rust/src/libcore/num/num.rs
2013-04-14 01:14:02 +10:00

243 lines
7.4 KiB
Rust

// Copyright 2012-2013 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.
//! An interface for numeric types
use cmp::{Eq, Ord};
use ops::{Neg, Add, Sub, Mul, Div, Modulo};
use option::Option;
use kinds::Copy;
pub mod strconv;
pub trait IntConvertible {
fn to_int(&self) -> int;
fn from_int(n: int) -> Self;
}
pub trait Zero {
fn zero() -> Self;
}
pub trait One {
fn one() -> Self;
}
pub fn abs<T:Ord + Zero + Neg<T>>(v: T) -> T {
if v < Zero::zero() { v.neg() } else { v }
}
pub trait Round {
fn round(&self, mode: RoundMode) -> Self;
fn floor(&self) -> Self;
fn ceil(&self) -> Self;
fn fract(&self) -> Self;
}
pub enum RoundMode {
RoundDown,
RoundUp,
RoundToZero,
RoundFromZero
}
/**
* Cast from one machine scalar to another
*
* # Example
*
* ~~~
* let twenty: f32 = num::cast(0x14);
* assert!(twenty == 20f32);
* ~~~
*/
#[inline(always)]
pub fn cast<T:NumCast,U:NumCast>(n: T) -> U {
NumCast::from(n)
}
/**
* An interface for casting between machine scalars
*/
pub trait NumCast {
fn from<T:NumCast>(n: T) -> Self;
fn to_u8(&self) -> u8;
fn to_u16(&self) -> u16;
fn to_u32(&self) -> u32;
fn to_u64(&self) -> u64;
fn to_uint(&self) -> uint;
fn to_i8(&self) -> i8;
fn to_i16(&self) -> i16;
fn to_i32(&self) -> i32;
fn to_i64(&self) -> i64;
fn to_int(&self) -> int;
fn to_f32(&self) -> f32;
fn to_f64(&self) -> f64;
fn to_float(&self) -> float;
}
macro_rules! impl_num_cast(
($T:ty, $conv:ident) => (
// FIXME #4375: This enclosing module is necessary because
// of a bug with macros expanding into multiple items
pub mod $conv {
use num::NumCast;
#[cfg(notest)]
impl NumCast for $T {
#[doc = "Cast `n` to a `$T`"]
#[inline(always)]
fn from<N:NumCast>(n: N) -> $T {
// `$conv` could be generated using `concat_idents!`, but that
// macro seems to be broken at the moment
n.$conv()
}
#[inline(always)] fn to_u8(&self) -> u8 { *self as u8 }
#[inline(always)] fn to_u16(&self) -> u16 { *self as u16 }
#[inline(always)] fn to_u32(&self) -> u32 { *self as u32 }
#[inline(always)] fn to_u64(&self) -> u64 { *self as u64 }
#[inline(always)] fn to_uint(&self) -> uint { *self as uint }
#[inline(always)] fn to_i8(&self) -> i8 { *self as i8 }
#[inline(always)] fn to_i16(&self) -> i16 { *self as i16 }
#[inline(always)] fn to_i32(&self) -> i32 { *self as i32 }
#[inline(always)] fn to_i64(&self) -> i64 { *self as i64 }
#[inline(always)] fn to_int(&self) -> int { *self as int }
#[inline(always)] fn to_f32(&self) -> f32 { *self as f32 }
#[inline(always)] fn to_f64(&self) -> f64 { *self as f64 }
#[inline(always)] fn to_float(&self) -> float { *self as float }
}
}
)
)
impl_num_cast!(u8, to_u8)
impl_num_cast!(u16, to_u16)
impl_num_cast!(u32, to_u32)
impl_num_cast!(u64, to_u64)
impl_num_cast!(uint, to_uint)
impl_num_cast!(i8, to_i8)
impl_num_cast!(i16, to_i16)
impl_num_cast!(i32, to_i32)
impl_num_cast!(i64, to_i64)
impl_num_cast!(int, to_int)
impl_num_cast!(f32, to_f32)
impl_num_cast!(f64, to_f64)
impl_num_cast!(float, to_float)
pub trait ToStrRadix {
pub fn to_str_radix(&self, radix: uint) -> ~str;
}
pub trait FromStrRadix {
pub fn from_str_radix(str: &str, radix: uint) -> Option<Self>;
}
// Generic math functions:
/**
* Calculates a power to a given radix, optimized for uint `pow` and `radix`.
*
* Returns `radix^pow` as `T`.
*
* Note:
* Also returns `1` for `0^0`, despite that technically being an
* undefined number. The reason for this is twofold:
* - If code written to use this function cares about that special case, it's
* probably going to catch it before making the call.
* - If code written to use this function doesn't care about it, it's
* probably assuming that `x^0` always equals `1`.
*/
pub fn pow_with_uint<T:NumCast+One+Zero+Copy+Div<T,T>+Mul<T,T>>(
radix: uint, pow: uint) -> T {
let _0: T = Zero::zero();
let _1: T = One::one();
if pow == 0u { return _1; }
if radix == 0u { return _0; }
let mut my_pow = pow;
let mut total = _1;
let mut multiplier = cast(radix as int);
while (my_pow > 0u) {
if my_pow % 2u == 1u {
total *= multiplier;
}
my_pow /= 2u;
multiplier *= multiplier;
}
total
}
macro_rules! test_cast_20(
($_20:expr) => ({
let _20 = $_20;
assert!(20u == _20.to_uint());
assert!(20u8 == _20.to_u8());
assert!(20u16 == _20.to_u16());
assert!(20u32 == _20.to_u32());
assert!(20u64 == _20.to_u64());
assert!(20i == _20.to_int());
assert!(20i8 == _20.to_i8());
assert!(20i16 == _20.to_i16());
assert!(20i32 == _20.to_i32());
assert!(20i64 == _20.to_i64());
assert!(20f == _20.to_float());
assert!(20f32 == _20.to_f32());
assert!(20f64 == _20.to_f64());
assert!(_20 == NumCast::from(20u));
assert!(_20 == NumCast::from(20u8));
assert!(_20 == NumCast::from(20u16));
assert!(_20 == NumCast::from(20u32));
assert!(_20 == NumCast::from(20u64));
assert!(_20 == NumCast::from(20i));
assert!(_20 == NumCast::from(20i8));
assert!(_20 == NumCast::from(20i16));
assert!(_20 == NumCast::from(20i32));
assert!(_20 == NumCast::from(20i64));
assert!(_20 == NumCast::from(20f));
assert!(_20 == NumCast::from(20f32));
assert!(_20 == NumCast::from(20f64));
assert!(_20 == cast(20u));
assert!(_20 == cast(20u8));
assert!(_20 == cast(20u16));
assert!(_20 == cast(20u32));
assert!(_20 == cast(20u64));
assert!(_20 == cast(20i));
assert!(_20 == cast(20i8));
assert!(_20 == cast(20i16));
assert!(_20 == cast(20i32));
assert!(_20 == cast(20i64));
assert!(_20 == cast(20f));
assert!(_20 == cast(20f32));
assert!(_20 == cast(20f64));
})
)
#[test] fn test_u8_cast() { test_cast_20!(20u8) }
#[test] fn test_u16_cast() { test_cast_20!(20u16) }
#[test] fn test_u32_cast() { test_cast_20!(20u32) }
#[test] fn test_u64_cast() { test_cast_20!(20u64) }
#[test] fn test_uint_cast() { test_cast_20!(20u) }
#[test] fn test_i8_cast() { test_cast_20!(20i8) }
#[test] fn test_i16_cast() { test_cast_20!(20i16) }
#[test] fn test_i32_cast() { test_cast_20!(20i32) }
#[test] fn test_i64_cast() { test_cast_20!(20i64) }
#[test] fn test_int_cast() { test_cast_20!(20i) }
#[test] fn test_f32_cast() { test_cast_20!(20f32) }
#[test] fn test_f64_cast() { test_cast_20!(20f64) }
#[test] fn test_float_cast() { test_cast_20!(20f) }