53 lines
1.2 KiB
Rust
53 lines
1.2 KiB
Rust
use int::LargeInt;
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trait Sub: LargeInt {
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fn sub(self, other: Self) -> Self {
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let neg_other = (!other).wrapping_add(Self::ONE);
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self.wrapping_add(neg_other)
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}
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}
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impl Sub for i128 {}
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impl Sub for u128 {}
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trait Subo: Sub {
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fn subo(self, other: Self, overflow: &mut i32) -> Self {
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*overflow = 0;
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let result = Sub::sub(self, other);
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if other >= Self::ZERO {
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if result > self {
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*overflow = 1;
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}
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} else {
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if result <= self {
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*overflow = 1;
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}
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}
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result
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}
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}
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impl Subo for i128 {}
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impl Subo for u128 {}
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#[cfg_attr(not(stage0), lang = "i128_sub")]
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pub fn rust_i128_sub(a: i128, b: i128) -> i128 {
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rust_u128_sub(a as _, b as _) as _
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}
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#[cfg_attr(not(stage0), lang = "i128_subo")]
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pub fn rust_i128_subo(a: i128, b: i128) -> (i128, bool) {
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let mut oflow = 0;
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let r = a.subo(b, &mut oflow);
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(r, oflow != 0)
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}
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#[cfg_attr(not(stage0), lang = "u128_sub")]
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pub fn rust_u128_sub(a: u128, b: u128) -> u128 {
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a.sub(b)
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}
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#[cfg_attr(not(stage0), lang = "u128_subo")]
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pub fn rust_u128_subo(a: u128, b: u128) -> (u128, bool) {
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let mut oflow = 0;
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let r = a.subo(b, &mut oflow);
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(r, oflow != 0)
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}
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