Merge pull request #102 from rust-osdev/mb2-hdr-no-std-fix

multiboot2-header: fix `no_std`-build + v0.1.1

Author: phip1611

multiboot2-header/Cargo.toml

@@ -4,7 +4,7 @@ description = """
 Library with type definitions and parsing functions for Multiboot2 headers.
 This library is `no_std` and can be used in bootloaders.
 """
-version = "0.1.0"
+version = "0.1.1"
 authors = [
     "Philipp Schuster <phip1611@gmail.com>"
 ]
@@ -27,6 +27,12 @@ homepage = "https://github.com/rust-osdev/multiboot2-header"
 repository = "https://github.com/rust-osdev/multiboot2"
 documentation = "https://docs.rs/multiboot2-header"
 
+[features]
+# by default, builder is included
+default = ["builder"]
+std = []
+builder = ["std"]
+
 [dependencies]
 # used for MBI tags
-multiboot2 = "0.12.2"
+multiboot2 = "0.13.2"

multiboot2-header/README.md

@@ -15,6 +15,18 @@ What this library is good for:
 What this library is not optimal for:
 - compiling a Multiboot2 header statically into an object file using only Rust code
 
+## Features and Usage in `no_std`
+This library is always `no_std`. However, the `builder`-feature requires the `alloc`-crate
+to be available. You need the `builder` only if you want to construct new headers. For parsing,
+this is not relevant.
+
+```toml
+# without `builder`-feature (and without `alloc`-crate)
+multiboot2-header = { version = "<latest>", default-features = false }
+# else (requires `alloc`-crate)
+multiboot2-header = "<latest>"
+```
+
 ## Example 1: Builder + Parse
 ```rust
 use multiboot2_header::builder::Multiboot2HeaderBuilder;

multiboot2-header/src/address.rs

@@ -1,4 +1,4 @@
-use crate::{HeaderTagFlag, HeaderTagType, StructAsBytes};
+use crate::{HeaderTagFlag, HeaderTagType};
 use core::mem::size_of;
 
 /// This information does not need to be provided if the kernel image is in ELF
@@ -65,4 +65,5 @@ impl AddressHeaderTag {
     }
 }
 
-impl StructAsBytes for AddressHeaderTag {}
+#[cfg(feature = "builder")]
+impl crate::StructAsBytes for AddressHeaderTag {}

multiboot2-header/src/console.rs

@@ -1,4 +1,4 @@
-use crate::{HeaderTagFlag, HeaderTagType, StructAsBytes};
+use crate::{HeaderTagFlag, HeaderTagType};
 use core::mem::size_of;
 
 /// Possible flags for [`ConsoleHeaderTag`].
@@ -46,7 +46,8 @@ impl ConsoleHeaderTag {
     }
 }
 
-impl StructAsBytes for ConsoleHeaderTag {}
+#[cfg(feature = "builder")]
+impl crate::StructAsBytes for ConsoleHeaderTag {}
 
 #[cfg(test)]
 mod tests {

multiboot2-header/src/end.rs

@@ -1,4 +1,4 @@
-use crate::{HeaderTagFlag, HeaderTagType, StructAsBytes};
+use crate::{HeaderTagFlag, HeaderTagType};
 use core::mem::size_of;
 
 /// Terminates a list of optional tags
@@ -33,4 +33,5 @@ impl EndHeaderTag {
     }
 }
 
-impl StructAsBytes for EndHeaderTag {}
+#[cfg(feature = "builder")]
+impl crate::StructAsBytes for EndHeaderTag {}

multiboot2-header/src/entry_efi_32.rs

@@ -1,4 +1,4 @@
-use crate::{HeaderTagFlag, HeaderTagType, StructAsBytes};
+use crate::{HeaderTagFlag, HeaderTagType};
 use core::fmt;
 use core::fmt::{Debug, Formatter};
 use core::mem::size_of;
@@ -50,4 +50,5 @@ impl Debug for EntryEfi32HeaderTag {
     }
 }
 
-impl StructAsBytes for EntryEfi32HeaderTag {}
+#[cfg(feature = "builder")]
+impl crate::StructAsBytes for EntryEfi32HeaderTag {}

multiboot2-header/src/entry_efi_64.rs

@@ -1,4 +1,4 @@
-use crate::{HeaderTagFlag, HeaderTagType, StructAsBytes};
+use crate::{HeaderTagFlag, HeaderTagType};
 use core::fmt;
 use core::fmt::{Debug, Formatter};
 use core::mem::size_of;
@@ -50,4 +50,5 @@ impl Debug for EntryEfi64HeaderTag {
     }
 }
 
-impl StructAsBytes for EntryEfi64HeaderTag {}
+#[cfg(feature = "builder")]
+impl crate::StructAsBytes for EntryEfi64HeaderTag {}

multiboot2-header/src/entry_header.rs

@@ -1,4 +1,4 @@
-use crate::{HeaderTagFlag, HeaderTagType, StructAsBytes};
+use crate::{HeaderTagFlag, HeaderTagType};
 use core::fmt;
 use core::fmt::{Debug, Formatter};
 use core::mem::size_of;
@@ -50,4 +50,5 @@ impl Debug for EntryHeaderTag {
     }
 }
 
-impl StructAsBytes for EntryHeaderTag {}
+#[cfg(feature = "builder")]
+impl crate::StructAsBytes for EntryHeaderTag {}

multiboot2-header/src/framebuffer.rs

@@ -1,4 +1,4 @@
-use crate::{HeaderTagFlag, HeaderTagType, StructAsBytes};
+use crate::{HeaderTagFlag, HeaderTagType};
 use core::mem::size_of;
 
 /// Specifies the preferred graphics mode. If this tag
@@ -48,4 +48,5 @@ impl FramebufferHeaderTag {
     }
 }
 
-impl StructAsBytes for FramebufferHeaderTag {}
+#[cfg(feature = "builder")]
+impl crate::StructAsBytes for FramebufferHeaderTag {}

multiboot2-header/src/header/builder.rs

@@ -6,6 +6,7 @@ use crate::{
     EntryEfi64HeaderTag, EntryHeaderTag, FramebufferHeaderTag, InformationRequestHeaderTagBuilder,
     ModuleAlignHeaderTag, Multiboot2BasicHeader, RelocatableHeaderTag, StructAsBytes,
 };
+use alloc::vec::Vec;
 use core::mem::size_of;
 
 /// Builder to construct a valid Multiboot2 header dynamically at runtime.