604 lines
22 KiB
OCaml
604 lines
22 KiB
OCaml
(***********************************************************************)
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(* *)
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(* Objective Caml *)
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(* *)
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(* Valerie Menissier-Morain, projet Cristal, INRIA Rocquencourt *)
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(* *)
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(* Copyright 1996 Institut National de Recherche en Informatique et *)
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(* en Automatique. All rights reserved. This file is distributed *)
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(* under the terms of the GNU Library General Public License, with *)
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(* the special exception on linking described in file ../../LICENSE. *)
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(* *)
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(***********************************************************************)
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(* $Id$ *)
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open Int_misc
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open Nat
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type big_int =
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{ sign : int;
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abs_value : nat }
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let create_big_int sign nat =
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if sign = 1 || sign = -1 ||
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(sign = 0 &&
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is_zero_nat nat 0 (num_digits_nat nat 0 (length_nat nat)))
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then { sign = sign;
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abs_value = nat }
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else invalid_arg "create_big_int"
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(* Sign of a big_int *)
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let sign_big_int bi = bi.sign
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let zero_big_int =
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{ sign = 0;
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abs_value = make_nat 1 }
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let unit_big_int =
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{ sign = 1;
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abs_value = nat_of_int 1 }
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(* Number of digits in a big_int *)
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let num_digits_big_int bi =
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num_digits_nat (bi.abs_value) 0 (length_nat bi.abs_value)
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(* Opposite of a big_int *)
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let minus_big_int bi =
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{ sign = - bi.sign;
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abs_value = copy_nat (bi.abs_value) 0 (num_digits_big_int bi)}
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(* Absolute value of a big_int *)
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let abs_big_int bi =
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{ sign = if bi.sign = 0 then 0 else 1;
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abs_value = copy_nat (bi.abs_value) 0 (num_digits_big_int bi)}
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(* Comparison operators on big_int *)
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(*
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compare_big_int (bi, bi2) = sign of (bi-bi2)
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i.e. 1 if bi > bi2
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0 if bi = bi2
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-1 if bi < bi2
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*)
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let compare_big_int bi1 bi2 =
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if bi1.sign = 0 && bi2.sign = 0 then 0
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else if bi1.sign < bi2.sign then -1
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else if bi1.sign > bi2.sign then 1
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else if bi1.sign = 1 then
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compare_nat (bi1.abs_value) 0 (num_digits_big_int bi1)
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(bi2.abs_value) 0 (num_digits_big_int bi2)
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else
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compare_nat (bi2.abs_value) 0 (num_digits_big_int bi2)
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(bi1.abs_value) 0 (num_digits_big_int bi1)
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let eq_big_int bi1 bi2 = compare_big_int bi1 bi2 = 0
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and le_big_int bi1 bi2 = compare_big_int bi1 bi2 <= 0
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and ge_big_int bi1 bi2 = compare_big_int bi1 bi2 >= 0
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and lt_big_int bi1 bi2 = compare_big_int bi1 bi2 < 0
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and gt_big_int bi1 bi2 = compare_big_int bi1 bi2 > 0
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let max_big_int bi1 bi2 = if lt_big_int bi1 bi2 then bi2 else bi1
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and min_big_int bi1 bi2 = if gt_big_int bi1 bi2 then bi2 else bi1
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(* Operations on big_int *)
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let pred_big_int bi =
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match bi.sign with
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0 -> { sign = -1; abs_value = nat_of_int 1}
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| 1 -> let size_bi = num_digits_big_int bi in
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let copy_bi = copy_nat (bi.abs_value) 0 size_bi in
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decr_nat copy_bi 0 size_bi 0;
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{ sign = if is_zero_nat copy_bi 0 size_bi then 0 else 1;
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abs_value = copy_bi }
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| _ -> let size_bi = num_digits_big_int bi in
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let size_res = succ (size_bi) in
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let copy_bi = create_nat (size_res) in
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blit_nat copy_bi 0 (bi.abs_value) 0 size_bi;
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set_digit_nat copy_bi size_bi 0;
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incr_nat copy_bi 0 size_res 1;
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{ sign = -1;
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abs_value = copy_bi }
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let succ_big_int bi =
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match bi.sign with
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0 -> {sign = 1; abs_value = nat_of_int 1}
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| -1 -> let size_bi = num_digits_big_int bi in
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let copy_bi = copy_nat (bi.abs_value) 0 size_bi in
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decr_nat copy_bi 0 size_bi 0;
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{ sign = if is_zero_nat copy_bi 0 size_bi then 0 else -1;
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abs_value = copy_bi }
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| _ -> let size_bi = num_digits_big_int bi in
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let size_res = succ (size_bi) in
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let copy_bi = create_nat (size_res) in
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blit_nat copy_bi 0 (bi.abs_value) 0 size_bi;
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set_digit_nat copy_bi size_bi 0;
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incr_nat copy_bi 0 size_res 1;
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{ sign = 1;
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abs_value = copy_bi }
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let add_big_int bi1 bi2 =
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let size_bi1 = num_digits_big_int bi1
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and size_bi2 = num_digits_big_int bi2 in
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if bi1.sign = bi2.sign
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then (* Add absolute values if signs are the same *)
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{ sign = bi1.sign;
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abs_value =
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match compare_nat (bi1.abs_value) 0 size_bi1
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(bi2.abs_value) 0 size_bi2 with
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-1 -> let res = create_nat (succ size_bi2) in
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(blit_nat res 0 (bi2.abs_value) 0 size_bi2;
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set_digit_nat res size_bi2 0;
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add_nat res 0 (succ size_bi2)
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(bi1.abs_value) 0 size_bi1 0;
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res)
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|_ -> let res = create_nat (succ size_bi1) in
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(blit_nat res 0 (bi1.abs_value) 0 size_bi1;
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set_digit_nat res size_bi1 0;
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add_nat res 0 (succ size_bi1)
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(bi2.abs_value) 0 size_bi2 0;
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res)}
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else (* Subtract absolute values if signs are different *)
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match compare_nat (bi1.abs_value) 0 size_bi1
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(bi2.abs_value) 0 size_bi2 with
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0 -> zero_big_int
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| 1 -> { sign = bi1.sign;
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abs_value =
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let res = copy_nat (bi1.abs_value) 0 size_bi1 in
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(sub_nat res 0 size_bi1
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(bi2.abs_value) 0 size_bi2 1;
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res) }
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| _ -> { sign = bi2.sign;
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abs_value =
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let res = copy_nat (bi2.abs_value) 0 size_bi2 in
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(sub_nat res 0 size_bi2
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(bi1.abs_value) 0 size_bi1 1;
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res) }
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(* Coercion with int type *)
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let big_int_of_int i =
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{ sign = sign_int i;
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abs_value =
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let res = (create_nat 1)
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in (if i = monster_int
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then (set_digit_nat res 0 biggest_int;
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incr_nat res 0 1 1; ())
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else set_digit_nat res 0 (abs i));
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res }
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let add_int_big_int i bi = add_big_int (big_int_of_int i) bi
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let sub_big_int bi1 bi2 = add_big_int bi1 (minus_big_int bi2)
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(* Returns i * bi *)
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let mult_int_big_int i bi =
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let size_bi = num_digits_big_int bi in
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let size_res = succ size_bi in
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if i = monster_int
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then let res = create_nat size_res in
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blit_nat res 0 (bi.abs_value) 0 size_bi;
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mult_digit_nat res 0 size_res (bi.abs_value) 0 size_bi
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(nat_of_int biggest_int) 0;
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{ sign = - (sign_big_int bi);
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abs_value = res }
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else let res = make_nat (size_res) in
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mult_digit_nat res 0 size_res (bi.abs_value) 0 size_bi
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(nat_of_int (abs i)) 0;
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{ sign = (sign_int i) * (sign_big_int bi);
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abs_value = res }
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let mult_big_int bi1 bi2 =
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let size_bi1 = num_digits_big_int bi1
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and size_bi2 = num_digits_big_int bi2 in
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let size_res = size_bi1 + size_bi2 in
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let res = make_nat (size_res) in
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{ sign = bi1.sign * bi2.sign;
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abs_value =
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if size_bi2 > size_bi1
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then (mult_nat res 0 size_res (bi2.abs_value) 0 size_bi2
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(bi1.abs_value) 0 size_bi1;res)
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else (mult_nat res 0 size_res (bi1.abs_value) 0 size_bi1
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(bi2.abs_value) 0 size_bi2;res) }
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(* (quotient, rest) of the euclidian division of 2 big_int *)
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let quomod_big_int bi1 bi2 =
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if bi2.sign = 0 then raise Division_by_zero
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else
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let size_bi1 = num_digits_big_int bi1
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and size_bi2 = num_digits_big_int bi2 in
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match compare_nat (bi1.abs_value) 0 size_bi1
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(bi2.abs_value) 0 size_bi2 with
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-1 -> (* 1/2 -> 0, reste 1, -1/2 -> -1, reste 1 *)
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if bi1.sign = -1
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then (big_int_of_int(-1), add_big_int bi2 bi1)
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else (big_int_of_int 0, bi1)
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| 0 -> (big_int_of_int (bi1.sign * bi2.sign), zero_big_int)
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| _ -> let bi1_negatif = bi1.sign = -1 in
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let size_q =
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if bi1_negatif
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then succ (max (succ (size_bi1 - size_bi2)) 1)
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else max (succ (size_bi1 - size_bi2)) 1
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and size_r = succ (max size_bi1 size_bi2)
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(* r is long enough to contain both quotient and remainder *)
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(* of the euclidian division *)
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in
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(* set up quotient, remainder *)
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let q = create_nat size_q
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and r = create_nat size_r in
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blit_nat r 0 (bi1.abs_value) 0 size_bi1;
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set_to_zero_nat r size_bi1 (size_r - size_bi1);
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(* do the division of |bi1| by |bi2|
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- at the beginning, r contains |bi1|
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- at the end, r contains
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* in the size_bi2 least significant digits, the remainder
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* in the size_r-size_bi2 most significant digits, the quotient
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note the conditions for application of div_nat are verified here
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*)
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div_nat r 0 size_r (bi2.abs_value) 0 size_bi2;
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(* separate quotient and remainder *)
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blit_nat q 0 r size_bi2 (size_r - size_bi2);
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let not_null_mod = not (is_zero_nat r 0 size_bi2) in
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(* correct the signs, adjusting the quotient and remainder *)
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if bi1_negatif && not_null_mod
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then
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(* bi1<0, r>0, noting r for (r, size_bi2) the remainder, *)
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(* we have |bi1|=q * |bi2| + r with 0 < r < |bi2|, *)
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(* thus -bi1 = q * |bi2| + r *)
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(* and bi1 = (-q) * |bi2| + (-r) with -|bi2| < (-r) < 0 *)
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(* thus bi1 = -(q+1) * |bi2| + (|bi2|-r) *)
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(* with 0 < (|bi2|-r) < |bi2| *)
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(* so the quotient has for sign the opposite of the bi2'one *)
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(* and for value q+1 *)
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(* and the remainder is strictly positive *)
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(* has for value |bi2|-r *)
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(let new_r = copy_nat (bi2.abs_value) 0 size_bi2 in
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(* new_r contains (r, size_bi2) the remainder *)
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{ sign = - bi2.sign;
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abs_value = (set_digit_nat q (pred size_q) 0;
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incr_nat q 0 size_q 1; q) },
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{ sign = 1;
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abs_value =
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(sub_nat new_r 0 size_bi2 r 0 size_bi2 1;
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new_r) })
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else
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(if bi1_negatif then set_digit_nat q (pred size_q) 0;
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{ sign = if is_zero_nat q 0 size_q
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then 0
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else bi1.sign * bi2.sign;
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abs_value = q },
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{ sign = if not_null_mod then 1 else 0;
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abs_value = copy_nat r 0 size_bi2 })
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let div_big_int bi1 bi2 = fst (quomod_big_int bi1 bi2)
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and mod_big_int bi1 bi2 = snd (quomod_big_int bi1 bi2)
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let gcd_big_int bi1 bi2 =
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let size_bi1 = num_digits_big_int bi1
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and size_bi2 = num_digits_big_int bi2 in
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if is_zero_nat (bi1.abs_value) 0 size_bi1 then abs_big_int bi2
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else if is_zero_nat (bi2.abs_value) 0 size_bi2 then
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{ sign = 1;
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abs_value = bi1.abs_value }
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else
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{ sign = 1;
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abs_value =
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match compare_nat (bi1.abs_value) 0 size_bi1
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(bi2.abs_value) 0 size_bi2 with
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0 -> bi1.abs_value
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| 1 ->
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let res = copy_nat (bi1.abs_value) 0 size_bi1 in
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let len =
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gcd_nat res 0 size_bi1 (bi2.abs_value) 0 size_bi2 in
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copy_nat res 0 len
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| _ ->
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let res = copy_nat (bi2.abs_value) 0 size_bi2 in
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let len =
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gcd_nat res 0 size_bi2 (bi1.abs_value) 0 size_bi1 in
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copy_nat res 0 len
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}
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(* Coercion operators *)
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let monster_big_int = big_int_of_int monster_int;;
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let monster_nat = monster_big_int.abs_value;;
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let is_int_big_int bi =
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num_digits_big_int bi == 1 &&
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match compare_nat bi.abs_value 0 1 monster_nat 0 1 with
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| 0 -> bi.sign == -1
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| -1 -> true
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| _ -> false;;
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let int_of_big_int bi =
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try let n = int_of_nat bi.abs_value in
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if bi.sign = -1 then - n else n
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with Failure _ ->
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if eq_big_int bi monster_big_int then monster_int
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else failwith "int_of_big_int";;
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(* Coercion with nat type *)
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let nat_of_big_int bi =
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if bi.sign = -1
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then failwith "nat_of_big_int"
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else copy_nat (bi.abs_value) 0 (num_digits_big_int bi)
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let sys_big_int_of_nat nat off len =
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let length = num_digits_nat nat off len in
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{ sign = if is_zero_nat nat off length then 0 else 1;
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abs_value = copy_nat nat off length }
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let big_int_of_nat nat =
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sys_big_int_of_nat nat 0 (length_nat nat)
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(* Coercion with string type *)
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let string_of_big_int bi =
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if bi.sign = -1
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then "-" ^ string_of_nat bi.abs_value
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else string_of_nat bi.abs_value
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let sys_big_int_of_string_aux s ofs len sgn =
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if len < 1 then failwith "sys_big_int_of_string";
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let n = sys_nat_of_string 10 s ofs len in
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if is_zero_nat n 0 (length_nat n) then zero_big_int
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else {sign = sgn; abs_value = n}
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;;
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let sys_big_int_of_string s ofs len =
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match s.[ofs] with
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| '-' -> sys_big_int_of_string_aux s (ofs+1) (len-1) (-1)
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| '+' -> sys_big_int_of_string_aux s (ofs+1) (len-1) 1
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| _ -> sys_big_int_of_string_aux s ofs len 1
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;;
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let big_int_of_string s =
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sys_big_int_of_string s 0 (String.length s)
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let power_base_nat base nat off len =
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if is_zero_nat nat off len then nat_of_int 1 else
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let power_base = make_nat (succ length_of_digit) in
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let (pmax, pint) = make_power_base base power_base in
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let (n, rem) =
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let (x, y) = quomod_big_int (sys_big_int_of_nat nat off len)
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(big_int_of_int (succ pmax)) in
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(int_of_big_int x, int_of_big_int y) in
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if n = 0 then copy_nat power_base (pred rem) 1 else
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begin
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let res = make_nat n
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and res2 = make_nat (succ n)
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and l = num_bits_int n - 2 in
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let p = ref (1 lsl l) in
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blit_nat res 0 power_base pmax 1;
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for i = l downto 0 do
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let len = num_digits_nat res 0 n in
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let len2 = min n (2 * len) in
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let succ_len2 = succ len2 in
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square_nat res2 0 len2 res 0 len;
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begin
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if n land !p > 0
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then (set_to_zero_nat res 0 len;
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mult_digit_nat res 0 succ_len2
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res2 0 len2
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power_base pmax; ())
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else blit_nat res 0 res2 0 len2
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end;
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set_to_zero_nat res2 0 len2;
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p := !p lsr 1
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done;
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if rem > 0
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then (mult_digit_nat res2 0 (succ n)
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res 0 n power_base (pred rem);
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res2)
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else res
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end
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let power_int_positive_int i n =
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match sign_int n with
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0 -> unit_big_int
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| -1 -> invalid_arg "power_int_positive_int"
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| _ -> let nat = power_base_int (abs i) n in
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{ sign = if i >= 0
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then sign_int i
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else if n land 1 = 0
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then 1
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else -1;
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abs_value = nat}
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let power_big_int_positive_int bi n =
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match sign_int n with
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0 -> unit_big_int
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| -1 -> invalid_arg "power_big_int_positive_int"
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| _ -> let bi_len = num_digits_big_int bi in
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let res_len = bi_len * n in
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let res = make_nat res_len
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and res2 = make_nat res_len
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and l = num_bits_int n - 2 in
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let p = ref (1 lsl l) in
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blit_nat res 0 (bi.abs_value) 0 bi_len;
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for i = l downto 0 do
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let len = num_digits_nat res 0 res_len in
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let len2 = min res_len (2 * len) in
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let succ_len2 = succ len2 in
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square_nat res2 0 len2 res 0 len;
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(if n land !p > 0
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then (set_to_zero_nat res 0 len;
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mult_nat res 0 succ_len2
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res2 0 len2 (bi.abs_value) 0 bi_len;
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set_to_zero_nat res2 0 len2)
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else blit_nat res 0 res2 0 len2;
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set_to_zero_nat res2 0 len2);
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p := !p lsr 1
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done;
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{sign = if bi.sign >= 0
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|
then bi.sign
|
|
else if n land 1 = 0
|
|
then 1
|
|
else -1;
|
|
abs_value = res}
|
|
|
|
let power_int_positive_big_int i bi =
|
|
match sign_big_int bi with
|
|
0 -> unit_big_int
|
|
| -1 -> invalid_arg "power_int_positive_big_int"
|
|
| _ -> let nat = power_base_nat
|
|
(abs i) (bi.abs_value) 0 (num_digits_big_int bi) in
|
|
{ sign = if i >= 0
|
|
then sign_int i
|
|
else if is_digit_odd (bi.abs_value) 0
|
|
then -1
|
|
else 1;
|
|
abs_value = nat }
|
|
|
|
let power_big_int_positive_big_int bi1 bi2 =
|
|
match sign_big_int bi2 with
|
|
0 -> unit_big_int
|
|
| -1 -> invalid_arg "power_big_int_positive_big_int"
|
|
| _ -> let nat = bi2.abs_value
|
|
and off = 0
|
|
and len_bi2 = num_digits_big_int bi2 in
|
|
let bi1_len = num_digits_big_int bi1 in
|
|
let res_len = int_of_big_int (mult_int_big_int bi1_len bi2) in
|
|
let res = make_nat res_len
|
|
and res2 = make_nat res_len
|
|
and l = (len_bi2 * length_of_digit
|
|
- num_leading_zero_bits_in_digit nat (pred len_bi2)) - 2 in
|
|
let p = ref (1 lsl l) in
|
|
blit_nat res 0 (bi1.abs_value) 0 bi1_len;
|
|
for i = l downto 0 do
|
|
let nat = copy_nat bi2.abs_value 0 len_bi2 in
|
|
let len = num_digits_nat res 0 res_len in
|
|
let len2 = min res_len (2 * len) in
|
|
let succ_len2 = succ len2 in
|
|
square_nat res2 0 len2 res 0 len;
|
|
land_digit_nat nat 0 (nat_of_int !p) 0;
|
|
if is_zero_nat nat 0 len_bi2
|
|
then (blit_nat res 0 res2 0 len2;
|
|
set_to_zero_nat res2 0 len2)
|
|
else (set_to_zero_nat res 0 len;
|
|
mult_nat res 0 succ_len2
|
|
res2 0 len2 (bi1.abs_value) 0 bi1_len;
|
|
set_to_zero_nat res2 0 len2);
|
|
p := !p lsr 1
|
|
done;
|
|
{sign = if bi1.sign >= 0
|
|
then bi1.sign
|
|
else if is_digit_odd (bi2.abs_value) 0
|
|
then -1
|
|
else 1;
|
|
abs_value = res}
|
|
|
|
(* base_power_big_int compute bi*base^n *)
|
|
let base_power_big_int base n bi =
|
|
match sign_int n with
|
|
0 -> bi
|
|
| -1 -> let nat = power_base_int base (-n) in
|
|
let len_nat = num_digits_nat nat 0 (length_nat nat)
|
|
and len_bi = num_digits_big_int bi in
|
|
if len_bi < len_nat then
|
|
invalid_arg "base_power_big_int"
|
|
else if len_bi = len_nat &&
|
|
compare_digits_nat (bi.abs_value) len_bi nat len_nat = -1
|
|
then invalid_arg "base_power_big_int"
|
|
else
|
|
let copy = create_nat (succ len_bi) in
|
|
blit_nat copy 0 (bi.abs_value) 0 len_bi;
|
|
set_digit_nat copy len_bi 0;
|
|
div_nat copy 0 (succ len_bi)
|
|
nat 0 len_nat;
|
|
if not (is_zero_nat copy 0 len_nat)
|
|
then invalid_arg "base_power_big_int"
|
|
else { sign = bi.sign;
|
|
abs_value = copy_nat copy len_nat 1 }
|
|
| _ -> let nat = power_base_int base n in
|
|
let len_nat = num_digits_nat nat 0 (length_nat nat)
|
|
and len_bi = num_digits_big_int bi in
|
|
let new_len = len_bi + len_nat in
|
|
let res = make_nat new_len in
|
|
(if len_bi > len_nat
|
|
then mult_nat res 0 new_len
|
|
(bi.abs_value) 0 len_bi
|
|
nat 0 len_nat
|
|
else mult_nat res 0 new_len
|
|
nat 0 len_nat
|
|
(bi.abs_value) 0 len_bi)
|
|
; if is_zero_nat res 0 new_len
|
|
then zero_big_int
|
|
else create_big_int (bi.sign) res
|
|
|
|
(* Coercion with float type *)
|
|
|
|
let float_of_big_int bi =
|
|
float_of_string (string_of_big_int bi)
|
|
|
|
(* XL: suppression de big_int_of_float et nat_of_float. *)
|
|
|
|
(* Other functions needed *)
|
|
|
|
(* Integer part of the square root of a big_int *)
|
|
let sqrt_big_int bi =
|
|
match bi.sign with
|
|
| 0 -> zero_big_int
|
|
| -1 -> invalid_arg "sqrt_big_int"
|
|
| _ -> {sign = 1;
|
|
abs_value = sqrt_nat (bi.abs_value) 0 (num_digits_big_int bi)}
|
|
|
|
let square_big_int bi =
|
|
if bi.sign == 0 then zero_big_int else
|
|
let len_bi = num_digits_big_int bi in
|
|
let len_res = 2 * len_bi in
|
|
let res = make_nat len_res in
|
|
square_nat res 0 len_res (bi.abs_value) 0 len_bi;
|
|
{sign = 1; abs_value = res}
|
|
|
|
(* round off of the futur last digit (of the integer represented by the string
|
|
argument of the function) that is now the previous one.
|
|
if s contains an integer of the form (10^n)-1
|
|
then s <- only 0 digits and the result_int is true
|
|
else s <- the round number and the result_int is false *)
|
|
let round_futur_last_digit s off_set length =
|
|
let l = pred (length + off_set) in
|
|
if Char.code(String.get s l) >= Char.code '5'
|
|
then
|
|
let rec round_rec l =
|
|
let current_char = String.get s l in
|
|
if current_char = '9'
|
|
then
|
|
(String.set s l '0';
|
|
if l = off_set then true else round_rec (pred l))
|
|
else
|
|
(String.set s l (Char.chr (succ (Char.code current_char)));
|
|
false)
|
|
in round_rec (pred l)
|
|
else false
|
|
|
|
|
|
(* Approximation with floating decimal point a` la approx_ratio_exp *)
|
|
let approx_big_int prec bi =
|
|
let len_bi = num_digits_big_int bi in
|
|
let n =
|
|
max 0
|
|
(int_of_big_int (
|
|
add_int_big_int
|
|
(-prec)
|
|
(div_big_int (mult_big_int (big_int_of_int (pred len_bi))
|
|
(big_int_of_string "963295986"))
|
|
(big_int_of_string "100000000")))) in
|
|
let s =
|
|
string_of_big_int (div_big_int bi (power_int_positive_int 10 n)) in
|
|
let (sign, off, len) =
|
|
if String.get s 0 = '-'
|
|
then ("-", 1, succ prec)
|
|
else ("", 0, prec) in
|
|
if (round_futur_last_digit s off (succ prec))
|
|
then (sign^"1."^(String.make prec '0')^"e"^
|
|
(string_of_int (n + 1 - off + String.length s)))
|
|
else (sign^(String.sub s off 1)^"."^
|
|
(String.sub s (succ off) (pred prec))
|
|
^"e"^(string_of_int (n - succ off + String.length s)))
|