Overflow semantics changed
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@ -1,5 +1,6 @@
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#![feature(op_assign_traits)]
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#![feature(associated_consts)]
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#![feature(wrapping)]
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//! Ethcore-util library
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//!
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//! ### Rust version:
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src/uint.rs
219
src/uint.rs
@ -26,6 +26,7 @@ use std::cmp::*;
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use std::ops::*;
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use std::str::FromStr;
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use std::hash::{Hash, Hasher};
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use std::num::wrapping::OverflowingOps;
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use rustc_serialize::hex::{FromHex, FromHexError};
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pub trait FromDecStr: Sized {
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@ -43,6 +44,14 @@ macro_rules! impl_map_from {
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}
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}
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macro_rules! panic_on_overflow {
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($name:expr) => {
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if $name {
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panic!("arithmetic operation overflow")
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}
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}
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}
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macro_rules! construct_uint {
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($name:ident, $n_words:expr) => (
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/// Little-endian large integer type
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@ -157,6 +166,31 @@ macro_rules! construct_uint {
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}
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$name(ret) + $name(carry)
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}
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/// Overflowing multiplication by u32
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fn overflowing_mul_u32(self, other: u32) -> ($name, bool) {
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let $name(ref arr) = self;
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let mut carry = [0u64; $n_words];
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let mut ret = [0u64; $n_words];
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let mut overflow = false;
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for i in 0..$n_words {
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let upper = other as u64 * (arr[i] >> 32);
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let lower = other as u64 * (arr[i] & 0xFFFFFFFF);
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ret[i] = lower.wrapping_add(upper << 32);
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if i < $n_words - 1 {
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carry[i + 1] = upper >> 32;
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if ret[i] < lower {
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carry[i + 1] += 1;
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}
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} else if (upper >> 32) > 0 || ret[i] < lower {
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overflow = true
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}
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}
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let (result, add_overflow) = $name(ret).overflowing_add($name(carry));
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(result, add_overflow || overflow)
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}
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}
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impl From<u64> for $name {
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@ -214,6 +248,77 @@ macro_rules! construct_uint {
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}
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}
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impl OverflowingOps for $name {
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fn overflowing_add(self, other: $name) -> ($name, bool) {
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let $name(ref me) = self;
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let $name(ref you) = other;
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let mut ret = [0u64; $n_words];
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let mut carry = [0u64; $n_words];
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let mut b_carry = false;
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let mut overflow = false;
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for i in 0..$n_words {
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ret[i] = me[i].wrapping_add(you[i]);
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if ret[i] < me[i] {
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if i < $n_words - 1 {
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carry[i + 1] = 1;
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b_carry = true;
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} else {
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overflow = true
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}
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}
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}
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if b_carry {
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let (ret, add_overflow) = $name(ret).overflowing_add($name(carry));
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(ret, add_overflow || overflow)
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} else {
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($name(ret), overflow)
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}
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}
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fn overflowing_sub(self, other: $name) -> ($name, bool) {
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let (res, _overflow) = (!other).overflowing_add(From::from(1u64));
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let (res, _overflow) = self.overflowing_add(res);
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(res, self < other)
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}
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fn overflowing_mul(self, other: $name) -> ($name, bool) {
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let mut res = $name::from(0u64);
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let mut overflow = false;
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// TODO: be more efficient about this
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for i in 0..(2 * $n_words) {
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let (v, mul_overflow) = self.overflowing_mul_u32((other >> (32 * i)).low_u32());
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let (new_res, add_overflow) = res.overflowing_add(v << (32 * i));
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res = new_res;
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overflow = overflow || mul_overflow || add_overflow;
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}
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(res, overflow)
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}
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fn overflowing_div(self, other: $name) -> ($name, bool) {
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(self / other, false)
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}
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fn overflowing_rem(self, other: $name) -> ($name, bool) {
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(self % other, false)
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}
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fn overflowing_neg(self) -> ($name, bool) {
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(!self, true)
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}
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fn overflowing_shl(self, _shift32: u32) -> ($name, bool) {
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// TODO [todr] not used for now
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unimplemented!();
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}
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fn overflowing_shr(self, _shift32: u32) -> ($name, bool) {
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// TODO [todr] not used for now
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unimplemented!();
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}
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}
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impl Add<$name> for $name {
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type Output = $name;
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@ -224,11 +329,15 @@ macro_rules! construct_uint {
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let mut carry = [0u64; $n_words];
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let mut b_carry = false;
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for i in 0..$n_words {
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if i < $n_words - 1 {
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ret[i] = me[i].wrapping_add(you[i]);
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if i < $n_words - 1 && ret[i] < me[i] {
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if ret[i] < me[i] {
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carry[i + 1] = 1;
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b_carry = true;
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}
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} else {
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ret[i] = me[i] + you[i];
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}
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}
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if b_carry { $name(ret) + $name(carry) } else { $name(ret) }
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}
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@ -239,7 +348,10 @@ macro_rules! construct_uint {
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#[inline]
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fn sub(self, other: $name) -> $name {
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self + !other + From::from(1u64)
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panic_on_overflow!(self < other);
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let (res, _overflow) = (!other).overflowing_add(From::from(1u64));
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let (res, _overflow) = self.overflowing_add(res);
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res
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}
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}
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@ -281,7 +393,8 @@ macro_rules! construct_uint {
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loop {
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if sub_copy >= shift_copy {
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ret[shift / 64] |= 1 << (shift % 64);
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sub_copy = sub_copy - shift_copy;
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let (copy, _overflow) = sub_copy.overflowing_sub(shift_copy);
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sub_copy = copy
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}
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shift_copy = shift_copy >> 1;
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if shift == 0 { break; }
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@ -370,7 +483,7 @@ macro_rules! construct_uint {
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let bit_shift = shift % 64;
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for i in 0..$n_words {
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// Shift
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if bit_shift < 64 && i + word_shift < $n_words {
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if i + word_shift < $n_words {
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ret[i + word_shift] += original[i] << bit_shift;
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}
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// Carry
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@ -567,6 +680,7 @@ mod tests {
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use uint::U512;
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use uint::FromDecStr;
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use std::str::FromStr;
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use std::num::wrapping::OverflowingOps;
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#[test]
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pub fn uint256_from() {
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@ -692,7 +806,7 @@ mod tests {
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let incr = shr + U256::from(1u64);
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assert_eq!(incr, U256([0x7DDE000000000001u64, 0x0001BD5B7DDFBD5B, 0, 0]));
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// Subtraction
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let sub = incr - init;
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let (sub, _of) = incr.overflowing_sub(init);
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assert_eq!(sub, U256([0x9F30411021524112u64, 0x0001BD5B7DDFBD5A, 0, 0]));
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// Multiplication
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let mult = sub.mul_u32(300);
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@ -740,7 +854,7 @@ mod tests {
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}
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#[test]
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pub fn uint256_mul() {
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pub fn uint256_mul1() {
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assert_eq!(U256::from(1u64) * U256::from(10u64), U256::from(10u64));
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}
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@ -756,11 +870,21 @@ mod tests {
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pub fn uint128_add_overflow() {
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assert_eq!(
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U128::from_str("ffffffffffffffffffffffffffffffff").unwrap()
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+ U128::from_str("ffffffffffffffffffffffffffffffff").unwrap(),
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U128::from_str("fffffffffffffffffffffffffffffffe").unwrap()
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.overflowing_add(
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U128::from_str("ffffffffffffffffffffffffffffffff").unwrap()
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),
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(U128::from_str("fffffffffffffffffffffffffffffffe").unwrap(), true)
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);
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}
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#[test]
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#[should_panic]
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pub fn uint128_add_overflow_panic() {
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U128::from_str("ffffffffffffffffffffffffffffffff").unwrap()
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+
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U128::from_str("ffffffffffffffffffffffffffffffff").unwrap();
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}
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#[test]
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pub fn uint128_mul() {
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assert_eq!(
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@ -782,14 +906,85 @@ mod tests {
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pub fn uint256_mul_overflow() {
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assert_eq!(
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U256::from_str("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()
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*
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U256::from_str("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap(),
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U256::from_str("1").unwrap()
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.overflowing_mul(
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U256::from_str("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()
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),
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(U256::from_str("1").unwrap(), true)
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);
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}
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#[test]
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pub fn uint256_mul_overflow2() {
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#[should_panic]
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pub fn uint256_mul_overflow_panic() {
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U256::from_str("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()
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*
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U256::from_str("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap();
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}
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#[test]
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pub fn uint256_sub_overflow() {
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assert_eq!(
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U256::from_str("0").unwrap()
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.overflowing_sub(
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U256::from_str("1").unwrap()
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),
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(U256::from_str("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap(), true)
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);
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}
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#[test]
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#[should_panic]
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pub fn uint256_sub_overflow_panic() {
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U256::from_str("0").unwrap()
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-
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U256::from_str("1").unwrap();
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}
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#[ignore]
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#[test]
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pub fn uint256_shl_overflow() {
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assert_eq!(
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U256::from_str("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()
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.overflowing_shl(4),
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(U256::from_str("fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff0").unwrap(), true)
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);
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}
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#[ignore]
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#[test]
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#[should_panic]
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pub fn uint256_shl_overflow2() {
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assert_eq!(
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U256::from_str("0fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()
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.overflowing_shl(4),
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(U256::from_str("fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff0").unwrap(), false)
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);
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}
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#[ignore]
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#[test]
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pub fn uint256_shr_overflow() {
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assert_eq!(
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U256::from_str("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()
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.overflowing_shr(4),
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(U256::from_str("0fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap(), true)
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);
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}
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#[ignore]
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#[test]
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pub fn uint256_shr_overflow2() {
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assert_eq!(
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U256::from_str("fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff0").unwrap()
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.overflowing_shr(4),
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(U256::from_str("0fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap(), false)
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);
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}
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#[test]
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pub fn uint256_mul() {
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assert_eq!(
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U256::from_str("7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()
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*
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