Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

20 files changed, 2518 insertions, 0 deletions

diff --git a/third_party/rust/tinystr/.cargo-checksum.json b/third_party/rust/tinystr/.cargo-checksum.json
new file mode 100644
index 0000000000..8608630b3f
--- /dev/null
+++ b/third_party/rust/tinystr/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{"Cargo.toml":"6beb3627cfc6a20263af586baaf821337375279823e2808ff2e729dd4c8a908a","LICENSE":"853f87c96f3d249f200fec6db1114427bc8bdf4afddc93c576956d78152ce978","README.md":"b7b7a33a29865bc653a6696b079c1527ba61cd58a815fc792ed6fa5bfc680ad5","benches/common/mod.rs":"7e709fcabc2f96b10d3db8968ef3ea7fcc25e88211ce97b64b2126c7a0d7387a","benches/construct.rs":"f61e87e177dd994b700303b75c499a3e95183bb5ff6566889eb085825238dff4","benches/overview.rs":"cac8cfdcf397644ada6bc0bab8f92afc15071b0a64e3119aee4153b616eb9cff","benches/read.rs":"cbf349393a50eb90e7ba53906f98a689d585242292f867a37acf6842263af4d9","benches/serde.rs":"5c88866d08c07088b82dbd5472e6276c632d11e064417f5d8f2025a5ade867f0","src/ascii.rs":"7ad651b33c221a656a48eb44980d9b94bb0a681e79f4955648764968d3a5d62f","src/asciibyte.rs":"fa29de7403c0424c52c2f30bb47002b9abf4bd08b302c411ffe679d3decfb8de","src/databake.rs":"0dc32b7901f73a09357257a57f6150ba7197a88c489c2542081fcdc12336dca8","src/error.rs":"e0cbc912258d6e56aad148404d7cc3213d89736fa9ebe56c41f6cb0df7b2dd63","src/int_ops.rs":"c2be314d19dd41cf18fb3589901d7e58ee32fe3f764fb6a66b08a1e005336406","src/lib.rs":"97cd144b22a402746f4251afc061af075be9d3e6e111d3835f1c1e5cb465d469","src/macros.rs":"3fe76e258b0db2896284bcf4f50a4ac35b7efc542649b4c9f13c6e71c5957ae4","src/serde.rs":"a2c2120043e3334e1cca6fe0fd045ae035849fe6bb33ab0668804334606165dc","src/ule.rs":"52d76c91eeb73eb1885a0b1f40903fc68ea83f7a8b953a71b072eb7d242b3c63","src/unvalidated.rs":"6e41ce55d5f9a2a73f59467c5aff467d12f2b5f297695f109c09812595492efe","tests/serde.rs":"cf8cee82f731928375888d1b5e7e5e50368d3e16ce372fced230c9b1ee2a7451"},"package":"d5d0e245e80bdc9b4e5356fc45a72184abbc3861992603f515270e9340f5a219"}
\ No newline at end of file
diff --git a/third_party/rust/tinystr/Cargo.toml b/third_party/rust/tinystr/Cargo.toml
new file mode 100644
index 0000000000..f82bb66b8c
--- /dev/null
+++ b/third_party/rust/tinystr/Cargo.toml
@@ -0,0 +1,123 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2021"
+rust-version = "1.66"
+name = "tinystr"
+version = "0.7.4"
+authors = ["The ICU4X Project Developers"]
+include = [
+    "data/**/*",
+    "src/**/*",
+    "examples/**/*",
+    "benches/**/*",
+    "tests/**/*",
+    "Cargo.toml",
+    "LICENSE",
+    "README.md",
+]
+description = "A small ASCII-only bounded length string representation."
+readme = "README.md"
+keywords = [
+    "string",
+    "str",
+    "small",
+    "tiny",
+    "no_std",
+]
+categories = ["data-structures"]
+license-file = "LICENSE"
+repository = "https://github.com/unicode-org/icu4x"
+
+[package.metadata.cargo-all-features]
+denylist = ["bench"]
+
+[package.metadata.docs.rs]
+all-features = true
+
+[package.metadata.workspaces]
+independent = true
+
+[lib]
+bench = false
+
+[[test]]
+name = "serde"
+required-features = ["serde"]
+
+[[bench]]
+name = "overview"
+harness = false
+
+[[bench]]
+name = "construct"
+harness = false
+required-features = ["bench"]
+
+[[bench]]
+name = "read"
+harness = false
+required-features = ["bench"]
+
+[[bench]]
+name = "serde"
+harness = false
+required-features = [
+    "bench",
+    "serde",
+]
+
+[dependencies.databake]
+version = "0.1.6"
+optional = true
+default-features = false
+
+[dependencies.displaydoc]
+version = "0.2.3"
+default-features = false
+
+[dependencies.serde]
+version = "1.0.123"
+features = ["alloc"]
+optional = true
+default-features = false
+
+[dependencies.zerovec]
+version = "0.10.0"
+optional = true
+default-features = false
+
+[dev-dependencies.bincode]
+version = "1.3"
+
+[dev-dependencies.postcard]
+version = "1.0.0"
+features = ["use-std"]
+default-features = false
+
+[dev-dependencies.rand]
+version = "0.8.5"
+features = ["small_rng"]
+
+[dev-dependencies.serde_json]
+version = "1.0"
+features = ["alloc"]
+default-features = false
+
+[features]
+alloc = []
+bench = []
+default = ["alloc"]
+std = []
+
+[target."cfg(not(target_arch = \"wasm32\"))".dev-dependencies.criterion]
+version = "0.4"
diff --git a/third_party/rust/tinystr/LICENSE b/third_party/rust/tinystr/LICENSE
new file mode 100644
index 0000000000..9845aa5f48
--- /dev/null
+++ b/third_party/rust/tinystr/LICENSE
@@ -0,0 +1,44 @@
+UNICODE LICENSE V3
+
+COPYRIGHT AND PERMISSION NOTICE
+
+Copyright © 2020-2023 Unicode, Inc.
+
+NOTICE TO USER: Carefully read the following legal agreement. BY
+DOWNLOADING, INSTALLING, COPYING OR OTHERWISE USING DATA FILES, AND/OR
+SOFTWARE, YOU UNEQUIVOCALLY ACCEPT, AND AGREE TO BE BOUND BY, ALL OF THE
+TERMS AND CONDITIONS OF THIS AGREEMENT. IF YOU DO NOT AGREE, DO NOT
+DOWNLOAD, INSTALL, COPY, DISTRIBUTE OR USE THE DATA FILES OR SOFTWARE.
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of data files and any associated documentation (the "Data Files") or
+software and any associated documentation (the "Software") to deal in the
+Data Files or Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, and/or sell
+copies of the Data Files or Software, and to permit persons to whom the
+Data Files or Software are furnished to do so, provided that either (a)
+this copyright and permission notice appear with all copies of the Data
+Files or Software, or (b) this copyright and permission notice appear in
+associated Documentation.
+
+THE DATA FILES AND SOFTWARE ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
+THIRD PARTY RIGHTS.
+
+IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS INCLUDED IN THIS NOTICE
+BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES,
+OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THE DATA
+FILES OR SOFTWARE.
+
+Except as contained in this notice, the name of a copyright holder shall
+not be used in advertising or otherwise to promote the sale, use or other
+dealings in these Data Files or Software without prior written
+authorization of the copyright holder.
+
+—
+
+Portions of ICU4X may have been adapted from ICU4C and/or ICU4J.
+ICU 1.8.1 to ICU 57.1 © 1995-2016 International Business Machines Corporation and others.
diff --git a/third_party/rust/tinystr/README.md b/third_party/rust/tinystr/README.md
new file mode 100644
index 0000000000..92b74c0d1b
--- /dev/null
+++ b/third_party/rust/tinystr/README.md
@@ -0,0 +1,57 @@
+# tinystr [![crates.io](https://img.shields.io/crates/v/tinystr)](https://crates.io/crates/tinystr)
+
+<!-- cargo-rdme start -->
+
+`tinystr` is a utility crate of the [`ICU4X`] project.
+
+It includes [`TinyAsciiStr`], a core API for representing small ASCII-only bounded length strings.
+
+It is optimized for operations on strings of size 8 or smaller. When use cases involve comparison
+and conversion of strings for lowercase/uppercase/titlecase, or checking
+numeric/alphabetic/alphanumeric, `TinyAsciiStr` is the edge performance library.
+
+## Examples
+
+```rust
+use tinystr::TinyAsciiStr;
+
+let s1: TinyAsciiStr<4> = "tEsT".parse().expect("Failed to parse.");
+
+assert_eq!(s1, "tEsT");
+assert_eq!(s1.to_ascii_uppercase(), "TEST");
+assert_eq!(s1.to_ascii_lowercase(), "test");
+assert_eq!(s1.to_ascii_titlecase(), "Test");
+assert!(s1.is_ascii_alphanumeric());
+assert!(!s1.is_ascii_numeric());
+
+let s2 = TinyAsciiStr::<8>::try_from_raw(*b"New York")
+    .expect("Failed to parse.");
+
+assert_eq!(s2, "New York");
+assert_eq!(s2.to_ascii_uppercase(), "NEW YORK");
+assert_eq!(s2.to_ascii_lowercase(), "new york");
+assert_eq!(s2.to_ascii_titlecase(), "New york");
+assert!(!s2.is_ascii_alphanumeric());
+```
+
+## Details
+
+When strings are of size 8 or smaller, the struct transforms the strings as `u32`/`u64` and uses
+bitmasking to provide basic string manipulation operations:
+* `is_ascii_numeric`
+* `is_ascii_alphabetic`
+* `is_ascii_alphanumeric`
+* `to_ascii_lowercase`
+* `to_ascii_uppercase`
+* `to_ascii_titlecase`
+* `PartialEq`
+
+`TinyAsciiStr` will fall back to `u8` character manipulation for strings of length greater than 8.
+
+[`ICU4X`]: ../icu/index.html
+
+<!-- cargo-rdme end -->
+
+## More Information
+
+For more information on development, authorship, contributing etc. please visit [`ICU4X home page`](https://github.com/unicode-org/icu4x).
diff --git a/third_party/rust/tinystr/benches/common/mod.rs b/third_party/rust/tinystr/benches/common/mod.rs
new file mode 100644
index 0000000000..84090b6c2e
--- /dev/null
+++ b/third_party/rust/tinystr/benches/common/mod.rs
@@ -0,0 +1,55 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+// This file was adapted from parts of https://github.com/zbraniecki/tinystr
+
+pub static STRINGS_4: &[&str] = &[
+    "US", "GB", "AR", "Hans", "CN", "AT", "PL", "FR", "AT", "Cyrl", "SR", "NO", "FR", "MK", "UK",
+];
+
+pub static STRINGS_8: &[&str] = &[
+    "Latn", "windows", "AR", "Hans", "macos", "AT", "pl", "FR", "en", "Cyrl", "SR", "NO", "419",
+    "und", "UK",
+];
+
+pub static STRINGS_16: &[&str] = &[
+    "Latn",
+    "windows",
+    "AR",
+    "Hans",
+    "macos",
+    "AT",
+    "infiniband",
+    "FR",
+    "en",
+    "Cyrl",
+    "FromIntegral",
+    "NO",
+    "419",
+    "MacintoshOSX2019",
+    "UK",
+];
+
+#[macro_export]
+macro_rules! bench_block {
+    ($c:expr, $name:expr, $action:ident) => {
+        let mut group4 = $c.benchmark_group(&format!("{}/4", $name));
+        group4.bench_function("String", $action!(String, STRINGS_4));
+        group4.bench_function("TinyAsciiStr<4>", $action!(TinyAsciiStr<4>, STRINGS_4));
+        group4.bench_function("TinyAsciiStr<8>", $action!(TinyAsciiStr<8>, STRINGS_4));
+        group4.bench_function("TinyAsciiStr<16>", $action!(TinyAsciiStr<16>, STRINGS_4));
+        group4.finish();
+
+        let mut group8 = $c.benchmark_group(&format!("{}/8", $name));
+        group8.bench_function("String", $action!(String, STRINGS_8));
+        group8.bench_function("TinyAsciiStr<8>", $action!(TinyAsciiStr<8>, STRINGS_8));
+        group8.bench_function("TinyAsciiStr<16>", $action!(TinyAsciiStr<16>, STRINGS_8));
+        group8.finish();
+
+        let mut group16 = $c.benchmark_group(&format!("{}/16", $name));
+        group16.bench_function("String", $action!(String, STRINGS_16));
+        group16.bench_function("TinyAsciiStr<16>", $action!(TinyAsciiStr<16>, STRINGS_16));
+        group16.finish();
+    };
+}
diff --git a/third_party/rust/tinystr/benches/construct.rs b/third_party/rust/tinystr/benches/construct.rs
new file mode 100644
index 0000000000..19b18121ff
--- /dev/null
+++ b/third_party/rust/tinystr/benches/construct.rs
@@ -0,0 +1,65 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+// This file was adapted from https://github.com/zbraniecki/tinystr
+
+mod common;
+use common::*;
+
+use criterion::black_box;
+use criterion::criterion_group;
+use criterion::criterion_main;
+use criterion::Bencher;
+use criterion::Criterion;
+
+use tinystr::TinyAsciiStr;
+
+fn construct_from_str(c: &mut Criterion) {
+    macro_rules! cfs {
+        ($r:ty, $inputs:expr) => {
+            |b: &mut Bencher| {
+                b.iter(|| {
+                    for s in $inputs {
+                        let _: $r = black_box(s.parse().unwrap());
+                    }
+                })
+            }
+        };
+    }
+
+    bench_block!(c, "construct_from_str", cfs);
+}
+
+fn construct_from_bytes(c: &mut Criterion) {
+    macro_rules! cfu {
+        ($r:ty, $inputs:expr) => {
+            |b| {
+                let raw: Vec<&[u8]> = $inputs.iter().map(|s| s.as_bytes()).collect();
+                b.iter(move || {
+                    for u in &raw {
+                        let _ = black_box(<$r>::from_bytes(*u).unwrap());
+                    }
+                })
+            }
+        };
+    }
+
+    let mut group4 = c.benchmark_group("construct_from_bytes/4");
+    group4.bench_function("TinyAsciiStr<4>", cfu!(TinyAsciiStr<4>, STRINGS_4));
+    group4.bench_function("TinyAsciiStr<8>", cfu!(TinyAsciiStr<8>, STRINGS_4));
+    group4.bench_function("TinyAsciiStr<16>", cfu!(TinyAsciiStr<16>, STRINGS_4));
+    group4.finish();
+
+    let mut group8 = c.benchmark_group("construct_from_bytes/8");
+    group8.bench_function("TinyAsciiStr<8>", cfu!(TinyAsciiStr<8>, STRINGS_8));
+    group8.bench_function("TinyAsciiStr<16>", cfu!(TinyAsciiStr<16>, STRINGS_8));
+    group8.finish();
+
+    let mut group16 = c.benchmark_group("construct_from_bytes/16");
+    group16.bench_function("TinyAsciiStr<16>", cfu!(TinyAsciiStr<16>, STRINGS_16));
+    group16.finish();
+}
+
+criterion_group!(benches, construct_from_str, construct_from_bytes,);
+criterion_main!(benches);
diff --git a/third_party/rust/tinystr/benches/overview.rs b/third_party/rust/tinystr/benches/overview.rs
new file mode 100644
index 0000000000..ccdd21ac40
--- /dev/null
+++ b/third_party/rust/tinystr/benches/overview.rs
@@ -0,0 +1,91 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+mod common;
+use common::*;
+
+use criterion::black_box;
+use criterion::criterion_group;
+use criterion::criterion_main;
+use criterion::Criterion;
+
+use tinystr::TinyAsciiStr;
+
+fn overview(c: &mut Criterion) {
+    let mut g = c.benchmark_group("overview");
+
+    g.bench_function("construct/TinyAsciiStr", |b| {
+        b.iter(|| {
+            for s in STRINGS_4 {
+                let _: TinyAsciiStr<4> = black_box(s).parse().unwrap();
+                let _: TinyAsciiStr<8> = black_box(s).parse().unwrap();
+                let _: TinyAsciiStr<16> = black_box(s).parse().unwrap();
+            }
+            for s in STRINGS_8 {
+                let _: TinyAsciiStr<8> = black_box(s).parse().unwrap();
+                let _: TinyAsciiStr<16> = black_box(s).parse().unwrap();
+            }
+            for s in STRINGS_16 {
+                let _: TinyAsciiStr<16> = black_box(s).parse().unwrap();
+            }
+        });
+    });
+
+    let parsed_ascii_4: Vec<TinyAsciiStr<4>> = STRINGS_4
+        .iter()
+        .map(|s| s.parse::<TinyAsciiStr<4>>().unwrap())
+        .collect();
+    let parsed_ascii_8: Vec<TinyAsciiStr<8>> = STRINGS_4
+        .iter()
+        .chain(STRINGS_8)
+        .map(|s| s.parse::<TinyAsciiStr<8>>().unwrap())
+        .collect();
+    let parsed_ascii_16: Vec<TinyAsciiStr<16>> = STRINGS_4
+        .iter()
+        .chain(STRINGS_8)
+        .chain(STRINGS_16)
+        .map(|s| s.parse::<TinyAsciiStr<16>>().unwrap())
+        .collect();
+
+    g.bench_function("read/TinyAsciiStr", |b| {
+        b.iter(|| {
+            let mut collector: usize = 0;
+            for t in black_box(&parsed_ascii_4) {
+                let s: &str = t;
+                collector += s.bytes().map(usize::from).sum::<usize>();
+            }
+            for t in black_box(&parsed_ascii_8) {
+                let s: &str = t;
+                collector += s.bytes().map(usize::from).sum::<usize>();
+            }
+            for t in black_box(&parsed_ascii_16) {
+                let s: &str = t;
+                collector += s.bytes().map(usize::from).sum::<usize>();
+            }
+            collector
+        });
+    });
+
+    g.bench_function("compare/TinyAsciiStr", |b| {
+        b.iter(|| {
+            let mut collector: usize = 0;
+            for ts in black_box(&parsed_ascii_4).windows(2) {
+                let o = ts[0].cmp(&ts[1]);
+                collector ^= o as usize;
+            }
+            for ts in black_box(&parsed_ascii_8).windows(2) {
+                let o = ts[0].cmp(&ts[1]);
+                collector ^= o as usize;
+            }
+            for ts in black_box(&parsed_ascii_16).windows(2) {
+                let o = ts[0].cmp(&ts[1]);
+                collector ^= o as usize;
+            }
+            collector
+        });
+    });
+}
+
+criterion_group!(benches, overview,);
+criterion_main!(benches);
diff --git a/third_party/rust/tinystr/benches/read.rs b/third_party/rust/tinystr/benches/read.rs
new file mode 100644
index 0000000000..793bb14f87
--- /dev/null
+++ b/third_party/rust/tinystr/benches/read.rs
@@ -0,0 +1,34 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+mod common;
+use common::*;
+
+use criterion::black_box;
+use criterion::criterion_group;
+use criterion::criterion_main;
+use criterion::Bencher;
+use criterion::Criterion;
+
+use tinystr::TinyAsciiStr;
+
+fn read(c: &mut Criterion) {
+    macro_rules! cfs {
+        ($r:ty, $inputs:expr) => {
+            |b: &mut Bencher| {
+                let parsed: Vec<$r> = $inputs.iter().map(|s| s.parse().unwrap()).collect();
+                b.iter(|| {
+                    for s in &parsed {
+                        let _: &str = black_box(&**s);
+                    }
+                })
+            }
+        };
+    }
+
+    bench_block!(c, "read", cfs);
+}
+
+criterion_group!(benches, read,);
+criterion_main!(benches);
diff --git a/third_party/rust/tinystr/benches/serde.rs b/third_party/rust/tinystr/benches/serde.rs
new file mode 100644
index 0000000000..b0341221d0
--- /dev/null
+++ b/third_party/rust/tinystr/benches/serde.rs
@@ -0,0 +1,37 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+mod common;
+use common::*;
+
+use criterion::black_box;
+use criterion::criterion_group;
+use criterion::criterion_main;
+use criterion::Bencher;
+use criterion::Criterion;
+
+use tinystr::TinyAsciiStr;
+
+fn deserialize(c: &mut Criterion) {
+    macro_rules! cfs {
+        ($r:ty, $inputs:expr) => {
+            |b: &mut Bencher| {
+                let serialized: Vec<Vec<u8>> = $inputs
+                    .iter()
+                    .map(|s| postcard::to_stdvec(&s.parse::<$r>().unwrap()).unwrap())
+                    .collect();
+                b.iter(|| {
+                    for bytes in &serialized {
+                        let _: Result<$r, _> = black_box(postcard::from_bytes(bytes));
+                    }
+                })
+            }
+        };
+    }
+
+    bench_block!(c, "deserialize", cfs);
+}
+
+criterion_group!(benches, deserialize,);
+criterion_main!(benches);
diff --git a/third_party/rust/tinystr/src/ascii.rs b/third_party/rust/tinystr/src/ascii.rs
new file mode 100644
index 0000000000..9ab694f02a
--- /dev/null
+++ b/third_party/rust/tinystr/src/ascii.rs
@@ -0,0 +1,984 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+use crate::asciibyte::AsciiByte;
+use crate::int_ops::{Aligned4, Aligned8};
+use crate::TinyStrError;
+use core::fmt;
+use core::ops::Deref;
+use core::str::{self, FromStr};
+
+#[repr(transparent)]
+#[derive(PartialEq, Eq, Ord, PartialOrd, Copy, Clone, Hash)]
+pub struct TinyAsciiStr<const N: usize> {
+    bytes: [AsciiByte; N],
+}
+
+impl<const N: usize> TinyAsciiStr<N> {
+    /// Creates a `TinyAsciiStr<N>` from the given byte slice.
+    /// `bytes` may contain at most `N` non-null ASCII bytes.
+    pub const fn from_bytes(bytes: &[u8]) -> Result<Self, TinyStrError> {
+        Self::from_bytes_inner(bytes, 0, bytes.len(), false)
+    }
+
+    /// Attempts to parse a fixed-length byte array to a `TinyAsciiStr`.
+    ///
+    /// The byte array may contain trailing NUL bytes.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use tinystr::tinystr;
+    /// use tinystr::TinyAsciiStr;
+    ///
+    /// assert_eq!(
+    ///     TinyAsciiStr::<3>::try_from_raw(*b"GB\0"),
+    ///     Ok(tinystr!(3, "GB"))
+    /// );
+    /// assert_eq!(
+    ///     TinyAsciiStr::<3>::try_from_raw(*b"USD"),
+    ///     Ok(tinystr!(3, "USD"))
+    /// );
+    /// assert!(matches!(TinyAsciiStr::<3>::try_from_raw(*b"\0A\0"), Err(_)));
+    /// ```
+    pub const fn try_from_raw(raw: [u8; N]) -> Result<Self, TinyStrError> {
+        Self::from_bytes_inner(&raw, 0, N, true)
+    }
+
+    /// Equivalent to [`from_bytes(bytes[start..end])`](Self::from_bytes),
+    /// but callable in a `const` context (which range indexing is not).
+    pub const fn from_bytes_manual_slice(
+        bytes: &[u8],
+        start: usize,
+        end: usize,
+    ) -> Result<Self, TinyStrError> {
+        Self::from_bytes_inner(bytes, start, end, false)
+    }
+
+    #[inline]
+    pub(crate) const fn from_bytes_inner(
+        bytes: &[u8],
+        start: usize,
+        end: usize,
+        allow_trailing_null: bool,
+    ) -> Result<Self, TinyStrError> {
+        let len = end - start;
+        if len > N {
+            return Err(TinyStrError::TooLarge { max: N, len });
+        }
+
+        let mut out = [0; N];
+        let mut i = 0;
+        let mut found_null = false;
+        // Indexing is protected by TinyStrError::TooLarge
+        #[allow(clippy::indexing_slicing)]
+        while i < len {
+            let b = bytes[start + i];
+
+            if b == 0 {
+                found_null = true;
+            } else if b >= 0x80 {
+                return Err(TinyStrError::NonAscii);
+            } else if found_null {
+                // Error if there are contentful bytes after null
+                return Err(TinyStrError::ContainsNull);
+            }
+            out[i] = b;
+
+            i += 1;
+        }
+
+        if !allow_trailing_null && found_null {
+            // We found some trailing nulls, error
+            return Err(TinyStrError::ContainsNull);
+        }
+
+        Ok(Self {
+            // SAFETY: `out` only contains ASCII bytes and has same size as `self.bytes`
+            bytes: unsafe { AsciiByte::to_ascii_byte_array(&out) },
+        })
+    }
+
+    // TODO: This function shadows the FromStr trait. Rename?
+    #[inline]
+    pub const fn from_str(s: &str) -> Result<Self, TinyStrError> {
+        Self::from_bytes_inner(s.as_bytes(), 0, s.len(), false)
+    }
+
+    #[inline]
+    pub const fn as_str(&self) -> &str {
+        // as_bytes is valid utf8
+        unsafe { str::from_utf8_unchecked(self.as_bytes()) }
+    }
+
+    #[inline]
+    #[must_use]
+    pub const fn len(&self) -> usize {
+        if N <= 4 {
+            Aligned4::from_ascii_bytes(&self.bytes).len()
+        } else if N <= 8 {
+            Aligned8::from_ascii_bytes(&self.bytes).len()
+        } else {
+            let mut i = 0;
+            #[allow(clippy::indexing_slicing)] // < N is safe
+            while i < N && self.bytes[i] as u8 != AsciiByte::B0 as u8 {
+                i += 1
+            }
+            i
+        }
+    }
+
+    #[inline]
+    #[must_use]
+    pub const fn is_empty(&self) -> bool {
+        self.bytes[0] as u8 == AsciiByte::B0 as u8
+    }
+
+    #[inline]
+    #[must_use]
+    pub const fn as_bytes(&self) -> &[u8] {
+        // Safe because `self.bytes.as_slice()` pointer-casts to `&[u8]`,
+        // and changing the length of that slice to self.len() < N is safe.
+        unsafe {
+            core::slice::from_raw_parts(self.bytes.as_slice().as_ptr() as *const u8, self.len())
+        }
+    }
+
+    #[inline]
+    #[must_use]
+    pub const fn all_bytes(&self) -> &[u8; N] {
+        // SAFETY: `self.bytes` has same size as [u8; N]
+        unsafe { &*(self.bytes.as_ptr() as *const [u8; N]) }
+    }
+
+    #[inline]
+    #[must_use]
+    /// Resizes a `TinyAsciiStr<N>` to a `TinyAsciiStr<M>`.
+    ///
+    /// If `M < len()` the string gets truncated, otherwise only the
+    /// memory representation changes.
+    pub const fn resize<const M: usize>(self) -> TinyAsciiStr<M> {
+        let mut bytes = [0; M];
+        let mut i = 0;
+        // Indexing is protected by the loop guard
+        #[allow(clippy::indexing_slicing)]
+        while i < M && i < N {
+            bytes[i] = self.bytes[i] as u8;
+            i += 1;
+        }
+        // `self.bytes` only contains ASCII bytes, with no null bytes between
+        // ASCII characters, so this also holds for `bytes`.
+        unsafe { TinyAsciiStr::from_bytes_unchecked(bytes) }
+    }
+
+    /// # Safety
+    /// Must be called with a bytes array made of valid ASCII bytes, with no null bytes
+    /// between ASCII characters
+    #[must_use]
+    pub const unsafe fn from_bytes_unchecked(bytes: [u8; N]) -> Self {
+        Self {
+            bytes: AsciiByte::to_ascii_byte_array(&bytes),
+        }
+    }
+}
+
+macro_rules! check_is {
+    ($self:ident, $check_int:ident, $check_u8:ident) => {
+        if N <= 4 {
+            Aligned4::from_ascii_bytes(&$self.bytes).$check_int()
+        } else if N <= 8 {
+            Aligned8::from_ascii_bytes(&$self.bytes).$check_int()
+        } else {
+            let mut i = 0;
+            // Won't panic because self.bytes has length N
+            #[allow(clippy::indexing_slicing)]
+            while i < N && $self.bytes[i] as u8 != AsciiByte::B0 as u8 {
+                if !($self.bytes[i] as u8).$check_u8() {
+                    return false;
+                }
+                i += 1;
+            }
+            true
+        }
+    };
+    ($self:ident, $check_int:ident, !$check_u8_0_inv:ident, !$check_u8_1_inv:ident) => {
+        if N <= 4 {
+            Aligned4::from_ascii_bytes(&$self.bytes).$check_int()
+        } else if N <= 8 {
+            Aligned8::from_ascii_bytes(&$self.bytes).$check_int()
+        } else {
+            // Won't panic because N is > 8
+            if ($self.bytes[0] as u8).$check_u8_0_inv() {
+                return false;
+            }
+            let mut i = 1;
+            // Won't panic because self.bytes has length N
+            #[allow(clippy::indexing_slicing)]
+            while i < N && $self.bytes[i] as u8 != AsciiByte::B0 as u8 {
+                if ($self.bytes[i] as u8).$check_u8_1_inv() {
+                    return false;
+                }
+                i += 1;
+            }
+            true
+        }
+    };
+    ($self:ident, $check_int:ident, $check_u8_0_inv:ident, $check_u8_1_inv:ident) => {
+        if N <= 4 {
+            Aligned4::from_ascii_bytes(&$self.bytes).$check_int()
+        } else if N <= 8 {
+            Aligned8::from_ascii_bytes(&$self.bytes).$check_int()
+        } else {
+            // Won't panic because N is > 8
+            if !($self.bytes[0] as u8).$check_u8_0_inv() {
+                return false;
+            }
+            let mut i = 1;
+            // Won't panic because self.bytes has length N
+            #[allow(clippy::indexing_slicing)]
+            while i < N && $self.bytes[i] as u8 != AsciiByte::B0 as u8 {
+                if !($self.bytes[i] as u8).$check_u8_1_inv() {
+                    return false;
+                }
+                i += 1;
+            }
+            true
+        }
+    };
+}
+
+impl<const N: usize> TinyAsciiStr<N> {
+    /// Checks if the value is composed of ASCII alphabetic characters:
+    ///
+    ///  * U+0041 'A' ..= U+005A 'Z', or
+    ///  * U+0061 'a' ..= U+007A 'z'.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use tinystr::TinyAsciiStr;
+    ///
+    /// let s1: TinyAsciiStr<4> = "Test".parse().expect("Failed to parse.");
+    /// let s2: TinyAsciiStr<4> = "Te3t".parse().expect("Failed to parse.");
+    ///
+    /// assert!(s1.is_ascii_alphabetic());
+    /// assert!(!s2.is_ascii_alphabetic());
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn is_ascii_alphabetic(&self) -> bool {
+        check_is!(self, is_ascii_alphabetic, is_ascii_alphabetic)
+    }
+
+    /// Checks if the value is composed of ASCII alphanumeric characters:
+    ///
+    ///  * U+0041 'A' ..= U+005A 'Z', or
+    ///  * U+0061 'a' ..= U+007A 'z', or
+    ///  * U+0030 '0' ..= U+0039 '9'.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use tinystr::TinyAsciiStr;
+    ///
+    /// let s1: TinyAsciiStr<4> = "A15b".parse().expect("Failed to parse.");
+    /// let s2: TinyAsciiStr<4> = "[3@w".parse().expect("Failed to parse.");
+    ///
+    /// assert!(s1.is_ascii_alphanumeric());
+    /// assert!(!s2.is_ascii_alphanumeric());
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn is_ascii_alphanumeric(&self) -> bool {
+        check_is!(self, is_ascii_alphanumeric, is_ascii_alphanumeric)
+    }
+
+    /// Checks if the value is composed of ASCII decimal digits:
+    ///
+    ///  * U+0030 '0' ..= U+0039 '9'.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use tinystr::TinyAsciiStr;
+    ///
+    /// let s1: TinyAsciiStr<4> = "312".parse().expect("Failed to parse.");
+    /// let s2: TinyAsciiStr<4> = "3d".parse().expect("Failed to parse.");
+    ///
+    /// assert!(s1.is_ascii_numeric());
+    /// assert!(!s2.is_ascii_numeric());
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn is_ascii_numeric(&self) -> bool {
+        check_is!(self, is_ascii_numeric, is_ascii_digit)
+    }
+
+    /// Checks if the value is in ASCII lower case.
+    ///
+    /// All letter characters are checked for case. Non-letter characters are ignored.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use tinystr::TinyAsciiStr;
+    ///
+    /// let s1: TinyAsciiStr<4> = "teSt".parse().expect("Failed to parse.");
+    /// let s2: TinyAsciiStr<4> = "test".parse().expect("Failed to parse.");
+    /// let s3: TinyAsciiStr<4> = "001z".parse().expect("Failed to parse.");
+    ///
+    /// assert!(!s1.is_ascii_lowercase());
+    /// assert!(s2.is_ascii_lowercase());
+    /// assert!(s3.is_ascii_lowercase());
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn is_ascii_lowercase(&self) -> bool {
+        check_is!(
+            self,
+            is_ascii_lowercase,
+            !is_ascii_uppercase,
+            !is_ascii_uppercase
+        )
+    }
+
+    /// Checks if the value is in ASCII title case.
+    ///
+    /// This verifies that the first character is ASCII uppercase and all others ASCII lowercase.
+    /// Non-letter characters are ignored.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use tinystr::TinyAsciiStr;
+    ///
+    /// let s1: TinyAsciiStr<4> = "teSt".parse().expect("Failed to parse.");
+    /// let s2: TinyAsciiStr<4> = "Test".parse().expect("Failed to parse.");
+    /// let s3: TinyAsciiStr<4> = "001z".parse().expect("Failed to parse.");
+    ///
+    /// assert!(!s1.is_ascii_titlecase());
+    /// assert!(s2.is_ascii_titlecase());
+    /// assert!(s3.is_ascii_titlecase());
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn is_ascii_titlecase(&self) -> bool {
+        check_is!(
+            self,
+            is_ascii_titlecase,
+            !is_ascii_lowercase,
+            !is_ascii_uppercase
+        )
+    }
+
+    /// Checks if the value is in ASCII upper case.
+    ///
+    /// All letter characters are checked for case. Non-letter characters are ignored.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use tinystr::TinyAsciiStr;
+    ///
+    /// let s1: TinyAsciiStr<4> = "teSt".parse().expect("Failed to parse.");
+    /// let s2: TinyAsciiStr<4> = "TEST".parse().expect("Failed to parse.");
+    /// let s3: TinyAsciiStr<4> = "001z".parse().expect("Failed to parse.");
+    ///
+    /// assert!(!s1.is_ascii_uppercase());
+    /// assert!(s2.is_ascii_uppercase());
+    /// assert!(!s3.is_ascii_uppercase());
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn is_ascii_uppercase(&self) -> bool {
+        check_is!(
+            self,
+            is_ascii_uppercase,
+            !is_ascii_lowercase,
+            !is_ascii_lowercase
+        )
+    }
+
+    /// Checks if the value is composed of ASCII alphabetic lower case characters:
+    ///
+    ///  * U+0061 'a' ..= U+007A 'z',
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use tinystr::TinyAsciiStr;
+    ///
+    /// let s1: TinyAsciiStr<4> = "Test".parse().expect("Failed to parse.");
+    /// let s2: TinyAsciiStr<4> = "Te3t".parse().expect("Failed to parse.");
+    /// let s3: TinyAsciiStr<4> = "teSt".parse().expect("Failed to parse.");
+    /// let s4: TinyAsciiStr<4> = "test".parse().expect("Failed to parse.");
+    /// let s5: TinyAsciiStr<4> = "001z".parse().expect("Failed to parse.");
+    ///
+    /// assert!(!s1.is_ascii_alphabetic_lowercase());
+    /// assert!(!s2.is_ascii_alphabetic_lowercase());
+    /// assert!(!s3.is_ascii_alphabetic_lowercase());
+    /// assert!(s4.is_ascii_alphabetic_lowercase());
+    /// assert!(!s5.is_ascii_alphabetic_lowercase());
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn is_ascii_alphabetic_lowercase(&self) -> bool {
+        check_is!(
+            self,
+            is_ascii_alphabetic_lowercase,
+            is_ascii_lowercase,
+            is_ascii_lowercase
+        )
+    }
+
+    /// Checks if the value is composed of ASCII alphabetic, with the first character being ASCII uppercase, and all others ASCII lowercase.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use tinystr::TinyAsciiStr;
+    ///
+    /// let s1: TinyAsciiStr<4> = "Test".parse().expect("Failed to parse.");
+    /// let s2: TinyAsciiStr<4> = "Te3t".parse().expect("Failed to parse.");
+    /// let s3: TinyAsciiStr<4> = "teSt".parse().expect("Failed to parse.");
+    /// let s4: TinyAsciiStr<4> = "test".parse().expect("Failed to parse.");
+    /// let s5: TinyAsciiStr<4> = "001z".parse().expect("Failed to parse.");
+    ///
+    /// assert!(s1.is_ascii_alphabetic_titlecase());
+    /// assert!(!s2.is_ascii_alphabetic_titlecase());
+    /// assert!(!s3.is_ascii_alphabetic_titlecase());
+    /// assert!(!s4.is_ascii_alphabetic_titlecase());
+    /// assert!(!s5.is_ascii_alphabetic_titlecase());
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn is_ascii_alphabetic_titlecase(&self) -> bool {
+        check_is!(
+            self,
+            is_ascii_alphabetic_titlecase,
+            is_ascii_uppercase,
+            is_ascii_lowercase
+        )
+    }
+
+    /// Checks if the value is composed of ASCII alphabetic upper case characters:
+    ///
+    ///  * U+0041 'A' ..= U+005A 'Z',
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use tinystr::TinyAsciiStr;
+    ///
+    /// let s1: TinyAsciiStr<4> = "Test".parse().expect("Failed to parse.");
+    /// let s2: TinyAsciiStr<4> = "Te3t".parse().expect("Failed to parse.");
+    /// let s3: TinyAsciiStr<4> = "teSt".parse().expect("Failed to parse.");
+    /// let s4: TinyAsciiStr<4> = "TEST".parse().expect("Failed to parse.");
+    /// let s5: TinyAsciiStr<4> = "001z".parse().expect("Failed to parse.");
+    ///
+    /// assert!(!s1.is_ascii_alphabetic_uppercase());
+    /// assert!(!s2.is_ascii_alphabetic_uppercase());
+    /// assert!(!s3.is_ascii_alphabetic_uppercase());
+    /// assert!(s4.is_ascii_alphabetic_uppercase());
+    /// assert!(!s5.is_ascii_alphabetic_uppercase());
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn is_ascii_alphabetic_uppercase(&self) -> bool {
+        check_is!(
+            self,
+            is_ascii_alphabetic_uppercase,
+            is_ascii_uppercase,
+            is_ascii_uppercase
+        )
+    }
+}
+
+macro_rules! to {
+    ($self:ident, $to:ident, $later_char_to:ident $(,$first_char_to:ident)?) => {{
+        let mut i = 0;
+        if N <= 4 {
+            let aligned = Aligned4::from_ascii_bytes(&$self.bytes).$to().to_ascii_bytes();
+            // Won't panic because self.bytes has length N and aligned has length >= N
+            #[allow(clippy::indexing_slicing)]
+            while i < N {
+                $self.bytes[i] = aligned[i];
+                i += 1;
+            }
+        } else if N <= 8 {
+            let aligned = Aligned8::from_ascii_bytes(&$self.bytes).$to().to_ascii_bytes();
+            // Won't panic because self.bytes has length N and aligned has length >= N
+            #[allow(clippy::indexing_slicing)]
+            while i < N {
+                $self.bytes[i] = aligned[i];
+                i += 1;
+            }
+        } else {
+            // Won't panic because self.bytes has length N
+            #[allow(clippy::indexing_slicing)]
+            while i < N && $self.bytes[i] as u8 != AsciiByte::B0 as u8 {
+                // SAFETY: AsciiByte is repr(u8) and has same size as u8
+                unsafe {
+                    $self.bytes[i] = core::mem::transmute(
+                        ($self.bytes[i] as u8).$later_char_to()
+                    );
+                }
+                i += 1;
+            }
+            // SAFETY: AsciiByte is repr(u8) and has same size as u8
+            $(
+                $self.bytes[0] = unsafe {
+                    core::mem::transmute(($self.bytes[0] as u8).$first_char_to())
+                };
+            )?
+        }
+        $self
+    }};
+}
+
+impl<const N: usize> TinyAsciiStr<N> {
+    /// Converts this type to its ASCII lower case equivalent in-place.
+    ///
+    /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', other characters are unchanged.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use tinystr::TinyAsciiStr;
+    ///
+    /// let s1: TinyAsciiStr<4> = "TeS3".parse().expect("Failed to parse.");
+    ///
+    /// assert_eq!(&*s1.to_ascii_lowercase(), "tes3");
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn to_ascii_lowercase(mut self) -> Self {
+        to!(self, to_ascii_lowercase, to_ascii_lowercase)
+    }
+
+    /// Converts this type to its ASCII title case equivalent in-place.
+    ///
+    /// The first character is converted to ASCII uppercase; the remaining characters
+    /// are converted to ASCII lowercase.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use tinystr::TinyAsciiStr;
+    ///
+    /// let s1: TinyAsciiStr<4> = "teSt".parse().expect("Failed to parse.");
+    ///
+    /// assert_eq!(&*s1.to_ascii_titlecase(), "Test");
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn to_ascii_titlecase(mut self) -> Self {
+        to!(
+            self,
+            to_ascii_titlecase,
+            to_ascii_lowercase,
+            to_ascii_uppercase
+        )
+    }
+
+    /// Converts this type to its ASCII upper case equivalent in-place.
+    ///
+    /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', other characters are unchanged.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use tinystr::TinyAsciiStr;
+    ///
+    /// let s1: TinyAsciiStr<4> = "Tes3".parse().expect("Failed to parse.");
+    ///
+    /// assert_eq!(&*s1.to_ascii_uppercase(), "TES3");
+    /// ```
+    #[inline]
+    #[must_use]
+    pub const fn to_ascii_uppercase(mut self) -> Self {
+        to!(self, to_ascii_uppercase, to_ascii_uppercase)
+    }
+}
+
+impl<const N: usize> fmt::Debug for TinyAsciiStr<N> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(self.as_str(), f)
+    }
+}
+
+impl<const N: usize> fmt::Display for TinyAsciiStr<N> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(self.as_str(), f)
+    }
+}
+
+impl<const N: usize> Deref for TinyAsciiStr<N> {
+    type Target = str;
+    #[inline]
+    fn deref(&self) -> &str {
+        self.as_str()
+    }
+}
+
+impl<const N: usize> FromStr for TinyAsciiStr<N> {
+    type Err = TinyStrError;
+    #[inline]
+    fn from_str(s: &str) -> Result<Self, TinyStrError> {
+        Self::from_str(s)
+    }
+}
+
+impl<const N: usize> PartialEq<str> for TinyAsciiStr<N> {
+    fn eq(&self, other: &str) -> bool {
+        self.deref() == other
+    }
+}
+
+impl<const N: usize> PartialEq<&str> for TinyAsciiStr<N> {
+    fn eq(&self, other: &&str) -> bool {
+        self.deref() == *other
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl<const N: usize> PartialEq<alloc::string::String> for TinyAsciiStr<N> {
+    fn eq(&self, other: &alloc::string::String) -> bool {
+        self.deref() == other.deref()
+    }
+}
+
+#[cfg(feature = "alloc")]
+impl<const N: usize> PartialEq<TinyAsciiStr<N>> for alloc::string::String {
+    fn eq(&self, other: &TinyAsciiStr<N>) -> bool {
+        self.deref() == other.deref()
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use rand::distributions::Distribution;
+    use rand::distributions::Standard;
+    use rand::rngs::SmallRng;
+    use rand::seq::SliceRandom;
+    use rand::SeedableRng;
+
+    const STRINGS: [&str; 26] = [
+        "Latn",
+        "laTn",
+        "windows",
+        "AR",
+        "Hans",
+        "macos",
+        "AT",
+        "infiniband",
+        "FR",
+        "en",
+        "Cyrl",
+        "FromIntegral",
+        "NO",
+        "419",
+        "MacintoshOSX2019",
+        "a3z",
+        "A3z",
+        "A3Z",
+        "a3Z",
+        "3A",
+        "3Z",
+        "3a",
+        "3z",
+        "@@[`{",
+        "UK",
+        "E12",
+    ];
+
+    fn gen_strings(num_strings: usize, allowed_lengths: &[usize]) -> Vec<String> {
+        let mut rng = SmallRng::seed_from_u64(2022);
+        // Need to do this in 2 steps since the RNG is needed twice
+        let string_lengths = core::iter::repeat_with(|| *allowed_lengths.choose(&mut rng).unwrap())
+            .take(num_strings)
+            .collect::<Vec<usize>>();
+        string_lengths
+            .iter()
+            .map(|len| {
+                Standard
+                    .sample_iter(&mut rng)
+                    .filter(|b: &u8| *b > 0 && *b < 0x80)
+                    .take(*len)
+                    .collect::<Vec<u8>>()
+            })
+            .map(|byte_vec| String::from_utf8(byte_vec).expect("All ASCII"))
+            .collect()
+    }
+
+    fn check_operation<T, F1, F2, const N: usize>(reference_f: F1, tinystr_f: F2)
+    where
+        F1: Fn(&str) -> T,
+        F2: Fn(TinyAsciiStr<N>) -> T,
+        T: core::fmt::Debug + core::cmp::PartialEq,
+    {
+        for s in STRINGS
+            .into_iter()
+            .map(str::to_owned)
+            .chain(gen_strings(100, &[3, 4, 5, 8, 12]))
+        {
+            let t = match TinyAsciiStr::<N>::from_str(&s) {
+                Ok(t) => t,
+                Err(TinyStrError::TooLarge { .. }) => continue,
+                Err(e) => panic!("{}", e),
+            };
+            let expected = reference_f(&s);
+            let actual = tinystr_f(t);
+            assert_eq!(expected, actual, "TinyAsciiStr<{N}>: {s:?}");
+        }
+    }
+
+    #[test]
+    fn test_is_ascii_alphabetic() {
+        fn check<const N: usize>() {
+            check_operation(
+                |s| s.chars().all(|c| c.is_ascii_alphabetic()),
+                |t: TinyAsciiStr<N>| TinyAsciiStr::is_ascii_alphabetic(&t),
+            )
+        }
+        check::<2>();
+        check::<3>();
+        check::<4>();
+        check::<5>();
+        check::<8>();
+        check::<16>();
+    }
+
+    #[test]
+    fn test_is_ascii_alphanumeric() {
+        fn check<const N: usize>() {
+            check_operation(
+                |s| s.chars().all(|c| c.is_ascii_alphanumeric()),
+                |t: TinyAsciiStr<N>| TinyAsciiStr::is_ascii_alphanumeric(&t),
+            )
+        }
+        check::<2>();
+        check::<3>();
+        check::<4>();
+        check::<5>();
+        check::<8>();
+        check::<16>();
+    }
+
+    #[test]
+    fn test_is_ascii_numeric() {
+        fn check<const N: usize>() {
+            check_operation(
+                |s| s.chars().all(|c| c.is_ascii_digit()),
+                |t: TinyAsciiStr<N>| TinyAsciiStr::is_ascii_numeric(&t),
+            )
+        }
+        check::<2>();
+        check::<3>();
+        check::<4>();
+        check::<5>();
+        check::<8>();
+        check::<16>();
+    }
+
+    #[test]
+    fn test_is_ascii_lowercase() {
+        fn check<const N: usize>() {
+            check_operation(
+                |s| {
+                    s == TinyAsciiStr::<16>::from_str(s)
+                        .unwrap()
+                        .to_ascii_lowercase()
+                        .as_str()
+                },
+                |t: TinyAsciiStr<N>| TinyAsciiStr::is_ascii_lowercase(&t),
+            )
+        }
+        check::<2>();
+        check::<3>();
+        check::<4>();
+        check::<5>();
+        check::<8>();
+        check::<16>();
+    }
+
+    #[test]
+    fn test_is_ascii_titlecase() {
+        fn check<const N: usize>() {
+            check_operation(
+                |s| {
+                    s == TinyAsciiStr::<16>::from_str(s)
+                        .unwrap()
+                        .to_ascii_titlecase()
+                        .as_str()
+                },
+                |t: TinyAsciiStr<N>| TinyAsciiStr::is_ascii_titlecase(&t),
+            )
+        }
+        check::<2>();
+        check::<3>();
+        check::<4>();
+        check::<5>();
+        check::<8>();
+        check::<16>();
+    }
+
+    #[test]
+    fn test_is_ascii_uppercase() {
+        fn check<const N: usize>() {
+            check_operation(
+                |s| {
+                    s == TinyAsciiStr::<16>::from_str(s)
+                        .unwrap()
+                        .to_ascii_uppercase()
+                        .as_str()
+                },
+                |t: TinyAsciiStr<N>| TinyAsciiStr::is_ascii_uppercase(&t),
+            )
+        }
+        check::<2>();
+        check::<3>();
+        check::<4>();
+        check::<5>();
+        check::<8>();
+        check::<16>();
+    }
+
+    #[test]
+    fn test_is_ascii_alphabetic_lowercase() {
+        fn check<const N: usize>() {
+            check_operation(
+                |s| {
+                    // Check alphabetic
+                    s.chars().all(|c| c.is_ascii_alphabetic()) &&
+                    // Check lowercase
+                    s == TinyAsciiStr::<16>::from_str(s)
+                        .unwrap()
+                        .to_ascii_lowercase()
+                        .as_str()
+                },
+                |t: TinyAsciiStr<N>| TinyAsciiStr::is_ascii_alphabetic_lowercase(&t),
+            )
+        }
+        check::<2>();
+        check::<3>();
+        check::<4>();
+        check::<5>();
+        check::<8>();
+        check::<16>();
+    }
+
+    #[test]
+    fn test_is_ascii_alphabetic_titlecase() {
+        fn check<const N: usize>() {
+            check_operation(
+                |s| {
+                    // Check alphabetic
+                    s.chars().all(|c| c.is_ascii_alphabetic()) &&
+                    // Check titlecase
+                    s == TinyAsciiStr::<16>::from_str(s)
+                        .unwrap()
+                        .to_ascii_titlecase()
+                        .as_str()
+                },
+                |t: TinyAsciiStr<N>| TinyAsciiStr::is_ascii_alphabetic_titlecase(&t),
+            )
+        }
+        check::<2>();
+        check::<3>();
+        check::<4>();
+        check::<5>();
+        check::<8>();
+        check::<16>();
+    }
+
+    #[test]
+    fn test_is_ascii_alphabetic_uppercase() {
+        fn check<const N: usize>() {
+            check_operation(
+                |s| {
+                    // Check alphabetic
+                    s.chars().all(|c| c.is_ascii_alphabetic()) &&
+                    // Check uppercase
+                    s == TinyAsciiStr::<16>::from_str(s)
+                        .unwrap()
+                        .to_ascii_uppercase()
+                        .as_str()
+                },
+                |t: TinyAsciiStr<N>| TinyAsciiStr::is_ascii_alphabetic_uppercase(&t),
+            )
+        }
+        check::<2>();
+        check::<3>();
+        check::<4>();
+        check::<5>();
+        check::<8>();
+        check::<16>();
+    }
+
+    #[test]
+    fn test_to_ascii_lowercase() {
+        fn check<const N: usize>() {
+            check_operation(
+                |s| {
+                    s.chars()
+                        .map(|c| c.to_ascii_lowercase())
+                        .collect::<String>()
+                },
+                |t: TinyAsciiStr<N>| TinyAsciiStr::to_ascii_lowercase(t).as_str().to_owned(),
+            )
+        }
+        check::<2>();
+        check::<3>();
+        check::<4>();
+        check::<5>();
+        check::<8>();
+        check::<16>();
+    }
+
+    #[test]
+    fn test_to_ascii_titlecase() {
+        fn check<const N: usize>() {
+            check_operation(
+                |s| {
+                    let mut r = s
+                        .chars()
+                        .map(|c| c.to_ascii_lowercase())
+                        .collect::<String>();
+                    // Safe because the string is nonempty and an ASCII string
+                    unsafe { r.as_bytes_mut()[0].make_ascii_uppercase() };
+                    r
+                },
+                |t: TinyAsciiStr<N>| TinyAsciiStr::to_ascii_titlecase(t).as_str().to_owned(),
+            )
+        }
+        check::<2>();
+        check::<3>();
+        check::<4>();
+        check::<5>();
+        check::<8>();
+        check::<16>();
+    }
+
+    #[test]
+    fn test_to_ascii_uppercase() {
+        fn check<const N: usize>() {
+            check_operation(
+                |s| {
+                    s.chars()
+                        .map(|c| c.to_ascii_uppercase())
+                        .collect::<String>()
+                },
+                |t: TinyAsciiStr<N>| TinyAsciiStr::to_ascii_uppercase(t).as_str().to_owned(),
+            )
+        }
+        check::<2>();
+        check::<3>();
+        check::<4>();
+        check::<5>();
+        check::<8>();
+        check::<16>();
+    }
+}
diff --git a/third_party/rust/tinystr/src/asciibyte.rs b/third_party/rust/tinystr/src/asciibyte.rs
new file mode 100644
index 0000000000..f41a033414
--- /dev/null
+++ b/third_party/rust/tinystr/src/asciibyte.rs
@@ -0,0 +1,145 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+#[repr(u8)]
+#[allow(dead_code)]
+#[derive(PartialEq, Eq, Ord, PartialOrd, Copy, Clone, Hash)]
+pub enum AsciiByte {
+    B0 = 0,
+    B1 = 1,
+    B2 = 2,
+    B3 = 3,
+    B4 = 4,
+    B5 = 5,
+    B6 = 6,
+    B7 = 7,
+    B8 = 8,
+    B9 = 9,
+    B10 = 10,
+    B11 = 11,
+    B12 = 12,
+    B13 = 13,
+    B14 = 14,
+    B15 = 15,
+    B16 = 16,
+    B17 = 17,
+    B18 = 18,
+    B19 = 19,
+    B20 = 20,
+    B21 = 21,
+    B22 = 22,
+    B23 = 23,
+    B24 = 24,
+    B25 = 25,
+    B26 = 26,
+    B27 = 27,
+    B28 = 28,
+    B29 = 29,
+    B30 = 30,
+    B31 = 31,
+    B32 = 32,
+    B33 = 33,
+    B34 = 34,
+    B35 = 35,
+    B36 = 36,
+    B37 = 37,
+    B38 = 38,
+    B39 = 39,
+    B40 = 40,
+    B41 = 41,
+    B42 = 42,
+    B43 = 43,
+    B44 = 44,
+    B45 = 45,
+    B46 = 46,
+    B47 = 47,
+    B48 = 48,
+    B49 = 49,
+    B50 = 50,
+    B51 = 51,
+    B52 = 52,
+    B53 = 53,
+    B54 = 54,
+    B55 = 55,
+    B56 = 56,
+    B57 = 57,
+    B58 = 58,
+    B59 = 59,
+    B60 = 60,
+    B61 = 61,
+    B62 = 62,
+    B63 = 63,
+    B64 = 64,
+    B65 = 65,
+    B66 = 66,
+    B67 = 67,
+    B68 = 68,
+    B69 = 69,
+    B70 = 70,
+    B71 = 71,
+    B72 = 72,
+    B73 = 73,
+    B74 = 74,
+    B75 = 75,
+    B76 = 76,
+    B77 = 77,
+    B78 = 78,
+    B79 = 79,
+    B80 = 80,
+    B81 = 81,
+    B82 = 82,
+    B83 = 83,
+    B84 = 84,
+    B85 = 85,
+    B86 = 86,
+    B87 = 87,
+    B88 = 88,
+    B89 = 89,
+    B90 = 90,
+    B91 = 91,
+    B92 = 92,
+    B93 = 93,
+    B94 = 94,
+    B95 = 95,
+    B96 = 96,
+    B97 = 97,
+    B98 = 98,
+    B99 = 99,
+    B100 = 100,
+    B101 = 101,
+    B102 = 102,
+    B103 = 103,
+    B104 = 104,
+    B105 = 105,
+    B106 = 106,
+    B107 = 107,
+    B108 = 108,
+    B109 = 109,
+    B110 = 110,
+    B111 = 111,
+    B112 = 112,
+    B113 = 113,
+    B114 = 114,
+    B115 = 115,
+    B116 = 116,
+    B117 = 117,
+    B118 = 118,
+    B119 = 119,
+    B120 = 120,
+    B121 = 121,
+    B122 = 122,
+    B123 = 123,
+    B124 = 124,
+    B125 = 125,
+    B126 = 126,
+    B127 = 127,
+}
+
+impl AsciiByte {
+    // Convert [u8; N] to [AsciiByte; N]
+    #[inline]
+    pub const unsafe fn to_ascii_byte_array<const N: usize>(bytes: &[u8; N]) -> [AsciiByte; N] {
+        *(bytes as *const [u8; N] as *const [AsciiByte; N])
+    }
+}
diff --git a/third_party/rust/tinystr/src/databake.rs b/third_party/rust/tinystr/src/databake.rs
new file mode 100644
index 0000000000..0b127f97c7
--- /dev/null
+++ b/third_party/rust/tinystr/src/databake.rs
@@ -0,0 +1,48 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+use crate::TinyAsciiStr;
+use crate::UnvalidatedTinyAsciiStr;
+use databake::*;
+
+impl<const N: usize> Bake for TinyAsciiStr<N> {
+    fn bake(&self, env: &CrateEnv) -> TokenStream {
+        env.insert("tinystr");
+        let string = self.as_str();
+        quote! {
+            tinystr::tinystr!(#N, #string)
+        }
+    }
+}
+
+impl<const N: usize> databake::Bake for UnvalidatedTinyAsciiStr<N> {
+    fn bake(&self, env: &databake::CrateEnv) -> databake::TokenStream {
+        match self.try_into_tinystr() {
+            Ok(tiny) => {
+                let tiny = tiny.bake(env);
+                databake::quote! {
+                    #tiny.to_unvalidated()
+                }
+            }
+            Err(_) => {
+                let bytes = self.0.bake(env);
+                env.insert("tinystr");
+                databake::quote! {
+                    tinystr::UnvalidatedTinyAsciiStr::from_bytes_unchecked(*#bytes)
+                }
+            }
+        }
+    }
+}
+
+#[test]
+fn test() {
+    test_bake!(TinyAsciiStr<10>, const: crate::tinystr!(10usize, "foo"), tinystr);
+}
+
+#[test]
+fn test_unvalidated() {
+    test_bake!(UnvalidatedTinyAsciiStr<10>, const: crate::tinystr!(10usize, "foo").to_unvalidated(), tinystr);
+    test_bake!(UnvalidatedTinyAsciiStr<3>, const: crate::UnvalidatedTinyAsciiStr::from_bytes_unchecked(*b"AB\xCD"), tinystr);
+}
diff --git a/third_party/rust/tinystr/src/error.rs b/third_party/rust/tinystr/src/error.rs
new file mode 100644
index 0000000000..7910f8b484
--- /dev/null
+++ b/third_party/rust/tinystr/src/error.rs
@@ -0,0 +1,19 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+use displaydoc::Display;
+
+#[cfg(feature = "std")]
+impl std::error::Error for TinyStrError {}
+
+#[derive(Display, Debug, PartialEq, Eq)]
+#[non_exhaustive]
+pub enum TinyStrError {
+    #[displaydoc("found string of larger length {len} when constructing string of length {max}")]
+    TooLarge { max: usize, len: usize },
+    #[displaydoc("tinystr types do not support strings with null bytes")]
+    ContainsNull,
+    #[displaydoc("attempted to construct TinyStrAuto from a non-ascii string")]
+    NonAscii,
+}
diff --git a/third_party/rust/tinystr/src/int_ops.rs b/third_party/rust/tinystr/src/int_ops.rs
new file mode 100644
index 0000000000..102b052f22
--- /dev/null
+++ b/third_party/rust/tinystr/src/int_ops.rs
@@ -0,0 +1,315 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+use crate::asciibyte::AsciiByte;
+
+/// Internal helper struct that performs operations on aligned integers.
+/// Supports strings up to 4 bytes long.
+#[repr(transparent)]
+pub struct Aligned4(u32);
+
+impl Aligned4 {
+    /// # Panics
+    /// Panics if N is greater than 4
+    #[inline]
+    pub const fn from_bytes<const N: usize>(src: &[u8; N]) -> Self {
+        let mut bytes = [0; 4];
+        let mut i = 0;
+        // The function documentation defines when panics may occur
+        #[allow(clippy::indexing_slicing)]
+        while i < N {
+            bytes[i] = src[i];
+            i += 1;
+        }
+        Self(u32::from_ne_bytes(bytes))
+    }
+
+    #[inline]
+    pub const fn from_ascii_bytes<const N: usize>(src: &[AsciiByte; N]) -> Self {
+        Self::from_bytes::<N>(unsafe { core::mem::transmute(src) })
+    }
+
+    #[inline]
+    pub const fn to_bytes(&self) -> [u8; 4] {
+        self.0.to_ne_bytes()
+    }
+
+    #[inline]
+    pub const fn to_ascii_bytes(&self) -> [AsciiByte; 4] {
+        unsafe { core::mem::transmute(self.to_bytes()) }
+    }
+
+    pub const fn len(&self) -> usize {
+        let word = self.0;
+        #[cfg(target_endian = "little")]
+        let len = (4 - word.leading_zeros() / 8) as usize;
+        #[cfg(target_endian = "big")]
+        let len = (4 - word.trailing_zeros() / 8) as usize;
+        len
+    }
+
+    pub const fn is_ascii_alphabetic(&self) -> bool {
+        let word = self.0;
+        // Each of the following bitmasks set *the high bit* (0x8) to 0 for valid and 1 for invalid.
+        // `mask` sets all NUL bytes to 0.
+        let mask = (word + 0x7f7f_7f7f) & 0x8080_8080;
+        // `lower` converts the string to lowercase. It may also change the value of non-alpha
+        // characters, but this does not matter for the alphabetic test that follows.
+        let lower = word | 0x2020_2020;
+        // `alpha` sets all alphabetic bytes to 0. We only need check for lowercase characters.
+        let alpha = !(lower + 0x1f1f_1f1f) | (lower + 0x0505_0505);
+        // The overall string is valid if every character passes at least one test.
+        // We performed two tests here: non-NUL (`mask`) and alphabetic (`alpha`).
+        (alpha & mask) == 0
+    }
+
+    pub const fn is_ascii_alphanumeric(&self) -> bool {
+        let word = self.0;
+        // See explanatory comments in is_ascii_alphabetic
+        let mask = (word + 0x7f7f_7f7f) & 0x8080_8080;
+        let numeric = !(word + 0x5050_5050) | (word + 0x4646_4646);
+        let lower = word | 0x2020_2020;
+        let alpha = !(lower + 0x1f1f_1f1f) | (lower + 0x0505_0505);
+        (alpha & numeric & mask) == 0
+    }
+
+    pub const fn is_ascii_numeric(&self) -> bool {
+        let word = self.0;
+        // See explanatory comments in is_ascii_alphabetic
+        let mask = (word + 0x7f7f_7f7f) & 0x8080_8080;
+        let numeric = !(word + 0x5050_5050) | (word + 0x4646_4646);
+        (numeric & mask) == 0
+    }
+
+    pub const fn is_ascii_lowercase(&self) -> bool {
+        let word = self.0;
+        // For efficiency, this function tests for an invalid string rather than a valid string.
+        // A string is ASCII lowercase iff it contains no uppercase ASCII characters.
+        // `invalid_case` sets all uppercase ASCII characters to 0 and all others to 1.
+        let invalid_case = !(word + 0x3f3f_3f3f) | (word + 0x2525_2525);
+        // The string is valid if it contains no invalid characters (if all high bits are 1).
+        (invalid_case & 0x8080_8080) == 0x8080_8080
+    }
+
+    pub const fn is_ascii_titlecase(&self) -> bool {
+        let word = self.0;
+        // See explanatory comments in is_ascii_lowercase
+        let invalid_case = if cfg!(target_endian = "little") {
+            !(word + 0x3f3f_3f1f) | (word + 0x2525_2505)
+        } else {
+            !(word + 0x1f3f_3f3f) | (word + 0x0525_2525)
+        };
+        (invalid_case & 0x8080_8080) == 0x8080_8080
+    }
+
+    pub const fn is_ascii_uppercase(&self) -> bool {
+        let word = self.0;
+        // See explanatory comments in is_ascii_lowercase
+        let invalid_case = !(word + 0x1f1f_1f1f) | (word + 0x0505_0505);
+        (invalid_case & 0x8080_8080) == 0x8080_8080
+    }
+
+    pub const fn is_ascii_alphabetic_lowercase(&self) -> bool {
+        let word = self.0;
+        // `mask` sets all NUL bytes to 0.
+        let mask = (word + 0x7f7f_7f7f) & 0x8080_8080;
+        // `lower_alpha` sets all lowercase ASCII characters to 0 and all others to 1.
+        let lower_alpha = !(word + 0x1f1f_1f1f) | (word + 0x0505_0505);
+        // The overall string is valid if every character passes at least one test.
+        // We performed two tests here: non-NUL (`mask`) and lowercase ASCII character (`alpha`).
+        (lower_alpha & mask) == 0
+    }
+
+    pub const fn is_ascii_alphabetic_titlecase(&self) -> bool {
+        let word = self.0;
+        // See explanatory comments in is_ascii_alphabetic_lowercase
+        let mask = (word + 0x7f7f_7f7f) & 0x8080_8080;
+        let title_case = if cfg!(target_endian = "little") {
+            !(word + 0x1f1f_1f3f) | (word + 0x0505_0525)
+        } else {
+            !(word + 0x3f1f_1f1f) | (word + 0x2505_0505)
+        };
+        (title_case & mask) == 0
+    }
+
+    pub const fn is_ascii_alphabetic_uppercase(&self) -> bool {
+        let word = self.0;
+        // See explanatory comments in is_ascii_alphabetic_lowercase
+        let mask = (word + 0x7f7f_7f7f) & 0x8080_8080;
+        let upper_alpha = !(word + 0x3f3f_3f3f) | (word + 0x2525_2525);
+        (upper_alpha & mask) == 0
+    }
+
+    pub const fn to_ascii_lowercase(&self) -> Self {
+        let word = self.0;
+        let result = word | (((word + 0x3f3f_3f3f) & !(word + 0x2525_2525) & 0x8080_8080) >> 2);
+        Self(result)
+    }
+
+    pub const fn to_ascii_titlecase(&self) -> Self {
+        let word = self.0.to_le();
+        let mask = ((word + 0x3f3f_3f1f) & !(word + 0x2525_2505) & 0x8080_8080) >> 2;
+        let result = (word | mask) & !(0x20 & mask);
+        Self(u32::from_le(result))
+    }
+
+    pub const fn to_ascii_uppercase(&self) -> Self {
+        let word = self.0;
+        let result = word & !(((word + 0x1f1f_1f1f) & !(word + 0x0505_0505) & 0x8080_8080) >> 2);
+        Self(result)
+    }
+}
+
+/// Internal helper struct that performs operations on aligned integers.
+/// Supports strings up to 8 bytes long.
+#[repr(transparent)]
+pub struct Aligned8(u64);
+
+impl Aligned8 {
+    /// # Panics
+    /// Panics if N is greater than 8
+    #[inline]
+    pub const fn from_bytes<const N: usize>(src: &[u8; N]) -> Self {
+        let mut bytes = [0; 8];
+        let mut i = 0;
+        // The function documentation defines when panics may occur
+        #[allow(clippy::indexing_slicing)]
+        while i < N {
+            bytes[i] = src[i];
+            i += 1;
+        }
+        Self(u64::from_ne_bytes(bytes))
+    }
+
+    #[inline]
+    pub const fn from_ascii_bytes<const N: usize>(src: &[AsciiByte; N]) -> Self {
+        Self::from_bytes::<N>(unsafe { core::mem::transmute(src) })
+    }
+
+    #[inline]
+    pub const fn to_bytes(&self) -> [u8; 8] {
+        self.0.to_ne_bytes()
+    }
+
+    #[inline]
+    pub const fn to_ascii_bytes(&self) -> [AsciiByte; 8] {
+        unsafe { core::mem::transmute(self.to_bytes()) }
+    }
+
+    pub const fn len(&self) -> usize {
+        let word = self.0;
+        #[cfg(target_endian = "little")]
+        let len = (8 - word.leading_zeros() / 8) as usize;
+        #[cfg(target_endian = "big")]
+        let len = (8 - word.trailing_zeros() / 8) as usize;
+        len
+    }
+
+    pub const fn is_ascii_alphabetic(&self) -> bool {
+        let word = self.0;
+        let mask = (word + 0x7f7f_7f7f_7f7f_7f7f) & 0x8080_8080_8080_8080;
+        let lower = word | 0x2020_2020_2020_2020;
+        let alpha = !(lower + 0x1f1f_1f1f_1f1f_1f1f) | (lower + 0x0505_0505_0505_0505);
+        (alpha & mask) == 0
+    }
+
+    pub const fn is_ascii_alphanumeric(&self) -> bool {
+        let word = self.0;
+        let mask = (word + 0x7f7f_7f7f_7f7f_7f7f) & 0x8080_8080_8080_8080;
+        let numeric = !(word + 0x5050_5050_5050_5050) | (word + 0x4646_4646_4646_4646);
+        let lower = word | 0x2020_2020_2020_2020;
+        let alpha = !(lower + 0x1f1f_1f1f_1f1f_1f1f) | (lower + 0x0505_0505_0505_0505);
+        (alpha & numeric & mask) == 0
+    }
+
+    pub const fn is_ascii_numeric(&self) -> bool {
+        let word = self.0;
+        let mask = (word + 0x7f7f_7f7f_7f7f_7f7f) & 0x8080_8080_8080_8080;
+        let numeric = !(word + 0x5050_5050_5050_5050) | (word + 0x4646_4646_4646_4646);
+        (numeric & mask) == 0
+    }
+
+    pub const fn is_ascii_lowercase(&self) -> bool {
+        let word = self.0;
+        let invalid_case = !(word + 0x3f3f_3f3f_3f3f_3f3f) | (word + 0x2525_2525_2525_2525);
+        (invalid_case & 0x8080_8080_8080_8080) == 0x8080_8080_8080_8080
+    }
+
+    pub const fn is_ascii_titlecase(&self) -> bool {
+        let word = self.0;
+        let invalid_case = if cfg!(target_endian = "little") {
+            !(word + 0x3f3f_3f3f_3f3f_3f1f) | (word + 0x2525_2525_2525_2505)
+        } else {
+            !(word + 0x1f3f_3f3f_3f3f_3f3f) | (word + 0x0525_2525_2525_2525)
+        };
+        (invalid_case & 0x8080_8080_8080_8080) == 0x8080_8080_8080_8080
+    }
+
+    pub const fn is_ascii_uppercase(&self) -> bool {
+        let word = self.0;
+        let invalid_case = !(word + 0x1f1f_1f1f_1f1f_1f1f) | (word + 0x0505_0505_0505_0505);
+        (invalid_case & 0x8080_8080_8080_8080) == 0x8080_8080_8080_8080
+    }
+
+    pub const fn is_ascii_alphabetic_lowercase(&self) -> bool {
+        let word = self.0;
+        // `mask` sets all NUL bytes to 0.
+        let mask = (word + 0x7f7f_7f7f_7f7f_7f7f) & 0x8080_8080_8080_8080;
+        // `lower_alpha` sets all lowercase ASCII characters to 0 and all others to 1.
+        let lower_alpha = !(word + 0x1f1f_1f1f_1f1f_1f1f) | (word + 0x0505_0505_0505_0505);
+        // The overall string is valid if every character passes at least one test.
+        // We performed two tests here: non-NUL (`mask`) and lowercase ASCII character (`alpha`).
+        (lower_alpha & mask) == 0
+    }
+
+    pub const fn is_ascii_alphabetic_titlecase(&self) -> bool {
+        let word = self.0;
+        // See explanatory comments in is_ascii_alphabetic_lowercase
+        let mask = (word + 0x7f7f_7f7f_7f7f_7f7f) & 0x8080_8080_8080_8080;
+        let title_case = if cfg!(target_endian = "little") {
+            !(word + 0x1f1f_1f1f_1f1f_1f3f) | (word + 0x0505_0505_0505_0525)
+        } else {
+            !(word + 0x3f1f_1f1f_1f1f_1f1f) | (word + 0x2505_0505_0505_0505)
+        };
+        (title_case & mask) == 0
+    }
+
+    pub const fn is_ascii_alphabetic_uppercase(&self) -> bool {
+        let word = self.0;
+        // See explanatory comments in is_ascii_alphabetic_lowercase
+        let mask = (word + 0x7f7f_7f7f_7f7f_7f7f) & 0x8080_8080_8080_8080;
+        let upper_alpha = !(word + 0x3f3f_3f3f_3f3f_3f3f) | (word + 0x2525_2525_2525_2525);
+        (upper_alpha & mask) == 0
+    }
+
+    pub const fn to_ascii_lowercase(&self) -> Self {
+        let word = self.0;
+        let result = word
+            | (((word + 0x3f3f_3f3f_3f3f_3f3f)
+                & !(word + 0x2525_2525_2525_2525)
+                & 0x8080_8080_8080_8080)
+                >> 2);
+        Self(result)
+    }
+
+    pub const fn to_ascii_titlecase(&self) -> Self {
+        let word = self.0.to_le();
+        let mask = ((word + 0x3f3f_3f3f_3f3f_3f1f)
+            & !(word + 0x2525_2525_2525_2505)
+            & 0x8080_8080_8080_8080)
+            >> 2;
+        let result = (word | mask) & !(0x20 & mask);
+        Self(u64::from_le(result))
+    }
+
+    pub const fn to_ascii_uppercase(&self) -> Self {
+        let word = self.0;
+        let result = word
+            & !(((word + 0x1f1f_1f1f_1f1f_1f1f)
+                & !(word + 0x0505_0505_0505_0505)
+                & 0x8080_8080_8080_8080)
+                >> 2);
+        Self(result)
+    }
+}
diff --git a/third_party/rust/tinystr/src/lib.rs b/third_party/rust/tinystr/src/lib.rs
new file mode 100644
index 0000000000..3d13e95ea5
--- /dev/null
+++ b/third_party/rust/tinystr/src/lib.rs
@@ -0,0 +1,118 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+//! `tinystr` is a utility crate of the [`ICU4X`] project.
+//!
+//! It includes [`TinyAsciiStr`], a core API for representing small ASCII-only bounded length strings.
+//!
+//! It is optimized for operations on strings of size 8 or smaller. When use cases involve comparison
+//! and conversion of strings for lowercase/uppercase/titlecase, or checking
+//! numeric/alphabetic/alphanumeric, `TinyAsciiStr` is the edge performance library.
+//!
+//! # Examples
+//!
+//! ```rust
+//! use tinystr::TinyAsciiStr;
+//!
+//! let s1: TinyAsciiStr<4> = "tEsT".parse().expect("Failed to parse.");
+//!
+//! assert_eq!(s1, "tEsT");
+//! assert_eq!(s1.to_ascii_uppercase(), "TEST");
+//! assert_eq!(s1.to_ascii_lowercase(), "test");
+//! assert_eq!(s1.to_ascii_titlecase(), "Test");
+//! assert!(s1.is_ascii_alphanumeric());
+//! assert!(!s1.is_ascii_numeric());
+//!
+//! let s2 = TinyAsciiStr::<8>::try_from_raw(*b"New York")
+//!     .expect("Failed to parse.");
+//!
+//! assert_eq!(s2, "New York");
+//! assert_eq!(s2.to_ascii_uppercase(), "NEW YORK");
+//! assert_eq!(s2.to_ascii_lowercase(), "new york");
+//! assert_eq!(s2.to_ascii_titlecase(), "New york");
+//! assert!(!s2.is_ascii_alphanumeric());
+//! ```
+//!
+//! # Details
+//!
+//! When strings are of size 8 or smaller, the struct transforms the strings as `u32`/`u64` and uses
+//! bitmasking to provide basic string manipulation operations:
+//! * `is_ascii_numeric`
+//! * `is_ascii_alphabetic`
+//! * `is_ascii_alphanumeric`
+//! * `to_ascii_lowercase`
+//! * `to_ascii_uppercase`
+//! * `to_ascii_titlecase`
+//! * `PartialEq`
+//!
+//! `TinyAsciiStr` will fall back to `u8` character manipulation for strings of length greater than 8.
+
+//!
+//! [`ICU4X`]: ../icu/index.html
+
+// https://github.com/unicode-org/icu4x/blob/main/docs/process/boilerplate.md#library-annotations
+#![cfg_attr(not(any(test, feature = "std")), no_std)]
+#![cfg_attr(
+    not(test),
+    deny(
+        clippy::indexing_slicing,
+        clippy::unwrap_used,
+        clippy::expect_used,
+        clippy::panic,
+        clippy::exhaustive_structs,
+        clippy::exhaustive_enums,
+        missing_debug_implementations,
+    )
+)]
+
+mod macros;
+
+mod ascii;
+mod asciibyte;
+mod error;
+mod int_ops;
+mod unvalidated;
+
+#[cfg(feature = "serde")]
+mod serde;
+
+#[cfg(feature = "databake")]
+mod databake;
+
+#[cfg(feature = "zerovec")]
+mod ule;
+
+#[cfg(any(feature = "serde", feature = "alloc"))]
+extern crate alloc;
+
+pub use ascii::TinyAsciiStr;
+pub use error::TinyStrError;
+pub use unvalidated::UnvalidatedTinyAsciiStr;
+
+/// These are temporary compatability reexports that will be removed
+/// in a future version.
+pub type TinyStr4 = TinyAsciiStr<4>;
+/// These are temporary compatability reexports that will be removed
+/// in a future version.
+pub type TinyStr8 = TinyAsciiStr<8>;
+/// These are temporary compatability reexports that will be removed
+/// in a future version.
+pub type TinyStr16 = TinyAsciiStr<16>;
+
+#[test]
+fn test_size() {
+    assert_eq!(
+        core::mem::size_of::<TinyStr4>(),
+        core::mem::size_of::<Option<TinyStr4>>()
+    );
+    assert_eq!(
+        core::mem::size_of::<TinyStr8>(),
+        core::mem::size_of::<Option<TinyStr8>>()
+    );
+}
+// /// Allows unit tests to use the macro
+// #[cfg(test)]
+// mod tinystr {
+//     pub use super::{TinyAsciiStr, TinyStrError};
+// }
diff --git a/third_party/rust/tinystr/src/macros.rs b/third_party/rust/tinystr/src/macros.rs
new file mode 100644
index 0000000000..b00185238e
--- /dev/null
+++ b/third_party/rust/tinystr/src/macros.rs
@@ -0,0 +1,32 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+#[macro_export]
+macro_rules! tinystr {
+    ($n:literal, $s:literal) => {{
+        // Force it into a const context; otherwise it may get evaluated at runtime instead.
+        const TINYSTR_MACRO_CONST: $crate::TinyAsciiStr<$n> = {
+            match $crate::TinyAsciiStr::from_bytes($s.as_bytes()) {
+                Ok(s) => s,
+                // We are okay with panicking here because this is in a const context
+                #[allow(clippy::panic)]
+                // Cannot format the error since formatting isn't const yet
+                Err(_) => panic!(concat!("Failed to construct tinystr from ", $s)),
+            }
+        };
+        TINYSTR_MACRO_CONST
+    }};
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test_macro_construction() {
+        let s1 = tinystr!(8, "foobar");
+        assert_eq!(&*s1, "foobar");
+
+        let s1 = tinystr!(12, "foobarbaz");
+        assert_eq!(&*s1, "foobarbaz");
+    }
+}
diff --git a/third_party/rust/tinystr/src/serde.rs b/third_party/rust/tinystr/src/serde.rs
new file mode 100644
index 0000000000..4c3f8be132
--- /dev/null
+++ b/third_party/rust/tinystr/src/serde.rs
@@ -0,0 +1,91 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+use crate::TinyAsciiStr;
+use alloc::borrow::Cow;
+use alloc::string::ToString;
+use core::fmt;
+use core::marker::PhantomData;
+use core::ops::Deref;
+use serde::de::{Error, SeqAccess, Visitor};
+use serde::ser::SerializeTuple;
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+
+impl<const N: usize> Serialize for TinyAsciiStr<N> {
+    #[inline]
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        if serializer.is_human_readable() {
+            self.deref().serialize(serializer)
+        } else {
+            let mut seq = serializer.serialize_tuple(N)?;
+            for byte in self.all_bytes() {
+                seq.serialize_element(byte)?;
+            }
+            seq.end()
+        }
+    }
+}
+
+struct TinyAsciiStrVisitor<const N: usize> {
+    marker: PhantomData<TinyAsciiStr<N>>,
+}
+
+impl<const N: usize> TinyAsciiStrVisitor<N> {
+    fn new() -> Self {
+        TinyAsciiStrVisitor {
+            marker: PhantomData,
+        }
+    }
+}
+
+impl<'de, const N: usize> Visitor<'de> for TinyAsciiStrVisitor<N> {
+    type Value = TinyAsciiStr<N>;
+
+    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        write!(formatter, "a TinyAsciiStr<{N}>")
+    }
+
+    #[inline]
+    fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+    where
+        A: SeqAccess<'de>,
+    {
+        let mut bytes = [0u8; N];
+        let mut zeroes = false;
+        for out in &mut bytes.iter_mut().take(N) {
+            let byte = seq
+                .next_element()?
+                .ok_or_else(|| Error::invalid_length(N, &self))?;
+            if byte == 0 {
+                zeroes = true;
+            } else if zeroes {
+                return Err(Error::custom("TinyAsciiStr cannot contain null bytes"));
+            }
+
+            if byte >= 0x80 {
+                return Err(Error::custom("TinyAsciiStr cannot contain non-ascii bytes"));
+            }
+            *out = byte;
+        }
+
+        Ok(unsafe { TinyAsciiStr::from_bytes_unchecked(bytes) })
+    }
+}
+
+impl<'de, const N: usize> Deserialize<'de> for TinyAsciiStr<N> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        if deserializer.is_human_readable() {
+            let x: Cow<'de, str> = Deserialize::deserialize(deserializer)?;
+            TinyAsciiStr::from_str(&x).map_err(|e| Error::custom(e.to_string()))
+        } else {
+            deserializer.deserialize_tuple(N, TinyAsciiStrVisitor::<N>::new())
+        }
+    }
+}
diff --git a/third_party/rust/tinystr/src/ule.rs b/third_party/rust/tinystr/src/ule.rs
new file mode 100644
index 0000000000..eda43890b5
--- /dev/null
+++ b/third_party/rust/tinystr/src/ule.rs
@@ -0,0 +1,116 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+use crate::{TinyAsciiStr, UnvalidatedTinyAsciiStr};
+use zerovec::maps::ZeroMapKV;
+use zerovec::ule::*;
+use zerovec::{ZeroSlice, ZeroVec};
+
+// Safety (based on the safety checklist on the ULE trait):
+//  1. TinyAsciiStr does not include any uninitialized or padding bytes.
+//     (achieved by `#[repr(transparent)]` on a type that satisfies this invariant)
+//  2. TinyAsciiStr is aligned to 1 byte.
+//     (achieved by `#[repr(transparent)]` on a type that satisfies this invariant)
+//  3. The impl of validate_byte_slice() returns an error if any byte is not valid.
+//  4. The impl of validate_byte_slice() returns an error if there are extra bytes.
+//  5. The other ULE methods use the default impl.
+//  6. TinyAsciiStr byte equality is semantic equality
+unsafe impl<const N: usize> ULE for TinyAsciiStr<N> {
+    #[inline]
+    fn validate_byte_slice(bytes: &[u8]) -> Result<(), ZeroVecError> {
+        if bytes.len() % N != 0 {
+            return Err(ZeroVecError::length::<Self>(bytes.len()));
+        }
+        // Validate the bytes
+        for chunk in bytes.chunks_exact(N) {
+            let _ = TinyAsciiStr::<N>::from_bytes_inner(chunk, 0, N, true)
+                .map_err(|_| ZeroVecError::parse::<Self>())?;
+        }
+        Ok(())
+    }
+}
+
+impl<const N: usize> AsULE for TinyAsciiStr<N> {
+    type ULE = Self;
+
+    #[inline]
+    fn to_unaligned(self) -> Self::ULE {
+        self
+    }
+
+    #[inline]
+    fn from_unaligned(unaligned: Self::ULE) -> Self {
+        unaligned
+    }
+}
+
+impl<'a, const N: usize> ZeroMapKV<'a> for TinyAsciiStr<N> {
+    type Container = ZeroVec<'a, TinyAsciiStr<N>>;
+    type Slice = ZeroSlice<TinyAsciiStr<N>>;
+    type GetType = TinyAsciiStr<N>;
+    type OwnedType = TinyAsciiStr<N>;
+}
+
+// Safety (based on the safety checklist on the ULE trait):
+//  1. UnvalidatedTinyAsciiStr does not include any uninitialized or padding bytes.
+//     (achieved by `#[repr(transparent)]` on a type that satisfies this invariant)
+//  2. UnvalidatedTinyAsciiStr is aligned to 1 byte.
+//     (achieved by `#[repr(transparent)]` on a type that satisfies this invariant)
+//  3. The impl of validate_byte_slice() returns an error if any byte is not valid.
+//  4. The impl of validate_byte_slice() returns an error if there are extra bytes.
+//  5. The other ULE methods use the default impl.
+//  6. UnvalidatedTinyAsciiStr byte equality is semantic equality
+unsafe impl<const N: usize> ULE for UnvalidatedTinyAsciiStr<N> {
+    #[inline]
+    fn validate_byte_slice(bytes: &[u8]) -> Result<(), ZeroVecError> {
+        if bytes.len() % N != 0 {
+            return Err(ZeroVecError::length::<Self>(bytes.len()));
+        }
+        Ok(())
+    }
+}
+
+impl<const N: usize> AsULE for UnvalidatedTinyAsciiStr<N> {
+    type ULE = Self;
+
+    #[inline]
+    fn to_unaligned(self) -> Self::ULE {
+        self
+    }
+
+    #[inline]
+    fn from_unaligned(unaligned: Self::ULE) -> Self {
+        unaligned
+    }
+}
+
+impl<'a, const N: usize> ZeroMapKV<'a> for UnvalidatedTinyAsciiStr<N> {
+    type Container = ZeroVec<'a, UnvalidatedTinyAsciiStr<N>>;
+    type Slice = ZeroSlice<UnvalidatedTinyAsciiStr<N>>;
+    type GetType = UnvalidatedTinyAsciiStr<N>;
+    type OwnedType = UnvalidatedTinyAsciiStr<N>;
+}
+
+#[cfg(test)]
+mod test {
+    use crate::*;
+    use zerovec::*;
+
+    #[test]
+    fn test_zerovec() {
+        let mut vec = ZeroVec::<TinyAsciiStr<7>>::new();
+
+        vec.with_mut(|v| v.push("foobar".parse().unwrap()));
+        vec.with_mut(|v| v.push("baz".parse().unwrap()));
+        vec.with_mut(|v| v.push("quux".parse().unwrap()));
+
+        let bytes = vec.as_bytes();
+
+        let vec: ZeroVec<TinyAsciiStr<7>> = ZeroVec::parse_byte_slice(bytes).unwrap();
+
+        assert_eq!(&*vec.get(0).unwrap(), "foobar");
+        assert_eq!(&*vec.get(1).unwrap(), "baz");
+        assert_eq!(&*vec.get(2).unwrap(), "quux");
+    }
+}
diff --git a/third_party/rust/tinystr/src/unvalidated.rs b/third_party/rust/tinystr/src/unvalidated.rs
new file mode 100644
index 0000000000..2fffbbc119
--- /dev/null
+++ b/third_party/rust/tinystr/src/unvalidated.rs
@@ -0,0 +1,104 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+use crate::TinyAsciiStr;
+use crate::TinyStrError;
+
+/// A fixed-length bytes array that is expected to be an ASCII string but does not enforce that invariant.
+///
+/// Use this type instead of `TinyAsciiStr` if you don't need to enforce ASCII during deserialization. For
+/// example, strings that are keys of a map don't need to ever be reified as `TinyAsciiStr`s.
+///
+/// The main advantage of this type over `[u8; N]` is that it serializes as a string in
+/// human-readable formats like JSON.
+#[derive(Debug, PartialEq, PartialOrd, Eq, Ord, Clone, Copy)]
+pub struct UnvalidatedTinyAsciiStr<const N: usize>(pub(crate) [u8; N]);
+
+impl<const N: usize> UnvalidatedTinyAsciiStr<N> {
+    #[inline]
+    // Converts into a [`TinyAsciiStr`]. Fails if the bytes are not valid ASCII.
+    pub fn try_into_tinystr(&self) -> Result<TinyAsciiStr<N>, TinyStrError> {
+        TinyAsciiStr::try_from_raw(self.0)
+    }
+
+    #[doc(hidden)]
+    pub const fn from_bytes_unchecked(bytes: [u8; N]) -> Self {
+        Self(bytes)
+    }
+}
+
+impl<const N: usize> TinyAsciiStr<N> {
+    #[inline]
+    // Converts into a [`UnvalidatedTinyAsciiStr`]
+    pub const fn to_unvalidated(self) -> UnvalidatedTinyAsciiStr<N> {
+        UnvalidatedTinyAsciiStr(*self.all_bytes())
+    }
+}
+
+#[cfg(feature = "serde")]
+impl<const N: usize> serde::Serialize for UnvalidatedTinyAsciiStr<N> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        use serde::ser::Error;
+        self.try_into_tinystr()
+            .map_err(|_| S::Error::custom("invalid ascii in UnvalidatedTinyAsciiStr"))?
+            .serialize(serializer)
+    }
+}
+
+macro_rules! deserialize {
+    ($size:literal) => {
+        #[cfg(feature = "serde")]
+        impl<'de, 'a> serde::Deserialize<'de> for UnvalidatedTinyAsciiStr<$size>
+        where
+            'de: 'a,
+        {
+            fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+            where
+                D: serde::Deserializer<'de>,
+            {
+                if deserializer.is_human_readable() {
+                    Ok(TinyAsciiStr::deserialize(deserializer)?.to_unvalidated())
+                } else {
+                    Ok(Self(<[u8; $size]>::deserialize(deserializer)?))
+                }
+            }
+        }
+    };
+}
+
+deserialize!(1);
+deserialize!(2);
+deserialize!(3);
+deserialize!(4);
+deserialize!(5);
+deserialize!(6);
+deserialize!(7);
+deserialize!(8);
+deserialize!(9);
+deserialize!(10);
+deserialize!(11);
+deserialize!(12);
+deserialize!(13);
+deserialize!(14);
+deserialize!(15);
+deserialize!(16);
+deserialize!(17);
+deserialize!(18);
+deserialize!(19);
+deserialize!(20);
+deserialize!(21);
+deserialize!(22);
+deserialize!(23);
+deserialize!(24);
+deserialize!(25);
+deserialize!(26);
+deserialize!(27);
+deserialize!(28);
+deserialize!(29);
+deserialize!(30);
+deserialize!(31);
+deserialize!(32);
diff --git a/third_party/rust/tinystr/tests/serde.rs b/third_party/rust/tinystr/tests/serde.rs
new file mode 100644
index 0000000000..282914e6fc
--- /dev/null
+++ b/third_party/rust/tinystr/tests/serde.rs
@@ -0,0 +1,39 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+use tinystr::*;
+
+// Tests largely adapted from `tinystr` crate
+// https://github.com/zbraniecki/tinystr/blob/4e4eab55dd6bded7f29a18b41452c506c461716c/tests/serde.rs
+
+macro_rules! test_roundtrip {
+    ($f:ident, $n:literal, $val:expr) => {
+        #[test]
+        fn $f() {
+            let tiny: TinyAsciiStr<$n> = $val.parse().unwrap();
+            let json_string = serde_json::to_string(&tiny).unwrap();
+            let expected_json = concat!("\"", $val, "\"");
+            assert_eq!(json_string, expected_json);
+            let recover: TinyAsciiStr<$n> = serde_json::from_str(&json_string).unwrap();
+            assert_eq!(&*tiny, &*recover);
+
+            let bin = bincode::serialize(&tiny).unwrap();
+            assert_eq!(bin, &tiny.all_bytes()[..]);
+            let debin: TinyAsciiStr<$n> = bincode::deserialize(&bin).unwrap();
+            assert_eq!(&*tiny, &*debin);
+
+            let post = postcard::to_stdvec(&tiny).unwrap();
+            assert_eq!(post, &tiny.all_bytes()[..]);
+            let unpost: TinyAsciiStr<$n> = postcard::from_bytes(&post).unwrap();
+            assert_eq!(&*tiny, &*unpost);
+        }
+    };
+}
+
+test_roundtrip!(test_roundtrip4_1, 4, "en");
+test_roundtrip!(test_roundtrip4_2, 4, "Latn");
+test_roundtrip!(test_roundtrip8, 8, "calendar");
+test_roundtrip!(test_roundtrip16, 16, "verylongstring");
+test_roundtrip!(test_roundtrip10, 11, "shortstring");
+test_roundtrip!(test_roundtrip30, 24, "veryveryverylongstring");