// Copyright (c) 2017 Gilad Naaman | |
// | |
// Permission is hereby granted, free of charge, to any person obtaining a copy | |
// of this software and associated documentation files (the "Software"), to deal | |
// in the Software without restriction, including without limitation the rights | |
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
// copies of the Software, and to permit persons to whom the Software is | |
// furnished to do so, subject to the following conditions: | |
// | |
// The above copyright notice and this permission notice shall be included in all | |
// copies or substantial portions of the Software. | |
// | |
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
// SOFTWARE. | |
//! A crate used for calculating offsets of struct members and their spans. | |
//! | |
//! This functionality currently can not be used in compile time code such as `const` or `const fn` definitions. | |
//! | |
//! ## Examples | |
//! ``` | |
//! #[macro_use] | |
//! extern crate memoffset; | |
//! | |
//! #[repr(C, packed)] | |
//! struct HelpMeIAmTrappedInAStructFactory { | |
//! help_me_before_they_: [u8; 15], | |
//! a: u32 | |
//! } | |
//! | |
//! fn main() { | |
//! assert_eq!(offset_of!(HelpMeIAmTrappedInAStructFactory, a), 15); | |
//! assert_eq!(span_of!(HelpMeIAmTrappedInAStructFactory, a), 15..19); | |
//! assert_eq!(span_of!(HelpMeIAmTrappedInAStructFactory, help_me_before_they_ .. a), 0..15); | |
//! } | |
//! ``` | |
//! | |
//! This functionality can be useful, for example, for checksum calculations: | |
//! | |
//! ```ignore | |
//! #[repr(C, packed)] | |
//! struct Message { | |
//! header: MessageHeader, | |
//! fragment_index: u32, | |
//! fragment_count: u32, | |
//! payload: [u8; 1024], | |
//! checksum: u16 | |
//! } | |
//! | |
//! let checksum_range = &raw[span_of!(Message, header..checksum)]; | |
//! let checksum = crc16(checksum_range); | |
//! ``` | |
#![no_std] | |
#[macro_use] | |
#[cfg(memoffset_doctests)] | |
#[cfg(doctest)] | |
extern crate doc_comment; | |
#[cfg(memoffset_doctests)] | |
#[cfg(doctest)] | |
doctest!("../README.md"); | |
// This `use` statement enables the macros to use `$crate::mem`. | |
// Doing this enables this crate to function under both std and no-std crates. | |
#[doc(hidden)] | |
pub use core::mem; | |
#[doc(hidden)] | |
pub use core::ptr; | |
#[macro_use] | |
mod offset_of; | |
#[macro_use] | |
mod span_of; |