1 files changed, 104 insertions, 0 deletions
diff --git a/third_party/rust/encoding_rs/src/replacement.rs b/third_party/rust/encoding_rs/src/replacement.rs
new file mode 100644
index 0000000000..3d1bcc1f57
--- /dev/null
+++ b/third_party/rust/encoding_rs/src/replacement.rs
@@ -0,0 +1,104 @@
+// Copyright Mozilla Foundation. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use super::*;
+use crate::variant::*;
+
+pub struct ReplacementDecoder {
+    emitted: bool,
+}
+
+impl ReplacementDecoder {
+    pub fn new() -> VariantDecoder {
+        VariantDecoder::Replacement(ReplacementDecoder { emitted: false })
+    }
+
+    pub fn max_utf16_buffer_length(&self, _u16_length: usize) -> Option<usize> {
+        Some(1)
+    }
+
+    pub fn max_utf8_buffer_length_without_replacement(&self, _byte_length: usize) -> Option<usize> {
+        Some(3)
+    }
+
+    pub fn max_utf8_buffer_length(&self, _byte_length: usize) -> Option<usize> {
+        Some(3)
+    }
+
+    pub fn decode_to_utf16_raw(
+        &mut self,
+        src: &[u8],
+        dst: &mut [u16],
+        _last: bool,
+    ) -> (DecoderResult, usize, usize) {
+        // Don't err if the input stream is empty. See
+        // https://github.com/whatwg/encoding/issues/33
+        if self.emitted || src.is_empty() {
+            (DecoderResult::InputEmpty, src.len(), 0)
+        } else if dst.is_empty() {
+            // Make sure there's room for the replacement character.
+            (DecoderResult::OutputFull, 0, 0)
+        } else {
+            self.emitted = true;
+            (DecoderResult::Malformed(1, 0), 1, 0)
+        }
+    }
+
+    pub fn decode_to_utf8_raw(
+        &mut self,
+        src: &[u8],
+        dst: &mut [u8],
+        _last: bool,
+    ) -> (DecoderResult, usize, usize) {
+        // Don't err if the input stream is empty. See
+        // https://github.com/whatwg/encoding/issues/33
+        if self.emitted || src.is_empty() {
+            (DecoderResult::InputEmpty, src.len(), 0)
+        } else if dst.len() < 3 {
+            // Make sure there's room for the replacement character.
+            (DecoderResult::OutputFull, 0, 0)
+        } else {
+            self.emitted = true;
+            (DecoderResult::Malformed(1, 0), 1, 0)
+        }
+    }
+}
+
+// Any copyright to the test code below this comment is dedicated to the
+// Public Domain. http://creativecommons.org/publicdomain/zero/1.0/
+
+#[cfg(all(test, feature = "alloc"))]
+mod tests {
+    use super::super::testing::*;
+    use super::super::*;
+
+    fn decode_replacement(bytes: &[u8], expect: &str) {
+        decode_without_padding(REPLACEMENT, bytes, expect);
+    }
+
+    fn encode_replacement(string: &str, expect: &[u8]) {
+        encode(REPLACEMENT, string, expect);
+    }
+
+    #[test]
+    fn test_replacement_decode() {
+        decode_replacement(b"", "");
+        decode_replacement(b"A", "\u{FFFD}");
+        decode_replacement(b"AB", "\u{FFFD}");
+    }
+
+    #[test]
+    fn test_replacement_encode() {
+        // Empty
+        encode_replacement("", b"");
+
+        assert_eq!(REPLACEMENT.new_encoder().encoding(), UTF_8);
+        encode_replacement("\u{1F4A9}\u{2603}", "\u{1F4A9}\u{2603}".as_bytes());
+    }
+}