// Copyright 2012 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.

use T = self::inst::T;
use T_SIGNED = self::inst::T_SIGNED;

use to_str::ToStr;
use from_str::FromStr;
use num::{ToStrRadix, FromStrRadix};
use num::strconv;
use num;
use option::Option;
use prelude::*;

#[cfg(notest)] use cmp::{Eq, Ord};

pub use cmp::{min, max};

pub static bits : uint = inst::bits;
pub static bytes : uint = (inst::bits / 8);

pub static min_value: T = 0 as T;
pub static max_value: T = 0 as T - 1 as T;

#[inline(always)]
pub fn add(x: T, y: T) -> T { x + y }
#[inline(always)]
pub fn sub(x: T, y: T) -> T { x - y }
#[inline(always)]
pub fn mul(x: T, y: T) -> T { x * y }
#[inline(always)]
pub fn div(x: T, y: T) -> T { x / y }
#[inline(always)]
pub fn rem(x: T, y: T) -> T { x % y }

#[inline(always)]
pub fn lt(x: T, y: T) -> bool { x < y }
#[inline(always)]
pub fn le(x: T, y: T) -> bool { x <= y }
#[inline(always)]
pub fn eq(x: T, y: T) -> bool { x == y }
#[inline(always)]
pub fn ne(x: T, y: T) -> bool { x != y }
#[inline(always)]
pub fn ge(x: T, y: T) -> bool { x >= y }
#[inline(always)]
pub fn gt(x: T, y: T) -> bool { x > y }

#[inline(always)]
pub fn is_positive(x: T) -> bool { x > 0 as T }
#[inline(always)]
pub fn is_negative(x: T) -> bool { x < 0 as T }
#[inline(always)]
pub fn is_nonpositive(x: T) -> bool { x <= 0 as T }
#[inline(always)]
pub fn is_nonnegative(x: T) -> bool { x >= 0 as T }

#[inline(always)]
/**
 * Iterate over the range [`start`,`start`+`step`..`stop`)
 *
 */
pub fn range_step(start: T,
                       stop: T,
                       step: T_SIGNED,
                       it: &fn(T) -> bool) {
    let mut i = start;
    if step == 0 {
        fail!(~"range_step called with step == 0");
    }
    if step >= 0 {
        while i < stop {
            if !it(i) { break }
            i += step as T;
        }
    }
    else {
        while i > stop {
            if !it(i) { break }
            i -= -step as T;
        }
    }
}

#[inline(always)]
/// Iterate over the range [`lo`..`hi`)
pub fn range(lo: T, hi: T, it: &fn(T) -> bool) {
    range_step(lo, hi, 1 as T_SIGNED, it);
}

#[inline(always)]
/// Iterate over the range [`hi`..`lo`)
pub fn range_rev(hi: T, lo: T, it: &fn(T) -> bool) {
    range_step(hi, lo, -1 as T_SIGNED, it);
}

/// Computes the bitwise complement
#[inline(always)]
pub fn compl(i: T) -> T {
    max_value ^ i
}

#[cfg(notest)]
impl Ord for T {
    #[inline(always)]
    fn lt(&self, other: &T) -> bool { (*self) < (*other) }
    #[inline(always)]
    fn le(&self, other: &T) -> bool { (*self) <= (*other) }
    #[inline(always)]
    fn ge(&self, other: &T) -> bool { (*self) >= (*other) }
    #[inline(always)]
    fn gt(&self, other: &T) -> bool { (*self) > (*other) }
}

#[cfg(notest)]
impl Eq for T {
    #[inline(always)]
    fn eq(&self, other: &T) -> bool { return (*self) == (*other); }
    #[inline(always)]
    fn ne(&self, other: &T) -> bool { return (*self) != (*other); }
}

impl num::Zero for T {
    #[inline(always)]
    fn zero() -> T { 0 }
}

impl num::One for T {
    #[inline(always)]
    fn one() -> T { 1 }
}

#[cfg(notest)]
impl ops::Add<T,T> for T {
    fn add(&self, other: &T) -> T { *self + *other }
}
#[cfg(notest)]
impl ops::Sub<T,T> for T {
    fn sub(&self, other: &T) -> T { *self - *other }
}
#[cfg(notest)]
impl ops::Mul<T,T> for T {
    fn mul(&self, other: &T) -> T { *self * *other }
}
#[cfg(notest)]
impl ops::Div<T,T> for T {
    fn div(&self, other: &T) -> T { *self / *other }
}
#[cfg(notest)]
impl ops::Modulo<T,T> for T {
    fn modulo(&self, other: &T) -> T { *self % *other }
}
#[cfg(notest)]
impl ops::Neg<T> for T {
    fn neg(&self) -> T { -*self }
}

// String conversion functions and impl str -> num

/// Parse a string as a number in base 10.
#[inline(always)]
pub fn from_str(s: &str) -> Option<T> {
    strconv::from_str_common(s, 10u, false, false, false,
                             strconv::ExpNone, false)
}

/// Parse a string as a number in the given base.
#[inline(always)]
pub fn from_str_radix(s: &str, radix: uint) -> Option<T> {
    strconv::from_str_common(s, radix, false, false, false,
                             strconv::ExpNone, false)
}

/// Parse a byte slice as a number in the given base.
#[inline(always)]
pub fn parse_bytes(buf: &[u8], radix: uint) -> Option<T> {
    strconv::from_str_bytes_common(buf, radix, false, false, false,
                                   strconv::ExpNone, false)
}

impl FromStr for T {
    #[inline(always)]
    fn from_str(s: &str) -> Option<T> {
        from_str(s)
    }
}

impl FromStrRadix for T {
    #[inline(always)]
    fn from_str_radix(s: &str, radix: uint) -> Option<T> {
        from_str_radix(s, radix)
    }
}

// String conversion functions and impl num -> str

/// Convert to a string as a byte slice in a given base.
#[inline(always)]
pub fn to_str_bytes<U>(n: T, radix: uint, f: &fn(v: &[u8]) -> U) -> U {
    let (buf, _) = strconv::to_str_bytes_common(&n, radix, false,
                            strconv::SignNeg, strconv::DigAll);
    f(buf)
}

/// Convert to a string in base 10.
#[inline(always)]
pub fn to_str(num: T) -> ~str {
    let (buf, _) = strconv::to_str_common(&num, 10u, false,
                            strconv::SignNeg, strconv::DigAll);
    buf
}

/// Convert to a string in a given base.
#[inline(always)]
pub fn to_str_radix(num: T, radix: uint) -> ~str {
    let (buf, _) = strconv::to_str_common(&num, radix, false,
                            strconv::SignNeg, strconv::DigAll);
    buf
}

impl ToStr for T {
    #[inline(always)]
    fn to_str(&self) -> ~str {
        to_str(*self)
    }
}

impl ToStrRadix for T {
    #[inline(always)]
    fn to_str_radix(&self, radix: uint) -> ~str {
        to_str_radix(*self, radix)
    }
}

#[test]
pub fn test_to_str() {
    assert!(to_str_radix(0 as T, 10u) == ~"0");
    assert!(to_str_radix(1 as T, 10u) == ~"1");
    assert!(to_str_radix(2 as T, 10u) == ~"2");
    assert!(to_str_radix(11 as T, 10u) == ~"11");
    assert!(to_str_radix(11 as T, 16u) == ~"b");
    assert!(to_str_radix(255 as T, 16u) == ~"ff");
    assert!(to_str_radix(0xff as T, 10u) == ~"255");
}

#[test]
pub fn test_from_str() {
    assert!(from_str(~"0") == Some(0u as T));
    assert!(from_str(~"3") == Some(3u as T));
    assert!(from_str(~"10") == Some(10u as T));
    assert!(u32::from_str(~"123456789") == Some(123456789 as u32));
    assert!(from_str(~"00100") == Some(100u as T));

    assert!(from_str(~"").is_none());
    assert!(from_str(~" ").is_none());
    assert!(from_str(~"x").is_none());
}

#[test]
pub fn test_parse_bytes() {
    use str::to_bytes;
    assert!(parse_bytes(to_bytes(~"123"), 10u) == Some(123u as T));
    assert!(parse_bytes(to_bytes(~"1001"), 2u) == Some(9u as T));
    assert!(parse_bytes(to_bytes(~"123"), 8u) == Some(83u as T));
    assert!(u16::parse_bytes(to_bytes(~"123"), 16u) ==
                 Some(291u as u16));
    assert!(u16::parse_bytes(to_bytes(~"ffff"), 16u) ==
                 Some(65535u as u16));
    assert!(parse_bytes(to_bytes(~"z"), 36u) == Some(35u as T));

    assert!(parse_bytes(to_bytes(~"Z"), 10u).is_none());
    assert!(parse_bytes(to_bytes(~"_"), 2u).is_none());
}

#[test]
fn test_uint_to_str_overflow() {
    let mut u8_val: u8 = 255_u8;
    assert!((u8::to_str(u8_val) == ~"255"));

    u8_val += 1 as u8;
    assert!((u8::to_str(u8_val) == ~"0"));

    let mut u16_val: u16 = 65_535_u16;
    assert!((u16::to_str(u16_val) == ~"65535"));

    u16_val += 1 as u16;
    assert!((u16::to_str(u16_val) == ~"0"));

    let mut u32_val: u32 = 4_294_967_295_u32;
    assert!((u32::to_str(u32_val) == ~"4294967295"));

    u32_val += 1 as u32;
    assert!((u32::to_str(u32_val) == ~"0"));

    let mut u64_val: u64 = 18_446_744_073_709_551_615_u64;
    assert!((u64::to_str(u64_val) == ~"18446744073709551615"));

    u64_val += 1 as u64;
    assert!((u64::to_str(u64_val) == ~"0"));
}

#[test]
fn test_uint_from_str_overflow() {
    let mut u8_val: u8 = 255_u8;
    assert!((u8::from_str(~"255") == Some(u8_val)));
    assert!((u8::from_str(~"256").is_none()));

    u8_val += 1 as u8;
    assert!((u8::from_str(~"0") == Some(u8_val)));
    assert!((u8::from_str(~"-1").is_none()));

    let mut u16_val: u16 = 65_535_u16;
    assert!((u16::from_str(~"65535") == Some(u16_val)));
    assert!((u16::from_str(~"65536").is_none()));

    u16_val += 1 as u16;
    assert!((u16::from_str(~"0") == Some(u16_val)));
    assert!((u16::from_str(~"-1").is_none()));

    let mut u32_val: u32 = 4_294_967_295_u32;
    assert!((u32::from_str(~"4294967295") == Some(u32_val)));
    assert!((u32::from_str(~"4294967296").is_none()));

    u32_val += 1 as u32;
    assert!((u32::from_str(~"0") == Some(u32_val)));
    assert!((u32::from_str(~"-1").is_none()));

    let mut u64_val: u64 = 18_446_744_073_709_551_615_u64;
    assert!((u64::from_str(~"18446744073709551615") == Some(u64_val)));
    assert!((u64::from_str(~"18446744073709551616").is_none()));

    u64_val += 1 as u64;
    assert!((u64::from_str(~"0") == Some(u64_val)));
    assert!((u64::from_str(~"-1").is_none()));
}

#[test]
#[should_fail]
#[ignore(cfg(windows))]
pub fn to_str_radix1() {
    uint::to_str_radix(100u, 1u);
}

#[test]
#[should_fail]
#[ignore(cfg(windows))]
pub fn to_str_radix37() {
    uint::to_str_radix(100u, 37u);
}

#[test]
pub fn test_ranges() {
    let mut l = ~[];

    for range(0,3) |i| {
        l.push(i);
    }
    for range_rev(13,10) |i| {
        l.push(i);
    }
    for range_step(20,26,2) |i| {
        l.push(i);
    }
    for range_step(36,30,-2) |i| {
        l.push(i);
    }

    assert!(l == ~[0,1,2,
                        13,12,11,
                        20,22,24,
                        36,34,32]);

    // None of the `fail`s should execute.
    for range(0,0) |_i| {
        fail!(~"unreachable");
    }
    for range_rev(0,0) |_i| {
        fail!(~"unreachable");
    }
    for range_step(10,0,1) |_i| {
        fail!(~"unreachable");
    }
    for range_step(0,1,-10) |_i| {
        fail!(~"unreachable");
    }
}

#[test]
pub fn test_num() {
    let ten: T = num::cast(10);
    let two: T = num::cast(2);

    assert!((ten.add(&two)    == num::cast(12)));
    assert!((ten.sub(&two)    == num::cast(8)));
    assert!((ten.mul(&two)    == num::cast(20)));
    assert!((ten.div(&two)    == num::cast(5)));
    assert!((ten.modulo(&two) == num::cast(0)));
}

#[test]
#[should_fail]
#[ignore(cfg(windows))]
fn test_range_step_zero_step_up() {
    for range_step(0,10,0) |_i| {}
}
#[test]
#[should_fail]
#[ignore(cfg(windows))]
fn test_range_step_zero_step_down() {
    for range_step(0,-10,0) |_i| {}
}