr_set (y, x, MPFR_RNDN);
      set_bit (x, i + 1, 1);
      set_bit (y, i + 1, 0);
      for (j = 0; j < 64; j++) /* |v| = j */
        {
          b = randlimb () % 2;
          set_bit (x, i + j + 2, b);
          set_bit (y, i + j + 2, b);
          for (k = 0; k < 64; k++)
            {
              if (k)
                set_bit (x, i + j + k + 1, 0);
              if (k)
                set_bit (y, i + j + k + 1, 1);
              set_bit (x, i + j + k + 2, 1);
              set_bit (y, i + j + k + 2, 0);
              l = 0; mpfr_cmp2 (x, y, &l);
              expected = i + j + k + 1;
              if (l != expected)
                {
                  printf ("Error in mpfr_cmp2:\nx=");
                  mpfr_out_str (stdout, 2, 0, x, MPFR_RNDN);
                  printf ("\ny=");
                  mpfr_out_str (stdout, 2, 0, y, MPFR_RNDN);
                  printf ("\ngot %lu instead of %u\n", l, expected);
                  exit (1);
                }
              set_bit (x, i + j + k + 2, 0);
              set_bit (x, i + j + k + 3, 0);
              set_bit (y, i + j + k + 3, 1);
              l = 0; mpfr_cmp2 (x, y, &l);
              expected = i + j + k + 2;
              if (l != expected)
                {
                  printf ("Error in mpfr_cmp2:\nx=");
                  mpfr_out_str (stdout, 2, 0, x, MPFR_RNDN);
                  printf ("\ny=");
                  mpfr_out_str (stdout, 2, 0, y, MPFR_RNDN);
                  printf ("\ngot %lu instead of %u\n", l, expected);
                  exit (1);
                }
            }
        }
    }

  mpfr_clear (x);
  mpfr_clear (y);
}

static void
tcmp2 (double x, double y, int i)
{
  mpfr_t xx, yy;
  mpfr_prec_t j;

  if (i == -1)
    {
      if (x == y)
        i = 53;
      else
        i = (int) (__gmpfr_floor_log2 (x) - __gmpfr_floor_log2 (x - y));
    }
  mpfr_init2(xx, 53); mpfr_init2(yy, 53);
  mpfr_set_d (xx, x, MPFR_RNDN);
  mpfr_set_d (yy, y, MPFR_RNDN);
  j = 0;
  if (mpfr_cmp2 (xx, yy, &j) == 0)
    {
      if (x != y)
        {
          printf ("Error in mpfr_cmp2 for\nx=");
          mpfr_out_str (stdout, 2, 0, xx, MPFR_RNDN);
          printf ("\ny=");
          mpfr_out_str (stdout, 2, 0, yy, MPFR_RNDN);
          printf ("\ngot sign 0 for x != y\n");
          exit (1);
        }
    }
  else if (j != (unsigned) i)
    {
      printf ("Error in mpfr_cmp2 for\nx=");
      mpfr_out_str (stdout, 2, 0, xx, MPFR_RNDN);
      printf ("\ny=");
      mpfr_out_str (stdout, 2, 0, yy, MPFR_RNDN);
      printf ("\ngot %lu instead of %d\n", j, i);
      exit (1);
    }
  mpfr_clear(xx); mpfr_clear(yy);
}

static void
special (void)
{
  mpfr_t x, y;
  mpfr_prec_t j;

  mpfr_init (x); mpfr_init (y);

  /* bug found by Nathalie Revol, 21 March 2001 */
  mpfr_set_prec (x, 65);
  mpfr_set_prec (y, 65);
  mpfr_set_str_binary (x, "0.10000000000000000000000000000000000001110010010110100110011110000E1");
  mpfr_set_str_binary (y, "0.11100100101101001100111011111111110001101001000011101001001010010E-35");
  j = 0;
  if (mpfr_cmp2 (x, y, &j) <= 0 || j != 1)
    {
      printf ("Error in mpfr_cmp2:\n");
      printf ("x=");
      mpfr_print_binary (x);
      puts ("");
      printf ("y=");
      mpfr_print_binary (y);
      puts ("");
      printf ("got %lu, expected 1\n", j);
      exit (1);
    }

  mpfr_set_prec(x, 127); mpfr_set_prec(y, 127);
  mpfr_set_str_binary(x, "0.1011010000110111111000000101011110110001000101101011011110010010011110010000101101000010011001100110010000000010110000101000101E6");
  mpfr_set_str_binary(y, "0.1011010000110111111000000101011011111100011101000011001111000010100010100110110100110010011001100110010000110010010110000010110E6");
  j = 0;
  if (mpfr_cmp2(x, y, &j) <= 0 || j != 32)
    {
      printf ("Error in mpfr_cmp2:\n");
      printf ("x="); mpfr_print_binary(x); puts ("");
      printf ("y="); mpfr_print_binary(y); puts ("");
      printf ("got %lu, expected 32\n", j);
      exit (1);
    }

  mpfr_set_prec (x, 128); mpfr_set_prec (y, 239);
  mpfr_set_str_binary (x, "0.10001000110110000111011000101011111100110010010011001101000011111010010110001000000010100110100111111011011010101100100000000000E167");
  mpfr_set_str_binary (y, "0.10001000110110000111011000101011111100110010010011001101000011111010010110001000000010100110100111111011011010101100011111111111111111111111111111111111111111111111011111100101011100011001101000100111000010000000000101100110000111111000101E167");
  j = 0;
  if (mpfr_cmp2(x, y, &j) <= 0 || j != 164)
    {
      printf ("Error in mpfr_cmp2:\n");
      printf ("x="); mpfr_print_binary(x); puts ("");
      printf ("y="); mpfr_print_binary(y); puts ("");
      printf ("got %lu, expected 164\n", j);
      exit (1);
    }

  /* bug found by Nathalie Revol, 29 March 2001 */
  mpfr_set_prec (x, 130); mpfr_set_prec (y, 130);
  mpfr_set_str_binary (x, "0.1100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000E2");
  mpfr_set_str_binary (y, "0.1011111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111100E2");
  j = 0;
  if (mpfr_cmp2(x, y, &j) <= 0 || j != 127)
    {
      printf ("Error in mpfr_cmp2:\n");
      printf ("x="); mpfr_print_binary(x); puts ("");
      printf ("y="); mpfr_print_binary(y); puts ("");
      printf ("got %lu, expected 127\n", j);
      exit (1);
    }

  /* bug found by Nathalie Revol, 2 Apr 2001 */
  mpfr_set_prec (x, 65); mpfr_set_prec (y, 65);
  mpfr_set_ui (x, 5, MPFR_RNDN);
  mpfr_set_str_binary (y, "0.10011111111111111111111111111111111111111111111111111111111111101E3");
  j = 0;
  if (mpfr_cmp2(x, y, &j) <= 0 || j != 63)
    {
      printf ("Error in mpfr_cmp2:\n");
      printf ("x="); mpfr_print_binary(x); puts ("");
      printf ("y="); mpfr_print_binary(y); puts ("");
      printf ("got %lu, expected 63\n", j);
      exit (1);
    }

  /* bug found by Nathalie Revol, 2 Apr 2001 */
  mpfr_set_prec (x, 65); mpfr_set_prec (y, 65);
  mpfr_set_str_binary (x, "0.10011011111000101001110000000000000000000000000000000000000000000E-69");
  mpfr_set_str_binary (y, "0.10011011111000101001101111111111111111111111111111111111111111101E-69");
  j = 0;
  if (mpfr_cmp2(x, y, &j) <= 0 || j != 63)
    {
      printf ("Error in mpfr_cmp2:\n");
      printf ("x="); mpfr_print_binary(x); puts ("");
      printf ("y="); mpfr_print_binary(y); puts ("");
      printf ("got %lu, expected 63\n", j);
      exit (1);
    }

  mpfr_set_prec (x, 65);
  mpfr_set_prec (y, 32);
  mpfr_set_str_binary (x, "1.1110111011110001110111011111111111101000011001011100101100101101");
  mpfr_set_str_binary (y, "0.11101110111100011101110111111111");
  if (mpfr_cmp2 (x, y, &j) <= 0 || j != 0)
    {
      printf ("Error in mpfr_cmp2 (1)\n");
      exit (1);
    }

  mpfr_set_prec (x, 2 * GMP_NUMB_BITS);
  mpfr_set_prec (y, GMP_NUMB_BITS);
  mpfr_set_ui (x, 1, MPFR_RNDN); /* x = 1 */
  mpfr_set_ui (y, 1, MPFR_RNDN);
  mpfr_nextbelow (y);            /* y = 1 - 2^(-GMP_NUMB_BITS) */
  mpfr_cmp2 (x, y, &j);
  if (mpfr_cmp2 (x, y, &j) <= 0 || j != GMP_NUMB_BITS)
    {
      printf ("Error in mpfr_cmp2 (2)\n");
      exit (1);
    }

  mpfr_clear (x);
  mpfr_clear (y);
}

int
main (void)
{
  int i;
  long j;
  double x, y, z;

  tests_start_mpfr ();
  mpfr_test_init ();

  worst_cases ();
  special ();
  tcmp2 (5.43885304644369510000e+185, -1.87427265794105340000e-57, 1);
  tcmp2 (1.06022698059744327881e+71, 1.05824655795525779205e+71, -1);
  tcmp2 (1.0, 1.0, 53);
  /* warning: cmp2 does not allow 0 as input */
  for (x = 0.5, i = 1; i < 54; i++)
    {
      tcmp2 (1.0, 1.0-x, i);
      x /= 2.0;
    }
  for (x = 0.5, i = 1; i < 100; i++)
    {
      tcmp2 (1.0, x, 1);
      x /= 2.0;
    }
  for (j = 0; j < 100000; j++)
    {
      x = DBL_RAND ();
      y = DBL_RAND ();
      if (x < y)
        {
          z = x;
          x = y;
          y = z;
        }
      if (y != 0.0)
        tcmp2 (x, y, -1);
    }

  tests_end_mpfr ();

  return 0;
}
