From 1d77ba2bc447b83307327bd78d1ea236a1625989 Mon Sep 17 00:00:00 2001
From: Hannes Karppila <hannes.karppila@gmail.com>
Date: Thu, 9 Apr 2020 19:20:10 +0300
Subject: [PATCH] Add no_std + alloc support

---
 .travis.yml           |  2 ++
 Cargo.toml            |  5 +++++
 src/__test_api.rs     |  5 +++++
 src/decompose.rs      |  6 +++---
 src/lib.rs            | 11 ++++++++++-
 src/no_std_prelude.rs |  6 ++++++
 src/normalize.rs      |  4 ++--
 src/recompose.rs      |  2 +-
 src/stream_safe.rs    |  8 ++++++--
 src/test.rs           |  5 ++++-
 10 files changed, 44 insertions(+), 10 deletions(-)
 create mode 100755 src/no_std_prelude.rs

diff --git a/.travis.yml b/.travis.yml
index a736bf7..f1132c9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,9 +7,11 @@ sudo: false
 script:
   - cargo build --verbose
   - cargo test --verbose
+  - cargo test --verbose --no-default-features
   - cargo package
   - cd target/package/unicode-normalization-*
   - cargo test --verbose
+  - cargo test --verbose --no-default-features
 notifications:
   email:
     on_success: never
diff --git a/Cargo.toml b/Cargo.toml
index 423eeef..6cf8fa7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,3 +25,8 @@ exclude = [ "target/*", "Cargo.lock", "scripts/tmp", "*.txt", "tests/*" ]
 [dependencies.tinyvec]
 version = "0.3.3"
 features = ["alloc"]
+
+
+[features]
+default = ["std"]
+std = []
diff --git a/src/__test_api.rs b/src/__test_api.rs
index 934fa72..f1a3f92 100644
--- a/src/__test_api.rs
+++ b/src/__test_api.rs
@@ -4,10 +4,15 @@
 //
 // If you're caught using this outside this crates tests/, you get to clean up the mess.
 
+#[cfg(not(feature = "std"))]
+use crate::no_std_prelude::*;
+
 use crate::stream_safe::StreamSafe;
+
 pub fn stream_safe(s: &str) -> String {
     StreamSafe::new(s.chars()).collect()
 }
+
 pub mod quick_check {
     pub use crate::quick_check::*;
 }
diff --git a/src/decompose.rs b/src/decompose.rs
index 0ba15d0..f228023 100644
--- a/src/decompose.rs
+++ b/src/decompose.rs
@@ -7,9 +7,9 @@
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
-use std::fmt::{self, Write};
-use std::iter::Fuse;
-use std::ops::Range;
+use core::fmt::{self, Write};
+use core::iter::Fuse;
+use core::ops::Range;
 use tinyvec::TinyVec;
 
 #[derive(Clone)]
diff --git a/src/lib.rs b/src/lib.rs
index dc58c50..6749adc 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -42,6 +42,13 @@
     html_logo_url = "https://unicode-rs.github.io/unicode-rs_sm.png",
     html_favicon_url = "https://unicode-rs.github.io/unicode-rs_sm.png"
 )]
+#![cfg_attr(not(feature = "std"), no_std)]
+
+#[cfg(not(feature = "std"))]
+extern crate alloc;
+
+#[cfg(feature = "std")]
+extern crate core;
 
 extern crate tinyvec;
 
@@ -54,7 +61,9 @@ pub use crate::quick_check::{
 pub use crate::recompose::Recompositions;
 pub use crate::stream_safe::StreamSafe;
 pub use crate::tables::UNICODE_VERSION;
-use std::str::Chars;
+use core::str::Chars;
+
+mod no_std_prelude;
 
 mod decompose;
 mod lookups;
diff --git a/src/no_std_prelude.rs b/src/no_std_prelude.rs
new file mode 100755
index 0000000..838d122
--- /dev/null
+++ b/src/no_std_prelude.rs
@@ -0,0 +1,6 @@
+#[cfg(not(feature = "std"))]
+pub use alloc::{
+    str::Chars,
+    string::{String, ToString},
+    vec::Vec,
+};
diff --git a/src/normalize.rs b/src/normalize.rs
index 3d54360..1097c42 100644
--- a/src/normalize.rs
+++ b/src/normalize.rs
@@ -12,8 +12,8 @@
 use crate::lookups::{
     canonical_fully_decomposed, compatibility_fully_decomposed, composition_table,
 };
-use std::char;
-use std::ops::FnMut;
+
+use core::{char, ops::FnMut};
 
 /// Compute canonical Unicode decomposition for character.
 /// See [Unicode Standard Annex #15](http://www.unicode.org/reports/tr15/)
diff --git a/src/recompose.rs b/src/recompose.rs
index 29022e2..2a1960a 100644
--- a/src/recompose.rs
+++ b/src/recompose.rs
@@ -9,7 +9,7 @@
 // except according to those terms.
 
 use crate::decompose::Decompositions;
-use std::fmt::{self, Write};
+use core::fmt::{self, Write};
 use tinyvec::TinyVec;
 
 #[derive(Clone)]
diff --git a/src/stream_safe.rs b/src/stream_safe.rs
index 80123f0..1ba7d76 100644
--- a/src/stream_safe.rs
+++ b/src/stream_safe.rs
@@ -107,7 +107,11 @@ mod tests {
     use super::{classify_nonstarters, StreamSafe};
     use crate::lookups::canonical_combining_class;
     use crate::normalize::decompose_compatible;
-    use std::char;
+
+    #[cfg(not(feature = "std"))]
+    use crate::no_std_prelude::*;
+
+    use core::char;
 
     fn stream_safe(s: &str) -> String {
         StreamSafe::new(s.chars()).collect()
@@ -131,7 +135,7 @@ mod tests {
                 None => continue,
             };
             let c = classify_nonstarters(ch);
-            let mut s = vec![];
+            let mut s = Vec::new();
             decompose_compatible(ch, |c| s.push(c));
 
             assert_eq!(s.len(), c.decomposition_len);
diff --git a/src/test.rs b/src/test.rs
index 1a0f13a..2e87a87 100644
--- a/src/test.rs
+++ b/src/test.rs
@@ -10,7 +10,10 @@
 
 use super::char::is_combining_mark;
 use super::UnicodeNormalization;
-use std::char;
+use core::char;
+
+#[cfg(not(feature = "std"))]
+use crate::no_std_prelude::*;
 
 #[test]
 fn test_nfd() {