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ver. 0.2.0: add unsigned integer type; private raw fields

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This commit is contained in:
EvilMuffinHa 2022-08-02 23:33:31 -04:00
parent 209cd7aa83
commit 5eb006e4c7
2 changed files with 163 additions and 38 deletions
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2
Cargo.toml
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@ -1,6 +1,6 @@
[package]
name = "smallint"
version = "0.1.0"
version = "0.2.0"
edition = "2021"
authors = ["artofrev"]
description = "A library for optimized arbitrary precision integers."

199
src/lib.rs
View File

@ -5,9 +5,17 @@
//! inline an integer and store it on the stack if that integer is small. However, for larger values,
//! this will be instead stored on the heap as a pointer to a `u32` slice, a length, and a sign.
// Invariant: If a small integer is within the bounds of an inline value, it must be inline.
// Invariant: If a small integer is on the heap, the size is the minimum digits required to
// represent it.
#[cfg(feature="num-bigint")]
use num_bigint::BigInt;
#[cfg(feature="num-bigint")]
use num_bigint::BigUint;
#[cfg(feature="num-bigint")]
use num_bigint::Sign;
@ -30,23 +38,34 @@ impl core::fmt::Display for SmallIntError {
}
/// An integer-like type that will store small integers up to `i64` inline. Larger integers are
/// represented as `BigInt` types, which are stored on the heap.
/// An integer-like type that will store small integers up to `i128` inline. Larger integers are
/// represented as a slice to a sequence of base 2<sup>32</sup> digits represented as a `*mut u32`.
#[derive(Clone, PartialEq, Eq)]
pub enum SmallInt {
/// An integer stored inline.
pub struct SmallInt(SmallIntType);
/// An integer-like type that will store small integers up to `u128` inline. Larger integers are
/// represented as a slice to a sequence of base 2<sup>32</sup> digits represented as a `*mut u32`.
#[derive(Clone, PartialEq, Eq)]
pub struct SmallUint(SmallUintType);
#[derive(Clone, PartialEq, Eq)]
enum SmallIntType {
Inline(i128),
/// A larger integer stored on the heap. This value is represented in base 2<sup>32</sup> and
/// ordered least significant digit first. Also stored with the size and sign of the integer.
///
/// It is assumed that values stored on the heap are larger than the maximum value of inline
/// integers.
Heap((*mut u32, isize))
}
#[derive(Clone, PartialEq, Eq)]
enum SmallUintType {
Inline(u128),
Heap((*mut u32, usize))
}
impl Drop for SmallInt {
fn drop(&mut self) {
if let Self::Heap((r, s)) = self {
if let Self(SmallIntType::Heap((r, s))) = self {
let size = usize::try_from(s.abs()).unwrap();
let slice = unsafe { core::slice::from_raw_parts_mut(*r, size) };
unsafe { std::mem::drop(Box::from_raw(slice)) }
@ -55,43 +74,90 @@ impl Drop for SmallInt {
}
impl Drop for SmallUint {
fn drop(&mut self) {
if let Self(SmallUintType::Heap((r, s))) = self {
let slice = unsafe { core::slice::from_raw_parts_mut(*r, *s) };
unsafe { std::mem::drop(Box::from_raw(slice)) }
}
}
}
macro_rules! int_impl {
($itype:ty) => {
impl From<$itype> for SmallInt {
($itype:ty, $rt:tt, $rtt:tt, $n:tt) => {
impl From<$itype> for $rt {
fn from(a: $itype) -> Self {
SmallInt::Inline(i128::from(a))
Self(<$rtt>::Inline($n::from(a)))
}
}
impl TryFrom<SmallInt> for $itype {
impl TryFrom<$rt> for $itype {
type Error = SmallIntError;
fn try_from(s: SmallInt) -> Result<Self, Self::Error> {
match s {
SmallInt::Inline(i) => <$itype>::try_from(i).map_err(|_| SmallIntError::ConversionError),
SmallInt::Heap((_, _)) => Err(SmallIntError::ConversionError),
fn try_from(s: $rt) -> Result<Self, Self::Error> {
match s.0 {
$rtt::Inline(i) => <$itype>::try_from(i).map_err(|_| SmallIntError::ConversionError),
$rtt::Heap((_, _)) => Err(SmallIntError::ConversionError),
}
}
}
}
}
int_impl!(u8);
int_impl!(u16);
int_impl!(u32);
int_impl!(u64);
int_impl!(i8);
int_impl!(i16);
int_impl!(i32);
int_impl!(i64);
int_impl!(i128);
int_impl!(u8, SmallInt, SmallIntType, i128);
int_impl!(u16, SmallInt, SmallIntType, i128);
int_impl!(u32, SmallInt, SmallIntType, i128);
int_impl!(u64, SmallInt, SmallIntType, i128);
int_impl!(i8, SmallInt, SmallIntType, i128);
int_impl!(i16, SmallInt, SmallIntType, i128);
int_impl!(i32, SmallInt, SmallIntType, i128);
int_impl!(i64, SmallInt, SmallIntType, i128);
int_impl!(i128, SmallInt, SmallIntType, i128);
int_impl!(u8, SmallUint, SmallUintType, u128);
int_impl!(u16, SmallUint, SmallUintType, u128);
int_impl!(u32, SmallUint, SmallUintType, u128);
int_impl!(u64, SmallUint, SmallUintType, u128);
int_impl!(u128, SmallUint, SmallUintType, u128);
macro_rules! try_from_itou {
($itype:ty) => {
impl TryFrom<$itype> for SmallUint {
type Error = SmallIntError;
fn try_from(a: $itype) -> Result<Self, Self::Error> {
Ok(Self(SmallUintType::Inline(u128::try_from(a).map_err(|_| SmallIntError::ConversionError)?)))
}
}
impl TryFrom<SmallUint> for $itype {
type Error = SmallIntError;
fn try_from(s: SmallUint) -> Result<Self, Self::Error> {
match s.0 {
SmallUintType::Inline(i) => <$itype>::try_from(i).map_err(|_| SmallIntError::ConversionError),
SmallUintType::Heap((_, _)) => Err(SmallIntError::ConversionError),
}
}
}
}
}
try_from_itou!(i8);
try_from_itou!(i16);
try_from_itou!(i32);
try_from_itou!(i64);
try_from_itou!(i128);
impl From<u128> for SmallInt {
fn from(a: u128) -> Self {
match i128::try_from(a) {
Ok(i) => Self::Inline(i),
Ok(i) => Self(SmallIntType::Inline(i)),
Err(_) => {
let mut v = a;
let mut vec = Vec::with_capacity(4);
@ -101,7 +167,7 @@ impl From<u128> for SmallInt {
v >>= 32;
}
let mut slice = ManuallyDrop::new(vec.into_boxed_slice());
SmallInt::Heap((slice.as_mut_ptr(), isize::try_from(slice.len()).unwrap()))
Self(SmallIntType::Heap((slice.as_mut_ptr(), isize::try_from(slice.len()).unwrap())))
}
}
}
@ -112,9 +178,9 @@ impl TryFrom<SmallInt> for u128 {
type Error = SmallIntError;
fn try_from(s: SmallInt) -> Result<Self, Self::Error> {
match s {
SmallInt::Inline(i) => u128::try_from(i).map_err(|_| SmallIntError::ConversionError),
SmallInt::Heap((r, s)) => {
match s.0 {
SmallIntType::Inline(i) => u128::try_from(i).map_err(|_| SmallIntError::ConversionError),
SmallIntType::Heap((r, s)) => {
let mut ret: u128 = 0;
let mut bits = 0;
let size = usize::try_from(s.abs()).unwrap();
@ -133,12 +199,42 @@ impl TryFrom<SmallInt> for u128 {
}
}
impl From<SmallUint> for SmallInt {
fn from(s: SmallUint) -> Self {
match s.0 {
SmallUintType::Inline(i) => SmallInt::from(i),
SmallUintType::Heap((r, s)) => SmallInt(SmallIntType::Heap((r, isize::try_from(s).unwrap())))
}
}
}
impl TryFrom<SmallInt> for SmallUint {
type Error = SmallIntError;
fn try_from(value: SmallInt) -> Result<Self, Self::Error> {
match value.0 {
SmallIntType::Inline(i) => Self::try_from(i),
SmallIntType::Heap((r, s)) => {
let size = usize::try_from(s).map_err(|_| SmallIntError::ConversionError)?;
if size > 4 {
Ok(Self(SmallUintType::Heap((r, size))))
} else {
Ok(Self(SmallUintType::Inline(u128::try_from(value)?)))
}
}
}
}
}
#[cfg(feature="num-bigint")]
impl From<BigInt> for SmallInt {
fn from(b: BigInt) -> Self {
match (&b).try_into() {
Ok(i) => SmallInt::Inline(i),
Ok(i) => Self(SmallIntType::Inline(i)),
Err(_) => {
let (sign, vec) = b.to_u32_digits();
let mut slice = ManuallyDrop::new(vec.into_boxed_slice());
@ -147,7 +243,7 @@ impl From<BigInt> for SmallInt {
Sign::NoSign => panic!("Shouldn't happen; BigInts which store zero should convert to inline."),
Sign::Plus => isize::try_from(slice.len()).unwrap()
};
SmallInt::Heap((slice.as_mut_ptr(), size)) }
Self(SmallIntType::Heap((slice.as_mut_ptr(), size))) }
}
}
}
@ -155,9 +251,9 @@ impl From<BigInt> for SmallInt {
#[cfg(feature="num-bigint")]
impl From<SmallInt> for BigInt {
fn from(s: SmallInt) -> Self {
match s {
SmallInt::Inline(i) => Self::from(i),
SmallInt::Heap((r, s)) => {
match s.0 {
SmallIntType::Inline(i) => Self::from(i),
SmallIntType::Heap((r, s)) => {
let size = usize::try_from(s.abs()).unwrap();
let sign = s.signum();
let slice = unsafe { core::slice::from_raw_parts(r, size) };
@ -174,6 +270,35 @@ impl From<SmallInt> for BigInt {
}
}
#[cfg(feature="num-bigint")]
impl From<BigUint> for SmallUint {
fn from(b: BigUint) -> Self {
match (&b).try_into() {
Ok(i) => Self(SmallUintType::Inline(i)),
Err(_) => {
let vec = b.to_u32_digits();
let mut slice = ManuallyDrop::new(vec.into_boxed_slice());
let size = slice.len();
Self(SmallUintType::Heap((slice.as_mut_ptr(), size))) }
}
}
}
#[cfg(feature="num-bigint")]
impl From<SmallUint> for BigUint {
fn from(s: SmallUint) -> Self {
match s.0 {
SmallUintType::Inline(i) => Self::from(i),
SmallUintType::Heap((r, s)) => {
let slice = unsafe { core::slice::from_raw_parts(r, s) };
BigUint::new(slice.to_vec())
}
}
}
}
#[cfg(test)]
mod conversion_tests {