//! Rust binding to the [zstd library][zstd].

//!

//! This crate provides:

//!

//! * An [encoder](stream/write/struct.Encoder.html) to compress data using zstd

//!   and send the output to another write.

//! * A [decoder](stream/read/struct.Decoder.html) to read input data from a `Read`

//!   and decompress it.

//! * Convenient functions for common tasks.

//!

//! # Example

//!

//! ```no_run

//! use std::io;

//!

//! // Uncompress input and print the result.

//! zstd::stream::copy_decode(io::stdin(), io::stdout()).unwrap();

//! ```

//!

//! # Cargo features

//!

//! Enabled by default: `legacy`, `arrays`, `zdict_builder`.

//!

//! | Feature | Default | Description |

//! | --- | --- | --- |

//! | `arrays` | yes | Use fixed-size arrays (`[u8; N]`) as output buffers. |

//! | `legacy` | yes | Decode frames written by zstd versions older than 0.8. |

//! | `zdict_builder` | yes | Train new dictionaries. *Using* a dictionary always works. |

//! | `experimental` | | Expose zstd's experimental API, which has no stability guarantees. |

//! | `zstdmt` | | Multi-threaded compression inside the C library. |

//! | `thin` | | Build a smaller C library, at some cost in speed and error reporting. |

//! | `debug` | | Enable zstd's debug logs. |

//! | `no_asm` | | Do not build the x86-64 assembly. |

//! | `fat-lto`, `thin-lto` | | Cross-language LTO. Only works if `clang` builds the C library. |

//! | `bindgen` | | Generate the bindings at build time rather than using the pre-generated ones. |

//! | `pkg-config` | | Link against a system-installed libzstd instead of building the bundled source. |

//! | `vendored` | | Always build the bundled source, even when `pkg-config` is also enabled. |

//! | `cmake` | | Build the C library with zstd's own CMake files instead of the `cc` crate. |

//!

//! See the [readme] for more about the build-related ones.

//!

//! [zstd]: https://github.com/facebook/zstd

//! [readme]: https://github.com/gyscos/zstd-rs#cargo-features

#![deny(missing_docs)]

#![cfg_attr(feature = "doc-cfg", feature(doc_cfg))]

// Re-export the zstd-safe crate.

pub use zstd_safe;

pub mod bulk;

pub mod dict;

#[macro_use]

pub mod stream;

use std::io;

/// Default compression level.

pub use zstd_safe::CLEVEL_DEFAULT as DEFAULT_COMPRESSION_LEVEL;

/// The accepted range of compression levels.

pub fn compression_level_range(

) -> std::ops::RangeInclusive<zstd_safe::CompressionLevel> {

    zstd_safe::min_c_level()..=zstd_safe::max_c_level()

}

/// How large a buffer a compressed block might need, at worst.

///

/// This is what to reserve before [`bulk::compress_to_buffer()`], which writes

/// into a destination you provide rather than allocating one.

///

/// Re-exported from `zstd_safe`, where it lives alongside the rest of the

/// direct bindings.

pub use zstd_safe::compress_bound;

#[doc(no_inline)]

pub use crate::stream::{

    compress_file, compress_file_into, compress_sized, compress_sized_into,

    decode_all, decompressed_size, encode_all, Decoder, Encoder,

};

/// Returns the error message as io::Error based on error_code.

fn map_error_code(code: usize) -> io::Error {

    let msg = zstd_safe::get_error_name(code);

    io::Error::new(io::ErrorKind::Other, msg.to_string())

}

// Some helper functions to write full-cycle tests.

#[cfg(test)]

fn test_cycle<F, G>(data: &[u8], f: F, g: G)

where

    F: Fn(&[u8]) -> Vec<u8>,

    G: Fn(&[u8]) -> Vec<u8>,

{

    let mid = f(data);

    let end = g(&mid);

    assert_eq!(data, &end[..]);

}

#[cfg(test)]

fn test_cycle_unwrap<F, G>(data: &[u8], f: F, g: G)

where

    F: Fn(&[u8]) -> io::Result<Vec<u8>>,

    G: Fn(&[u8]) -> io::Result<Vec<u8>>,

{

    test_cycle(data, |data| f(data).unwrap(), |data| g(data).unwrap())

}

#[test]

fn default_compression_level_in_range() {

    assert!(compression_level_range().contains(&DEFAULT_COMPRESSION_LEVEL));

}