Implement Bigint from implementation for integer types larger than the pointer type
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@ -14,7 +14,7 @@ use alloc::string::*;
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use std::prelude::v1::*;
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use core::cmp::{Ordering, PartialOrd, PartialEq};
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use core::convert::TryInto;
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use core::convert::*;
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use core::mem::replace;
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use core::ops::{
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Add, AddAssign, Div, DivAssign, Mul, MulAssign, Neg, Not, Rem, RemAssign, Sub, SubAssign,
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@ -465,7 +465,36 @@ macro_rules! impl_from_larger {
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impl From<$s> for BigInt {
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/// Create a `BigInt` from a signed integer primitive
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fn from(n: $s) -> Self {
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todo!();
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use core::usize::MAX;
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let target_radix: $s = (MAX as $s) + 1;
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let sign = if n < 0 { Sign::Negative } else { Sign::Positive };
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let n = n.abs();
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let mut quotient = n / target_radix;
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let mut rem = n % target_radix;
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if quotient == 0 {
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Self::from(rem as usize)
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} else {
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let mut inner: Vec<usize> = Vec::new();
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inner.push(rem as usize);
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loop {
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rem = quotient % target_radix;
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quotient = quotient / target_radix;
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inner.push(rem as usize);
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if (quotient == 0) {
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break;
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}
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}
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BigInt {
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inner,
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sign,
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}
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}
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}
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}
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@ -473,14 +502,32 @@ macro_rules! impl_from_larger {
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/// Create a `BigInt` from an unsigned integer primitive
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fn from(n: $u) -> Self {
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use core::usize::MAX;
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let target_radix: $u = (MAX as $u) + 1;
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let base_usize_value = n / MAX as $u;
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let rem = n % MAX as $u;
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let mut quotient = n / target_radix;
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let mut rem = n % target_radix;
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if base_usize_value == 0 {
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if quotient == 0 {
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Self::from(rem as usize)
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} else {
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todo!();
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let mut inner: Vec<usize> = Vec::new();
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inner.push(rem as usize);
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loop {
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rem = quotient % target_radix;
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quotient = quotient / target_radix;
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inner.push(rem as usize);
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if (quotient == 0) {
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break;
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}
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}
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BigInt {
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inner,
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sign: Sign::Positive
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}
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}
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}
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}
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@ -536,6 +583,9 @@ impl_ord_literal!(i8,u8,i16,u16,i32,u32,i64,u64,i128,u128);
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mod tests {
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use super::*;
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const RADIX: u128 = core::usize::MAX as u128 + 1;
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const I_RADIX: i128 = core::usize::MAX as i128 + 1;
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#[test]
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fn sanity_checks() {
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let int = BigInt::from(45u8);
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@ -555,14 +605,14 @@ mod tests {
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#[test]
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fn test_trim_zeros() {
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let mut lotsoftrailing = BigInt {
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let mut lots_of_leading = BigInt {
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inner: vec![1, 0, 0, 0, 0, 0, 0, 0, 0],
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sign: Positive,
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};
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lotsoftrailing.trim_zeros();
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lots_of_leading.trim_zeros();
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assert_eq!(BigInt::from(1), lotsoftrailing);
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assert_eq!(BigInt::from(1), lots_of_leading);
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}
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#[test]
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@ -815,15 +865,23 @@ mod tests {
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}
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#[test]
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#[should_panic]
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fn test_from_large_unsigned() {
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BigInt::from(core::u128::MAX);
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let big_num: u128 = 9*RADIX + 8;
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let res = BigInt::from(big_num);
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assert_eq!(res.sign, Sign::Positive, "{:#?}", res);
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assert_eq!(res.inner[0], 8usize, "{:#?}", res);
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assert_eq!(res.inner[1], 9usize, "{:#?}", res);
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}
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#[test]
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#[should_panic]
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fn test_from_large_signed() {
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BigInt::from(128i128);
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let big_num: i128 = 2*I_RADIX + 3;
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let res = BigInt::from(-big_num);
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assert_eq!(res.sign, Sign::Negative, "{:#?}", res);
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assert_eq!(res.inner[0], 3usize, "{:#?}", res);
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assert_eq!(res.inner[1], 2usize, "{:#?}", res);
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}
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#[test]
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