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-rw-r--r--vendor/kstring/src/string.rs865
1 files changed, 865 insertions, 0 deletions
diff --git a/vendor/kstring/src/string.rs b/vendor/kstring/src/string.rs
new file mode 100644
index 000000000..ed39d188a
--- /dev/null
+++ b/vendor/kstring/src/string.rs
@@ -0,0 +1,865 @@
+use std::{borrow::Cow, fmt};
+
+use crate::stack::StackString;
+use crate::KStringCowBase;
+use crate::KStringRef;
+
+pub(crate) type StdString = std::string::String;
+
+/// A UTF-8 encoded, immutable string.
+pub type KString = KStringBase<crate::backend::DefaultStr>;
+
+/// A UTF-8 encoded, immutable string.
+#[derive(Clone)]
+#[repr(transparent)]
+pub struct KStringBase<B> {
+ inner: KStringInner<B>,
+}
+
+impl<B> KStringBase<B> {
+ pub const EMPTY: Self = KStringBase::from_static("");
+
+ /// Create a new empty `KStringBase`.
+ #[inline]
+ #[must_use]
+ pub fn new() -> Self {
+ Self::EMPTY
+ }
+
+ /// Create a reference to a `'static` data.
+ #[inline]
+ #[must_use]
+ pub const fn from_static(other: &'static str) -> Self {
+ Self {
+ inner: KStringInner::from_static(other),
+ }
+ }
+
+ /// Create an inline string, if possible
+ #[inline]
+ #[must_use]
+ pub fn try_inline(other: &str) -> Option<Self> {
+ KStringInner::try_inline(other).map(|inner| Self { inner })
+ }
+}
+
+impl<B: crate::backend::HeapStr> KStringBase<B> {
+ /// Create an owned `KStringBase`.
+ #[inline]
+ #[must_use]
+ pub fn from_boxed(other: crate::backend::BoxedStr) -> Self {
+ Self {
+ inner: KStringInner::from_boxed(other),
+ }
+ }
+
+ /// Create an owned `KStringBase`.
+ #[inline]
+ #[must_use]
+ pub fn from_string(other: StdString) -> Self {
+ Self {
+ inner: KStringInner::from_string(other),
+ }
+ }
+
+ /// Create an owned `KStringBase` optimally from a reference.
+ #[inline]
+ #[must_use]
+ pub fn from_ref(other: &str) -> Self {
+ Self {
+ inner: KStringInner::from_ref(other),
+ }
+ }
+
+ /// Get a reference to the `KStringBase`.
+ #[inline]
+ #[must_use]
+ pub fn as_ref(&self) -> KStringRef<'_> {
+ self.inner.as_ref()
+ }
+
+ /// Extracts a string slice containing the entire `KStringBase`.
+ #[inline]
+ #[must_use]
+ pub fn as_str(&self) -> &str {
+ self.inner.as_str()
+ }
+
+ /// Convert to a mutable string type, cloning the data if necessary.
+ #[inline]
+ #[must_use]
+ pub fn into_string(self) -> StdString {
+ String::from(self.into_boxed_str())
+ }
+
+ /// Convert to a mutable string type, cloning the data if necessary.
+ #[inline]
+ #[must_use]
+ pub fn into_boxed_str(self) -> crate::backend::BoxedStr {
+ self.inner.into_boxed_str()
+ }
+
+ /// Convert to a Cow str
+ #[inline]
+ #[must_use]
+ pub fn into_cow_str(self) -> Cow<'static, str> {
+ self.inner.into_cow_str()
+ }
+}
+
+impl<B: crate::backend::HeapStr> std::ops::Deref for KStringBase<B> {
+ type Target = str;
+
+ #[inline]
+ fn deref(&self) -> &str {
+ self.as_str()
+ }
+}
+
+impl<B: crate::backend::HeapStr> Eq for KStringBase<B> {}
+
+impl<'s, B: crate::backend::HeapStr> PartialEq<KStringBase<B>> for KStringBase<B> {
+ #[inline]
+ fn eq(&self, other: &Self) -> bool {
+ PartialEq::eq(self.as_str(), other.as_str())
+ }
+}
+
+impl<'s, B: crate::backend::HeapStr> PartialEq<str> for KStringBase<B> {
+ #[inline]
+ fn eq(&self, other: &str) -> bool {
+ PartialEq::eq(self.as_str(), other)
+ }
+}
+
+impl<'s, B: crate::backend::HeapStr> PartialEq<&'s str> for KStringBase<B> {
+ #[inline]
+ fn eq(&self, other: &&str) -> bool {
+ PartialEq::eq(self.as_str(), *other)
+ }
+}
+
+impl<'s, B: crate::backend::HeapStr> PartialEq<String> for KStringBase<B> {
+ #[inline]
+ fn eq(&self, other: &StdString) -> bool {
+ PartialEq::eq(self.as_str(), other.as_str())
+ }
+}
+
+impl<B: crate::backend::HeapStr> Ord for KStringBase<B> {
+ #[inline]
+ fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+ self.as_str().cmp(other.as_str())
+ }
+}
+
+impl<B: crate::backend::HeapStr> PartialOrd for KStringBase<B> {
+ #[inline]
+ fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+ self.as_str().partial_cmp(other.as_str())
+ }
+}
+
+impl<B: crate::backend::HeapStr> std::hash::Hash for KStringBase<B> {
+ #[inline]
+ fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+ self.as_str().hash(state);
+ }
+}
+
+impl<B: crate::backend::HeapStr> fmt::Debug for KStringBase<B> {
+ #[inline]
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ self.as_str().fmt(f)
+ }
+}
+
+impl<B: crate::backend::HeapStr> fmt::Display for KStringBase<B> {
+ #[inline]
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ fmt::Display::fmt(self.as_str(), f)
+ }
+}
+
+impl<B: crate::backend::HeapStr> AsRef<str> for KStringBase<B> {
+ #[inline]
+ fn as_ref(&self) -> &str {
+ self.as_str()
+ }
+}
+
+impl<B: crate::backend::HeapStr> AsRef<[u8]> for KStringBase<B> {
+ #[inline]
+ fn as_ref(&self) -> &[u8] {
+ self.as_bytes()
+ }
+}
+
+impl<B: crate::backend::HeapStr> AsRef<std::ffi::OsStr> for KStringBase<B> {
+ #[inline]
+ fn as_ref(&self) -> &std::ffi::OsStr {
+ (&**self).as_ref()
+ }
+}
+
+impl<B: crate::backend::HeapStr> AsRef<std::path::Path> for KStringBase<B> {
+ #[inline]
+ fn as_ref(&self) -> &std::path::Path {
+ std::path::Path::new(self)
+ }
+}
+
+impl<B: crate::backend::HeapStr> std::borrow::Borrow<str> for KStringBase<B> {
+ #[inline]
+ fn borrow(&self) -> &str {
+ self.as_str()
+ }
+}
+
+impl<B: crate::backend::HeapStr> Default for KStringBase<B> {
+ #[inline]
+ fn default() -> Self {
+ Self::new()
+ }
+}
+
+impl<'s, B: crate::backend::HeapStr> From<KStringRef<'s>> for KStringBase<B> {
+ #[inline]
+ fn from(other: KStringRef<'s>) -> Self {
+ other.to_owned()
+ }
+}
+
+impl<'s, B: crate::backend::HeapStr> From<&'s KStringRef<'s>> for KStringBase<B> {
+ #[inline]
+ fn from(other: &'s KStringRef<'s>) -> Self {
+ other.to_owned()
+ }
+}
+
+impl<'s, B: crate::backend::HeapStr> From<KStringCowBase<'s, B>> for KStringBase<B> {
+ #[inline]
+ fn from(other: KStringCowBase<'s, B>) -> Self {
+ other.into_owned()
+ }
+}
+
+impl<'s, B: crate::backend::HeapStr> From<&'s KStringCowBase<'s, B>> for KStringBase<B> {
+ #[inline]
+ fn from(other: &'s KStringCowBase<'s, B>) -> Self {
+ other.clone().into_owned()
+ }
+}
+
+impl<B: crate::backend::HeapStr> From<StdString> for KStringBase<B> {
+ #[inline]
+ fn from(other: StdString) -> Self {
+ Self::from_string(other)
+ }
+}
+
+impl<'s, B: crate::backend::HeapStr> From<&'s StdString> for KStringBase<B> {
+ #[inline]
+ fn from(other: &'s StdString) -> Self {
+ Self::from_ref(other)
+ }
+}
+
+impl<B: crate::backend::HeapStr> From<crate::backend::BoxedStr> for KStringBase<B> {
+ #[inline]
+ fn from(other: crate::backend::BoxedStr) -> Self {
+ Self::from_boxed(other)
+ }
+}
+
+impl<'s, B: crate::backend::HeapStr> From<&'s crate::backend::BoxedStr> for KStringBase<B> {
+ #[inline]
+ fn from(other: &'s crate::backend::BoxedStr) -> Self {
+ Self::from_ref(other)
+ }
+}
+
+impl<B: crate::backend::HeapStr> From<&'static str> for KStringBase<B> {
+ #[inline]
+ fn from(other: &'static str) -> Self {
+ Self::from_static(other)
+ }
+}
+
+impl<B: crate::backend::HeapStr> std::str::FromStr for KStringBase<B> {
+ type Err = std::convert::Infallible;
+ #[inline]
+ fn from_str(s: &str) -> Result<Self, Self::Err> {
+ Ok(Self::from_ref(s))
+ }
+}
+
+#[cfg(feature = "serde")]
+impl<B: crate::backend::HeapStr> serde::Serialize for KStringBase<B> {
+ #[inline]
+ fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+ where
+ S: serde::Serializer,
+ {
+ serializer.serialize_str(self.as_str())
+ }
+}
+
+#[cfg(feature = "serde")]
+impl<'de, B: crate::backend::HeapStr> serde::Deserialize<'de> for KStringBase<B> {
+ fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+ where
+ D: serde::Deserializer<'de>,
+ {
+ deserializer.deserialize_string(StringVisitor(std::marker::PhantomData))
+ }
+}
+
+#[cfg(feature = "serde")]
+struct StringVisitor<B>(std::marker::PhantomData<B>);
+
+#[cfg(feature = "serde")]
+impl<'de, B: crate::backend::HeapStr> serde::de::Visitor<'de> for StringVisitor<B> {
+ type Value = KStringBase<B>;
+
+ fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
+ formatter.write_str("a string")
+ }
+
+ fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
+ where
+ E: serde::de::Error,
+ {
+ Ok(Self::Value::from_ref(v))
+ }
+
+ fn visit_string<E>(self, v: String) -> Result<Self::Value, E>
+ where
+ E: serde::de::Error,
+ {
+ Ok(Self::Value::from_string(v))
+ }
+
+ fn visit_bytes<E>(self, v: &[u8]) -> Result<Self::Value, E>
+ where
+ E: serde::de::Error,
+ {
+ match std::str::from_utf8(v) {
+ Ok(s) => Ok(Self::Value::from_ref(s)),
+ Err(_) => Err(serde::de::Error::invalid_value(
+ serde::de::Unexpected::Bytes(v),
+ &self,
+ )),
+ }
+ }
+
+ fn visit_byte_buf<E>(self, v: Vec<u8>) -> Result<Self::Value, E>
+ where
+ E: serde::de::Error,
+ {
+ match String::from_utf8(v) {
+ Ok(s) => Ok(Self::Value::from_string(s)),
+ Err(e) => Err(serde::de::Error::invalid_value(
+ serde::de::Unexpected::Bytes(&e.into_bytes()),
+ &self,
+ )),
+ }
+ }
+}
+
+use inner::KStringInner;
+
+#[cfg(not(feature = "unsafe"))]
+mod inner {
+ use super::*;
+
+ pub(super) enum KStringInner<B> {
+ Singleton(&'static str),
+ Inline(StackString<CAPACITY>),
+ Owned(B),
+ }
+
+ impl<B> KStringInner<B> {
+ /// Create a reference to a `'static` data.
+ #[inline]
+ pub const fn from_static(other: &'static str) -> Self {
+ Self::Singleton(other)
+ }
+
+ #[inline]
+ pub fn try_inline(other: &str) -> Option<Self> {
+ StackString::try_new(other).map(Self::Inline)
+ }
+ }
+
+ impl<B: crate::backend::HeapStr> KStringInner<B> {
+ #[inline]
+ pub(super) fn from_boxed(other: crate::backend::BoxedStr) -> Self {
+ #[allow(clippy::useless_conversion)]
+ Self::Owned(B::from_boxed_str(other))
+ }
+
+ #[inline]
+ pub(super) fn from_string(other: StdString) -> Self {
+ if (0..=CAPACITY).contains(&other.len()) {
+ let inline = { StackString::new(other.as_str()) };
+ Self::Inline(inline)
+ } else {
+ Self::from_boxed(other.into_boxed_str())
+ }
+ }
+
+ #[inline]
+ pub(super) fn from_ref(other: &str) -> Self {
+ if (0..=CAPACITY).contains(&other.len()) {
+ let inline = { StackString::new(other) };
+ Self::Inline(inline)
+ } else {
+ Self::Owned(B::from_str(other))
+ }
+ }
+
+ #[inline]
+ pub(super) fn as_ref(&self) -> KStringRef<'_> {
+ match self {
+ Self::Singleton(s) => KStringRef::from_static(s),
+ Self::Inline(s) => KStringRef::from_ref(s.as_str()),
+ Self::Owned(s) => KStringRef::from_ref(s.as_str()),
+ }
+ }
+
+ #[inline]
+ pub(super) fn as_str(&self) -> &str {
+ match self {
+ Self::Singleton(s) => s,
+ Self::Inline(s) => s.as_str(),
+ Self::Owned(s) => s.as_str(),
+ }
+ }
+
+ #[inline]
+ pub(super) fn into_boxed_str(self) -> crate::backend::BoxedStr {
+ match self {
+ Self::Singleton(s) => crate::backend::BoxedStr::from(s),
+ Self::Inline(s) => crate::backend::BoxedStr::from(s.as_str()),
+ Self::Owned(s) => crate::backend::BoxedStr::from(s.as_str()),
+ }
+ }
+
+ /// Convert to a Cow str
+ #[inline]
+ pub(super) fn into_cow_str(self) -> Cow<'static, str> {
+ match self {
+ Self::Singleton(s) => Cow::Borrowed(s),
+ Self::Inline(s) => Cow::Owned(s.as_str().into()),
+ Self::Owned(s) => Cow::Owned(s.as_str().into()),
+ }
+ }
+ }
+
+ // Explicit to avoid inlining which cuts clone times in half.
+ //
+ // An automatically derived `clone()` has 10ns overhead while the explicit `Deref`/`as_str` has
+ // none of that. Being explicit and removing the `#[inline]` attribute dropped the overhead to
+ // 5ns.
+ //
+ // My only guess is that the `clone()` calls we delegate to are just that much bigger than
+ // `as_str()` that, when combined with a jump table, is blowing the icache, slowing things down.
+ impl<B: Clone> Clone for KStringInner<B> {
+ fn clone(&self) -> Self {
+ match self {
+ Self::Singleton(s) => Self::Singleton(s),
+ Self::Inline(s) => Self::Inline(*s),
+ Self::Owned(s) => Self::Owned(s.clone()),
+ }
+ }
+ }
+
+ #[allow(unused)]
+ const LEN_SIZE: usize = std::mem::size_of::<crate::stack::Len>();
+
+ #[allow(unused)]
+ const TAG_SIZE: usize = std::mem::size_of::<u8>();
+
+ #[allow(unused)]
+ const MAX_CAPACITY: usize =
+ std::mem::size_of::<crate::string::StdString>() - TAG_SIZE - LEN_SIZE;
+
+ // Performance seems to slow down when trying to occupy all of the padding left by `String`'s
+ // discriminant. The question is whether faster len=1-16 "allocations" outweighs going to the heap
+ // for len=17-22.
+ #[allow(unused)]
+ const ALIGNED_CAPACITY: usize = std::mem::size_of::<crate::backend::DefaultStr>() - LEN_SIZE;
+
+ #[cfg(feature = "max_inline")]
+ const CAPACITY: usize = MAX_CAPACITY;
+ #[cfg(not(feature = "max_inline"))]
+ const CAPACITY: usize = ALIGNED_CAPACITY;
+}
+
+#[cfg(feature = "unsafe")]
+mod inner {
+ use super::*;
+
+ pub(super) union KStringInner<B> {
+ tag: TagVariant,
+ singleton: SingletonVariant,
+ owned: std::mem::ManuallyDrop<OwnedVariant<B>>,
+ inline: InlineVariant,
+ }
+
+ impl<B> KStringInner<B> {
+ /// Create a reference to a `'static` data.
+ #[inline]
+ pub const fn from_static(other: &'static str) -> Self {
+ Self {
+ singleton: SingletonVariant::new(other),
+ }
+ }
+
+ #[inline]
+ pub fn try_inline(other: &str) -> Option<Self> {
+ StackString::try_new(other).map(|inline| Self {
+ inline: InlineVariant::new(inline),
+ })
+ }
+
+ #[inline]
+ const fn tag(&self) -> Tag {
+ unsafe {
+ // SAFETY: `tag` is in the same spot in each variant
+ self.tag.tag
+ }
+ }
+ }
+
+ impl<B: crate::backend::HeapStr> KStringInner<B> {
+ #[inline]
+ pub(super) fn from_boxed(other: crate::backend::BoxedStr) -> Self {
+ #[allow(clippy::useless_conversion)]
+ let payload = B::from_boxed_str(other);
+ Self {
+ owned: std::mem::ManuallyDrop::new(OwnedVariant::new(payload)),
+ }
+ }
+
+ #[inline]
+ pub(super) fn from_string(other: StdString) -> Self {
+ if (0..=CAPACITY).contains(&other.len()) {
+ let payload = unsafe {
+ // SAFETY: range check ensured this is always safe
+ StackString::new_unchecked(other.as_str())
+ };
+ Self {
+ inline: InlineVariant::new(payload),
+ }
+ } else {
+ Self::from_boxed(other.into_boxed_str())
+ }
+ }
+
+ #[inline]
+ pub(super) fn from_ref(other: &str) -> Self {
+ if (0..=CAPACITY).contains(&other.len()) {
+ let payload = unsafe {
+ // SAFETY: range check ensured this is always safe
+ StackString::new_unchecked(other)
+ };
+ Self {
+ inline: InlineVariant::new(payload),
+ }
+ } else {
+ #[allow(clippy::useless_conversion)]
+ let payload = B::from_str(other);
+ Self {
+ owned: std::mem::ManuallyDrop::new(OwnedVariant::new(payload)),
+ }
+ }
+ }
+
+ #[inline]
+ pub(super) fn as_ref(&self) -> KStringRef<'_> {
+ let tag = self.tag();
+ unsafe {
+ // SAFETY: `tag` ensures access to correct variant
+ if tag.is_singleton() {
+ KStringRef::from_static(self.singleton.payload)
+ } else if tag.is_owned() {
+ KStringRef::from_ref(self.owned.payload.as_str())
+ } else {
+ debug_assert!(tag.is_inline());
+ KStringRef::from_ref(self.inline.payload.as_str())
+ }
+ }
+ }
+
+ #[inline]
+ pub(super) fn as_str(&self) -> &str {
+ let tag = self.tag();
+ unsafe {
+ // SAFETY: `tag` ensures access to correct variant
+ if tag.is_singleton() {
+ self.singleton.payload
+ } else if tag.is_owned() {
+ self.owned.payload.as_str()
+ } else {
+ debug_assert!(tag.is_inline());
+ self.inline.payload.as_str()
+ }
+ }
+ }
+
+ #[inline]
+ pub(super) fn into_boxed_str(self) -> crate::backend::BoxedStr {
+ let tag = self.tag();
+ unsafe {
+ // SAFETY: `tag` ensures access to correct variant
+ if tag.is_singleton() {
+ crate::backend::BoxedStr::from(self.singleton.payload)
+ } else if tag.is_owned() {
+ crate::backend::BoxedStr::from(self.owned.payload.as_str())
+ } else {
+ debug_assert!(tag.is_inline());
+ crate::backend::BoxedStr::from(self.inline.payload.as_ref())
+ }
+ }
+ }
+
+ /// Convert to a Cow str
+ #[inline]
+ pub(super) fn into_cow_str(self) -> Cow<'static, str> {
+ let tag = self.tag();
+ unsafe {
+ // SAFETY: `tag` ensures access to correct variant
+ if tag.is_singleton() {
+ Cow::Borrowed(self.singleton.payload)
+ } else if tag.is_owned() {
+ Cow::Owned(self.owned.payload.as_str().into())
+ } else {
+ debug_assert!(tag.is_inline());
+ Cow::Owned(self.inline.payload.as_str().into())
+ }
+ }
+ }
+ }
+
+ // Explicit to avoid inlining which cuts clone times in half.
+ //
+ // An automatically derived `clone()` has 10ns overhead while the explicit `Deref`/`as_str` has
+ // none of that. Being explicit and removing the `#[inline]` attribute dropped the overhead to
+ // 5ns.
+ //
+ // My only guess is that the `clone()` calls we delegate to are just that much bigger than
+ // `as_str()` that, when combined with a jump table, is blowing the icache, slowing things down.
+ impl<B: Clone> Clone for KStringInner<B> {
+ fn clone(&self) -> Self {
+ let tag = self.tag();
+ if tag.is_owned() {
+ unsafe {
+ // SAFETY: `tag` ensures access to correct variant
+ Self {
+ owned: std::mem::ManuallyDrop::new(OwnedVariant::new(
+ self.owned.payload.clone(),
+ )),
+ }
+ }
+ } else {
+ unsafe {
+ // SAFETY: `tag` ensures access to correct variant
+ // SAFETY: non-owned types are copyable
+ std::mem::transmute_copy(self)
+ }
+ }
+ }
+ }
+
+ impl<B> Drop for KStringInner<B> {
+ fn drop(&mut self) {
+ let tag = self.tag();
+ if tag.is_owned() {
+ unsafe {
+ // SAFETY: `tag` ensures we are using the right variant
+ std::mem::ManuallyDrop::drop(&mut self.owned)
+ }
+ }
+ }
+ }
+
+ #[allow(unused)]
+ const LEN_SIZE: usize = std::mem::size_of::<crate::stack::Len>();
+
+ #[allow(unused)]
+ const TAG_SIZE: usize = std::mem::size_of::<Tag>();
+
+ #[allow(unused)]
+ const PAYLOAD_SIZE: usize = std::mem::size_of::<crate::backend::DefaultStr>();
+ type Payload = Padding<PAYLOAD_SIZE>;
+
+ #[allow(unused)]
+ const TARGET_SIZE: usize = std::mem::size_of::<Target>();
+ type Target = crate::string::StdString;
+
+ #[allow(unused)]
+ const MAX_CAPACITY: usize = TARGET_SIZE - LEN_SIZE - TAG_SIZE;
+
+ // Performance seems to slow down when trying to occupy all of the padding left by `String`'s
+ // discriminant. The question is whether faster len=1-16 "allocations" outweighs going to the heap
+ // for len=17-22.
+ #[allow(unused)]
+ const ALIGNED_CAPACITY: usize = PAYLOAD_SIZE - LEN_SIZE;
+
+ #[cfg(feature = "max_inline")]
+ const CAPACITY: usize = MAX_CAPACITY;
+ #[cfg(not(feature = "max_inline"))]
+ const CAPACITY: usize = ALIGNED_CAPACITY;
+
+ const PAYLOAD_PAD_SIZE: usize = TARGET_SIZE - PAYLOAD_SIZE - TAG_SIZE;
+ const INLINE_PAD_SIZE: usize = TARGET_SIZE - CAPACITY - LEN_SIZE - TAG_SIZE;
+
+ #[derive(Copy, Clone)]
+ #[repr(C)]
+ struct TagVariant {
+ payload: Payload,
+ pad: Padding<PAYLOAD_PAD_SIZE>,
+ tag: Tag,
+ }
+ static_assertions::assert_eq_size!(Target, TagVariant);
+
+ #[derive(Copy, Clone)]
+ #[repr(C)]
+ struct SingletonVariant {
+ payload: &'static str,
+ pad: Padding<PAYLOAD_PAD_SIZE>,
+ tag: Tag,
+ }
+ static_assertions::assert_eq_size!(Payload, &'static str);
+ static_assertions::assert_eq_size!(Target, SingletonVariant);
+
+ impl SingletonVariant {
+ #[inline]
+ const fn new(payload: &'static str) -> Self {
+ Self {
+ payload,
+ pad: Padding::new(),
+ tag: Tag::SINGLETON,
+ }
+ }
+ }
+
+ impl std::fmt::Debug for SingletonVariant {
+ #[inline]
+ fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+ self.payload.fmt(f)
+ }
+ }
+
+ #[derive(Clone)]
+ #[repr(C)]
+ struct OwnedVariant<B> {
+ payload: B,
+ pad: Padding<PAYLOAD_PAD_SIZE>,
+ tag: Tag,
+ }
+ static_assertions::assert_eq_size!(Payload, crate::backend::DefaultStr);
+ static_assertions::assert_eq_size!(Target, OwnedVariant<crate::backend::DefaultStr>);
+
+ impl<B> OwnedVariant<B> {
+ #[inline]
+ const fn new(payload: B) -> Self {
+ Self {
+ payload,
+ pad: Padding::new(),
+ tag: Tag::OWNED,
+ }
+ }
+ }
+
+ impl<B: crate::backend::HeapStr> std::fmt::Debug for OwnedVariant<B> {
+ #[inline]
+ fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+ self.payload.fmt(f)
+ }
+ }
+
+ #[derive(Copy, Clone)]
+ #[repr(C)]
+ struct InlineVariant {
+ payload: StackString<CAPACITY>,
+ pad: Padding<INLINE_PAD_SIZE>,
+ tag: Tag,
+ }
+ static_assertions::assert_eq_size!(Target, InlineVariant);
+
+ impl InlineVariant {
+ #[inline]
+ const fn new(payload: StackString<CAPACITY>) -> Self {
+ Self {
+ payload,
+ pad: Padding::new(),
+ tag: Tag::INLINE,
+ }
+ }
+ }
+
+ impl std::fmt::Debug for InlineVariant {
+ #[inline]
+ fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+ self.payload.fmt(f)
+ }
+ }
+
+ #[derive(Copy, Clone, PartialEq, Eq)]
+ #[repr(transparent)]
+ struct Tag(u8);
+
+ impl Tag {
+ const SINGLETON: Tag = Tag(0);
+ const OWNED: Tag = Tag(u8::MAX);
+ const INLINE: Tag = Tag(1);
+
+ #[inline]
+ const fn is_singleton(self) -> bool {
+ self.0 == Self::SINGLETON.0
+ }
+
+ #[inline]
+ const fn is_owned(self) -> bool {
+ self.0 == Self::OWNED.0
+ }
+
+ #[inline]
+ const fn is_inline(self) -> bool {
+ !self.is_singleton() && !self.is_owned()
+ }
+ }
+
+ #[derive(Copy, Clone)]
+ #[repr(transparent)]
+ struct Padding<const L: usize>([std::mem::MaybeUninit<u8>; L]);
+
+ impl<const L: usize> Padding<L> {
+ const fn new() -> Self {
+ let padding = unsafe {
+ // SAFETY: Padding, never actually used
+ std::mem::MaybeUninit::uninit().assume_init()
+ };
+ Self(padding)
+ }
+ }
+
+ impl<const L: usize> Default for Padding<L> {
+ fn default() -> Self {
+ Self::new()
+ }
+ }
+}
+
+#[cfg(test)]
+mod test {
+ use super::*;
+
+ #[test]
+ fn test_size() {
+ println!("KString: {}", std::mem::size_of::<KString>());
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-28 21:53:09 +0000