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+/*!
+The ucd-trie crate provides a compressed trie set specifically tailored for
+Unicode codepoints. The principle use case for such a trie is to represent
+properties defined by Unicode that correspond to sets of Unicode codepoints.
+(These properties are formally called boolean properties or "single valued"
+properties. See
+[UTR#23 S3.3](http://www.unicode.org/reports/tr23/#PropertyTypeDefinitions)
+for more details.)
+
+This crate has two principle types: `TrieSetOwned` and `TrieSetSlice`,
+corresponding to a similar split as there is between `Vec<T>` and `&[T]`.
+`TrieSetOwned` is the only way to construct a trie from a set of Unicode
+codepoints.
+
+The intended use of this library is to embed a static instance of
+`TrieSetSlice` into your source code, and then use its methods as defined in
+this crate to test membership. (The `ucd-generate` tool can likely generate
+this code for you.)
+
+Finally, while this crate uses the standard library by default, it provides
+`no_std` functionality by disabling the `std` feature. When `no_std` is
+enabled, then `TrieSetOwned` is not provided. Instead, only `TrieSetSlice` is
+provided, which means `no_std` crates can still embed tries into their code.
+*/
+
+#![deny(missing_docs)]
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use core::fmt;
+
+#[cfg(feature = "std")]
+pub use crate::owned::{Error, Result, TrieSetOwned};
+
+#[cfg(test)]
+#[allow(dead_code)]
+mod general_category;
+#[cfg(feature = "std")]
+mod owned;
+
+const CHUNK_SIZE: usize = 64;
+
+/// A type alias for `TrieSetSlice<'static>`.
+pub type TrieSet = TrieSetSlice<'static>;
+
+/// A borrowed trie set.
+#[derive(Clone, Copy)]
+pub struct TrieSetSlice<'a> {
+    /// first tree, one level
+    #[doc(hidden)]
+    pub tree1_level1: &'a [u64],
+    /// second tree, first level
+    #[doc(hidden)]
+    pub tree2_level1: &'a [u8],
+    /// second tree, second level
+    #[doc(hidden)]
+    pub tree2_level2: &'a [u64],
+    /// third tree, first level
+    #[doc(hidden)]
+    pub tree3_level1: &'a [u8],
+    /// third tree, second level
+    #[doc(hidden)]
+    pub tree3_level2: &'a [u8],
+    /// third tree, third level
+    #[doc(hidden)]
+    pub tree3_level3: &'a [u64],
+}
+
+impl<'a> fmt::Debug for TrieSetSlice<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "TrieSetSlice(...)")
+    }
+}
+
+impl<'a> TrieSetSlice<'a> {
+    /// Returns true if and only if the given Unicode scalar value is in this
+    /// set.
+    pub fn contains_char(&self, c: char) -> bool {
+        self.contains(c as usize)
+    }
+
+    /// Returns true if and only if the given codepoint is in this set.
+    ///
+    /// If the given value exceeds the codepoint range (i.e., it's greater
+    /// than `0x10FFFF`), then this returns false.
+    pub fn contains_u32(&self, cp: u32) -> bool {
+        if cp > 0x10FFFF {
+            return false;
+        }
+        self.contains(cp as usize)
+    }
+
+    #[inline(always)]
+    fn contains(&self, cp: usize) -> bool {
+        if cp < 0x800 {
+            self.chunk_contains(cp, self.tree1_level1[cp >> 6])
+        } else if cp < 0x10000 {
+            let leaf = match self.tree2_level1.get((cp >> 6) - 0x20) {
+                None => return false,
+                Some(&leaf) => leaf,
+            };
+            self.chunk_contains(cp, self.tree2_level2[leaf as usize])
+        } else {
+            let child = match self.tree3_level1.get((cp >> 12) - 0x10) {
+                None => return false,
+                Some(&child) => child,
+            };
+            let i = ((child as usize) * CHUNK_SIZE) + ((cp >> 6) & 0b111111);
+            let leaf = self.tree3_level2[i];
+            self.chunk_contains(cp, self.tree3_level3[leaf as usize])
+        }
+    }
+
+    #[inline(always)]
+    fn chunk_contains(&self, cp: usize, chunk: u64) -> bool {
+        ((chunk >> (cp & 0b111111)) & 1) == 1
+    }
+}