add support for no std environments

.gitignore

@@ -1,2 +1 @@
 /target
-.env

Cargo.lock

@@ -2,12 +2,43 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "ahash"
+version = "0.8.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a15f179cd60c4584b8a8c596927aadc462e27f2ca70c04e0071964a73ba7a75"
+dependencies = [
+ "cfg-if",
+ "getrandom",
+ "once_cell",
+ "version_check",
+ "zerocopy",
+]
+
+[[package]]
+name = "cfg-if"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
+
 [[package]]
 name = "equivalent"
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "877a4ace8713b0bcf2a4e7eec82529c029f1d0619886d18145fea96c3ffe5c0f"
 
+[[package]]
+name = "getrandom"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "899def5c37c4fd7b2664648c28120ecec138e4d395b459e5ca34f9cce2dd77fd"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "r-efi",
+ "wasip2",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.16.0"
@@ -24,9 +55,104 @@ dependencies = [
  "hashbrown",
 ]
 
+[[package]]
+name = "libc"
+version = "0.2.177"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2874a2af47a2325c2001a6e6fad9b16a53b802102b528163885171cf92b15976"
+
+[[package]]
+name = "once_cell"
+version = "1.21.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.103"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5ee95bc4ef87b8d5ba32e8b7714ccc834865276eab0aed5c9958d00ec45f49e8"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.41"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ce25767e7b499d1b604768e7cde645d14cc8584231ea6b295e9c9eb22c02e1d1"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "r-efi"
+version = "5.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"
+
+[[package]]
+name = "syn"
+version = "2.0.108"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "da58917d35242480a05c2897064da0a80589a2a0476c9a3f2fdc83b53502e917"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "462eeb75aeb73aea900253ce739c8e18a67423fadf006037cd3ff27e82748a06"
+
 [[package]]
 name = "urigen"
 version = "0.3.0"
 dependencies = [
+ "ahash",
  "indexmap",
 ]
+
+[[package]]
+name = "version_check"
+version = "0.9.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"
+
+[[package]]
+name = "wasip2"
+version = "1.0.1+wasi-0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0562428422c63773dad2c345a1882263bbf4d65cf3f42e90921f787ef5ad58e7"
+dependencies = [
+ "wit-bindgen",
+]
+
+[[package]]
+name = "wit-bindgen"
+version = "0.46.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f17a85883d4e6d00e8a97c586de764dabcc06133f7f1d55dce5cdc070ad7fe59"
+
+[[package]]
+name = "zerocopy"
+version = "0.8.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0894878a5fa3edfd6da3f88c4805f4c8558e2b996227a3d864f47fe11e38282c"
+dependencies = [
+ "zerocopy-derive",
+]
+
+[[package]]
+name = "zerocopy-derive"
+version = "0.8.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "88d2b8d9c68ad2b9e4340d7832716a4d21a22a1154777ad56ea55c51a9cf3831"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]

Cargo.toml

@@ -3,5 +3,10 @@ name = "urigen"
 version = "0.3.0"
 edition = "2024"
 
+[features]
+default = ["std"]
+std = ["indexmap/std"]
+
 [dependencies]
-indexmap = "2.6.0"
+indexmap = { version = "2.12.0", default-features = false }
+ahash = { version = "0.8.12" }

src/error.rs

@@ -1,4 +1,4 @@
-use std::{error, fmt};
+use core::{error, fmt};
 
 #[derive(Debug)]
 pub enum Error {

src/lib.rs

@@ -1,9 +1,23 @@
+#![cfg_attr(not(feature = "std"), no_std)]
+
+#[cfg(feature = "std")]
+extern crate std;
+
 mod error;
 pub use error::Error;
 
-use indexmap::IndexMap;
+type Result<T> = core::result::Result<T, Error>;
 
-type Result<T> = std::result::Result<T, Error>;
+#[cfg(not(feature = "std"))]
+#[macro_use]
+extern crate alloc;
+
+#[cfg(not(feature = "std"))]
+use alloc::string::{String, ToString};
+#[cfg(not(feature = "std"))]
+use alloc::vec::Vec;
+
+type IndexMap<K, V> = indexmap::IndexMap<K, V, ahash::RandomState>;
 
 /// Represents an authority of a URI.
 ///
@@ -84,7 +98,7 @@ impl URI {
             scheme: None,
             authority: None,
             path: None,
-            query: IndexMap::new(),
+            query: IndexMap::default(),
             fragment: None,
         }
     }