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auto merge of #10555 : TeXitoi/rust/pidigits-resurected, r=alexcrichton
Changes: * default value when no args * license * removed libc printing * use extra::bigint instead of handmade gmp binding The drawback is that it's 2 order of magnitude slower, the good news is that there is a good bench for extra::bigint.
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// xfail-test | ||
// Copyright 2013 The Rust Project Developers. See the COPYRIGHT | ||
// file at the top-level directory of this distribution and at | ||
// http://rust-lang.org/COPYRIGHT. | ||
// | ||
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | ||
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | ||
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | ||
// option. This file may not be copied, modified, or distributed | ||
// except according to those terms. | ||
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extern mod extra; | ||
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use std::cast::transmute; | ||
use std::from_str::FromStr; | ||
use std::libc::{STDOUT_FILENO, c_char, c_int, c_uint, c_void, fdopen, fputc}; | ||
use std::libc::{fputs}; | ||
use std::ptr::null; | ||
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struct mpz_t { | ||
_mp_alloc: c_int, | ||
_mp_size: c_int, | ||
_mp_limb_t: *c_void, | ||
} | ||
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impl mpz_t { | ||
fn new() -> mpz_t { | ||
mpz_t { | ||
_mp_alloc: 0, | ||
_mp_size: 0, | ||
_mp_limb_t: null(), | ||
} | ||
} | ||
} | ||
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#[link_args="-lgmp"] | ||
extern { | ||
#[link_name="__gmpz_add"] | ||
fn mpz_add(x: *mpz_t, y: *mpz_t, z: *mpz_t); | ||
#[link_name="__gmpz_cmp"] | ||
fn mpz_cmp(x: *mpz_t, y: *mpz_t) -> c_int; | ||
#[link_name="__gmpz_fdiv_qr"] | ||
fn mpz_fdiv_qr(a: *mpz_t, b: *mpz_t, c: *mpz_t, d: *mpz_t); | ||
#[link_name="__gmpz_get_ui"] | ||
fn mpz_get_ui(x: *mpz_t) -> c_uint; | ||
#[link_name="__gmpz_init"] | ||
fn mpz_init(x: *mpz_t); | ||
#[link_name="__gmpz_init_set_ui"] | ||
fn mpz_init_set_ui(x: *mpz_t, y: c_uint); | ||
#[link_name="__gmpz_mul_2exp"] | ||
fn mpz_mul_2exp(x: *mpz_t, y: *mpz_t, z: c_uint); | ||
#[link_name="__gmpz_mul_ui"] | ||
fn mpz_mul_ui(x: *mpz_t, y: *mpz_t, z: c_uint); | ||
#[link_name="__gmpz_submul_ui"] | ||
fn mpz_submul_ui(x: *mpz_t, y: *mpz_t, z: c_uint); | ||
} | ||
use std::num::One; | ||
use std::num::Zero; | ||
use std::num::FromPrimitive; | ||
use extra::bigint::BigInt; | ||
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struct Context { | ||
numer: mpz_t, | ||
accum: mpz_t, | ||
denom: mpz_t, | ||
tmp1: mpz_t, | ||
tmp2: mpz_t, | ||
numer: BigInt, | ||
accum: BigInt, | ||
denom: BigInt, | ||
} | ||
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impl Context { | ||
fn new() -> Context { | ||
unsafe { | ||
let mut result = Context { | ||
numer: mpz_t::new(), | ||
accum: mpz_t::new(), | ||
denom: mpz_t::new(), | ||
tmp1: mpz_t::new(), | ||
tmp2: mpz_t::new(), | ||
}; | ||
mpz_init(&result.tmp1); | ||
mpz_init(&result.tmp2); | ||
mpz_init_set_ui(&result.numer, 1); | ||
mpz_init_set_ui(&result.accum, 0); | ||
mpz_init_set_ui(&result.denom, 1); | ||
result | ||
Context { | ||
numer: One::one(), | ||
accum: Zero::zero(), | ||
denom: One::one(), | ||
} | ||
} | ||
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fn extract_digit(&mut self) -> i32 { | ||
unsafe { | ||
if mpz_cmp(&self.numer, &self.accum) > 0 { | ||
return -1; | ||
} | ||
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// Compute (numer * 3 + accum) / denom | ||
mpz_mul_2exp(&self.tmp1, &self.numer, 1); | ||
mpz_add(&self.tmp1, &self.tmp1, &self.numer); | ||
mpz_add(&self.tmp1, &self.tmp1, &self.accum); | ||
mpz_fdiv_qr(&self.tmp1, &self.tmp2, &self.tmp1, &self.denom); | ||
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// Now, if (numer * 4 + accum) % denom... | ||
mpz_add(&self.tmp2, &self.tmp2, &self.numer); | ||
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// ... is normalized, then the two divisions have the same result. | ||
if mpz_cmp(&self.tmp2, &self.denom) >= 0 { | ||
return -1; | ||
} | ||
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mpz_get_ui(&self.tmp1) as i32 | ||
} | ||
fn from_int(i: int) -> BigInt { | ||
FromPrimitive::from_int(i).unwrap() | ||
} | ||
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fn next_term(&mut self, k: u32) { | ||
unsafe { | ||
let y2 = k*2 + 1; | ||
fn extract_digit(&self) -> int { | ||
if self.numer > self.accum {return -1;} | ||
let (q, r) = | ||
(self.numer * Context::from_int(3) + self.accum) | ||
.div_rem(&self.denom); | ||
if r + self.numer >= self.denom {return -1;} | ||
q.to_int().unwrap() | ||
} | ||
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mpz_mul_2exp(&self.tmp1, &self.numer, 1); | ||
mpz_add(&self.accum, &self.accum, &self.tmp1); | ||
mpz_mul_ui(&self.accum, &self.accum, y2); | ||
mpz_mul_ui(&self.numer, &self.numer, k); | ||
mpz_mul_ui(&self.denom, &self.denom, y2); | ||
} | ||
fn next_term(&mut self, k: int) { | ||
let y2 = Context::from_int(k * 2 + 1); | ||
self.accum = (self.accum + (self.numer << 1)) * y2; | ||
self.numer = self.numer * Context::from_int(k); | ||
self.denom = self.denom * y2; | ||
} | ||
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fn eliminate_digit(&mut self, d: u32) { | ||
unsafe { | ||
mpz_submul_ui(&self.accum, &self.denom, d); | ||
mpz_mul_ui(&self.accum, &self.accum, 10); | ||
mpz_mul_ui(&self.numer, &self.numer, 10); | ||
} | ||
fn eliminate_digit(&mut self, d: int) { | ||
let d = Context::from_int(d); | ||
let ten = Context::from_int(10); | ||
self.accum = (self.accum - self.denom * d) * ten; | ||
self.numer = self.numer * ten; | ||
} | ||
} | ||
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fn pidigits(n: u32) { | ||
unsafe { | ||
let mode = "w"; | ||
let stdout = fdopen(STDOUT_FILENO as c_int, transmute(&mode[0])); | ||
fn pidigits(n: int) { | ||
let mut k = 0; | ||
let mut context = Context::new(); | ||
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let mut d: i32; | ||
let mut i: u32 = 0, k: u32 = 0, m: u32; | ||
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let mut context = Context::new(); | ||
for i in range(1, n + 1) { | ||
let mut d; | ||
loop { | ||
loop { | ||
k += 1; | ||
context.next_term(k); | ||
d = context.extract_digit(); | ||
if d != -1 { | ||
break; | ||
} | ||
} | ||
k += 1; | ||
context.next_term(k); | ||
d = context.extract_digit(); | ||
if d != -1 {break;} | ||
} | ||
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fputc((d as c_int) + ('0' as c_int), stdout); | ||
print!("{}", d); | ||
if i % 10 == 0 {print!("\t:{}\n", i);} | ||
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i += 1; | ||
m = i % 10; | ||
if m == 0 { | ||
let res = fmt!("\t:%d\n", i as int); | ||
fputs(transmute(&res[0]), stdout); | ||
} | ||
if i >= n { | ||
break; | ||
} | ||
context.eliminate_digit(d as u32); | ||
} | ||
context.eliminate_digit(d); | ||
} | ||
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if m != 0 { | ||
m = 10 - m; | ||
while m != 0 { | ||
m -= 1; | ||
fputc(' ' as c_int, stdout); | ||
} | ||
let res = fmt!("\t:%d\n", i as int); | ||
fputs(transmute(&res[0]), stdout); | ||
} | ||
let m = n % 10; | ||
if m != 0 { | ||
for _ in range(m, 10) {print(" ");} | ||
print!("\t:{}\n", n); | ||
} | ||
} | ||
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fn main() { | ||
let n: u32 = FromStr::from_str(os::args()[1]).get(); | ||
let args = std::os::args(); | ||
let n = if args.len() < 2 { | ||
512 | ||
} else { | ||
FromStr::from_str(args[1]).unwrap() | ||
}; | ||
pidigits(n); | ||
} |