bigdecimal/lib.rs
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// Copyright 2016 Adam Sunderland
// 2016-2023 Andrew Kubera
// 2017 Ruben De Smet
// See the COPYRIGHT file at the top-level directory of this
// distribution.
//
// 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.
//! A Big Decimal
//!
//! `BigDecimal` allows storing any real number to arbitrary precision; which
//! avoids common floating point errors (such as 0.1 + 0.2 ≠0.3) at the
//! cost of complexity.
//!
//! Internally, `BigDecimal` uses a `BigInt` object, paired with a 64-bit
//! integer which determines the position of the decimal point. Therefore,
//! the precision *is not* actually arbitrary, but limited to 2<sup>63</sup>
//! decimal places.
//!
//! Common numerical operations are overloaded, so we can treat them
//! the same way we treat other numbers.
//!
//! It is not recommended to convert a floating point number to a decimal
//! directly, as the floating point representation may be unexpected.
//!
//! # Example
//!
//! ```
//! use bigdecimal::BigDecimal;
//! use std::str::FromStr;
//!
//! let input = "0.8";
//! let dec = BigDecimal::from_str(&input).unwrap();
//! let float = f32::from_str(&input).unwrap();
//!
//! println!("Input ({}) with 10 decimals: {} vs {})", input, dec, float);
//! ```
#![cfg_attr(not(feature = "std"), no_std)]
#![allow(clippy::style)]
#![allow(clippy::excessive_precision)]
#![allow(clippy::unreadable_literal)]
#![allow(clippy::needless_return)]
#![allow(clippy::suspicious_arithmetic_impl)]
#![allow(clippy::suspicious_op_assign_impl)]
#![allow(clippy::redundant_field_names)]
#![allow(clippy::approx_constant)]
#![cfg_attr(test, allow(clippy::useless_vec))]
#![allow(unused_imports)]
pub extern crate num_bigint;
pub extern crate num_traits;
extern crate num_integer;
#[cfg(test)]
extern crate paste;
#[cfg(feature = "serde")]
extern crate serde as serde_crate;
#[cfg(all(test, any(feature = "serde", feature = "serde_json")))]
extern crate serde_test;
#[cfg(all(test, feature = "serde_json"))]
extern crate serde_json;
#[cfg(feature = "std")]
include!("./with_std.rs");
#[cfg(not(feature = "std"))]
include!("./without_std.rs");
// make available some standard items
use self::stdlib::cmp::{self, Ordering};
use self::stdlib::convert::TryFrom;
use self::stdlib::default::Default;
use self::stdlib::hash::{Hash, Hasher};
use self::stdlib::num::{ParseFloatError, ParseIntError};
use self::stdlib::ops::{
Add, AddAssign, Div, DivAssign, Mul, MulAssign, Neg, Sub, SubAssign, Rem, RemAssign,
};
use self::stdlib::iter::Sum;
use self::stdlib::str::FromStr;
use self::stdlib::string::{String, ToString};
use self::stdlib::fmt;
use self::stdlib::Vec;
use num_bigint::{BigInt, BigUint, ParseBigIntError, Sign};
use num_integer::Integer as IntegerTrait;
pub use num_traits::{FromPrimitive, Num, One, Pow, Signed, ToPrimitive, Zero};
use stdlib::f64::consts::LOG2_10;
// const DEFAULT_PRECISION: u64 = ${RUST_BIGDECIMAL_DEFAULT_PRECISION} or 100;
include!(concat!(env!("OUT_DIR"), "/default_precision.rs"));
#[macro_use]
mod macros;
// "low level" functions
mod arithmetic;
// From<T>, To<T>, TryFrom<T> impls
mod impl_convert;
mod impl_trait_from_str;
// Add<T>, Sub<T>, etc...
mod impl_ops;
mod impl_ops_add;
mod impl_ops_sub;
mod impl_ops_mul;
mod impl_ops_div;
mod impl_ops_rem;
// PartialEq
mod impl_cmp;
// Implementations of num_traits
mod impl_num;
// Implementations of std::fmt traits and stringificaiton routines
mod impl_fmt;
// Implementations for deserializations and serializations
#[cfg(any(feature = "serde", feature="serde_json"))]
pub mod impl_serde;
/// re-export serde-json derive modules
#[cfg(feature = "serde_json")]
pub mod serde {
/// Parse JSON number directly to BigDecimal
pub use impl_serde::arbitrary_precision as json_num;
/// Parse JSON (number | null) directly to Option<BigDecimal>
pub use impl_serde::arbitrary_precision_option as json_num_option;
}
// construct BigDecimals from strings and floats
mod parsing;
// Routines for rounding
pub mod rounding;
pub use rounding::RoundingMode;
// Mathematical context
mod context;
pub use context::Context;
use arithmetic::{
ten_to_the,
ten_to_the_uint,
ten_to_the_u64,
diff,
diff_usize,
count_decimal_digits,
count_decimal_digits_uint,
};
/// Internal function used for rounding
///
/// returns 1 if most significant digit is >= 5, otherwise 0
///
/// This is used after dividing a number by a power of ten and
/// rounding the last digit.
///
#[inline(always)]
fn get_rounding_term(num: &BigInt) -> u8 {
if num.is_zero() {
return 0;
}
let digits = (num.bits() as f64 / LOG2_10) as u64;
let mut n = ten_to_the(digits);
// loop-method
loop {
if *num < n {
return 1;
}
n *= 5;
if *num < n {
return 0;
}
n *= 2;
}
// string-method
// let s = format!("{}", num);
// let high_digit = u8::from_str(&s[0..1]).unwrap();
// if high_digit < 5 { 0 } else { 1 }
}
/// A big decimal type.
///
#[derive(Clone, Eq)]
pub struct BigDecimal {
int_val: BigInt,
// A positive scale means a negative power of 10
scale: i64,
}
#[cfg(not(feature = "std"))]
// f64::exp2 is only available in std, we have to use an external crate like libm
fn exp2(x: f64) -> f64 {
libm::exp2(x)
}
#[cfg(feature = "std")]
fn exp2(x: f64) -> f64 {
x.exp2()
}
impl BigDecimal {
/// Creates and initializes a `BigDecimal`.
///
/// The more explicit method `from_bigint` should be preferred, as new
/// may change in the future.
///
#[inline]
pub fn new(digits: BigInt, scale: i64) -> BigDecimal {
BigDecimal::from_bigint(digits, scale)
}
/// Construct BigDecimal from BigInt and a scale
pub fn from_bigint(digits: BigInt, scale: i64) -> BigDecimal {
BigDecimal {
int_val: digits,
scale: scale,
}
}
/// Construct positive BigDecimal from BigUint and a scale
pub fn from_biguint(digits: BigUint, scale: i64) -> BigDecimal {
let n = BigInt::from_biguint(Sign::Plus, digits);
BigDecimal::from_bigint(n, scale)
}
/// Make a BigDecimalRef of this value
pub fn to_ref(&self) -> BigDecimalRef<'_> {
// search for "From<&'a BigDecimal> for BigDecimalRef<'a>"
self.into()
}
/// Returns the scale of the BigDecimal, the total number of
/// digits to the right of the decimal point (including insignificant
/// leading zeros)
///
/// # Examples
///
/// ```
/// use bigdecimal::BigDecimal;
/// use std::str::FromStr;
///
/// let a = BigDecimal::from(12345); // No fractional part
/// let b = BigDecimal::from_str("123.45").unwrap(); // Fractional part
/// let c = BigDecimal::from_str("0.0000012345").unwrap(); // Completely fractional part
/// let d = BigDecimal::from_str("5e9").unwrap(); // Negative-fractional part
///
/// assert_eq!(a.fractional_digit_count(), 0);
/// assert_eq!(b.fractional_digit_count(), 2);
/// assert_eq!(c.fractional_digit_count(), 10);
/// assert_eq!(d.fractional_digit_count(), -9);
/// ```
#[inline]
pub fn fractional_digit_count(&self) -> i64 {
self.scale
}
/// Creates and initializes a `BigDecimal`.
///
/// Decodes using `str::from_utf8` and forwards to `BigDecimal::from_str_radix`.
/// Only base-10 is supported.
///
/// # Examples
///
/// ```
/// use bigdecimal::{BigDecimal, Zero};
///
/// assert_eq!(BigDecimal::parse_bytes(b"0", 10).unwrap(), BigDecimal::zero());
/// assert_eq!(BigDecimal::parse_bytes(b"13", 10).unwrap(), BigDecimal::from(13));
/// ```
#[inline]
pub fn parse_bytes(buf: &[u8], radix: u32) -> Option<BigDecimal> {
stdlib::str::from_utf8(buf)
.ok()
.and_then(|s| BigDecimal::from_str_radix(s, radix).ok())
}
/// Return a new BigDecimal object equivalent to self, with internal
/// scaling set to the number specified.
/// If the new_scale is lower than the current value (indicating a larger
/// power of 10), digits will be dropped (as precision is lower)
///
#[inline]
pub fn with_scale(&self, new_scale: i64) -> BigDecimal {
if self.int_val.is_zero() {
return BigDecimal::new(BigInt::zero(), new_scale);
}
match new_scale.cmp(&self.scale) {
Ordering::Greater => {
let scale_diff = new_scale - self.scale;
let int_val = &self.int_val * ten_to_the(scale_diff as u64);
BigDecimal::new(int_val, new_scale)
}
Ordering::Less => {
let scale_diff = self.scale - new_scale;
let int_val = &self.int_val / ten_to_the(scale_diff as u64);
BigDecimal::new(int_val, new_scale)
}
Ordering::Equal => self.clone(),
}
}
/// Return a new BigDecimal after shortening the digits and rounding
///
/// ```
/// # use bigdecimal::*;
///
/// let n: BigDecimal = "129.41675".parse().unwrap();
///
/// assert_eq!(n.with_scale_round(2, RoundingMode::Up), "129.42".parse().unwrap());
/// assert_eq!(n.with_scale_round(-1, RoundingMode::Down), "120".parse().unwrap());
/// assert_eq!(n.with_scale_round(4, RoundingMode::HalfEven), "129.4168".parse().unwrap());
/// ```
pub fn with_scale_round(&self, new_scale: i64, mode: RoundingMode) -> BigDecimal {
use stdlib::cmp::Ordering::*;
if self.int_val.is_zero() {
return BigDecimal::new(BigInt::zero(), new_scale);
}
match new_scale.cmp(&self.scale) {
Ordering::Equal => {
self.clone()
}
Ordering::Greater => {
// increase number of zeros
let scale_diff = new_scale - self.scale;
let int_val = &self.int_val * ten_to_the(scale_diff as u64);
BigDecimal::new(int_val, new_scale)
}
Ordering::Less => {
let (sign, mut digits) = self.int_val.to_radix_le(10);
let digit_count = digits.len();
let int_digit_count = digit_count as i64 - self.scale;
let rounded_int = match int_digit_count.cmp(&-new_scale) {
Equal => {
let (&last_digit, remaining) = digits.split_last().unwrap();
let trailing_zeros = remaining.iter().all(Zero::is_zero);
let rounded_digit = mode.round_pair(sign, (0, last_digit), trailing_zeros);
BigInt::new(sign, vec![rounded_digit as u32])
}
Less => {
debug_assert!(!digits.iter().all(Zero::is_zero));
let rounded_digit = mode.round_pair(sign, (0, 0), false);
BigInt::new(sign, vec![rounded_digit as u32])
}
Greater => {
// location of new rounding point
let scale_diff = (self.scale - new_scale) as usize;
let low_digit = digits[scale_diff - 1];
let high_digit = digits[scale_diff];
let trailing_zeros = digits[0..scale_diff-1].iter().all(Zero::is_zero);
let rounded_digit = mode.round_pair(sign, (high_digit, low_digit), trailing_zeros);
debug_assert!(rounded_digit <= 10);
if rounded_digit < 10 {
digits[scale_diff] = rounded_digit;
} else {
digits[scale_diff] = 0;
let mut i = scale_diff + 1;
loop {
if i == digit_count {
digits.push(1);
break;
}
if digits[i] < 9 {
digits[i] += 1;
break;
}
digits[i] = 0;
i += 1;
}
}
BigInt::from_radix_le(sign, &digits[scale_diff..], 10).unwrap()
}
};
BigDecimal::new(rounded_int, new_scale)
}
}
}
/// Return a new BigDecimal object with same value and given scale,
/// padding with zeros or truncating digits as needed
///
/// Useful for aligning decimals before adding/subtracting.
///
fn take_and_scale(mut self, new_scale: i64) -> BigDecimal {
self.set_scale(new_scale);
self
}
/// Change to requested scale by multiplying or truncating
fn set_scale(&mut self, new_scale: i64) {
if self.int_val.is_zero() {
self.scale = new_scale;
return;
}
match diff(new_scale, self.scale) {
(Ordering::Greater, scale_diff) => {
self.scale = new_scale;
if scale_diff < 20 {
self.int_val *= ten_to_the_u64(scale_diff as u8);
} else {
self.int_val *= ten_to_the(scale_diff);
}
}
(Ordering::Less, scale_diff) => {
self.scale = new_scale;
if scale_diff < 20 {
self.int_val /= ten_to_the_u64(scale_diff as u8);
} else {
self.int_val /= ten_to_the(scale_diff);
}
}
(Ordering::Equal, _) => {},
}
}
/// set scale only if new_scale is greater than current
pub(crate) fn extend_scale_to(&mut self, new_scale: i64) {
if new_scale > self.scale {
self.set_scale(new_scale)
}
}
/// Take and return bigdecimal with the given sign
///
/// The Sign value `NoSign` is ignored: only use Plus & Minus
///
pub(crate) fn take_with_sign(self, sign: Sign) -> BigDecimal {
let BigDecimal { scale, mut int_val } = self;
if int_val.sign() != sign && sign != Sign::NoSign {
int_val = int_val.neg();
}
BigDecimal {
int_val: int_val,
scale: scale,
}
}
/// Return a new BigDecimal object with precision set to new value
///
/// ```
/// # use bigdecimal::*;
///
/// let n: BigDecimal = "129.41675".parse().unwrap();
///
/// assert_eq!(n.with_prec(2), "130".parse().unwrap());
///
/// let n_p12 = n.with_prec(12);
/// let (i, scale) = n_p12.as_bigint_and_exponent();
/// assert_eq!(n_p12, "129.416750000".parse().unwrap());
/// assert_eq!(i, 129416750000_u64.into());
/// assert_eq!(scale, 9);
/// ```
pub fn with_prec(&self, prec: u64) -> BigDecimal {
let digits = self.digits();
match digits.cmp(&prec) {
Ordering::Greater => {
let diff = digits - prec;
let p = ten_to_the(diff);
let (mut q, r) = self.int_val.div_rem(&p);
// check for "leading zero" in remainder term; otherwise round
if p < 10 * &r {
q += get_rounding_term(&r);
}
BigDecimal {
int_val: q,
scale: self.scale - diff as i64,
}
}
Ordering::Less => {
let diff = prec - digits;
BigDecimal {
int_val: &self.int_val * ten_to_the(diff),
scale: self.scale + diff as i64,
}
}
Ordering::Equal => self.clone(),
}
}
/// Return this BigDecimal with the given precision, rounding if needed
#[cfg(rustc_1_46)] // Option::zip
#[allow(clippy::incompatible_msrv)]
pub fn with_precision_round(&self, prec: stdlib::num::NonZeroU64, round: RoundingMode) -> BigDecimal {
let digit_count = self.digits();
let new_prec = prec.get().to_i64();
let new_scale = new_prec
.zip(digit_count.to_i64())
.and_then(|(new_prec, old_prec)| new_prec.checked_sub(old_prec))
.and_then(|prec_diff| self.scale.checked_add(prec_diff))
.expect("precision overflow");
self.with_scale_round(new_scale, round)
}
#[cfg(not(rustc_1_46))]
pub fn with_precision_round(&self, prec: stdlib::num::NonZeroU64, round: RoundingMode) -> BigDecimal {
let new_scale = self.digits().to_i64().and_then(
|old_prec| {
prec.get().to_i64().and_then(
|new_prec| { new_prec.checked_sub(old_prec) })})
.and_then(|prec_diff| self.scale.checked_add(prec_diff))
.expect("precision overflow");
self.with_scale_round(new_scale, round)
}
/// Return the sign of the `BigDecimal` as `num::bigint::Sign`.
///
/// ```
/// # use bigdecimal::{BigDecimal, num_bigint::Sign};
///
/// fn sign_of(src: &str) -> Sign {
/// let n: BigDecimal = src.parse().unwrap();
/// n.sign()
/// }
///
/// assert_eq!(sign_of("-1"), Sign::Minus);
/// assert_eq!(sign_of("0"), Sign::NoSign);
/// assert_eq!(sign_of("1"), Sign::Plus);
/// ```
#[inline]
pub fn sign(&self) -> num_bigint::Sign {
self.int_val.sign()
}
/// Return the internal big integer value and an exponent. Note that a positive
/// exponent indicates a negative power of 10.
///
/// # Examples
///
/// ```
/// use bigdecimal::{BigDecimal, num_bigint::BigInt};
///
/// let n: BigDecimal = "1.23456".parse().unwrap();
/// let expected = ("123456".parse::<BigInt>().unwrap(), 5);
/// assert_eq!(n.as_bigint_and_exponent(), expected);
/// ```
#[inline]
pub fn as_bigint_and_exponent(&self) -> (BigInt, i64) {
(self.int_val.clone(), self.scale)
}
/// Convert into the internal big integer value and an exponent. Note that a positive
/// exponent indicates a negative power of 10.
///
/// # Examples
///
/// ```
/// use bigdecimal::{BigDecimal, num_bigint::BigInt};
///
/// let n: BigDecimal = "1.23456".parse().unwrap();
/// let expected = ("123456".parse::<num_bigint::BigInt>().unwrap(), 5);
/// assert_eq!(n.into_bigint_and_exponent(), expected);
/// ```
#[inline]
pub fn into_bigint_and_exponent(self) -> (BigInt, i64) {
(self.int_val, self.scale)
}
/// Number of digits in the non-scaled integer representation
///
#[inline]
pub fn digits(&self) -> u64 {
count_decimal_digits(&self.int_val)
}
/// Compute the absolute value of number
///
/// ```
/// # use bigdecimal::BigDecimal;
/// let n: BigDecimal = "123.45".parse().unwrap();
/// assert_eq!(n.abs(), "123.45".parse().unwrap());
///
/// let n: BigDecimal = "-123.45".parse().unwrap();
/// assert_eq!(n.abs(), "123.45".parse().unwrap());
/// ```
#[inline]
pub fn abs(&self) -> BigDecimal {
BigDecimal {
int_val: self.int_val.abs(),
scale: self.scale,
}
}
/// Multiply decimal by 2 (efficiently)
///
/// ```
/// # use bigdecimal::BigDecimal;
/// let n: BigDecimal = "123.45".parse().unwrap();
/// assert_eq!(n.double(), "246.90".parse().unwrap());
/// ```
pub fn double(&self) -> BigDecimal {
if self.is_zero() {
self.clone()
} else {
BigDecimal {
int_val: self.int_val.clone() * 2,
scale: self.scale,
}
}
}
/// Divide decimal by 2 (efficiently)
///
/// *Note*: If the last digit in the decimal is odd, the precision
/// will increase by 1
///
/// ```
/// # use bigdecimal::BigDecimal;
/// let n: BigDecimal = "123.45".parse().unwrap();
/// assert_eq!(n.half(), "61.725".parse().unwrap());
/// ```
#[inline]
pub fn half(&self) -> BigDecimal {
if self.is_zero() {
self.clone()
} else if self.int_val.is_even() {
BigDecimal {
int_val: self.int_val.clone().div(2u8),
scale: self.scale,
}
} else {
BigDecimal {
int_val: self.int_val.clone().mul(5u8),
scale: self.scale + 1,
}
}
}
/// Square a decimal: *x²*
///
/// No rounding or truncating of digits; this is the full result
/// of the squaring operation.
///
/// *Note*: doubles the scale of bigdecimal, which might lead to
/// accidental exponential-complexity if used in a loop.
///
/// ```
/// # use bigdecimal::BigDecimal;
/// let n: BigDecimal = "1.1156024145937225657484".parse().unwrap();
/// assert_eq!(n.square(), "1.24456874744734405154288399835406316085210256".parse().unwrap());
///
/// let n: BigDecimal = "-9.238597585E+84".parse().unwrap();
/// assert_eq!(n.square(), "8.5351685337567832225E+169".parse().unwrap());
/// ```
pub fn square(&self) -> BigDecimal {
if self.is_zero() || self.is_one() {
self.clone()
} else {
BigDecimal {
int_val: self.int_val.clone() * &self.int_val,
scale: self.scale * 2,
}
}
}
/// Cube a decimal: *x³*
///
/// No rounding or truncating of digits; this is the full result
/// of the cubing operation.
///
/// *Note*: triples the scale of bigdecimal, which might lead to
/// accidental exponential-complexity if used in a loop.
///
/// ```
/// # use bigdecimal::BigDecimal;
/// let n: BigDecimal = "1.1156024145937225657484".parse().unwrap();
/// assert_eq!(n.cube(), "1.388443899780141911774491376394890472130000455312878627147979955904".parse().unwrap());
///
/// let n: BigDecimal = "-9.238597585E+84".parse().unwrap();
/// assert_eq!(n.cube(), "-7.88529874035334084567570176625E+254".parse().unwrap());
/// ```
pub fn cube(&self) -> BigDecimal {
if self.is_zero() || self.is_one() {
self.clone()
} else {
BigDecimal {
int_val: self.int_val.clone() * &self.int_val * &self.int_val,
scale: self.scale * 3,
}
}
}
/// Take the square root of the number
///
/// Uses default-precision, set from build time environment variable
//// `RUST_BIGDECIMAL_DEFAULT_PRECISION` (defaults to 100)
///
/// If the value is < 0, None is returned
///
/// ```
/// # use bigdecimal::BigDecimal;
/// let n: BigDecimal = "1.1156024145937225657484".parse().unwrap();
/// assert_eq!(n.sqrt().unwrap(), "1.056220817156016181190291268045893004363809142172289919023269377496528394924695970851558013658193913".parse().unwrap());
///
/// let n: BigDecimal = "-9.238597585E+84".parse().unwrap();
/// assert_eq!(n.sqrt(), None);
/// ```
#[inline]
pub fn sqrt(&self) -> Option<BigDecimal> {
self.sqrt_with_context(&Context::default())
}
/// Take the square root of the number, using context for precision and rounding
///
pub fn sqrt_with_context(&self, ctx: &Context) -> Option<BigDecimal> {
if self.is_zero() || self.is_one() {
return Some(self.clone());
}
if self.is_negative() {
return None;
}
let uint = self.int_val.magnitude();
let result = arithmetic::sqrt::impl_sqrt(uint, self.scale, ctx);
Some(result)
}
/// Take the cube root of the number, using default context
///
#[inline]
pub fn cbrt(&self) -> BigDecimal {
self.cbrt_with_context(&Context::default())
}
/// Take cube root of self, using properties of context
pub fn cbrt_with_context(&self, ctx: &Context) -> BigDecimal {
if self.is_zero() || self.is_one() {
return self.clone();
}
arithmetic::cbrt::impl_cbrt_int_scale(&self.int_val, self.scale, ctx)
}
/// Compute the reciprical of the number: x<sup>-1</sup>
#[inline]
pub fn inverse(&self) -> BigDecimal {
self.inverse_with_context(&Context::default())
}
/// Return inverse of self, rounding with ctx
pub fn inverse_with_context(&self, ctx: &Context) -> BigDecimal {
if self.is_zero() || self.is_one() {
return self.clone();
}
let uint = self.int_val.magnitude();
let result = arithmetic::inverse::impl_inverse_uint_scale(uint, self.scale, ctx);
// always copy sign
result.take_with_sign(self.sign())
}
/// Return given number rounded to 'round_digits' precision after the
/// decimal point, using default rounding mode
///
/// Default rounding mode is `HalfEven`, but can be configured at compile-time
/// by the environment variable: `RUST_BIGDECIMAL_DEFAULT_ROUNDING_MODE`
/// (or by patching _build.rs_ )
///
pub fn round(&self, round_digits: i64) -> BigDecimal {
self.with_scale_round(round_digits, Context::default().rounding_mode())
}
/// Return true if this number has zero fractional part (is equal
/// to an integer)
///
#[inline]
pub fn is_integer(&self) -> bool {
if self.scale <= 0 {
true
} else {
(self.int_val.clone() % ten_to_the(self.scale as u64)).is_zero()
}
}
/// Evaluate the natural-exponential function e<sup>x</sup>
///
#[inline]
pub fn exp(&self) -> BigDecimal {
if self.is_zero() {
return BigDecimal::one();
}
let target_precision = DEFAULT_PRECISION;
let precision = self.digits();
let mut term = self.clone();
let mut result = self.clone() + BigDecimal::one();
let mut prev_result = result.clone();
let mut factorial = BigInt::one();
for n in 2.. {
term *= self;
factorial *= n;
// ∑ term=x^n/n!
result += impl_division(term.int_val.clone(), &factorial, term.scale, 117 + precision);
let trimmed_result = result.with_prec(target_precision + 5);
if prev_result == trimmed_result {
return trimmed_result.with_prec(target_precision);
}
prev_result = trimmed_result;
}
unreachable!("Loop did not converge")
}
#[must_use]
pub fn normalized(&self) -> BigDecimal {
if self == &BigDecimal::zero() {
return BigDecimal::zero();
}
let (sign, mut digits) = self.int_val.to_radix_be(10);
let trailing_count = digits.iter().rev().take_while(|i| **i == 0).count();
let trunc_to = digits.len() - trailing_count;
digits.truncate(trunc_to);
let int_val = BigInt::from_radix_be(sign, &digits, 10).unwrap();
let scale = self.scale - trailing_count as i64;
BigDecimal::new(int_val, scale)
}
//////////////////////////
// Formatting methods
/// Create string of this bigdecimal in scientific notation
///
/// ```
/// # use bigdecimal::BigDecimal;
/// let n = BigDecimal::from(12345678);
/// assert_eq!(&n.to_scientific_notation(), "1.2345678e7");
/// ```
pub fn to_scientific_notation(&self) -> String {
let mut output = String::new();
self.write_scientific_notation(&mut output).expect("Could not write to string");
output
}
/// Write bigdecimal in scientific notation to writer `w`
pub fn write_scientific_notation<W: fmt::Write>(&self, w: &mut W) -> fmt::Result {
impl_fmt::write_scientific_notation(self, w)
}
/// Create string of this bigdecimal in engineering notation
///
/// Engineering notation is scientific notation with the exponent
/// coerced to a multiple of three
///
/// ```
/// # use bigdecimal::BigDecimal;
/// let n = BigDecimal::from(12345678);
/// assert_eq!(&n.to_engineering_notation(), "12.345678e6");
/// ```
///
pub fn to_engineering_notation(&self) -> String {
let mut output = String::new();
self.write_engineering_notation(&mut output).expect("Could not write to string");
output
}
/// Write bigdecimal in engineering notation to writer `w`
pub fn write_engineering_notation<W: fmt::Write>(&self, w: &mut W) -> fmt::Result {
impl_fmt::write_engineering_notation(self, w)
}
}
#[derive(Debug, PartialEq, Clone)]
pub enum ParseBigDecimalError {
ParseDecimal(ParseFloatError),
ParseInt(ParseIntError),
ParseBigInt(ParseBigIntError),
Empty,
Other(String),
}
impl fmt::Display for ParseBigDecimalError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
use ParseBigDecimalError::*;
match *self {
ParseDecimal(ref e) => e.fmt(f),
ParseInt(ref e) => e.fmt(f),
ParseBigInt(ref e) => e.fmt(f),
Empty => "Failed to parse empty string".fmt(f),
Other(ref reason) => reason[..].fmt(f),
}
}
}
#[cfg(feature = "std")]
impl std::error::Error for ParseBigDecimalError {
fn description(&self) -> &str {
"failed to parse bigint/biguint"
}
}
impl From<ParseFloatError> for ParseBigDecimalError {
fn from(err: ParseFloatError) -> ParseBigDecimalError {
ParseBigDecimalError::ParseDecimal(err)
}
}
impl From<ParseIntError> for ParseBigDecimalError {
fn from(err: ParseIntError) -> ParseBigDecimalError {
ParseBigDecimalError::ParseInt(err)
}
}
impl From<ParseBigIntError> for ParseBigDecimalError {
fn from(err: ParseBigIntError) -> ParseBigDecimalError {
ParseBigDecimalError::ParseBigInt(err)
}
}
#[allow(deprecated)] // trim_right_match -> trim_end_match
impl Hash for BigDecimal {
fn hash<H: Hasher>(&self, state: &mut H) {
let mut dec_str = self.int_val.to_str_radix(10);
let scale = self.scale;
let zero = self.int_val.is_zero();
if scale > 0 && !zero {
let mut cnt = 0;
dec_str = dec_str
.trim_right_matches(|x| {
cnt += 1;
x == '0' && cnt <= scale
})
.to_string();
} else if scale < 0 && !zero {
dec_str.push_str(&"0".repeat(self.scale.abs() as usize));
}
dec_str.hash(state);
}
}
impl Default for BigDecimal {
#[inline]
fn default() -> BigDecimal {
Zero::zero()
}
}
impl Zero for BigDecimal {
#[inline]
fn zero() -> BigDecimal {
BigDecimal::new(BigInt::zero(), 0)
}
#[inline]
fn is_zero(&self) -> bool {
self.int_val.is_zero()
}
}
impl One for BigDecimal {
#[inline]
fn one() -> BigDecimal {
BigDecimal::new(BigInt::one(), 0)
}
}
fn impl_division(mut num: BigInt, den: &BigInt, mut scale: i64, max_precision: u64) -> BigDecimal {
// quick zero check
if num.is_zero() {
return BigDecimal::new(num, 0);
}
match (num.is_negative(), den.is_negative()) {
(true, true) => return impl_division(num.neg(), &den.neg(), scale, max_precision),
(true, false) => return -impl_division(num.neg(), den, scale, max_precision),
(false, true) => return -impl_division(num, &den.neg(), scale, max_precision),
(false, false) => (),
}
// shift digits until numerator is larger than denominator (set scale appropriately)
while num < *den {
scale += 1;
num *= 10;
}
// first division
let (mut quotient, mut remainder) = num.div_rem(den);
// division complete
if remainder.is_zero() {
return BigDecimal {
int_val: quotient,
scale: scale,
};
}
let mut precision = count_decimal_digits("ient);
// shift remainder by 1 decimal;
// quotient will be 1 digit upon next division
remainder *= 10;
while !remainder.is_zero() && precision < max_precision {
let (q, r) = remainder.div_rem(den);
quotient = quotient * 10 + q;
remainder = r * 10;
precision += 1;
scale += 1;
}
if !remainder.is_zero() {
// round final number with remainder
quotient += get_rounding_term(&remainder.div(den));
}
let result = BigDecimal::new(quotient, scale);
// println!(" {} / {}\n = {}\n", self, other, result);
return result;
}
impl Signed for BigDecimal {
#[inline]
fn abs(&self) -> BigDecimal {
match self.sign() {
Sign::Plus | Sign::NoSign => self.clone(),
Sign::Minus => -self,
}
}
#[inline]
fn abs_sub(&self, other: &BigDecimal) -> BigDecimal {
if *self <= *other {
Zero::zero()
} else {
self - other
}
}
#[inline]
fn signum(&self) -> BigDecimal {
match self.sign() {
Sign::Plus => One::one(),
Sign::NoSign => Zero::zero(),
Sign::Minus => -Self::one(),
}
}
#[inline]
fn is_positive(&self) -> bool {
self.sign() == Sign::Plus
}
#[inline]
fn is_negative(&self) -> bool {
self.sign() == Sign::Minus
}
}
impl Sum for BigDecimal {
#[inline]
fn sum<I: Iterator<Item = BigDecimal>>(iter: I) -> BigDecimal {
iter.fold(Zero::zero(), |a, b| a + b)
}
}
impl<'a> Sum<&'a BigDecimal> for BigDecimal {
#[inline]
fn sum<I: Iterator<Item = &'a BigDecimal>>(iter: I) -> BigDecimal {
iter.fold(Zero::zero(), |a, b| a + b)
}
}
/// Immutable big-decimal, referencing a borrowed buffer of digits
///
/// The non-digit information like `scale` and `sign` may be changed
/// on these objects, which otherwise would require cloning the full
/// digit buffer in the BigDecimal.
///
/// Built from full `BigDecimal` object using the `to_ref()` method.
/// `BigDecimal` not implement `AsRef`, so we will reserve the method
/// `as_ref()` for a later time.
///
/// May be transformed into full BigDecimal object using the `to_owned()`
/// method.
/// This clones the bigdecimal digits.
///
/// BigDecimalRef (or `Into<BigDecimalRef>`) should be preferred over
/// using `&BigDecimal` for library functions that need an immutable
/// reference to a bigdecimal, as it may be much more efficient.
///
/// NOTE: Using `&BigDecimalRef` is redundant, and not recommended.
///
/// ## Examples
///
/// ```
/// # use bigdecimal::*; use std::ops::Neg;
/// fn add_one<'a, N: Into<BigDecimalRef<'a>>>(n: N) -> BigDecimal {
/// n.into() + 1
/// }
///
/// let n: BigDecimal = "123.456".parse().unwrap();
///
/// // call via "standard" reference (implements Into)
/// let m = add_one(&n);
/// assert_eq!(m, "124.456".parse().unwrap());
///
/// // call by negating the reference (fast: no-digit cloning involved)
/// let m = add_one(n.to_ref().neg());
/// assert_eq!(m, "-122.456".parse().unwrap());
/// ```
///
#[derive(Clone, Copy, Debug, Eq)]
pub struct BigDecimalRef<'a> {
sign: Sign,
digits: &'a BigUint,
scale: i64,
}
impl BigDecimalRef<'_> {
/// Clone digits to make this reference a full BigDecimal object
pub fn to_owned(&self) -> BigDecimal {
BigDecimal {
scale: self.scale,
int_val: BigInt::from_biguint(self.sign, self.digits.clone()),
}
}
/// Clone digits, returning BigDecimal with given scale
///
/// ```
/// # use bigdecimal::*;
///
/// let n: BigDecimal = "123.45678".parse().unwrap();
/// let r = n.to_ref();
/// assert_eq!(r.to_owned_with_scale(5), n.clone());
/// assert_eq!(r.to_owned_with_scale(0), "123".parse().unwrap());
/// assert_eq!(r.to_owned_with_scale(-1), "12e1".parse().unwrap());
///
/// let x = r.to_owned_with_scale(8);
/// assert_eq!(&x, &n);
/// assert_eq!(x.fractional_digit_count(), 8);
/// ```
pub fn to_owned_with_scale(&self, scale: i64) -> BigDecimal {
use stdlib::cmp::Ordering::*;
let digits = match arithmetic::diff(self.scale, scale) {
(Equal, _) => self.digits.clone(),
(Less, scale_diff) => {
if scale_diff < 20 {
self.digits * ten_to_the_u64(scale_diff as u8)
} else {
self.digits * ten_to_the_uint(scale_diff)
}
}
(Greater, scale_diff) => {
if scale_diff < 20 {
self.digits / ten_to_the_u64(scale_diff as u8)
} else {
self.digits / ten_to_the_uint(scale_diff)
}
}
};
BigDecimal {
scale: scale,
int_val: BigInt::from_biguint(self.sign, digits),
}
}
/// Sign of decimal
pub fn sign(&self) -> Sign {
self.sign
}
/// Return number of digits 'right' of the decimal point
/// (including leading zeros)
pub fn fractional_digit_count(&self) -> i64 {
self.scale
}
/// Count total number of decimal digits
pub fn count_digits(&self) -> u64 {
count_decimal_digits_uint(self.digits)
}
/// Return the number of trailing zeros in the referenced integer
#[allow(dead_code)]
fn count_trailing_zeroes(&self) -> usize {
if self.digits.is_zero() || self.digits.is_odd() {
return 0;
}
let digit_pairs = self.digits.to_radix_le(100);
let loc = digit_pairs.iter().position(|&d| d != 0).unwrap_or(0);
2 * loc + usize::from(digit_pairs[loc] % 10 == 0)
}
/// Split into components
pub(crate) fn as_parts(&self) -> (Sign, i64, &BigUint) {
(self.sign, self.scale, self.digits)
}
/// Take absolute value of the decimal (non-negative sign)
pub fn abs(&self) -> Self {
Self {
sign: self.sign * self.sign,
digits: self.digits,
scale: self.scale,
}
}
/// Create BigDecimal from this reference, rounding to precision and
/// with rounding-mode of the given context
///
///
pub fn round_with_context(&self, ctx: &Context) -> BigDecimal {
ctx.round_decimal_ref(*self)
}
/// Take square root of this number
pub fn sqrt_with_context(&self, ctx: &Context) -> Option<BigDecimal> {
use Sign::*;
let (sign, scale, uint) = self.as_parts();
match sign {
Minus => None,
NoSign => Some(Zero::zero()),
Plus => Some(arithmetic::sqrt::impl_sqrt(uint, scale, ctx)),
}
}
/// Take square root of absolute-value of the number
pub fn sqrt_abs_with_context(&self, ctx: &Context) -> BigDecimal {
use Sign::*;
let (_, scale, uint) = self.as_parts();
arithmetic::sqrt::impl_sqrt(uint, scale, ctx)
}
/// Take square root, copying sign of the initial decimal
pub fn sqrt_copysign_with_context(&self, ctx: &Context) -> BigDecimal {
use Sign::*;
let (sign, scale, uint) = self.as_parts();
let mut result = arithmetic::sqrt::impl_sqrt(uint, scale, ctx);
if sign == Minus {
result.int_val = result.int_val.neg();
}
result
}
/// Return if the referenced decimal is zero
pub fn is_zero(&self) -> bool {
self.digits.is_zero()
}
/// Clone this value into dest
pub fn clone_into(&self, dest: &mut BigDecimal) {
dest.int_val = num_bigint::BigInt::from_biguint(self.sign, self.digits.clone());
dest.scale = self.scale;
}
}
impl<'a> From<&'a BigDecimal> for BigDecimalRef<'a> {
fn from(n: &'a BigDecimal) -> Self {
let sign = n.int_val.sign();
let mag = n.int_val.magnitude();
Self {
sign: sign,
digits: mag,
scale: n.scale,
}
}
}
impl<'a> From<&'a BigInt> for BigDecimalRef<'a> {
fn from(n: &'a BigInt) -> Self {
Self {
sign: n.sign(),
digits: n.magnitude(),
scale: 0,
}
}
}
/// pair i64 'scale' with some other value
#[derive(Clone, Copy)]
struct WithScale<T> {
pub value: T,
pub scale: i64,
}
impl<T: fmt::Debug> fmt::Debug for WithScale<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "(scale={} {:?})", self.scale, self.value)
}
}
impl<T> From<(T, i64)> for WithScale<T> {
fn from(pair: (T, i64)) -> Self {
Self { value: pair.0, scale: pair.1 }
}
}
impl<'a> From<WithScale<&'a BigInt>> for BigDecimalRef<'a> {
fn from(obj: WithScale<&'a BigInt>) -> Self {
Self {
scale: obj.scale,
sign: obj.value.sign(),
digits: obj.value.magnitude(),
}
}
}
impl<'a> From<WithScale<&'a BigUint>> for BigDecimalRef<'a> {
fn from(obj: WithScale<&'a BigUint>) -> Self {
Self {
scale: obj.scale,
sign: Sign::Plus,
digits: obj.value,
}
}
}
impl<T: Zero> WithScale<&T> {
fn is_zero(&self) -> bool {
self.value.is_zero()
}
}
#[rustfmt::skip]
#[cfg(test)]
#[allow(non_snake_case)]
mod bigdecimal_tests {
use crate::{stdlib, BigDecimal, ToString, FromStr, TryFrom};
use num_traits::{ToPrimitive, FromPrimitive, Signed, Zero, One};
use num_bigint;
use paste::paste;
mod from_biguint {
use super::*;
use num_bigint::BigUint;
use num_bigint::Sign;
macro_rules! impl_case {
($name:ident; $i:literal; $scale:literal) => {
impl_case!($name; $i.into(); $scale; Plus);
};
($name:ident; $i:expr; $scale:literal; $sign:ident) => {
#[test]
fn $name() {
let i: BigUint = $i;
let d = BigDecimal::from_biguint(i.clone(), $scale);
assert_eq!(d.int_val.magnitude(), &i);
assert_eq!(d.scale, $scale);
assert_eq!(d.sign(), Sign::$sign);
}
};
}
impl_case!(case_0en3; BigUint::zero(); 3; NoSign);
impl_case!(case_30e2; 30u8; -2);
impl_case!(case_7446124798en5; 7446124798u128; 5);
}
#[test]
fn test_fractional_digit_count() {
// Zero value
let vals = BigDecimal::from(0);
assert_eq!(vals.fractional_digit_count(), 0);
assert_eq!(vals.to_ref().fractional_digit_count(), 0);
// Fractional part with trailing zeros
let vals = BigDecimal::from_str("1.0").unwrap();
assert_eq!(vals.fractional_digit_count(), 1);
assert_eq!(vals.to_ref().fractional_digit_count(), 1);
// Fractional part
let vals = BigDecimal::from_str("1.23").unwrap();
assert_eq!(vals.fractional_digit_count(), 2);
assert_eq!(vals.to_ref().fractional_digit_count(), 2);
// shifted to 'left' has negative scale
let vals = BigDecimal::from_str("123e5").unwrap();
assert_eq!(vals.fractional_digit_count(), -5);
assert_eq!(vals.to_ref().fractional_digit_count(), -5);
}
#[test]
fn test_sum() {
let vals = vec![
BigDecimal::from_f32(2.5).unwrap(),
BigDecimal::from_f32(0.3).unwrap(),
BigDecimal::from_f32(0.001).unwrap(),
];
let expected_sum = BigDecimal::from_str("2.801000011968426406383514404296875").unwrap();
let sum = vals.iter().sum::<BigDecimal>();
assert_eq!(expected_sum, sum);
}
#[test]
fn test_sum1() {
let vals = vec![
BigDecimal::from_f32(0.1).unwrap(),
BigDecimal::from_f32(0.2).unwrap(),
];
let expected_sum = BigDecimal::from_str("0.300000004470348358154296875").unwrap();
let sum = vals.iter().sum::<BigDecimal>();
assert_eq!(expected_sum, sum);
}
#[test]
fn test_to_i64() {
let vals = vec![
("12.34", 12),
("3.14", 3),
("50", 50),
("50000", 50000),
("0.001", 0),
// TODO: Is the desired behaviour to round?
//("0.56", 1),
];
for (s, ans) in vals {
let calculated = BigDecimal::from_str(s).unwrap().to_i64().unwrap();
assert_eq!(ans, calculated);
}
}
#[test]
fn test_to_i128() {
let vals = vec![
("170141183460469231731687303715884105727", 170141183460469231731687303715884105727),
("-170141183460469231731687303715884105728", -170141183460469231731687303715884105728),
("12.34", 12),
("3.14", 3),
("50", 50),
("0.001", 0),
];
for (s, ans) in vals {
let calculated = BigDecimal::from_str(s).unwrap().to_i128().unwrap();
assert_eq!(ans, calculated);
}
}
#[test]
fn test_to_u128() {
let vals = vec![
("340282366920938463463374607431768211455", 340282366920938463463374607431768211455),
("12.34", 12),
("3.14", 3),
("50", 50),
("0.001", 0),
];
for (s, ans) in vals {
let calculated = BigDecimal::from_str(s).unwrap().to_u128().unwrap();
assert_eq!(ans, calculated);
}
}
#[test]
fn test_to_f64() {
let vals = vec![
("12.34", 12.34),
("3.14", 3.14),
("50", 50.),
("50000", 50000.),
("0.001", 0.001),
];
for (s, ans) in vals {
let diff = BigDecimal::from_str(s).unwrap().to_f64().unwrap() - ans;
let diff = diff.abs();
assert!(diff < 1e-10);
}
}
#[test]
fn test_from_i8() {
let vals = vec![
("0", 0),
("1", 1),
("12", 12),
("-13", -13),
("111", 111),
("-128", i8::MIN),
("127", i8::MAX),
];
for (s, n) in vals {
let expected = BigDecimal::from_str(s).unwrap();
let value = BigDecimal::from_i8(n).unwrap();
assert_eq!(expected, value);
}
}
#[test]
fn test_from_f32() {
let vals = vec![
("0.0", 0.0),
("1.0", 1.0),
("0.5", 0.5),
("0.25", 0.25),
("50.", 50.0),
("50000", 50000.),
("0.001000000047497451305389404296875", 0.001),
("12.340000152587890625", 12.34),
("0.15625", 0.15625),
("3.1415927410125732421875", stdlib::f32::consts::PI),
("31415.927734375", stdlib::f32::consts::PI * 10000.0),
("94247.78125", stdlib::f32::consts::PI * 30000.0),
("1048576", 1048576.),
];
for (s, n) in vals {
let expected = BigDecimal::from_str(s).unwrap();
let value = BigDecimal::from_f32(n).unwrap();
assert_eq!(expected, value);
}
}
#[test]
fn test_from_f64() {
let vals = vec![
("1.0", 1.0f64),
("0.5", 0.5),
("50", 50.),
("50000", 50000.),
("0.001000000000000000020816681711721685132943093776702880859375", 0.001),
("0.25", 0.25),
("12.339999999999999857891452847979962825775146484375", 12.34),
("0.15625", 5.0 * 0.03125),
("0.333333333333333314829616256247390992939472198486328125", 1.0 / 3.0),
("3.141592653589793115997963468544185161590576171875", stdlib::f64::consts::PI),
("31415.926535897931898944079875946044921875", stdlib::f64::consts::PI * 10000.0f64),
("94247.779607693795696832239627838134765625", stdlib::f64::consts::PI * 30000.0f64),
];
for (s, n) in vals {
let expected = BigDecimal::from_str(s).unwrap();
let value = BigDecimal::from_f64(n).unwrap();
assert_eq!(expected, value);
// assert_eq!(expected, n);
}
}
#[test]
fn test_nan_float() {
assert!(BigDecimal::try_from(f32::NAN).is_err());
assert!(BigDecimal::try_from(f64::NAN).is_err());
}
#[test]
fn test_equal() {
let vals = vec![
("2", ".2e1"),
("0e1", "0.0"),
("0e0", "0.0"),
("0e-0", "0.0"),
("-0901300e-3", "-901.3"),
("-0.901300e+3", "-901.3"),
("-0e-1", "-0.0"),
("2123121e1231", "212.3121e1235"),
];
for &(x, y) in vals.iter() {
let a = BigDecimal::from_str(x).unwrap();
let b = BigDecimal::from_str(y).unwrap();
assert_eq!(a, b);
}
}
#[test]
fn test_not_equal() {
let vals = vec![
("2", ".2e2"),
("1e45", "1e-900"),
("1e+900", "1e-900"),
];
for &(x, y) in vals.iter() {
let a = BigDecimal::from_str(x).unwrap();
let b = BigDecimal::from_str(y).unwrap();
assert!(a != b, "{} == {}", a, b);
}
}
#[test]
fn test_hash_equal() {
use stdlib::DefaultHasher;
use stdlib::hash::{Hash, Hasher};
fn hash<T>(obj: &T) -> u64
where T: Hash
{
let mut hasher = DefaultHasher::new();
obj.hash(&mut hasher);
hasher.finish()
}
let vals = vec![
("1.1234", "1.1234000"),
("1.12340000", "1.1234"),
("001.1234", "1.1234000"),
("001.1234", "0001.1234"),
("1.1234000000", "1.1234000"),
("1.12340", "1.1234000000"),
("-0901300e-3", "-901.3"),
("-0.901300e+3", "-901.3"),
("100", "100.00"),
("100.00", "100"),
("0.00", "0"),
("0.00", "0.000"),
("-0.00", "0.000"),
("0.00", "-0.000"),
];
for &(x,y) in vals.iter() {
let a = BigDecimal::from_str(x).unwrap();
let b = BigDecimal::from_str(y).unwrap();
assert_eq!(a, b);
assert_eq!(hash(&a), hash(&b), "hash({}) != hash({})", a, b);
}
}
#[test]
fn test_hash_not_equal() {
use stdlib::DefaultHasher;
use stdlib::hash::{Hash, Hasher};
fn hash<T>(obj: &T) -> u64
where T: Hash
{
let mut hasher = DefaultHasher::new();
obj.hash(&mut hasher);
hasher.finish()
}
let vals = vec![
("1.1234", "1.1234001"),
("10000", "10"),
("10", "10000"),
("10.0", "100"),
];
for &(x,y) in vals.iter() {
let a = BigDecimal::from_str(x).unwrap();
let b = BigDecimal::from_str(y).unwrap();
assert!(a != b, "{} == {}", a, b);
assert!(hash(&a) != hash(&b), "hash({}) == hash({})", a, b);
}
}
#[test]
fn test_hash_equal_scale() {
use stdlib::DefaultHasher;
use stdlib::hash::{Hash, Hasher};
fn hash<T>(obj: &T) -> u64
where T: Hash
{
let mut hasher = DefaultHasher::new();
obj.hash(&mut hasher);
hasher.finish()
}
let vals = vec![
("1234.5678", -2, "1200", 0),
("1234.5678", -2, "1200", -2),
("1234.5678", 0, "1234.1234", 0),
("1234.5678", -3, "1200", -3),
("-1234", -2, "-1200", 0),
];
for &(x,xs,y,ys) in vals.iter() {
let a = BigDecimal::from_str(x).unwrap().with_scale(xs);
let b = BigDecimal::from_str(y).unwrap().with_scale(ys);
assert_eq!(a, b);
assert_eq!(hash(&a), hash(&b), "hash({}) != hash({})", a, b);
}
}
#[test]
fn test_with_prec() {
let vals = vec![
("7", 1, "7"),
("7", 2, "7.0"),
("895", 2, "900"),
("8934", 2, "8900"),
("8934", 1, "9000"),
("1.0001", 5, "1.0001"),
("1.0001", 4, "1"),
("1.00009", 6, "1.00009"),
("1.00009", 5, "1.0001"),
("1.00009", 4, "1.000"),
];
for &(x, p, y) in vals.iter() {
let a = BigDecimal::from_str(x).unwrap().with_prec(p);
assert_eq!(a, BigDecimal::from_str(y).unwrap());
}
}
#[test]
fn test_digits() {
let vals = vec![
("0", 1),
("7", 1),
("10", 2),
("8934", 4),
];
for &(x, y) in vals.iter() {
let a = BigDecimal::from_str(x).unwrap();
assert_eq!(a.digits(), y);
}
}
#[test]
fn test_get_rounding_term() {
use num_bigint::BigInt;
use super::get_rounding_term;
let vals = vec![
("0", 0),
("4", 0),
("5", 1),
("10", 0),
("15", 0),
("49", 0),
("50", 1),
("51", 1),
("8934", 1),
("9999", 1),
("10000", 0),
("50000", 1),
("99999", 1),
("100000", 0),
("100001", 0),
("10000000000", 0),
("9999999999999999999999999999999999999999", 1),
("10000000000000000000000000000000000000000", 0),
];
for &(x, y) in vals.iter() {
let a = BigInt::from_str(x).unwrap();
assert_eq!(get_rounding_term(&a), y, "{}", x);
}
}
#[test]
fn test_abs() {
let vals = vec![
("10", "10"),
("-10", "10"),
];
for &(x, y) in vals.iter() {
let a = BigDecimal::from_str(x).unwrap().abs();
let b = BigDecimal::from_str(y).unwrap();
assert!(a == b, "{} == {}", a, b);
}
}
#[test]
fn test_count_decimal_digits() {
use num_bigint::BigInt;
use super::count_decimal_digits;
let vals = vec![
("10", 2),
("1", 1),
("9", 1),
("999", 3),
("1000", 4),
("9900", 4),
("9999", 4),
("10000", 5),
("99999", 5),
("100000", 6),
("999999", 6),
("1000000", 7),
("9999999", 7),
("999999999999", 12),
("999999999999999999999999", 24),
("999999999999999999999999999999999999999999999999", 48),
("999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999", 96),
("199999911199999999999999999999999999999999999999999999999999999999999999999999999999999999999000", 96),
("999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999991", 192),
("199999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999", 192),
("-1", 1),
("-6", 1),
("-10", 2),
("-999999999999999999999999", 24),
];
for &(x, y) in vals.iter() {
let a = BigInt::from_str(x).unwrap();
let b = count_decimal_digits(&a);
assert_eq!(b, y);
}
}
#[test]
fn test_half() {
let vals = vec![
("100", "50."),
("2", "1"),
(".2", ".1"),
("42", "21"),
("3", "1.5"),
("99", "49.5"),
("3.141592653", "1.5707963265"),
("3.1415926536", "1.5707963268"),
];
for &(x, y) in vals.iter() {
let a = BigDecimal::from_str(x).unwrap().half();
let b = BigDecimal::from_str(y).unwrap();
assert_eq!(a, b);
assert_eq!(a.scale, b.scale);
}
}
#[test]
fn test_round() {
let test_cases = vec![
("1.45", 1, "1.4"),
("1.444445", 1, "1.4"),
("1.44", 1, "1.4"),
("0.444", 2, "0.44"),
("4.5", 0, "4"),
("4.05", 1, "4.0"),
("4.050", 1, "4.0"),
("4.15", 1, "4.2"),
("0.0045", 2, "0.00"),
("5.5", -1, "10"),
("-1.555", 2, "-1.56"),
("-1.555", 99, "-1.555"),
("5.5", 0, "6"),
("-1", -1, "0"),
("5", -1, "0"),
("44", -1, "40"),
("44", -99, "0"),
("44", 99, "44"),
("1.4499999999", -1, "0"),
("1.4499999999", 0, "1"),
("1.4499999999", 1, "1.4"),
("1.4499999999", 2, "1.45"),
("1.4499999999", 3, "1.450"),
("1.4499999999", 4, "1.4500"),
("1.4499999999", 10, "1.4499999999"),
("1.4499999999", 15, "1.449999999900000"),
("-1.4499999999", 1, "-1.4"),
("1.449999999", 1, "1.4"),
("-9999.444455556666", 10, "-9999.4444555567"),
("-12345678987654321.123456789", 8, "-12345678987654321.12345679"),
("0.33333333333333333333333333333333333333333333333333333333333333333333333333333333333333", 0, "0"),
("0.1165085714285714285714285714285714285714", 0, "0"),
("0.1165085714285714285714285714285714285714", 2, "0.12"),
("0.1165085714285714285714285714285714285714", 5, "0.11651"),
("0.1165085714285714285714285714285714285714", 8, "0.11650857"),
("-1.5", 0, "-2"),
("-1.2", 0, "-1"),
("-0.68", 0, "-1"),
("-0.5", 0, "0"),
("-0.49", 0, "0"),
];
for &(x, digits, y) in test_cases.iter() {
let a = BigDecimal::from_str(x).unwrap();
let b = BigDecimal::from_str(y).unwrap();
let rounded = a.round(digits);
assert_eq!(rounded, b);
}
}
#[test]
fn round_large_number() {
use super::BigDecimal;
let z = BigDecimal::from_str("3.4613133327063255443352353815722045816611958409944513040035462804475524").unwrap();
let expected = BigDecimal::from_str("11.9806899871705702711783103817684242408972124568942276285200973527647213").unwrap();
let zsq = &z*&z;
let zsq = zsq.round(70);
debug_assert_eq!(zsq, expected);
}
#[test]
fn test_is_integer() {
let true_vals = vec![
"100",
"100.00",
"1724e4",
"31.47e8",
"-31.47e8",
"-0.0",
];
let false_vals = vec![
"100.1",
"0.001",
"3147e-3",
"3147e-8",
"-0.01",
"-1e-3",
];
for s in true_vals {
let d = BigDecimal::from_str(&s).unwrap();
assert!(d.is_integer());
}
for s in false_vals {
let d = BigDecimal::from_str(&s).unwrap();
assert!(!d.is_integer());
}
}
#[test]
fn test_inverse() {
let vals = vec![
("100", "0.01"),
("2", "0.5"),
(".2", "5"),
("3.141592653", "0.3183098862435492205742690218851870990799646487459493049686604293188738877535183744268834079171116523"),
];
for &(x, y) in vals.iter() {
let a = BigDecimal::from_str(x).unwrap();
let i = a.inverse();
let b = BigDecimal::from_str(y).unwrap();
assert_eq!(i, b);
assert_eq!(BigDecimal::from(1)/&a, b);
assert_eq!(i.inverse(), a);
// assert_eq!(a.scale, b.scale, "scale mismatch ({} != {}", a, b);
}
}
mod double {
use super::*;
include!("lib.tests.double.rs");
}
#[test]
fn test_square() {
let vals = vec![
("1.00", "1.00"),
("1.5", "2.25"),
("1.50", "2.2500"),
("5", "25"),
("5.0", "25.00"),
("-5.0", "25.00"),
("5.5", "30.25"),
("0.80", "0.6400"),
("0.01234", "0.0001522756"),
("3.1415926", "9.86960406437476"),
];
for &(x, y) in vals.iter() {
let a = BigDecimal::from_str(x).unwrap().square();
let b = BigDecimal::from_str(y).unwrap();
assert_eq!(a, b);
assert_eq!(a.scale, b.scale);
}
}
#[test]
fn test_cube() {
let vals = vec![
("1.00", "1.00"),
("1.50", "3.375000"),
("5", "125"),
("5.0", "125.000"),
("5.00", "125.000000"),
("-5", "-125"),
("-5.0", "-125.000"),
("2.01", "8.120601"),
("5.5", "166.375"),
("0.01234", "0.000001879080904"),
("3.1415926", "31.006275093569669642776"),
];
for &(x, y) in vals.iter() {
let a = BigDecimal::from_str(x).unwrap().cube();
let b = BigDecimal::from_str(y).unwrap();
assert_eq!(a, b);
assert_eq!(a.scale, b.scale);
}
}
#[test]
fn test_exp() {
let vals = vec![
("0", "1"),
("1", "2.718281828459045235360287471352662497757247093699959574966967627724076630353547594571382178525166427"),
("1.01", "2.745601015016916493989776316660387624073750819595962291667398087987297168243899027802501018008905180"),
("0.5", "1.648721270700128146848650787814163571653776100710148011575079311640661021194215608632776520056366643"),
("-1", "0.3678794411714423215955237701614608674458111310317678345078368016974614957448998033571472743459196437"),
("-0.01", "0.9900498337491680535739059771800365577720790812538374668838787452931477271687452950182155307793838110"),
("-10.04", "0.00004361977305405268676261569570537884674661515701779752139657120453194647205771372804663141467275928595"),
//("-1000.04", "4.876927702336787390535723208392195312680380995235400234563172353460484039061383367037381490416091595E-435"),
("-20.07", "1.921806899438469499721914055500607234723811054459447828795824348465763824284589956630853464778332349E-9"),
("10", "22026.46579480671651695790064528424436635351261855678107423542635522520281857079257519912096816452590"),
("20", "485165195.4097902779691068305415405586846389889448472543536108003159779961427097401659798506527473494"),
//("777.7", "5.634022488451236612534495413455282583175841288248965283178668787259870456538271615076138061788051442E+337"),
];
for &(x, y) in vals.iter() {
let a = BigDecimal::from_str(x).unwrap().exp();
let b = BigDecimal::from_str(y).unwrap();
assert_eq!(a, b);
}
}
#[test]
fn test_signed() {
assert!(!BigDecimal::zero().is_positive());
assert!(!BigDecimal::one().is_negative());
assert!(BigDecimal::one().is_positive());
assert!((-BigDecimal::one()).is_negative());
assert!((-BigDecimal::one()).abs().is_positive());
}
mod normalize {
use super::*;
macro_rules! impl_case {
( $name:ident: ($i:literal, $s:literal) => ($e_int_val:literal, $e_scale:literal) ) => {
#[test]
fn $name() {
let d = BigDecimal::new($i.into(), $s);
let n = d.normalized();
assert_eq!(n.int_val, $e_int_val.into());
assert_eq!(n.scale, $e_scale);
}
}
}
impl_case!(case_0e3: (0, -3) => (0, 0));
impl_case!(case_0en50: (0, 50) => (0, 0));
impl_case!(case_10en2: (10, 2) => (1, 1));
impl_case!(case_11en2: (11, 2) => (11, 2));
impl_case!(case_132400en4: (132400, 4) => (1324, 2));
impl_case!(case_1_900_000en3: (1_900_000, 3) => (19, -2));
impl_case!(case_834700e4: (834700, -4) => (8347, -6));
impl_case!(case_n834700e4: (-9900, 2) => (-99, 0));
}
#[test]
fn test_from_i128() {
let value = BigDecimal::from_i128(-368934881474191032320).unwrap();
let expected = BigDecimal::from_str("-368934881474191032320").unwrap();
assert_eq!(value, expected);
}
#[test]
fn test_from_u128() {
let value = BigDecimal::from_u128(668934881474191032320).unwrap();
let expected = BigDecimal::from_str("668934881474191032320").unwrap();
assert_eq!(value, expected);
}
#[test]
fn test_parse_roundtrip() {
let vals = vec![
"1.0",
"0.5",
"50",
"50000",
"0.001000000000000000020816681711721685132943093776702880859375",
"0.25",
"12.339999999999999857891452847979962825775146484375",
"0.15625",
"0.333333333333333314829616256247390992939472198486328125",
"3.141592653589793115997963468544185161590576171875",
"31415.926535897931898944079875946044921875",
"94247.779607693795696832239627838134765625",
"1331.107",
"1.0",
"2e1",
"0.00123",
"-123",
"-1230",
"12.3",
"123e-1",
"1.23e+1",
"1.23E+3",
"1.23E-8",
"-1.23E-10",
"123_",
"31_862_140.830_686_979",
"-1_1.2_2",
"999.521_939",
"679.35_84_03E-2",
"271576662.__E4",
// Large decimals with small text representations
"1E10000",
"1E-10000",
"1.129387461293874682630000000487984723987459E10000",
"11293874612938746826340000000087984723987459E10000",
];
for s in vals {
let expected = BigDecimal::from_str(s).unwrap();
let display = format!("{}", expected);
let parsed = BigDecimal::from_str(&display).unwrap();
assert_eq!(expected, parsed, "[{}] didn't round trip through [{}]", s, display);
}
}
}
#[cfg(test)]
#[allow(non_snake_case)]
mod test_with_scale_round {
use super::*;
use paste::paste;
include!("lib.tests.with_scale_round.rs");
}
#[cfg(all(test, property_tests))]
extern crate proptest;
#[cfg(all(test, property_tests))]
mod proptests {
use super::*;
use paste::paste;
use proptest::*;
include!("lib.tests.property-tests.rs");
}