/* Generate Fibonacci table data.

Copyright 2001, 2002, 2004, 2012, 2014, 2015 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 <stdio.h>

#include "bootstrap.c"

mpz_t  *f;

int    fnum, fib_limit, luc_limit;

void

generate (int numb_bits)

{

  mpz_t  limit, l;

  int    falloc, i;

  mpz_init2 (limit, numb_bits + 1);

  mpz_setbit (limit, numb_bits);

  /* fib(2n) > 2^n, so use 2n as a limit for the table size */

  falloc = 2 * numb_bits;

  f = (mpz_t*) xmalloc (falloc * sizeof (*f));

  mpz_init_set_ui (f[0], 1L);  /* F[-1] */

  mpz_init_set_ui (f[1], 0L);  /* F[0] */

  mpz_init (l);

  for (i = 2; ; i++)

    {

      assert (i < falloc);

      /* F[i] = F[i-1] + F[i-2] */

      mpz_init (f[i]);

      mpz_add (f[i], f[i-1], f[i-2]);

      if (mpz_cmp (f[i], limit) >= 0)

        break;

      fnum = i+1;

      fib_limit = i-1;

      /* L[i] = F[i]+2*F[i-1] */

      mpz_add (l, f[i], f[i-1]);

      mpz_add (l, l, f[i-1]);

      if (mpz_cmp (l, limit) < 0)

        luc_limit = i-1;

    }

  mpz_clear (limit);

}

void

header (int numb_bits)

{

  printf ("/* This file generated by gen-fib.c - DO NOT EDIT. */\n");

  printf ("\n");

  printf ("#if GMP_NUMB_BITS != %d\n", numb_bits);

  printf ("Error, error, this data is for %d bits\n", numb_bits);

  printf ("#endif\n");

  printf ("\n");

  printf ("#define FIB_TABLE_LIMIT         %d\n", fib_limit);

  printf ("#define FIB_TABLE_LUCNUM_LIMIT  %d\n", luc_limit);

}

void

table (int numb_bits)

{

  int  i;

  printf ("/* This file generated by gen-fib.c - DO NOT EDIT. */\n");

  printf ("\n");

  printf ("#include \"gmp.h\"\n");

  printf ("#include \"gmp-impl.h\"\n");

  printf ("\n");

  printf ("#if GMP_NUMB_BITS != %d\n", numb_bits);

  printf ("Error, error, this data is for %d bits\n", numb_bits);

  printf ("#endif\n");

  printf ("\n");

  printf ("const mp_limb_t\n");

  printf ("__gmp_fib_table[FIB_TABLE_LIMIT+2] = {\n");

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

    {

      printf ("  CNST_LIMB (0x");

      mpz_out_str (stdout, 16, f[i]);

      printf ("),  /* %d */\n", i-1);

    }

  printf ("};\n");

}

int

main (int argc, char *argv[])

{

  int  limb_bits, nail_bits, numb_bits;

  if (argc != 4)

    {

      fprintf (stderr, "Usage: gen-fib <header|table> <limbbits> <nailbits>\n");

      exit (1);

    }

  limb_bits = atoi (argv[2]);

  nail_bits = atoi (argv[3]);

  if (limb_bits <= 0

      || nail_bits < 0

      || nail_bits >= limb_bits)

    {

      fprintf (stderr, "Invalid limb/nail bits: %d %d\n",

               limb_bits, nail_bits);

      exit (1);

    }

  numb_bits = limb_bits - nail_bits;

  generate (numb_bits);

  if (strcmp (argv[1], "header") == 0)

    header (numb_bits);

  else if (strcmp (argv[1], "table") == 0)

    table (numb_bits);

  else

    {

      fprintf (stderr, "Invalid header/table choice: %s\n", argv[1]);

      exit (1);

    }

  return 0;

}