From 8eb6e776fece579fa218b9ced3aea1139ab2f5b4 Mon Sep 17 00:00:00 2001
From: Alexey Arbuzov <lexx.vir@gmail.com>
Date: Tue, 30 Apr 2019 16:46:34 +0300
Subject: [PATCH] Add support for no_std

---
 rust/Cargo.toml |  5 +++++
 rust/src/lib.rs | 16 ++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index d98c4bb..beb108d 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -9,3 +9,8 @@ readme = "Readme.markdown"
 keywords = ["qr-code", "barcode", "encoder", "image"]
 categories = ["encoding", "multimedia::images"]
 license = "MIT"
+
+[features]
+default = ["std"]
+std = []
+alloc = [] # required for nightly compiler before 1.36.0
diff --git a/rust/src/lib.rs b/rust/src/lib.rs
index 4fedaba..71b84b3 100644
--- a/rust/src/lib.rs
+++ b/rust/src/lib.rs
@@ -79,7 +79,22 @@
 //!     }
 //! }
 //! ```
+#![cfg_attr(not(feature = "std"), no_std)]
+#![cfg_attr(feature = "alloc", feature(alloc))]
 
+#![cfg(not(feature = "std"))]
+#[macro_use] extern crate alloc;
+
+#[cfg(not(feature = "std"))]
+use alloc::{string::String, vec::Vec};
+
+#[cfg(not(feature = "std"))]
+mod std {
+    pub use core::i32;
+    pub use core::cmp;
+    pub use core::fmt;
+    pub use alloc::collections;
+}
 
 /*---- QrCode functionality ----*/
 
@@ -1274,6 +1289,7 @@ impl BitBuffer {
 #[derive(Debug, Clone)]
 pub struct DataTooLong(String);
 
+#[cfg(feature = "std")]
 impl std::error::Error for DataTooLong {
 	fn description(&self) -> &str {
 		&self.0