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Diffstat (limited to 'third_party/rust/scroll/src/lib.rs')
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diff --git a/third_party/rust/scroll/src/lib.rs b/third_party/rust/scroll/src/lib.rs new file mode 100644 index 0000000000..f16f153810 --- /dev/null +++ b/third_party/rust/scroll/src/lib.rs @@ -0,0 +1,526 @@ +//! # Scroll +//! +//! ```text, no_run +//! _______________ +//! ()==( (@==() +//! '______________'| +//! | | +//! | ἀρετή | +//! __)_____________| +//! ()==( (@==() +//! '--------------' +//! +//! ``` +//! +//! Scroll is a library for efficiently and easily reading/writing types from byte arrays. All the builtin types are supported, e.g., `u32`, `i8`, etc., where the type is specified as a type parameter, or type inferred when possible. In addition, it supports zero-copy reading of string slices, or any other kind of slice. The library can be used in a no_std context as well; the [Error](enum.Error.html) type only has the `IO` and `String` variants if the default features are used, and is `no_std` safe when compiled without default features. +//! +//! There are 3 traits for reading that you can import: +//! +//! 1. [Pread](trait.Pread.html), for reading (immutable) data at an offset; +//! 2. [Gread](trait.Gread.html), for reading data at an offset which automatically gets incremented by the size; +//! 3. [IOread](trait.IOread.html), for reading _simple_ data out of a `std::io::Read` based interface, e.g., a stream. (**Note**: only available when compiled with `std`) +//! +//! Each of these interfaces also have their corresponding writer versions as well, e.g., [Pwrite](trait.Pwrite.html), [Gwrite](trait.Gwrite.html), and [IOwrite](trait.IOwrite.html), respectively. +//! +//! Most familiar will likely be the `Pread` trait (inspired from the C function), which in our case takes an immutable reference to self, an immutable offset to read at, (and _optionally_ a parsing context, more on that later), and then returns the deserialized value. +//! +//! Because self is immutable, _**all** reads can be performed in parallel_ and hence are trivially parallelizable. +//! +//! For most usecases, you can use [scroll_derive](https://docs.rs/scroll_derive) to annotate your types with `derive(Pread, Pwrite, IOread, IOwrite, SizeWith)` to automatically add sensible derive defaults, and you should be ready to roll. For more complex usescases, you can implement the conversion traits yourself, see the [context module](ctx/index.html) for more information. +//! +//! # Example +//! +//! A simple example demonstrates its flexibility: +//! +//! ```rust +//! use scroll::{ctx, Pread, LE}; +//! let bytes: [u8; 4] = [0xde, 0xad, 0xbe, 0xef]; +//! +//! // reads a u32 out of `b` with the endianness of the host machine, at offset 0, turbofish-style +//! let number: u32 = bytes.pread::<u32>(0).unwrap(); +//! // ...or a byte, with type ascription on the binding. +//! let byte: u8 = bytes.pread(0).unwrap(); +//! +//! //If the type is known another way by the compiler, say reading into a struct field, we can omit the turbofish, and type ascription altogether! +//! +//! // If we want, we can explicitly add a endianness to read with by calling `pread_with`. +//! // The following reads a u32 out of `b` with Big Endian byte order, at offset 0 +//! let be_number: u32 = bytes.pread_with(0, scroll::BE).unwrap(); +//! // or a u16 - specify the type either on the variable or with the beloved turbofish +//! let be_number2 = bytes.pread_with::<u16>(2, scroll::BE).unwrap(); +//! +//! // Scroll has core friendly errors (no allocation). This will have the type `scroll::Error::BadOffset` because it tried to read beyond the bound +//! let byte: scroll::Result<i64> = bytes.pread(0); +//! +//! // Scroll is extensible: as long as the type implements `TryWithCtx`, then you can read your type out of the byte array! +//! +//! // We can parse out custom datatypes, or types with lifetimes +//! // if they implement the conversion trait `TryFromCtx`; here we parse a C-style \0 delimited &str (safely) +//! let hello: &[u8] = b"hello_world\0more words"; +//! let hello_world: &str = hello.pread(0).unwrap(); +//! assert_eq!("hello_world", hello_world); +//! +//! // ... and this parses the string if its space separated! +//! use scroll::ctx::*; +//! let spaces: &[u8] = b"hello world some junk"; +//! let world: &str = spaces.pread_with(6, StrCtx::Delimiter(SPACE)).unwrap(); +//! assert_eq!("world", world); +//! ``` +//! +//! # `std::io` API +//! +//! Scroll can also read/write simple types from a `std::io::Read` or `std::io::Write` implementor. The built-in numeric types are taken care of for you. If you want to read a custom type, you need to implement the [FromCtx](trait.FromCtx.html) (_how_ to parse) and [SizeWith](ctx/trait.SizeWith.html) (_how_ big the parsed thing will be) traits. You must compile with default features. For example: +//! +//! ```rust +//! use std::io::Cursor; +//! use scroll::IOread; +//! let bytes_ = [0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00, 0xef,0xbe,0x00,0x00,]; +//! let mut bytes = Cursor::new(bytes_); +//! +//! // this will bump the cursor's Seek +//! let foo = bytes.ioread::<u64>().unwrap(); +//! // ..ditto +//! let bar = bytes.ioread::<u32>().unwrap(); +//! ``` +//! +//! Similarly, we can write to anything that implements `std::io::Write` quite naturally: +//! +//! ```rust +//! use scroll::{IOwrite, LE, BE}; +//! use std::io::{Write, Cursor}; +//! +//! let mut bytes = [0x0u8; 10]; +//! let mut cursor = Cursor::new(&mut bytes[..]); +//! cursor.write_all(b"hello").unwrap(); +//! cursor.iowrite_with(0xdeadbeef as u32, BE).unwrap(); +//! assert_eq!(cursor.into_inner(), [0x68, 0x65, 0x6c, 0x6c, 0x6f, 0xde, 0xad, 0xbe, 0xef, 0x0]); +//! ``` +//! +//! # Advanced Uses +//! +//! Scroll is designed to be highly configurable - it allows you to implement various context (`Ctx`) sensitive traits, which then grants the implementor _automatic_ uses of the `Pread` and/or `Pwrite` traits. +//! +//! For example, suppose we have a datatype and we want to specify how to parse or serialize this datatype out of some arbitrary +//! byte buffer. In order to do this, we need to provide a [TryFromCtx](trait.TryFromCtx.html) impl for our datatype. +//! +//! In particular, if we do this for the `[u8]` target, using the convention `(usize, YourCtx)`, you will automatically get access to +//! calling `pread_with::<YourDatatype>` on arrays of bytes. +//! +//! ```rust +//! use scroll::{self, ctx, Pread, BE, Endian}; +//! +//! struct Data<'a> { +//! name: &'a str, +//! id: u32, +//! } +//! +//! // note the lifetime specified here +//! impl<'a> ctx::TryFromCtx<'a, Endian> for Data<'a> { +//! type Error = scroll::Error; +//! // and the lifetime annotation on `&'a [u8]` here +//! fn try_from_ctx (src: &'a [u8], endian: Endian) +//! -> Result<(Self, usize), Self::Error> { +//! let offset = &mut 0; +//! let name = src.gread::<&str>(offset)?; +//! let id = src.gread_with(offset, endian)?; +//! Ok((Data { name: name, id: id }, *offset)) +//! } +//! } +//! +//! let bytes = b"UserName\x00\x01\x02\x03\x04"; +//! let data = bytes.pread_with::<Data>(0, BE).unwrap(); +//! assert_eq!(data.id, 0x01020304); +//! assert_eq!(data.name.to_string(), "UserName".to_string()); +//! ``` +//! +//! Please see the [Pread documentation examples](trait.Pread.html#implementing-your-own-reader) + +#![cfg_attr(not(feature = "std"), no_std)] + +#[cfg(feature = "derive")] +#[allow(unused_imports)] +pub use scroll_derive::{Pread, Pwrite, SizeWith, IOread, IOwrite}; + +#[cfg(feature = "std")] +extern crate core; + +pub mod ctx; +mod pread; +mod pwrite; +mod greater; +mod error; +mod endian; +mod leb128; +#[cfg(feature = "std")] +mod lesser; + +pub use crate::endian::*; +pub use crate::pread::*; +pub use crate::pwrite::*; +pub use crate::greater::*; +pub use crate::error::*; +pub use crate::leb128::*; +#[cfg(feature = "std")] +pub use crate::lesser::*; + +#[doc(hidden)] +pub mod export { + pub use ::core::result; + pub use ::core::mem; +} + +#[cfg(test)] +mod tests { + #[allow(overflowing_literals)] + use super::{LE}; + + #[test] + fn test_measure_with_bytes() { + use super::ctx::MeasureWith; + let bytes: [u8; 4] = [0xef, 0xbe, 0xad, 0xde]; + assert_eq!(bytes.measure_with(&()), 4); + } + + #[test] + fn test_measurable() { + use super::ctx::SizeWith; + assert_eq!(8, u64::size_with(&LE)); + } + + ////////////////////////////////////////////////////////////// + // begin pread_with + ////////////////////////////////////////////////////////////// + + macro_rules! pwrite_test { + ($write:ident, $read:ident, $deadbeef:expr) => { + #[test] + fn $write() { + use super::{Pwrite, Pread, BE}; + let mut bytes: [u8; 8] = [0, 0, 0, 0, 0, 0, 0, 0]; + let b = &mut bytes[..]; + b.pwrite_with::<$read>($deadbeef, 0, LE).unwrap(); + assert_eq!(b.pread_with::<$read>(0, LE).unwrap(), $deadbeef); + b.pwrite_with::<$read>($deadbeef, 0, BE).unwrap(); + assert_eq!(b.pread_with::<$read>(0, BE).unwrap(), $deadbeef); + } + } + } + + pwrite_test!(pwrite_and_pread_roundtrip_u16, u16, 0xbeef); + pwrite_test!(pwrite_and_pread_roundtrip_i16, i16, 0x7eef); + pwrite_test!(pwrite_and_pread_roundtrip_u32, u32, 0xbeefbeef); + pwrite_test!(pwrite_and_pread_roundtrip_i32, i32, 0x7eefbeef); + pwrite_test!(pwrite_and_pread_roundtrip_u64, u64, 0xbeefbeef7eef7eef); + pwrite_test!(pwrite_and_pread_roundtrip_i64, i64, 0x7eefbeef7eef7eef); + + #[test] + fn pread_with_be() { + use super::{Pread}; + let bytes: [u8; 2] = [0x7e, 0xef]; + let b = &bytes[..]; + let byte: u16 = b.pread_with(0, super::BE).unwrap(); + assert_eq!(0x7eef, byte); + let bytes: [u8; 2] = [0xde, 0xad]; + let dead: u16 = bytes.pread_with(0, super::BE).unwrap(); + assert_eq!(0xdead, dead); + } + + #[test] + fn pread() { + use super::{Pread}; + let bytes: [u8; 2] = [0x7e, 0xef]; + let b = &bytes[..]; + let byte: u16 = b.pread(0).unwrap(); + #[cfg(target_endian = "little")] + assert_eq!(0xef7e, byte); + #[cfg(target_endian = "big")] + assert_eq!(0x7eef, byte); + } + + #[test] + fn pread_slice() { + use super::{Pread}; + use super::ctx::StrCtx; + let bytes: [u8; 2] = [0x7e, 0xef]; + let b = &bytes[..]; + let iserr: Result<&str, _> = b.pread_with(0, StrCtx::Length(3)); + assert!(iserr.is_err()); + // let bytes2: &[u8] = b.pread_with(0, 2).unwrap(); + // assert_eq!(bytes2.len(), bytes[..].len()); + // for i in 0..bytes2.len() { + // assert_eq!(bytes2[i], bytes[i]) + // } + } + + #[test] + fn pread_str() { + use super::Pread; + use super::ctx::*; + let bytes: [u8; 2] = [0x2e, 0x0]; + let b = &bytes[..]; + let s: &str = b.pread(0).unwrap(); + println!("str: {}", s); + assert_eq!(s.len(), bytes[..].len() - 1); + let bytes: &[u8] = b"hello, world!\0some_other_things"; + let hello_world: &str = bytes.pread_with(0, StrCtx::Delimiter(NULL)).unwrap(); + println!("{:?}", &hello_world); + assert_eq!(hello_world.len(), 13); + let hello: &str = bytes.pread_with(0, StrCtx::Delimiter(SPACE)).unwrap(); + println!("{:?}", &hello); + assert_eq!(hello.len(), 6); + // this could result in underflow so we just try it + let _error = bytes.pread_with::<&str>(6, StrCtx::Delimiter(SPACE)); + let error = bytes.pread_with::<&str>(7, StrCtx::Delimiter(SPACE)); + println!("{:?}", &error); + assert!(error.is_ok()); + } + + #[test] + fn pread_str_weird() { + use super::Pread; + use super::ctx::*; + let bytes: &[u8] = b""; + let hello_world = bytes.pread_with::<&str>(0, StrCtx::Delimiter(NULL)); + println!("1 {:?}", &hello_world); + assert_eq!(hello_world.is_err(), true); + let error = bytes.pread_with::<&str>(7, StrCtx::Delimiter(SPACE)); + println!("2 {:?}", &error); + assert!(error.is_err()); + let bytes: &[u8] = b"\0"; + let null = bytes.pread::<&str>(0).unwrap(); + println!("3 {:?}", &null); + assert_eq!(null.len(), 0); + } + + #[test] + fn pwrite_str_and_bytes() { + use super::{Pread, Pwrite}; + use super::ctx::*; + let astring: &str = "lol hello_world lal\0ala imabytes"; + let mut buffer = [0u8; 33]; + buffer.pwrite(astring, 0).unwrap(); + { + let hello_world = buffer.pread_with::<&str>(4, StrCtx::Delimiter(SPACE)).unwrap(); + assert_eq!(hello_world, "hello_world"); + } + let bytes: &[u8] = b"more\0bytes"; + buffer.pwrite(bytes, 0).unwrap(); + let more = bytes.pread_with::<&str>(0, StrCtx::Delimiter(NULL)).unwrap(); + assert_eq!(more, "more"); + let bytes = bytes.pread_with::<&str>(more.len() + 1, StrCtx::Delimiter(NULL)).unwrap(); + assert_eq!(bytes, "bytes"); + } + + use std::error; + use std::fmt::{self, Display}; + + #[derive(Debug)] + pub struct ExternalError {} + + impl Display for ExternalError { + fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { + write!(fmt, "ExternalError") + } + } + + impl error::Error for ExternalError { + fn description(&self) -> &str { + "ExternalError" + } + fn cause(&self) -> Option<&dyn error::Error> { None} + } + + impl From<super::Error> for ExternalError { + fn from(err: super::Error) -> Self { + //use super::Error::*; + match err { + _ => ExternalError{}, + } + } + } + + #[derive(Debug, PartialEq, Eq)] + pub struct Foo(u16); + + impl super::ctx::TryIntoCtx<super::Endian> for Foo { + type Error = ExternalError; + fn try_into_ctx(self, this: &mut [u8], le: super::Endian) -> Result<usize, Self::Error> { + use super::Pwrite; + if this.len() < 2 { return Err((ExternalError {}).into()) } + this.pwrite_with(self.0, 0, le)?; + Ok(2) + } + } + + impl<'a> super::ctx::TryFromCtx<'a, super::Endian> for Foo { + type Error = ExternalError; + fn try_from_ctx(this: &'a [u8], le: super::Endian) -> Result<(Self, usize), Self::Error> { + use super::Pread; + if this.len() > 2 { return Err((ExternalError {}).into()) } + let n = this.pread_with(0, le)?; + Ok((Foo(n), 2)) + } + } + + #[test] + fn pread_with_iter_bytes() { + use super::{Pread}; + let mut bytes_to: [u8; 8] = [0, 0, 0, 0, 0, 0, 0, 0]; + let bytes_from: [u8; 8] = [1, 2, 3, 4, 5, 6, 7, 8]; + let bytes_to = &mut bytes_to[..]; + let bytes_from = &bytes_from[..]; + for i in 0..bytes_from.len() { + bytes_to[i] = bytes_from.pread(i).unwrap(); + } + assert_eq!(bytes_to, bytes_from); + } + + ////////////////////////////////////////////////////////////// + // end pread_with + ////////////////////////////////////////////////////////////// + + ////////////////////////////////////////////////////////////// + // begin gread_with + ////////////////////////////////////////////////////////////// + macro_rules! g_test { + ($read:ident, $deadbeef:expr, $typ:ty) => { + #[test] + fn $read() { + use super::Pread; + let bytes: [u8; 8] = [0xf, 0xe, 0xe, 0xb, 0xd, 0xa, 0xe, 0xd]; + let mut offset = 0; + let deadbeef: $typ = bytes.gread_with(&mut offset, LE).unwrap(); + assert_eq!(deadbeef, $deadbeef as $typ); + assert_eq!(offset, ::std::mem::size_of::<$typ>()); + } + } + } + + g_test!(simple_gread_u16, 0xe0f, u16); + g_test!(simple_gread_u32, 0xb0e0e0f, u32); + g_test!(simple_gread_u64, 0xd0e0a0d0b0e0e0f, u64); + g_test!(simple_gread_i64, 940700423303335439, i64); + + macro_rules! simple_float_test { + ($read:ident, $deadbeef:expr, $typ:ty) => { + #[test] + fn $read() { + use super::Pread; + let bytes: [u8; 8] = [0u8, 0, 0, 0, 0, 0, 224, 63]; + let mut offset = 0; + let deadbeef: $typ = bytes.gread_with(&mut offset, LE).unwrap(); + assert_eq!(deadbeef, $deadbeef as $typ); + assert_eq!(offset, ::std::mem::size_of::<$typ>()); + } + }; + } + + simple_float_test!(gread_f32, 0.0, f32); + simple_float_test!(gread_f64, 0.5, f64); + + macro_rules! g_read_write_test { + ($read:ident, $val:expr, $typ:ty) => { + #[test] + fn $read() { + use super::{LE, BE, Pread, Pwrite}; + let mut buffer = [0u8; 16]; + let offset = &mut 0; + buffer.gwrite_with($val.clone(), offset, LE).unwrap(); + let o2 = &mut 0; + let val: $typ = buffer.gread_with(o2, LE).unwrap(); + assert_eq!(val, $val); + assert_eq!(*offset, ::std::mem::size_of::<$typ>()); + assert_eq!(*o2, ::std::mem::size_of::<$typ>()); + assert_eq!(*o2, *offset); + buffer.gwrite_with($val.clone(), offset, BE).unwrap(); + let val: $typ = buffer.gread_with(o2, BE).unwrap(); + assert_eq!(val, $val); + } + }; + } + + g_read_write_test!(gread_gwrite_f64_1, 0.25f64, f64); + g_read_write_test!(gread_gwrite_f64_2, 0.5f64, f64); + g_read_write_test!(gread_gwrite_f64_3, 0.064, f64); + + g_read_write_test!(gread_gwrite_f32_1, 0.25f32, f32); + g_read_write_test!(gread_gwrite_f32_2, 0.5f32, f32); + g_read_write_test!(gread_gwrite_f32_3, 0.0f32, f32); + + g_read_write_test!(gread_gwrite_i64_1, 0i64, i64); + g_read_write_test!(gread_gwrite_i64_2, -1213213211111i64, i64); + g_read_write_test!(gread_gwrite_i64_3, -3000i64, i64); + + g_read_write_test!(gread_gwrite_i32_1, 0i32, i32); + g_read_write_test!(gread_gwrite_i32_2, -1213213232, i32); + g_read_write_test!(gread_gwrite_i32_3, -3000i32, i32); + + // useful for ferreting out problems with impls + #[test] + fn gread_with_iter_bytes() { + use super::{Pread}; + let mut bytes_to: [u8; 8] = [0, 0, 0, 0, 0, 0, 0, 0]; + let bytes_from: [u8; 8] = [1, 2, 3, 4, 5, 6, 7, 8]; + let bytes_to = &mut bytes_to[..]; + let bytes_from = &bytes_from[..]; + let mut offset = &mut 0; + for i in 0..bytes_from.len() { + bytes_to[i] = bytes_from.gread(&mut offset).unwrap(); + } + assert_eq!(bytes_to, bytes_from); + assert_eq!(*offset, bytes_to.len()); + } + + #[test] + fn gread_inout() { + use super::{Pread}; + let mut bytes_to: [u8; 8] = [0, 0, 0, 0, 0, 0, 0, 0]; + let bytes_from: [u8; 8] = [1, 2, 3, 4, 5, 6, 7, 8]; + let bytes = &bytes_from[..]; + let offset = &mut 0; + bytes.gread_inout(offset, &mut bytes_to[..]).unwrap(); + assert_eq!(bytes_to, bytes_from); + assert_eq!(*offset, bytes_to.len()); + } + + #[test] + fn gread_with_byte() { + use super::{Pread}; + let bytes: [u8; 1] = [0x7f]; + let b = &bytes[..]; + let offset = &mut 0; + let byte: u8 = b.gread(offset).unwrap(); + assert_eq!(0x7f, byte); + assert_eq!(*offset, 1); + } + + #[test] + fn gread_slice() { + use super::{Pread}; + use super::ctx::{StrCtx}; + let bytes: [u8; 2] = [0x7e, 0xef]; + let b = &bytes[..]; + let offset = &mut 0; + let res = b.gread_with::<&str>(offset, StrCtx::Length(3)); + assert!(res.is_err()); + *offset = 0; + let astring: [u8; 3] = [0x45, 042, 0x44]; + let string = astring.gread_with::<&str>(offset, StrCtx::Length(2)); + match &string { + &Ok(_) => {}, + &Err(ref err) => {println!("{}", &err); panic!();} + } + assert_eq!(string.unwrap(), "E*"); + *offset = 0; + let bytes2: &[u8] = b.gread_with(offset, 2).unwrap(); + assert_eq!(*offset, 2); + assert_eq!(bytes2.len(), bytes[..].len()); + for i in 0..bytes2.len() { + assert_eq!(bytes2[i], bytes[i]) + } + } + + ///////////////////////////////////////////////////////////////// + // end gread_with + ///////////////////////////////////////////////////////////////// +} |