103 lines
4.6 KiB
Markdown
103 lines
4.6 KiB
Markdown
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minimal-lexical
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===============
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This is a minimal version of [rust-lexical](https://github.com/Alexhuszagh/rust-lexical), meant to allow efficient round-trip float parsing. minimal-lexical implements a correct, fast float parser.
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Due to the small, stable nature of minimal-lexical, it is also well-adapted to private forks. If you do privately fork minimal-lexical, I recommend you contact me via [email](mailto:ahuszagh@gmail.com) or [Twitter](https://twitter.com/KardOnIce), so I can notify you of feature updates, bug fixes, or security vulnerabilities, as well as help you implement custom feature requests. I will not use your information for any other purpose, including, but not limited to disclosing your project or organization's use of minimal-lexical.
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minimal-lexical is designed for fast compile times and small binaries sizes, at the expense of a minor amount of performance. For improved performance, feel free to fork minimal-lexical with more aggressive inlining.
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**Similar Projects**
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For a high-level, all-in-one number conversion routines, see [rust-lexical](https://github.com/Alexhuszagh/rust-lexical).
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**Table Of Contents**
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- [Getting Started](#getting-started)
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- [Recipes](#recipes)
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- [Algorithms](#algorithms)
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- [Platform Support](platform-support)
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- [Minimum Version Support](minimum-version-support)
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- [Changelog](#changelog)
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- [License](#license)
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- [Contributing](#contributing)
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# Getting Started
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First, add the following to your `Cargo.toml`.
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```toml
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[dependencies]
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minimal-lexical = "0.2"
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```
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Next, to parse a simple float, use the following:
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```rust
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extern crate minimal_lexical;
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// Let's say we want to parse "1.2345".
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// First, we need an external parser to extract the integer digits ("1"),
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// the fraction digits ("2345"), and then parse the exponent to a 32-bit
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// integer (0).
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// Warning:
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// --------
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// Please note that leading zeros must be trimmed from the integer,
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// and trailing zeros must be trimmed from the fraction. This cannot
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// be handled by minimal-lexical, since we accept iterators
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let integer = b"1";
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let fraction = b"2345";
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let float: f64 = minimal_lexical::parse_float(integer.iter(), fraction.iter(), 0);
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println!("float={:?}", float); // 1.235
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```
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# Recipes
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You may be asking: where is the actual parser? Due to variation in float formats, and the goal of integrating utility for various data-interchange language parsers, such functionality would be beyond the scope of this library.
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For example, the following float is valid in Rust strings, but is invalid in JSON or TOML:
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```json
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1.e7
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```
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Therefore, to use the library, you need functionality that extracts the significant digits to pass to `create_float`. Please see [simple-example](https://github.com/Alexhuszagh/minimal-lexical/blob/master/examples/simple.rs) for a simple, annotated example on how to use minimal-lexical as a parser.
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# Algorithms
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For an in-depth explanation on the algorithms minimal-lexical uses, please see [lexical-core#string-to-float](https://github.com/Alexhuszagh/rust-lexical/tree/master/lexical-core#string-to-float).
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# Platform Support
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minimal-lexical is tested on a wide variety of platforms, including big and small-endian systems, to ensure portable code. Supported architectures include:
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- x86_64 Linux, Windows, macOS, Android, iOS, FreeBSD, and NetBSD.
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- x86 Linux, macOS, Android, iOS, and FreeBSD.
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- aarch64 (ARM8v8-A) Linux, Android, and iOS.
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- armv7 (ARMv7-A) Linux, Android, and iOS.
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- arm (ARMv6) Linux, and Android.
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- mips (MIPS) Linux.
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- mipsel (MIPS LE) Linux.
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- mips64 (MIPS64 BE) Linux.
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- mips64el (MIPS64 LE) Linux.
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- powerpc (PowerPC) Linux.
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- powerpc64 (PPC64) Linux.
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- powerpc64le (PPC64LE) Linux.
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- s390x (IBM Z) Linux.
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minimal-lexical should also work on a wide variety of other architectures and ISAs. If you have any issue compiling minimal-lexical on any architecture, please file a bug report.
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# Minimum Version Support
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Minimal-lexical is tested to support Rustc 1.36+, including stable, beta, and nightly. Please report any errors compiling a supported lexical version on a compatible Rustc version. Please note we may increment the MSRV for compiler versions older than 18 months, to support at least the current Debian stable version, without breaking changes.
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# Changelog
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All changes are documented in [CHANGELOG](CHANGELOG).
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# License
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Minimal-lexical is dual licensed under the Apache 2.0 license as well as the MIT license. See the [LICENSE.md](LICENSE.md) file for full license details.
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# Contributing
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Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in minimal-lexical by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
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