Initial import of cast-0.2.3. am: 80f5cd0831 am: 46353a3021 am: f8edbc5cc4 am: ab700367e7
Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/cast/+/1620970
Change-Id: I53797effda716124e6b433eb4c232f1d96725fa7
diff --git a/.cargo_vcs_info.json b/.cargo_vcs_info.json
new file mode 100644
index 0000000..13f1433
--- /dev/null
+++ b/.cargo_vcs_info.json
@@ -0,0 +1,5 @@
+{
+ "git": {
+ "sha1": "74cec5dcf2014ecfe7cb05837b147cbb4f49024e"
+ }
+}
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..dcc96f3
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+*.rs.bk
+Cargo.lock
+target/*
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..6da2fc0
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,35 @@
+language: rust
+
+matrix:
+ include:
+ # MSRV
+ - env: TARGET=x86_64-unknown-linux-gnu
+ rust: 1.13.0
+
+ # 32-bit
+ - env: TARGET=i686-unknown-linux-musl
+ - env: TARGET=x86_64-unknown-linux-gnu
+
+before_install: set -e
+
+install:
+ - bash ci/install.sh
+
+script:
+ - bash ci/script.sh
+
+after_script: set +e
+
+cache: cargo
+
+before_cache:
+ - chmod -R a+r $HOME/.cargo
+
+branches:
+ only:
+ - staging
+ - trying
+
+notifications:
+ email:
+ on_success: never
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..eb26758
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,54 @@
+# Change Log
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](http://keepachangelog.com/)
+and this project adheres to [Semantic Versioning](http://semver.org/).
+
+## [Unreleased]
+
+## [v0.2.3] - 2018-11-17
+
+### Changed
+
+- Documented the guaranteed MRSV to be 1.13
+- The `x128` feature now works on *stable* Rust 1.26+
+
+### Fixed
+
+- Overflow and underflow checks when casting a float to an unsigned integer
+
+## [v0.2.2] - 2017-05-07
+
+### Fixed
+
+- UB in the checked cast from `f32` to `u128`.
+
+## [v0.2.1] - 2017-05-06
+
+### Added
+
+- Support for 128-bit integers, behind the `x128` Cargo feature (nightly
+ needed).
+
+## [v0.2.0] - 2017-02-08
+
+### Added
+
+- Now `cast::Error` implements the `std::error::Error` trait among other traits
+ like `Display`, `Clone`, etc.
+
+### Changed
+
+- [breaking-change] This crate now depends on the `std` crate by default but you
+ can make it `no_std` by opting out of the `std` Cargo feature.
+
+## v0.1.0 - 2016-02-07
+
+Initial release
+
+[Unreleased]: https://github.com/japaric/cast.rs/compare/v0.2.3...HEAD
+[v0.2.3]: https://github.com/japaric/cast.rs/compare/v0.2.2...v0.2.3
+[v0.2.2]: https://github.com/japaric/cast.rs/compare/v0.2.1...v0.2.2
+[v0.2.1]: https://github.com/japaric/cast.rs/compare/v0.2.0...v0.2.1
+[v0.2.0]: https://github.com/japaric/cast.rs/compare/v0.1.0...v0.2.0
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..40df4af
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,31 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies
+#
+# If you believe there's an error in this file please file an
+# issue against the rust-lang/cargo repository. If you're
+# editing this file be aware that the upstream Cargo.toml
+# will likely look very different (and much more reasonable)
+
+[package]
+name = "cast"
+version = "0.2.3"
+authors = ["Jorge Aparicio <jorge@japaric.io>"]
+build = "build.rs"
+description = "Ergonomic, checked cast functions for primitive types"
+documentation = "https://docs.rs/cast"
+keywords = ["checked", "cast", "primitive", "integer", "float"]
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/japaric/cast.rs"
+[dev-dependencies.quickcheck]
+version = "0.9.0"
+[build-dependencies.rustc_version]
+version = "0.2.3"
+
+[features]
+default = ["std"]
+std = []
+x128 = []
diff --git a/Cargo.toml.orig b/Cargo.toml.orig
new file mode 100644
index 0000000..6e95860
--- /dev/null
+++ b/Cargo.toml.orig
@@ -0,0 +1,25 @@
+[package]
+authors = ["Jorge Aparicio <jorge@japaric.io>"]
+build = "build.rs"
+description = "Ergonomic, checked cast functions for primitive types"
+documentation = "https://docs.rs/cast"
+keywords = ["checked", "cast", "primitive", "integer", "float"]
+license = "MIT OR Apache-2.0"
+name = "cast"
+repository = "https://github.com/japaric/cast.rs"
+version = "0.2.3"
+
+[features]
+# Assume we should use `std` unless asked to do otherwise.
+default = ["std"]
+# Enable this to get a std::error::Error impl for convenient use with other
+# libraries.
+std = []
+# Enable this for i128/u128 support
+x128 = []
+
+[build-dependencies]
+rustc_version = "0.2.3"
+
+[dev-dependencies]
+quickcheck = "0.9.0"
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..3ed32f1
--- /dev/null
+++ b/README.md
@@ -0,0 +1,44 @@
+[](https://crates.io/crates/cast)
+[](https://crates.io/crates/cast)
+
+# `cast`
+
+> Ergonomic, checked cast functions for primitive types
+
+``` rust
+extern crate cast;
+
+// `u8` and `u16` are checked cast functions, use them to cast from any numeric
+// primitive to `u8`/`u16` respectively
+use cast::{u8, u16, Error};
+
+// Infallible operations, like integer promotion, are equivalent to a normal
+// cast with `as`
+assert_eq!(u16(0u8), 0u16);
+
+// Everything else will return a `Result` depending on the success of the
+// operation
+assert_eq!(u8(0u16), Ok(0u8));
+assert_eq!(u8(256u16), Err(Error::Overflow));
+assert_eq!(u8(-1i8), Err(Error::Underflow));
+assert_eq!(u8(1. / 0.), Err(Error::Infinite));
+assert_eq!(u8(0. / 0.), Err(Error::NaN));
+```
+
+## [API docs](https://docs.rs/cast)
+
+## License
+
+Licensed under either of
+
+- Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or
+ http://www.apache.org/licenses/LICENSE-2.0)
+- MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
+
+at your option.
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
+dual licensed as above, without any additional terms or conditions.
diff --git a/build.rs b/build.rs
new file mode 100644
index 0000000..2aa9f5b
--- /dev/null
+++ b/build.rs
@@ -0,0 +1,8 @@
+extern crate rustc_version;
+
+fn main() {
+ let vers = rustc_version::version().unwrap();
+ if vers.major == 1 && vers.minor >= 26 {
+ println!("cargo:rustc-cfg=stable_i128")
+ }
+}
diff --git a/ci/install.sh b/ci/install.sh
new file mode 100644
index 0000000..3c41921
--- /dev/null
+++ b/ci/install.sh
@@ -0,0 +1,9 @@
+set -euxo pipefail
+
+main() {
+ if [ $TARGET != x86_64-unknown-linux-gnu ]; then
+ rustup target add $TARGET
+ fi
+}
+
+main
diff --git a/ci/script.sh b/ci/script.sh
new file mode 100644
index 0000000..12b2619
--- /dev/null
+++ b/ci/script.sh
@@ -0,0 +1,43 @@
+set -euxo pipefail
+
+main() {
+ # not MSRV
+ if [ $TRAVIS_RUST_VERSION != 1.13.0 ]; then
+ cargo check --target $TARGET --no-default-features
+
+ cargo test --features x128 --target $TARGET
+ cargo test --features x128 --target $TARGET --release
+ else
+ cargo build --target $TARGET --no-default-features
+ cargo build --target $TARGET
+ fi
+}
+
+# fake Travis variables to be able to run this on a local machine
+if [ -z ${TRAVIS_BRANCH-} ]; then
+ TRAVIS_BRANCH=staging
+fi
+
+if [ -z ${TRAVIS_PULL_REQUEST-} ]; then
+ TRAVIS_PULL_REQUEST=false
+fi
+
+if [ -z ${TRAVIS_RUST_VERSION-} ]; then
+ case $(rustc -V) in
+ *nightly*)
+ TRAVIS_RUST_VERSION=nightly
+ ;;
+ *beta*)
+ TRAVIS_RUST_VERSION=beta
+ ;;
+ *)
+ TRAVIS_RUST_VERSION=stable
+ ;;
+ esac
+fi
+
+if [ -z ${TARGET-} ]; then
+ TARGET=$(rustc -Vv | grep host | cut -d ' ' -f2)
+fi
+
+main
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..4a8efe9
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,546 @@
+//! Ergonomic, checked cast functions for primitive types
+//!
+//! This crate provides one checked cast function for each numeric primitive.
+//! Use these functions to perform a cast from any other numeric primitive:
+//!
+//! ```
+//! extern crate cast;
+//!
+//! use cast::{u8, u16, Error};
+//!
+//! # fn main() {
+//! // Infallible operations, like integer promotion, are equivalent to a normal
+//! // cast with `as`
+//! assert_eq!(u16(0u8), 0u16);
+//!
+//! // Everything else will return a `Result` depending on the success of the
+//! // operation
+//! assert_eq!(u8(0u16), Ok(0u8));
+//! assert_eq!(u8(256u16), Err(Error::Overflow));
+//! assert_eq!(u8(-1i8), Err(Error::Underflow));
+//! assert_eq!(u8(1. / 0.), Err(Error::Infinite));
+//! assert_eq!(u8(0. / 0.), Err(Error::NaN));
+//! # }
+//! ```
+//!
+//! There are no namespace problems between these functions, the "primitive
+//! modules" in `core`/`std` and the built-in primitive types, so all them can
+//! be in the same scope:
+//!
+//! ```
+//! extern crate cast;
+//!
+//! use std::u8;
+//! use cast::{u8, u16};
+//!
+//! # fn main() {
+//! // `u8` as a type
+//! let x: u8 = 0;
+//! // `u8` as a module
+//! let y = u16(u8::MAX);
+//! // `u8` as a function
+//! let z = u8(y).unwrap();
+//! # }
+//! ```
+//!
+//! The checked cast functionality is also usable with type aliases via the
+//! `cast` static method:
+//!
+//! ```
+//! extern crate cast;
+//!
+//! use std::os::raw::c_ulonglong;
+//! // NOTE avoid shadowing `std::convert::From` - cf. rust-lang/rfcs#1311
+//! use cast::From as _0;
+//!
+//! # fn main() {
+//! assert_eq!(c_ulonglong::cast(0u8), 0u64);
+//! # }
+//! ```
+//!
+//! This crate also provides a `From` trait that can be used, for example,
+//! to create a generic function that accepts any type that can be infallibly
+//! casted to `u32`.
+//!
+//! ```
+//! extern crate cast;
+//!
+//! fn to_u32<T>(x: T) -> u32
+//! // reads as: "where u32 can be casted from T with output u32"
+//! where u32: cast::From<T, Output=u32>,
+//! {
+//! cast::u32(x)
+//! }
+//!
+//! # fn main() {
+//! assert_eq!(to_u32(0u8), 0u32);
+//! assert_eq!(to_u32(1u16), 1u32);
+//! assert_eq!(to_u32(2u32), 2u32);
+//!
+//! // to_u32(-1i32); // Compile error
+//! # }
+//! ```
+//!
+//! ## Minimal Supported Rust Version
+//!
+//! This crate is guaranteed to compile on stable Rust 1.13 and up. It *might* compile on older
+//! versions but that may change in any new patch release.
+//!
+//! ## Building without `std`
+//!
+//! This crate can be used without Rust's `std` crate by declaring it as
+//! follows in your `Cargo.toml`:
+//!
+//! ``` toml
+//! cast = { version = "*", default-features = false }
+//! ```
+
+#![deny(missing_docs)]
+#![deny(warnings)]
+#![allow(const_err)]
+#![cfg_attr(not(feature = "std"), no_std)]
+#![cfg_attr(all(feature = "x128", not(stable_i128)), feature(i128_type, i128))]
+
+#[cfg(feature = "std")]
+extern crate core;
+
+#[cfg(test)]
+#[macro_use]
+extern crate quickcheck;
+
+use core::fmt;
+#[cfg(feature = "std")]
+use std::error;
+
+#[cfg(test)]
+mod test;
+
+/// Cast errors
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum Error {
+ /// Infinite value casted to a type that can only represent finite values
+ Infinite,
+ /// NaN value casted to a type that can't represent a NaN value
+ NaN,
+ /// Source value is greater than the maximum value that the destination type
+ /// can hold
+ Overflow,
+ /// Source value is smaller than the minimum value that the destination type
+ /// can hold
+ Underflow,
+}
+
+impl Error {
+ /// A private helper function that implements `description`, because
+ /// `description` is only available when we have `std` enabled.
+ fn description_helper(&self) -> &str {
+ match *self {
+ Error::Infinite => "Cannot store infinite value in finite type",
+ Error::NaN => "Cannot store NaN in type which does not support it",
+ Error::Overflow => "Overflow during numeric conversion",
+ Error::Underflow => "Underflow during numeric conversion",
+ }
+ }
+}
+
+impl fmt::Display for Error {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ write!(f, "{}", self.description_helper())
+ }
+}
+
+#[cfg(feature = "std")]
+impl error::Error for Error {
+ fn description(&self) -> &str {
+ self.description_helper()
+ }
+}
+
+/// The "cast from" operation
+pub trait From<Src> {
+ /// The result of the cast operation: either `Self` or `Result<Self, Error>`
+ type Output;
+
+ /// Checked cast from `Src` to `Self`
+ fn cast(Src) -> Self::Output;
+}
+
+macro_rules! fns {
+ ($($ty:ident),+) => {
+ $(
+ /// Checked cast function
+ #[inline]
+ pub fn $ty<T>(x: T) -> <$ty as From<T>>::Output
+ where $ty: From<T>
+ {
+ <$ty as From<T>>::cast(x)
+ }
+ )+
+ }
+}
+
+fns!(f32, f64, i8, i16, i32, i64, isize, u8, u16, u32, u64, usize);
+
+#[cfg(feature = "x128")]
+fns!(i128, u128);
+
+/// `$dst` can hold any value of `$src`
+macro_rules! promotion {
+ ($($src:ty => $($dst: ty),+);+;) => {
+ $(
+ $(
+ impl From<$src> for $dst {
+ type Output = $dst;
+
+ #[inline]
+ fn cast(src: $src) -> $dst {
+ src as $dst
+ }
+ }
+ )+
+ )+
+ }
+}
+
+/// `$dst` can hold any positive value of `$src`
+macro_rules! half_promotion {
+ ($($src:ty => $($dst:ty),+);+;) => {
+ $(
+ $(
+ impl From<$src> for $dst {
+ type Output = Result<$dst, Error>;
+
+ #[inline]
+ fn cast(src: $src) -> Self::Output {
+ if src < 0 {
+ Err(Error::Underflow)
+ } else {
+ Ok(src as $dst)
+ }
+ }
+ }
+ )+
+ )+
+ }
+}
+
+/// From an unsigned `$src` to a smaller `$dst`
+macro_rules! from_unsigned {
+ ($($src:ident => $($dst:ident),+);+;) => {
+ $(
+ $(
+ impl From<$src> for $dst {
+ type Output = Result<$dst, Error>;
+
+ #[inline]
+ fn cast(src: $src) -> Self::Output {
+ use core::$dst;
+
+ if src > $dst::MAX as $src {
+ Err(Error::Overflow)
+ } else {
+ Ok(src as $dst)
+ }
+ }
+ }
+ )+
+ )+
+ }
+}
+
+/// From a signed `$src` to a smaller `$dst`
+macro_rules! from_signed {
+ ($($src:ident => $($dst:ident),+);+;) => {
+ $(
+ $(
+ impl From<$src> for $dst {
+ type Output = Result<$dst, Error>;
+
+ #[inline]
+ fn cast(src: $src) -> Self::Output {
+ use core::$dst;
+
+ Err(if src < $dst::MIN as $src {
+ Error::Underflow
+ } else if src > $dst::MAX as $src {
+ Error::Overflow
+ } else {
+ return Ok(src as $dst);
+ })
+ }
+ }
+ )+
+ )+
+ }
+}
+
+/// From a float `$src` to an integer `$dst`
+macro_rules! from_float {
+ ($($src:ident, $usrc:ident => $($dst:ident),+);+;) => {
+ $(
+ $(
+ impl From<$src> for $dst {
+ type Output = Result<$dst, Error>;
+
+ #[inline]
+ fn cast(src: $src) -> Self::Output {
+ use core::{$dst, $src};
+
+ Err(if src != src {
+ Error::NaN
+ } else if src == $src::INFINITY ||
+ src == $src::NEG_INFINITY {
+ Error::Infinite
+ } else if {
+ // we subtract 1 ULP (unit of least precision) here because some
+ // lossy conversions like `u64::MAX as f64` round *up* and we want
+ // to avoid this evaluating to false in that case
+ use core::mem::transmute;
+ let max = unsafe {
+ transmute::<_, $src>(transmute::<_, $usrc>($dst::MAX as $src) - 1)
+ };
+ src > max
+ } {
+ Error::Overflow
+ } else if $dst::MIN == 0 {
+ // when casting to unsigned integer, negative values close to 0 but
+ // larger than 1.0 should be truncated to 0; this behavior matches
+ // casting from a float to a signed integer
+ if src <= -1.0 {
+ Error::Underflow
+ } else {
+ return Ok(src as $dst);
+ }
+ } else if src < $dst::MIN as $src {
+ Error::Underflow
+ } else {
+ return Ok(src as $dst);
+ })
+ }
+ }
+ )+
+ )+
+ }
+}
+
+/// From a float `$src` to an integer `$dst`, where $dst is large enough to contain
+/// all values of `$src`. We can't ever overflow here
+#[cfg(feature = "x128")]
+macro_rules! from_float_dst {
+ ($($src:ident => $($dst:ident),+);+;) => {
+ $(
+ $(
+ impl From<$src> for $dst {
+ type Output = Result<$dst, Error>;
+
+ #[inline]
+ #[allow(unused_comparisons)]
+ fn cast(src: $src) -> Self::Output {
+ use core::{$dst, $src};
+
+ Err(if src != src {
+ Error::NaN
+ } else if src == $src::INFINITY ||
+ src == $src::NEG_INFINITY {
+ Error::Infinite
+ } else if ($dst::MIN == 0) && src <= -1.0 {
+ Error::Underflow
+ } else {
+ return Ok(src as $dst);
+ })
+ }
+ }
+ )+
+ )+
+ }
+}
+
+// PLAY TETRIS! ;-)
+
+#[cfg(target_pointer_width = "32")]
+mod _32 {
+ use {Error, From};
+
+ // Signed
+ promotion! {
+ i8 => f32, f64, i8, i16, i32, isize, i64;
+ i16 => f32, f64, i16, i32, isize, i64;
+ i32 => f32, f64, i32, isize, i64;
+ isize => f32, f64, i32, isize, i64;
+ i64 => f32, f64, i64;
+ }
+
+ half_promotion! {
+ i8 => u8, u16, u32, usize, u64;
+ i16 => u16, u32, usize, u64;
+ i32 => u32, usize, u64;
+ isize => u32, usize, u64;
+ i64 => u64;
+ }
+
+ from_signed! {
+
+ i16 => i8, u8;
+ i32 => i8, i16, u8, u16;
+ isize => i8, i16, u8, u16;
+ i64 => i8, i16, i32, isize, u8, u16, u32, usize;
+ }
+
+ // Unsigned
+ promotion! {
+ u8 => f32, f64, i16, i32, isize, i64, u8, u16, u32, usize, u64;
+ u16 => f32, f64, i32, isize, i64, u16, u32, usize, u64;
+ u32 => f32, f64, i64, u32, usize, u64;
+ usize => f32, f64, i64, u32, usize, u64;
+ u64 => f32, f64, u64;
+ }
+
+ from_unsigned! {
+ u8 => i8;
+ u16 => i8, i16, u8;
+ u32 => i8, i16, i32, isize, u8, u16;
+ usize => i8, i16, i32, isize, u8, u16;
+ u64 => i8, i16, i32, isize, i64, u8, u16, u32, usize;
+ }
+
+ // Float
+ promotion! {
+ f32 => f32, f64;
+ f64 => f64;
+ }
+
+ from_float! {
+ f32, u32 => i8, i16, i32, isize, i64, u8, u16, u32, usize, u64;
+ f64, u64 => i8, i16, i32, isize, i64, u8, u16, u32, usize, u64;
+ }
+}
+
+#[cfg(target_pointer_width = "64")]
+mod _64 {
+ use {Error, From};
+
+ // Signed
+ promotion! {
+ i8 => f32, f64, i8, i16, i32, i64, isize;
+ i16 => f32, f64, i16, i32, i64, isize;
+ i32 => f32, f64, i32, i64, isize;
+ i64 => f32, f64, i64, isize;
+ isize => f32, f64, i64, isize;
+ }
+
+ half_promotion! {
+ i8 => u8, u16, u32, u64, usize;
+ i16 => u16, u32, u64, usize;
+ i32 => u32, u64, usize;
+ i64 => u64, usize;
+ isize => u64, usize;
+ }
+
+ from_signed! {
+
+ i16 => i8, u8;
+ i32 => i8, i16, u8, u16;
+ i64 => i8, i16, i32, u8, u16, u32;
+ isize => i8, i16, i32, u8, u16, u32;
+ }
+
+ // Unsigned
+ promotion! {
+ u8 => f32, f64, i16, i32, i64, isize, u8, u16, u32, u64, usize;
+ u16 => f32, f64, i32, i64, isize, u16, u32, u64, usize;
+ u32 => f32, f64, i64, isize, u32, u64, usize;
+ u64 => f32, f64, u64, usize;
+ usize => f32, f64, u64, usize;
+ }
+
+ from_unsigned! {
+ u8 => i8;
+ u16 => i8, i16, u8;
+ u32 => i8, i16, i32, u8, u16;
+ u64 => i8, i16, i32, i64, isize, u8, u16, u32;
+ usize => i8, i16, i32, i64, isize, u8, u16, u32;
+ }
+
+ // Float
+ promotion! {
+ f32 => f32, f64;
+ f64 => f64;
+ }
+
+ from_float! {
+ f32, u32 => i8, i16, i32, i64, isize, u8, u16, u32, u64, usize;
+ f64, u64 => i8, i16, i32, i64, isize, u8, u16, u32, u64, usize;
+ }
+}
+
+#[cfg(feature = "x128")]
+mod _x128 {
+ use {Error, From};
+
+ // Signed
+ promotion! {
+ i8 => i128;
+ i16 => i128;
+ i32 => i128;
+ i64 => i128;
+ isize => i128;
+ i128 => f32, f64, i128;
+ }
+
+ half_promotion! {
+ i8 => u128;
+ i16 => u128;
+ i32 => u128;
+ i64 => u128;
+ isize => u128;
+ i128 => u128;
+ }
+
+ from_signed! {
+ i128 => i8, i16, i32, i64, isize, u8, u16, u32, u64, usize;
+ }
+
+ // Unsigned
+ promotion! {
+ u8 => i128, u128;
+ u16 => i128, u128;
+ u32 => i128, u128;
+ u64 => i128, u128;
+ usize => i128, u128;
+ u128 => f64, u128;
+ }
+
+ from_unsigned! {
+ u128 => f32, i8, i16, i32, i64, i128, isize, u8, u16, u32, u64, usize;
+ }
+
+ // Float
+ from_float! {
+ f32, u32 => i128;
+ f64, u64 => i128, u128;
+ }
+
+ from_float_dst! {
+ f32 => u128;
+ }
+}
+
+// The missing piece
+impl From<f64> for f32 {
+ type Output = Result<f32, Error>;
+
+ #[inline]
+ fn cast(src: f64) -> Self::Output {
+ use core::{f32, f64};
+
+ if src != src || src == f64::INFINITY || src == f64::NEG_INFINITY {
+ Ok(src as f32)
+ } else if src < f32::MIN as f64 {
+ Err(Error::Underflow)
+ } else if src > f32::MAX as f64 {
+ Err(Error::Overflow)
+ } else {
+ Ok(src as f32)
+ }
+ }
+}
diff --git a/src/test.rs b/src/test.rs
new file mode 100644
index 0000000..6b619ab
--- /dev/null
+++ b/src/test.rs
@@ -0,0 +1,221 @@
+// If `src` can be promoted to `$dst`, then it must be Ok to cast `dst` back to
+// `$src`
+macro_rules! promote_and_back {
+ ($($src:ident => $($dst:ident),+);+;) => {
+ mod demoting_to {
+ $(
+ mod $src {
+ mod from {
+ use From;
+
+ $(
+ quickcheck! {
+ fn $dst(src: $src) -> bool {
+ $src::cast($dst::cast(src)).is_ok()
+ }
+ }
+ )+
+ }
+ }
+ )+
+ }
+ }
+}
+
+#[cfg(target_pointer_width = "32")]
+promote_and_back! {
+ i8 => f32, f64, i16, i32, isize, i64 ;
+ i16 => f32, f64, i32, isize, i64 ;
+ i32 => f32, f64, i64 ;
+ isize => f32, f64, i64 ;
+ i64 => f32, f64 ;
+ u8 => f32, f64, i16, i32, isize, i64, u16, u32, usize, u64;
+ u16 => f32, f64, i32, isize, i64, u32, usize, u64;
+ u32 => f32, f64, i64, u64;
+ usize => f32, f64, i64, u64;
+ u64 => f32, f64 ;
+}
+
+#[cfg(target_pointer_width = "64")]
+promote_and_back! {
+ i8 => f32, f64, i16, i32, i64, isize ;
+ i16 => f32, f64, i32, i64, isize ;
+ i32 => f32, f64, i64, isize ;
+ i64 => f32, f64 ;
+ isize => f32, f64 ;
+ u8 => f32, f64, i16, i32, i64, isize, u16, u32, u64, usize;
+ u16 => f32, f64, i32, i64, isize, u32, u64, usize;
+ u32 => f32, f64, i64, isize, u64, usize;
+ u64 => f32, f64 ;
+ usize => f32, f64 ;
+}
+
+// TODO uncomment this once quickcheck supports Arbitrary for i128/u128
+// https://github.com/BurntSushi/quickcheck/issues/162
+/*#[cfg(feature = "x128")]
+promote_and_back! {
+ i8 => i128 ;
+ i16 => i128 ;
+ i32 => i128 ;
+ isize => i128 ;
+ i64 => i128 ;
+ i128 => f32, f64 ;
+ u8 => i128, u128;
+ u16 => i128, u128;
+ u32 => i128, u128;
+ usize => i128, u128;
+ u64 => i128, u128;
+ u128 => f32, f64 ;
+}*/
+
+// If it's Ok to cast `src` to `$dst`, it must also be Ok to cast `dst` back to
+// `$src`
+macro_rules! symmetric_cast_between {
+ ($($src:ident => $($dst:ident),+);+;) => {
+ mod symmetric_cast_between {
+ $(
+ mod $src {
+ mod and {
+ use quickcheck::TestResult;
+
+ use From;
+
+ $(
+ quickcheck! {
+ fn $dst(src: $src) -> TestResult {
+ if let Ok(dst) = $dst::cast(src) {
+ TestResult::from_bool(
+ $src::cast(dst).is_ok())
+ } else {
+ TestResult::discard()
+ }
+ }
+ }
+ )+
+ }
+ }
+ )+
+ }
+ }
+}
+
+#[cfg(target_pointer_width = "32")]
+symmetric_cast_between! {
+ u8 => i8 ;
+ u16 => i8, i16 ;
+ u32 => i8, i16, i32 ;
+ usize => i8, i16, i32 ;
+ u64 => i8, i16, i32, i64, isize;
+}
+
+#[cfg(target_pointer_width = "64")]
+symmetric_cast_between! {
+ u8 => i8 ;
+ u16 => i8, i16 ;
+ u32 => i8, i16, i32 ;
+ u64 => i8, i16, i32, i64, isize;
+ usize => i8, i16, i32, i64, isize;
+}
+
+// TODO uncomment this once quickcheck supports Arbitrary for i128/u128
+// https://github.com/BurntSushi/quickcheck/issues/162
+/*#[cfg(feature = "x128")]
+symmetric_cast_between! {
+ u128 => i8, i16, i32, isize, i64, i128;
+}*/
+
+macro_rules! from_float {
+ ($($src:ident => $($dst:ident),+);+;) => {
+ $(
+ mod $src {
+ mod inf {
+ mod to {
+ use {Error, From};
+
+ $(
+ #[test]
+ fn $dst() {
+ let _0: $src = 0.;
+ let _1: $src = 1.;
+ let inf = _1 / _0;
+ let neg_inf = -_1 / _0;
+
+ assert_eq!($dst::cast(inf),
+ Err(Error::Infinite));
+ assert_eq!($dst::cast(neg_inf),
+ Err(Error::Infinite));
+ }
+ )+
+ }
+ }
+
+ mod nan {
+ mod to {
+ use {Error, From};
+
+ $(
+ #[test]
+ fn $dst() {
+ let _0: $src = 0.;
+ let nan = _0 / _0;
+
+ assert_eq!($dst::cast(nan),
+ Err(Error::NaN));
+ }
+ )+
+ }
+ }
+ }
+ )+
+ }
+}
+
+from_float! {
+ f32 => i8, i16, i32, i64, isize, u8, u16, u32, u64, usize;
+ f64 => i8, i16, i32, i64, isize, u8, u16, u32, u64, usize;
+}
+
+// TODO uncomment this once quickcheck supports Arbitrary for i128/u128
+// https://github.com/BurntSushi/quickcheck/issues/162
+/*#[cfg(feature = "x128")]
+from_float! {
+ f32 => i128, u128;
+ f64 => i128, u128;
+}*/
+
+#[test]
+#[cfg(feature = "x128")]
+fn test_fl_conversion() {
+ use u128;
+ assert_eq!(u128(42.0f32), Ok(42));
+}
+
+#[test]
+fn gh16() {
+ assert_eq!(super::u64(-0.01_f64), Ok(0));
+ assert_eq!(super::u64(-0.99_f32), Ok(0));
+
+ assert_eq!(super::u32(-0.99_f64), Ok(0));
+ assert_eq!(super::u32(-0.01_f32), Ok(0));
+
+ assert_eq!(super::u64(0.01_f64), Ok(0));
+ assert_eq!(super::u64(0.99_f32), Ok(0));
+
+ assert_eq!(super::u32(0.99_f64), Ok(0));
+ assert_eq!(super::u32(0.01_f32), Ok(0));
+}
+
+#[test]
+fn gh15() {
+ assert_eq!(super::u32(32_f32.exp2()), Err(super::Error::Overflow));
+ assert_eq!(super::u32(32_f64.exp2()), Err(super::Error::Overflow));
+
+ assert_eq!(super::u64(64_f32.exp2()), Err(super::Error::Overflow));
+ assert_eq!(super::u64(64_f64.exp2()), Err(super::Error::Overflow));
+
+ assert_eq!(super::u8(8_f32.exp2()), Err(super::Error::Overflow));
+ assert_eq!(super::u8(8_f64.exp2()), Err(super::Error::Overflow));
+
+ assert_eq!(super::u16(16_f32.exp2()), Err(super::Error::Overflow));
+ assert_eq!(super::u16(16_f64.exp2()), Err(super::Error::Overflow));
+}
