Struct num_bigint_dig::BigInt

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pub struct BigInt { /* private fields */ }

Expand description

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pub fn from_signed_bytes_be(digits: &[u8]) -> BigInt

Creates and initializes a BigInt from an array of bytes in two’s complement binary representation.

The digits are in big-endian base 2⁸.

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pub fn from_signed_bytes_le(digits: &[u8]) -> BigInt

Creates and initializes a BigInt from an array of bytes in two’s complement.

The digits are in little-endian base 2⁸.

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pub fn parse_bytes(buf: &[u8], radix: u32) -> Option<BigInt>

Creates and initializes a BigInt.

§Examples

use num_bigint_dig::{BigInt, ToBigInt};

assert_eq!(BigInt::parse_bytes(b"1234", 10), ToBigInt::to_bigint(&1234));
assert_eq!(BigInt::parse_bytes(b"ABCD", 16), ToBigInt::to_bigint(&0xABCD));
assert_eq!(BigInt::parse_bytes(b"G", 16), None);

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pub fn from_radix_be(sign: Sign, buf: &[u8], radix: u32) -> Option<BigInt>

Creates and initializes a BigInt. Each u8 of the input slice is interpreted as one digit of the number and must therefore be less than radix.

The bytes are in big-endian byte order. radix must be in the range 2...256.

§Examples

use num_bigint_dig::{BigInt, Sign};

let inbase190 = vec![15, 33, 125, 12, 14];
let a = BigInt::from_radix_be(Sign::Minus, &inbase190, 190).unwrap();
assert_eq!(a.to_radix_be(190), (Sign:: Minus, inbase190));

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pub fn from_radix_le(sign: Sign, buf: &[u8], radix: u32) -> Option<BigInt>

Creates and initializes a BigInt. Each u8 of the input slice is interpreted as one digit of the number and must therefore be less than radix.

The bytes are in little-endian byte order. radix must be in the range 2...256.

§Examples

use num_bigint_dig::{BigInt, Sign};

let inbase190 = vec![14, 12, 125, 33, 15];
let a = BigInt::from_radix_be(Sign::Minus, &inbase190, 190).unwrap();
assert_eq!(a.to_radix_be(190), (Sign::Minus, inbase190));

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pub fn to_bytes_be(&self) -> (Sign, Vec<u8>)

Returns the sign and the byte representation of the BigInt in big-endian byte order.

§Examples

use num_bigint_dig::{ToBigInt, Sign};

let i = -1125.to_bigint().unwrap();
assert_eq!(i.to_bytes_be(), (Sign::Minus, vec![4, 101]));

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pub fn to_bytes_le(&self) -> (Sign, Vec<u8>)

Returns the sign and the byte representation of the BigInt in little-endian byte order.

§Examples

use num_bigint_dig::{ToBigInt, Sign};

let i = -1125.to_bigint().unwrap();
assert_eq!(i.to_bytes_le(), (Sign::Minus, vec![101, 4]));

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pub fn to_signed_bytes_be(&self) -> Vec<u8>

Returns the two’s complement byte representation of the BigInt in big-endian byte order.

§Examples

use num_bigint_dig::ToBigInt;

let i = -1125.to_bigint().unwrap();
assert_eq!(i.to_signed_bytes_be(), vec![251, 155]);

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pub fn to_signed_bytes_le(&self) -> Vec<u8>

Returns the two’s complement byte representation of the BigInt in little-endian byte order.

§Examples

use num_bigint_dig::ToBigInt;

let i = -1125.to_bigint().unwrap();
assert_eq!(i.to_signed_bytes_le(), vec![155, 251]);

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pub fn to_str_radix(&self, radix: u32) -> String

Returns the integer formatted as a string in the given radix. radix must be in the range 2...36.

§Examples

use num_bigint_dig::BigInt;

let i = BigInt::parse_bytes(b"ff", 16).unwrap();
assert_eq!(i.to_str_radix(16), "ff");

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pub fn to_radix_be(&self, radix: u32) -> (Sign, Vec<u8>)

Returns the integer in the requested base in big-endian digit order. The output is not given in a human readable alphabet but as a zero based u8 number. radix must be in the range 2...256.

§Examples

use num_bigint_dig::{BigInt, Sign};

assert_eq!(BigInt::from(-0xFFFFi64).to_radix_be(159),
           (Sign::Minus, vec![2, 94, 27]));
// 0xFFFF = 65535 = 2*(159^2) + 94*159 + 27

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pub fn to_radix_le(&self, radix: u32) -> (Sign, Vec<u8>)

Returns the integer in the requested base in little-endian digit order. The output is not given in a human readable alphabet but as a zero based u8 number. radix must be in the range 2...256.

§Examples

use num_bigint_dig::{BigInt, Sign};

assert_eq!(BigInt::from(-0xFFFFi64).to_radix_le(159),
           (Sign::Minus, vec![27, 94, 2]));
// 0xFFFF = 65535 = 27 + 94*159 + 2*(159^2)

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pub fn sign(&self) -> Sign

Returns the sign of the BigInt as a Sign.

§Examples

use num_bigint_dig::{ToBigInt, Sign};

assert_eq!(ToBigInt::to_bigint(&1234).unwrap().sign(), Sign::Plus);
assert_eq!(ToBigInt::to_bigint(&-4321).unwrap().sign(), Sign::Minus);
assert_eq!(ToBigInt::to_bigint(&0).unwrap().sign(), Sign::NoSign);

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pub fn bits(&self) -> usize

Determines the fewest bits necessary to express the BigInt, not including the sign.

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pub fn to_biguint(&self) -> Option<BigUint>

Converts this BigInt into a BigUint, if it’s not negative.

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pub fn modpow(&self, exponent: &Self, modulus: &Self) -> Self

Returns (self ^ exponent) mod modulus

Note that this rounds like mod_floor, not like the % operator, which makes a difference when given a negative self or modulus. The result will be in the interval [0, modulus) for modulus > 0, or in the interval (modulus, 0] for modulus < 0

Panics if the exponent is negative or the modulus is zero.

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