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use core::fmt;
use crate::parse;
/// An Objective-C type-encoding.
///
/// Can be retrieved in Objective-C for a type `T` using the `@encode(T)`
/// directive.
/// ```objc
/// NSLog(@"Encoding of NSException: %s", @encode(NSException));
/// ```
///
/// The [`Display`][`fmt::Display`] implementation converts the [`Encoding`]
/// into its string representation, that the the `@encode` directive would
/// return. This can be used conveniently through the `to_string` method:
///
/// ```
/// use objc2_encode::Encoding;
/// assert_eq!(Encoding::Int.to_string(), "i");
/// ```
///
/// For more information on the string value of an encoding, see [Apple's
/// documentation][ocrtTypeEncodings].
///
/// [ocrtTypeEncodings]: https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtTypeEncodings.html
///
/// # Examples
///
/// Comparing an encoding to a string from the Objective-C runtime:
///
/// ```
/// use objc2_encode::Encoding;
/// assert!(Encoding::Array(10, &Encoding::FloatComplex).equivalent_to_str("[10jf]"));
/// ```
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
#[non_exhaustive] // Maybe we're missing some encodings?
pub enum Encoding<'a> {
/// A C `char`. Corresponds to the `c` code.
Char,
/// A C `short`. Corresponds to the `s` code.
Short,
/// A C `int`. Corresponds to the `i` code.
Int,
/// A C `long`. Corresponds to the `l` code.
Long,
/// A C `long long`. Corresponds to the `q` code.
LongLong,
/// A C `unsigned char`. Corresponds to the `C` code.
UChar,
/// A C `unsigned short`. Corresponds to the `S` code.
UShort,
/// A C `unsigned int`. Corresponds to the `I` code.
UInt,
/// A C `unsigned long`. Corresponds to the `L` code.
ULong,
/// A C `unsigned long long`. Corresponds to the `Q` code.
ULongLong,
/// A C `float`. Corresponds to the `f` code.
Float,
/// A C `double`. Corresponds to the `d` code.
Double,
/// A C `long double`. Corresponds to the `D` code.
LongDouble,
/// A C `float _Complex`. Corresponds to the `jf` code.
FloatComplex,
/// A C `_Complex` or `double _Complex`. Corresponds to the `jd` code.
DoubleComplex,
/// A C `long double _Complex`. Corresponds to the `jD` code.
LongDoubleComplex,
// TODO: Complex(&Encoding) ???
/// A C++ `bool` / C99 `_Bool`. Corresponds to the `B` code.
Bool,
/// A C `void`. Corresponds to the `v` code.
Void,
/// A C `char *`. Corresponds to the `*` code.
String,
/// An Objective-C object (`id`). Corresponds to the `@` code.
Object,
/// An Objective-C block. Corresponds to the `@?` code.
Block,
/// An Objective-C class (`Class`). Corresponds to the `#` code.
Class,
/// An Objective-C selector (`SEL`). Corresponds to the `:` code.
Sel,
/// An unknown type. Corresponds to the `?` code.
///
/// This is usually used to encode functions.
Unknown,
/// A bitfield with the given number of bits.
///
/// Corresponds to the `b`num code.
BitField(u8),
/// A pointer to the given type.
///
/// Corresponds to the `^`type code.
Pointer(&'a Encoding<'a>),
/// An array with the given length and type.
///
/// Corresponds to the `[len type]` code.
Array(usize, &'a Encoding<'a>),
/// A struct with the given name and fields.
///
/// The order of the fields must match the order of the order in this.
///
/// It is not uncommon for the name to be `"?"`.
///
/// Corresponds to the `{name=fields...}` code.
Struct(&'a str, &'a [Encoding<'a>]),
/// A union with the given name and fields.
///
/// The order of the fields must match the order of the order in this.
///
/// Corresponds to the `(name=fields...)` code.
Union(&'a str, &'a [Encoding<'a>]),
// "Vector" types have the '!' encoding, but are not implemented in clang
// TODO: Atomic, const and other such specifiers
// typedef struct x {
// int a;
// void* b;
// } x_t;
// NSLog(@"Encoding: %s", @encode(_Atomic x_t)); // -> A{x}
// NSLog(@"Encoding: %s", @encode(const int*)); // -> r^i
}
impl Encoding<'_> {
/// Check if one encoding is equivalent to another.
pub fn equivalent_to(&self, other: &Self) -> bool {
// For now, because we don't allow representing qualifiers
self == other
}
/// Check if an encoding is equivalent to the given string representation.
pub fn equivalent_to_str(&self, s: &str) -> bool {
// if the given encoding can be successfully removed from the start
// and an empty string remains, they were fully equivalent!
if let Some(res) = self.equivalent_to_start_of_str(s) {
res.is_empty()
} else {
false
}
}
/// Check if an encoding is equivalent to the start of the given string
/// representation.
///
/// If it is equivalent, the remaining part of the string is returned.
/// Otherwise this returns [`None`].
pub fn equivalent_to_start_of_str<'a>(&self, s: &'a str) -> Option<&'a str> {
// strip leading qualifiers
let s = s.trim_start_matches(parse::QUALIFIERS);
// TODO: Allow missing/"?" names in structs and unions?
parse::rm_enc_prefix(s, self)
}
}
impl fmt::Display for Encoding<'_> {
fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
use Encoding::*;
let code = match *self {
Char => "c",
Short => "s",
Int => "i",
Long => "l",
LongLong => "q",
UChar => "C",
UShort => "S",
UInt => "I",
ULong => "L",
ULongLong => "Q",
Float => "f",
Double => "d",
LongDouble => "D",
FloatComplex => "jf",
DoubleComplex => "jd",
LongDoubleComplex => "jD",
Bool => "B",
Void => "v",
String => "*",
Object => "@",
Block => "@?",
Class => "#",
Sel => ":",
Unknown => "?",
BitField(b) => {
return write!(formatter, "b{}", b);
}
Pointer(t) => {
return write!(formatter, "^{}", t);
}
Array(len, item) => {
return write!(formatter, "[{}{}]", len, item);
}
Struct(name, fields) => {
write!(formatter, "{{{}=", name)?;
for field in fields {
fmt::Display::fmt(field, formatter)?;
}
return formatter.write_str("}");
}
Union(name, members) => {
write!(formatter, "({}=", name)?;
for member in members {
fmt::Display::fmt(member, formatter)?;
}
return formatter.write_str(")");
}
};
formatter.write_str(code)
}
}
// TODO: Deprecate and remove these PartialEq impls
/// Partial equality between an [`Encoding`] and a [`str`].
///
/// Using this is heavily discouraged, since it is not transitive; use
/// [`Encoding::equivalent_to_str`] instead for more correct semantics.
impl PartialEq<str> for Encoding<'_> {
/// Using this is discouraged.
fn eq(&self, other: &str) -> bool {
self.equivalent_to_str(other)
}
/// Using this is discouraged.
fn ne(&self, other: &str) -> bool {
!self.eq(other)
}
}
/// Partial equality between an [`Encoding`] and a [`str`].
///
/// Using this is heavily discouraged, since it is not transitive; use
/// [`Encoding::equivalent_to_str`] instead for more correct semantics.
impl PartialEq<Encoding<'_>> for str {
/// Using this is discouraged.
fn eq(&self, other: &Encoding<'_>) -> bool {
other.equivalent_to_str(self)
}
/// Using this is discouraged.
fn ne(&self, other: &Encoding<'_>) -> bool {
!self.eq(other)
}
}
#[cfg(test)]
mod tests {
use super::Encoding;
use alloc::string::ToString;
#[test]
fn test_array_display() {
let e = Encoding::Array(12, &Encoding::Int);
assert_eq!(e.to_string(), "[12i]");
assert!(e.equivalent_to_str("[12i]"));
}
#[test]
fn test_pointer_display() {
let e = Encoding::Pointer(&Encoding::Int);
assert_eq!(e.to_string(), "^i");
assert!(e.equivalent_to_str("^i"));
}
#[test]
fn test_pointer_eq() {
let i = Encoding::Int;
let p = Encoding::Pointer(&Encoding::Int);
assert_eq!(p, p);
assert_ne!(p, i);
}
#[test]
fn test_int_display() {
assert_eq!(Encoding::Int.to_string(), "i");
assert!(Encoding::Int.equivalent_to_str("i"));
}
#[test]
fn test_eq() {
let i = Encoding::Int;
let c = Encoding::Char;
assert_eq!(i, i);
assert_ne!(i, c);
}
#[test]
fn test_struct_display() {
let s = Encoding::Struct("CGPoint", &[Encoding::Char, Encoding::Int]);
assert_eq!(s.to_string(), "{CGPoint=ci}");
assert!(s.equivalent_to_str("{CGPoint=ci}"));
}
#[test]
fn test_struct_eq() {
let s = Encoding::Struct("CGPoint", &[Encoding::Char, Encoding::Int]);
assert_eq!(s, s);
assert_ne!(s, Encoding::Int);
}
#[test]
fn test_union_display() {
let u = Encoding::Union("Onion", &[Encoding::Char, Encoding::Int]);
assert_eq!(u.to_string(), "(Onion=ci)");
assert!(u.equivalent_to_str("(Onion=ci)"));
}
#[test]
fn test_union_eq() {
let u = Encoding::Union("Onion", &[Encoding::Char, Encoding::Int]);
assert_eq!(u, u);
assert_ne!(u, Encoding::Int);
}
}