feat: support no_std

Cargo.toml

@@ -61,3 +61,6 @@ required-features = ["compat"]
 [[test]]
 name = "special_pinyin"
 required-features = ["with_tone_num_end", "heteronym"]
+
+[dependencies]
+hashbrown = { version = "0.16.1", features = ["alloc"] }

src/compat.rs

@@ -1,7 +1,8 @@
 #![allow(deprecated)]
 
 use crate::{Pinyin, ToPinyin, ToPinyinMulti};
-use std::collections::HashSet;
+use alloc::string::{String, ToString};
+use alloc::vec::Vec;
 
 /// 拼音风格
 #[deprecated = "请使用 `Pinyin` 的方法代替"]
@@ -86,7 +87,7 @@ pub fn pinyin(s: &str, a: &Args) -> Vec<Vec<String>> {
         s.to_pinyin_multi()
             .map(|multi| match multi {
                 Some(multi) => {
-                    let mut set = HashSet::new();
+                    let mut set = hashbrown::HashSet::new();
                     multi
                         .into_iter()
                         .map(|pinyin| apply_style(pinyin, &a.style))

src/lib.rs

@@ -1,5 +1,9 @@
+#![no_std]
 use crate::data::CHAR_BLOCKS;
-use std::convert::TryFrom;
+use core::convert::TryFrom;
+
+#[macro_use]
+extern crate alloc;
 
 #[cfg(feature = "compat")]
 mod compat;
@@ -17,7 +21,7 @@ pub use crate::pinyin_multi::{PinyinMulti, PinyinMultiIter, PinyinMultiStrIter,
 /// 将给定输入字符串的拼音通过给定映射函数后存入 `Vec` 中
 ///
 /// 这个函数会跳过任何没有拼音的字符。本函数主要用于测试目的。
-pub fn to_pinyin_vec<F>(input: &str, f: F) -> Vec<&'static str>
+pub fn to_pinyin_vec<F>(input: &str, f: F) -> alloc::vec::Vec<&'static str>
 where
     F: Fn(Pinyin) -> &'static str,
 {

src/pinyin.rs

@@ -1,6 +1,6 @@
 use crate::data::PINYIN_DATA;
 use crate::{get_block_and_index, PinyinData};
-use std::str::Chars;
+use core::str::Chars;
 
 /// 单个字符的拼音信息
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]

src/pinyin_multi.rs

@@ -1,6 +1,6 @@
 use crate::data::{HETERONYM_TABLE, PINYIN_DATA};
 use crate::{get_block_and_index, Pinyin, PinyinData};
-use std::str::Chars;
+use core::str::Chars;
 
 /// 单个字符的多音字信息
 ///
@@ -184,6 +184,7 @@ mod tests {
     #[test]
     #[cfg(feature = "with_tone")]
     fn str_to_pinyin_multi() {
+        use alloc::vec::Vec;
         let actual = "还没"
             .to_pinyin_multi()
             .map(|multi| {