Lots of changes

Cargo.lock

@@ -2,15 +2,13 @@
 # It is not intended for manual editing.
 [[package]]
 name = "libc"
-version = "0.2.60"
+version = "0.2.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dea0c0405123bba743ee3f91f49b1c7cfb684eef0da0a50110f758ccf24cdff0"
 
 [[package]]
 name = "neco"
 version = "0.1.0"
 dependencies = [
- "libc 0.2.60 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc",
 ]
-
-[metadata]
-"checksum libc 0.2.60 (registry+https://github.com/rust-lang/crates.io-index)" = "d44e80633f007889c7eff624b709ab43c92d708caad982295768a7b13ca3b5eb"

Cargo.toml

@@ -5,7 +5,7 @@ authors = ["Matthias Schiffer <mschiffer@universe-factory.net>"]
 edition = "2018"
 
 [dependencies]
-libc = { version = "0.2.54", default-features = false }
+libc = { version = "0.2.68", default-features = false }
 
 [profile.dev]
 panic = "abort"

src/c/posix.rs

@@ -1,8 +1,7 @@
 extern "C" {
 	pub fn strndup(cs: *const libc::c_char, n: libc::size_t) -> *mut libc::c_char;
 
-	pub static mut stdin: *mut libc::FILE;
-	pub static mut stdout: *mut libc::FILE;
-	pub static mut stderr: *mut libc::FILE;
-
+	// pub static stdin: *mut libc::FILE;
+	pub static stdout: *mut libc::FILE;
+	pub static stderr: *mut libc::FILE;
 }

src/c/stdio.rs

@@ -7,8 +7,12 @@ pub struct OStream {
 	file: *mut libc::FILE
 }
 
-pub fn stdout() -> OStream {
-	OStream { file: unsafe { posix::stdout } }
+pub unsafe fn stdout() -> OStream {
+	OStream { file: posix::stdout }
+}
+
+pub unsafe fn stderr() -> OStream {
+	OStream { file: posix::stderr }
 }
 
 impl OStream {

src/c/string.rs

@@ -3,18 +3,20 @@ use core::{mem, ptr, slice};
 use core::ops::{Deref, DerefMut};
 
 fn must_succeed<T>(p: *mut T) -> *mut T {
-	if p.is_null() {
-		panic!("allocation failure");
-	}
+	assert!(!p.is_null(), "allocation failure");
 	p
 }
 
-fn malloc<T>() -> *mut T {
-	let size = mem::size_of::<T>();
-	let align = mem::align_of::<T>();
-	if size == 0 {
-		return align as *mut T;
+fn zst<T>(count: usize) -> bool {
+	mem::size_of::<T>() == 0 || count == 0
+}
+
+fn alloc<T>(count: usize) -> *mut T {
+	if zst::<T>(count) {
+		return ptr::null_mut();
 	}
+	let size = count * mem::size_of::<T>();
+	let align = mem::align_of::<T>();
 	must_succeed(
 		unsafe {
 			libc::memalign(align as libc::size_t, size as libc::size_t) as *mut T
@@ -22,18 +24,23 @@ fn malloc<T>() -> *mut T {
 	)
 }
 
-pub struct CBox<T>(*mut T);
+fn dangling<T>() -> *mut T {
+	mem::align_of::<T>() as *mut T
+}
 
-impl<T> CBox<T> {
-	pub fn new(value: T) -> CBox<T> {
-		let p = malloc();
-		unsafe {
-			ptr::write(p, value);
-			CBox::from_raw(p)
-		}
-	}
+fn check_ptr<T>(p: *const T, len: usize) {
+	debug_assert!((p as usize) % mem::align_of::<T>() == 0, "unaligned ptr");
+	assert!(zst::<T>(len) || !p.is_null(), "NULL ptr");
+}
 
-	pub const unsafe fn from_raw(p: *mut T) -> CBox<T> {
+fn slice_len<T>(p: *const [T]) -> usize {
+	unsafe { mem::transmute::<*const [T], [usize; 2]>(p)[1] }
+}
+
+pub struct CBox<T: ?Sized>(*mut T);
+
+impl<T: ?Sized> CBox<T> {
+	pub unsafe fn from_raw_unchecked(p: *mut T) -> CBox<T> {
 		CBox(p)
 	}
 
@@ -43,7 +50,7 @@ impl<T> CBox<T> {
 		p
 	}
 
-	pub const fn as_ptr(&self) -> *const T {
+	pub fn as_ptr(&self) -> *const T {
 		self.0
 	}
 
@@ -52,13 +59,56 @@ impl<T> CBox<T> {
 	}
 }
 
-impl<T> Drop for CBox<T> {
+impl<T> CBox<T> {
+	pub fn new(value: T) -> CBox<T> {
+		let p = alloc(1);
+		unsafe {
+			ptr::write(p, value);
+			CBox::from_raw_unchecked(p)
+		}
+	}
+
+	pub unsafe fn from_raw(p: *mut T) -> CBox<T> {
+		check_ptr(p, 1);
+		CBox(p)
+	}
+
+	pub unsafe fn slice_from_raw_parts_unchecked(p: *mut T, len: usize) -> CBox<[T]> {
+		CBox(ptr::slice_from_raw_parts_mut(p, len))
+	}
+
+	pub unsafe fn slice_from_raw_parts(p: *mut T, len: usize) -> CBox<[T]> {
+		check_ptr(p, len);
+		CBox::slice_from_raw_parts_unchecked(p, len)
+	}
+
+	fn safe_ptr(&self) -> *mut T {
+		if self.0.is_null() {
+			debug_assert!(zst::<T>(1), "NULL ptr");
+			return dangling();
+		}
+
+		self.0
+	}
+}
+
+impl<T> CBox<[T]> {
+	fn safe_ptr(&self) -> *mut [T] {
+		if self.0.is_null() {
+			let len = slice_len(self.0);
+			debug_assert!(zst::<T>(len), "NULL ptr");
+			return ptr::slice_from_raw_parts_mut(dangling(), len);
+		}
+
+		self.0
+	}
+}
+
+impl<T: ?Sized> Drop for CBox<T> {
 	fn drop(&mut self) {
-		unsafe { ptr::drop_in_place(self.0); }
-		if mem::size_of::<T>() != 0 {
-			unsafe {
-				libc::free(self.0 as *mut libc::c_void);
-			}
+		unsafe {
+			ptr::drop_in_place(self.0);
+			libc::free(self.0 as *mut libc::c_void);
 		}
 	}
 }
@@ -67,13 +117,27 @@ impl<T> Deref for CBox<T> {
 	type Target = T;
 
 	fn deref(&self) -> &T {
-		unsafe { &*self.0 }
+		unsafe { &*self.safe_ptr() }
 	}
 }
 
 impl<T> DerefMut for CBox<T> {
 	fn deref_mut(&mut self) -> &mut T {
-		unsafe { &mut *self.0 }
+		unsafe { &mut *self.safe_ptr() }
+	}
+}
+
+impl<T> Deref for CBox<[T]> {
+	type Target = [T];
+
+	fn deref(&self) -> &[T] {
+		unsafe { &*self.safe_ptr() }
+	}
+}
+
+impl<T> DerefMut for CBox<[T]> {
+	fn deref_mut(&mut self) -> &mut [T] {
+		unsafe { &mut *self.safe_ptr() }
 	}
 }
 
@@ -82,16 +146,26 @@ impl<T> DerefMut for CBox<T> {
 pub struct CStr { inner: libc::c_char }
 
 impl CStr {
-	pub unsafe fn from_ptr<'a>(p: *const libc::c_char) -> &'a CStr {
+	pub unsafe fn from_ptr_unchecked<'a>(p: *const libc::c_char) -> &'a CStr {
 		&*(p as *const CStr)
 	}
 
-	pub unsafe fn from_ptr_mut<'a>(p: *mut libc::c_char) -> &'a mut CStr {
+	pub unsafe fn from_ptr<'a>(p: *const libc::c_char) -> &'a CStr {
+		check_ptr(p, 1);
+		CStr::from_ptr_unchecked(p)
+	}
+
+	pub unsafe fn from_mut_ptr_unchecked<'a>(p: *mut libc::c_char) -> &'a mut CStr {
 		&mut *(p as *mut CStr)
 	}
 
+	pub unsafe fn from_mut_ptr<'a>(p: *mut libc::c_char) -> &'a mut CStr {
+		check_ptr(p, 1);
+		CStr::from_mut_ptr_unchecked(p)
+	}
+
 	pub unsafe fn from_bytes_with_nul_unchecked(bytes: &[u8]) -> &CStr {
-		CStr::from_ptr(bytes.as_ptr() as *const libc::c_char)
+		CStr::from_ptr_unchecked(bytes.as_ptr() as *const libc::c_char)
 	}
 
 	// TODO
@@ -117,7 +191,7 @@ impl CStr {
 		) }
 	}
 
-	pub fn as_bytes_mut(&mut self) -> &mut [u8] {
+	pub fn as_mut_bytes(&mut self) -> &mut [u8] {
 		unsafe { slice::from_raw_parts_mut(
 			self.as_mut_ptr() as *mut u8,
 			self.len(),
@@ -139,6 +213,10 @@ macro_rules! cstr {
 pub struct CString { inner: CBox<libc::c_char> }
 
 impl CString {
+	pub unsafe fn from_raw_unchecked(p: *mut libc::c_char) -> CString {
+		CString { inner: CBox::from_raw_unchecked(p) }
+	}
+
 	pub unsafe fn from_raw(p: *mut libc::c_char) -> CString {
 		CString { inner: CBox::from_raw(p) }
 	}
@@ -158,14 +236,14 @@ impl Deref for CString {
 
 impl DerefMut for CString {
 	fn deref_mut(&mut self) -> &mut CStr {
-		unsafe { CStr::from_ptr_mut(&mut *self.inner) }
+		unsafe { CStr::from_mut_ptr(&mut *self.inner) }
 	}
 }
 
 impl From<&[u8]> for CString {
 	fn from(s: &[u8]) -> CString {
 		unsafe {
-			CString::from_raw(must_succeed(posix::strndup(
+			CString::from_raw_unchecked(must_succeed(posix::strndup(
 				s.as_ptr() as *const libc::c_char,
 				s.len() as libc::size_t,
 			)))
@@ -182,7 +260,7 @@ impl From<&str> for CString {
 impl From<&CStr> for CString {
 	fn from(s: &CStr) -> CString {
 		unsafe {
-			CString::from_raw(must_succeed(libc::strdup(s.as_ptr())))
+			CString::from_raw_unchecked(must_succeed(libc::strdup(s.as_ptr())))
 		}
 	}
 }

src/main.rs

@@ -9,16 +9,22 @@ use core::fmt::Write;
 
 #[no_mangle]
 pub extern "C" fn main(_nargs: libc::c_int, _args: *const *const libc::c_char) -> libc::c_int {
+	let mut stdout = unsafe { c::stdio::stdout() };
 	let x = c::string::CString::from("foo");
-	let y = c::string::CBox::new(x);
+	let l = x.len();
+	let y = x.into_raw();
+	let z = unsafe {
+		c::string::CBox::slice_from_raw_parts(y, l)
+	};
+	//let y = unsafe { c::string::CBox::from_raw(x) };
 	//let foo = cstr!("Foo! %p\n");
 	//c::stdio::stdout().puts(foo);
-	let mut stdout = c::stdio::stdout();
-	writeln!(stdout, "Foo: {}", 42);
+	let _ = writeln!(stdout, "Foo: {} {} {}", z[0], z[1], z[2]);
 	0
 }
 
 #[panic_handler]
-fn panic(_info: &core::panic::PanicInfo) -> ! {
+fn panic(info: &core::panic::PanicInfo) -> ! {
+	let _ = writeln!(unsafe { c::stdio::stderr() }, "Panic: {}", info);
 	unsafe { libc::abort() }
 }