Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1194 insertions, 0 deletions

diff --git a/third_party/rust/encoding_c/src/lib.rs b/third_party/rust/encoding_c/src/lib.rs
new file mode 100644
index 0000000000..699e6427c8
--- /dev/null
+++ b/third_party/rust/encoding_c/src/lib.rs
@@ -0,0 +1,1194 @@
+// 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.
+
+#![doc(html_root_url = "https://docs.rs/encoding_c/0.9.7")]
+
+//! The C API for encoding_rs.
+//!
+//! # Mapping from Rust
+//!
+//! ## Naming convention
+//!
+//! The wrapper function for each method has a name that starts with the name
+//! of the struct lower-cased, followed by an underscore and ends with the
+//! name of the method.
+//!
+//! For example, `Encoding::for_label()` is wrapped as `encoding_for_label()`.
+//!
+//! ## Arguments
+//!
+//! Functions that wrap non-static methods take the `self` object as their
+//! first argument.
+//!
+//! Slice argument `foo` is decomposed into a pointer `foo` and a length
+//! `foo_len`.
+//!
+//! ## Return values
+//!
+//! Multiple return values become out-params. When an out-param is
+//! length-related, `foo_len` for a slice becomes a pointer in order to become
+//! an in/out-param.
+//!
+//! `DecoderResult`, `EncoderResult` and `CoderResult` become `uint32_t`.
+//! `InputEmpty` becomes `INPUT_EMPTY`. `OutputFull` becomes `OUTPUT_FULL`.
+//! `Unmappable` becomes the scalar value of the unmappable character.
+//! `Malformed` becomes a number whose lowest 8 bits, which can have the decimal
+//! value 0, 1, 2 or 3, indicate the number of bytes that were consumed after
+//! the malformed sequence and whose next-lowest 8 bits, when shifted right by
+//! 8 indicate the length of the malformed byte sequence (possible decimal
+//! values 1, 2, 3 or 4). The maximum possible sum of the two is 6.
+
+extern crate encoding_rs;
+
+use encoding_rs::*;
+
+/// Return value for `*_decode_*` and `*_encode_*` functions that indicates that
+/// the input has been exhausted.
+///
+/// (This is zero as a micro optimization. U+0000 is never unmappable and
+/// malformed sequences always have a positive length.)
+pub const INPUT_EMPTY: u32 = 0;
+
+/// Return value for `*_decode_*` and `*_encode_*` functions that indicates that
+/// the output space has been exhausted.
+pub const OUTPUT_FULL: u32 = 0xFFFFFFFF;
+
+/// Newtype for `*const Encoding` in order to be able to implement `Sync` for
+/// it.
+pub struct ConstEncoding(*const Encoding);
+
+/// Required for `static` fields.
+unsafe impl Sync for ConstEncoding {}
+
+// BEGIN GENERATED CODE. PLEASE DO NOT EDIT.
+// Instead, please regenerate using generate-encoding-data.py
+
+/// The minimum length of buffers that may be passed to `encoding_name()`.
+pub const ENCODING_NAME_MAX_LENGTH: usize = 14; // x-mac-cyrillic
+
+/// The Big5 encoding.
+#[no_mangle]
+pub static BIG5_ENCODING: ConstEncoding = ConstEncoding(&BIG5_INIT);
+
+/// The EUC-JP encoding.
+#[no_mangle]
+pub static EUC_JP_ENCODING: ConstEncoding = ConstEncoding(&EUC_JP_INIT);
+
+/// The EUC-KR encoding.
+#[no_mangle]
+pub static EUC_KR_ENCODING: ConstEncoding = ConstEncoding(&EUC_KR_INIT);
+
+/// The GBK encoding.
+#[no_mangle]
+pub static GBK_ENCODING: ConstEncoding = ConstEncoding(&GBK_INIT);
+
+/// The IBM866 encoding.
+#[no_mangle]
+pub static IBM866_ENCODING: ConstEncoding = ConstEncoding(&IBM866_INIT);
+
+/// The ISO-2022-JP encoding.
+#[no_mangle]
+pub static ISO_2022_JP_ENCODING: ConstEncoding = ConstEncoding(&ISO_2022_JP_INIT);
+
+/// The ISO-8859-10 encoding.
+#[no_mangle]
+pub static ISO_8859_10_ENCODING: ConstEncoding = ConstEncoding(&ISO_8859_10_INIT);
+
+/// The ISO-8859-13 encoding.
+#[no_mangle]
+pub static ISO_8859_13_ENCODING: ConstEncoding = ConstEncoding(&ISO_8859_13_INIT);
+
+/// The ISO-8859-14 encoding.
+#[no_mangle]
+pub static ISO_8859_14_ENCODING: ConstEncoding = ConstEncoding(&ISO_8859_14_INIT);
+
+/// The ISO-8859-15 encoding.
+#[no_mangle]
+pub static ISO_8859_15_ENCODING: ConstEncoding = ConstEncoding(&ISO_8859_15_INIT);
+
+/// The ISO-8859-16 encoding.
+#[no_mangle]
+pub static ISO_8859_16_ENCODING: ConstEncoding = ConstEncoding(&ISO_8859_16_INIT);
+
+/// The ISO-8859-2 encoding.
+#[no_mangle]
+pub static ISO_8859_2_ENCODING: ConstEncoding = ConstEncoding(&ISO_8859_2_INIT);
+
+/// The ISO-8859-3 encoding.
+#[no_mangle]
+pub static ISO_8859_3_ENCODING: ConstEncoding = ConstEncoding(&ISO_8859_3_INIT);
+
+/// The ISO-8859-4 encoding.
+#[no_mangle]
+pub static ISO_8859_4_ENCODING: ConstEncoding = ConstEncoding(&ISO_8859_4_INIT);
+
+/// The ISO-8859-5 encoding.
+#[no_mangle]
+pub static ISO_8859_5_ENCODING: ConstEncoding = ConstEncoding(&ISO_8859_5_INIT);
+
+/// The ISO-8859-6 encoding.
+#[no_mangle]
+pub static ISO_8859_6_ENCODING: ConstEncoding = ConstEncoding(&ISO_8859_6_INIT);
+
+/// The ISO-8859-7 encoding.
+#[no_mangle]
+pub static ISO_8859_7_ENCODING: ConstEncoding = ConstEncoding(&ISO_8859_7_INIT);
+
+/// The ISO-8859-8 encoding.
+#[no_mangle]
+pub static ISO_8859_8_ENCODING: ConstEncoding = ConstEncoding(&ISO_8859_8_INIT);
+
+/// The ISO-8859-8-I encoding.
+#[no_mangle]
+pub static ISO_8859_8_I_ENCODING: ConstEncoding = ConstEncoding(&ISO_8859_8_I_INIT);
+
+/// The KOI8-R encoding.
+#[no_mangle]
+pub static KOI8_R_ENCODING: ConstEncoding = ConstEncoding(&KOI8_R_INIT);
+
+/// The KOI8-U encoding.
+#[no_mangle]
+pub static KOI8_U_ENCODING: ConstEncoding = ConstEncoding(&KOI8_U_INIT);
+
+/// The Shift_JIS encoding.
+#[no_mangle]
+pub static SHIFT_JIS_ENCODING: ConstEncoding = ConstEncoding(&SHIFT_JIS_INIT);
+
+/// The UTF-16BE encoding.
+#[no_mangle]
+pub static UTF_16BE_ENCODING: ConstEncoding = ConstEncoding(&UTF_16BE_INIT);
+
+/// The UTF-16LE encoding.
+#[no_mangle]
+pub static UTF_16LE_ENCODING: ConstEncoding = ConstEncoding(&UTF_16LE_INIT);
+
+/// The UTF-8 encoding.
+#[no_mangle]
+pub static UTF_8_ENCODING: ConstEncoding = ConstEncoding(&UTF_8_INIT);
+
+/// The gb18030 encoding.
+#[no_mangle]
+pub static GB18030_ENCODING: ConstEncoding = ConstEncoding(&GB18030_INIT);
+
+/// The macintosh encoding.
+#[no_mangle]
+pub static MACINTOSH_ENCODING: ConstEncoding = ConstEncoding(&MACINTOSH_INIT);
+
+/// The replacement encoding.
+#[no_mangle]
+pub static REPLACEMENT_ENCODING: ConstEncoding = ConstEncoding(&REPLACEMENT_INIT);
+
+/// The windows-1250 encoding.
+#[no_mangle]
+pub static WINDOWS_1250_ENCODING: ConstEncoding = ConstEncoding(&WINDOWS_1250_INIT);
+
+/// The windows-1251 encoding.
+#[no_mangle]
+pub static WINDOWS_1251_ENCODING: ConstEncoding = ConstEncoding(&WINDOWS_1251_INIT);
+
+/// The windows-1252 encoding.
+#[no_mangle]
+pub static WINDOWS_1252_ENCODING: ConstEncoding = ConstEncoding(&WINDOWS_1252_INIT);
+
+/// The windows-1253 encoding.
+#[no_mangle]
+pub static WINDOWS_1253_ENCODING: ConstEncoding = ConstEncoding(&WINDOWS_1253_INIT);
+
+/// The windows-1254 encoding.
+#[no_mangle]
+pub static WINDOWS_1254_ENCODING: ConstEncoding = ConstEncoding(&WINDOWS_1254_INIT);
+
+/// The windows-1255 encoding.
+#[no_mangle]
+pub static WINDOWS_1255_ENCODING: ConstEncoding = ConstEncoding(&WINDOWS_1255_INIT);
+
+/// The windows-1256 encoding.
+#[no_mangle]
+pub static WINDOWS_1256_ENCODING: ConstEncoding = ConstEncoding(&WINDOWS_1256_INIT);
+
+/// The windows-1257 encoding.
+#[no_mangle]
+pub static WINDOWS_1257_ENCODING: ConstEncoding = ConstEncoding(&WINDOWS_1257_INIT);
+
+/// The windows-1258 encoding.
+#[no_mangle]
+pub static WINDOWS_1258_ENCODING: ConstEncoding = ConstEncoding(&WINDOWS_1258_INIT);
+
+/// The windows-874 encoding.
+#[no_mangle]
+pub static WINDOWS_874_ENCODING: ConstEncoding = ConstEncoding(&WINDOWS_874_INIT);
+
+/// The x-mac-cyrillic encoding.
+#[no_mangle]
+pub static X_MAC_CYRILLIC_ENCODING: ConstEncoding = ConstEncoding(&X_MAC_CYRILLIC_INIT);
+
+/// The x-user-defined encoding.
+#[no_mangle]
+pub static X_USER_DEFINED_ENCODING: ConstEncoding = ConstEncoding(&X_USER_DEFINED_INIT);
+
+// END GENERATED CODE
+
+#[inline(always)]
+fn coder_result_to_u32(result: CoderResult) -> u32 {
+    match result {
+        CoderResult::InputEmpty => INPUT_EMPTY,
+        CoderResult::OutputFull => OUTPUT_FULL,
+    }
+}
+
+#[inline(always)]
+fn decoder_result_to_u32(result: DecoderResult) -> u32 {
+    match result {
+        DecoderResult::InputEmpty => INPUT_EMPTY,
+        DecoderResult::OutputFull => OUTPUT_FULL,
+        DecoderResult::Malformed(bad, good) => ((good as u32) << 8) | (bad as u32),
+    }
+}
+
+#[inline(always)]
+fn encoder_result_to_u32(result: EncoderResult) -> u32 {
+    match result {
+        EncoderResult::InputEmpty => INPUT_EMPTY,
+        EncoderResult::OutputFull => OUTPUT_FULL,
+        EncoderResult::Unmappable(c) => c as u32,
+    }
+}
+
+#[inline(always)]
+fn option_to_ptr(opt: Option<&'static Encoding>) -> *const Encoding {
+    match opt {
+        None => ::std::ptr::null(),
+        Some(e) => e,
+    }
+}
+
+/// Implements the
+/// [_get an encoding_](https://encoding.spec.whatwg.org/#concept-encoding-get)
+/// algorithm.
+///
+/// If, after ASCII-lowercasing and removing leading and trailing
+/// whitespace, the argument matches a label defined in the Encoding
+/// Standard, `const Encoding*` representing the corresponding
+/// encoding is returned. If there is no match, `NULL` is returned.
+///
+/// This is the right function to use if the action upon the method returning
+/// `NULL` is to use a fallback encoding (e.g. `WINDOWS_1252_ENCODING`) instead.
+/// When the action upon the method returning `NULL` is not to proceed with
+/// a fallback but to refuse processing, `encoding_for_label_no_replacement()` is
+/// more appropriate.
+///
+/// The argument buffer can be in any ASCII-compatible encoding. It is not
+/// required to be UTF-8.
+///
+/// `label` must be non-`NULL` even if `label_len` is zero. When `label_len`
+/// is zero, it is OK for `label` to be something non-dereferencable,
+/// such as `0x1`. This is required due to Rust's optimization for slices
+/// within `Option`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if `label` and `label_len` don't designate a valid memory block
+/// of if `label` is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_for_label(label: *const u8, label_len: usize) -> *const Encoding {
+    let label_slice = ::std::slice::from_raw_parts(label, label_len);
+    option_to_ptr(Encoding::for_label(label_slice))
+}
+
+/// This function behaves the same as `encoding_for_label()`, except when
+/// `encoding_for_label()` would return `REPLACEMENT_ENCODING`, this method
+/// returns `NULL` instead.
+///
+/// This method is useful in scenarios where a fatal error is required
+/// upon invalid label, because in those cases the caller typically wishes
+/// to treat the labels that map to the replacement encoding as fatal
+/// errors, too.
+///
+/// It is not OK to use this funciton when the action upon the method returning
+/// `NULL` is to use a fallback encoding (e.g. `WINDOWS_1252_ENCODING`). In
+/// such a case, the `encoding_for_label()` function should be used instead
+/// in order to avoid unsafe fallback for labels that `encoding_for_label()`
+/// maps to `REPLACEMENT_ENCODING`.
+///
+/// The argument buffer can be in any ASCII-compatible encoding. It is not
+/// required to be UTF-8.
+///
+/// `label` must be non-`NULL` even if `label_len` is zero. When `label_len`
+/// is zero, it is OK for `label` to be something non-dereferencable,
+/// such as `0x1`. This is required due to Rust's optimization for slices
+/// within `Option`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if `label` and `label_len` don't designate a valid memory block
+/// of if `label` is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_for_label_no_replacement(
+    label: *const u8,
+    label_len: usize,
+) -> *const Encoding {
+    let label_slice = ::std::slice::from_raw_parts(label, label_len);
+    option_to_ptr(Encoding::for_label_no_replacement(label_slice))
+}
+
+/// Performs non-incremental BOM sniffing.
+///
+/// The argument must either be a buffer representing the entire input
+/// stream (non-streaming case) or a buffer representing at least the first
+/// three bytes of the input stream (streaming case).
+///
+/// Returns `UTF_8_ENCODING`, `UTF_16LE_ENCODING` or `UTF_16BE_ENCODING` if the
+/// argument starts with the UTF-8, UTF-16LE or UTF-16BE BOM or `NULL`
+/// otherwise. Upon return, `*buffer_len` is the length of the BOM (zero if
+/// there is no BOM).
+///
+/// `buffer` must be non-`NULL` even if `*buffer_len` is zero. When
+/// `*buffer_len` is zero, it is OK for `buffer` to be something
+/// non-dereferencable, such as `0x1`. This is required due to Rust's
+/// optimization for slices within `Option`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if `buffer` and `*buffer_len` don't designate a valid memory
+/// block of if `buffer` is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_for_bom(
+    buffer: *const u8,
+    buffer_len: *mut usize,
+) -> *const Encoding {
+    let buffer_slice = ::std::slice::from_raw_parts(buffer, *buffer_len);
+    let (encoding, bom_length) = match Encoding::for_bom(buffer_slice) {
+        Some((encoding, bom_length)) => (encoding as *const Encoding, bom_length),
+        None => (::std::ptr::null(), 0),
+    };
+    *buffer_len = bom_length;
+    encoding
+}
+
+/// Writes the name of the given `Encoding` to a caller-supplied buffer as
+/// ASCII and returns the number of bytes / ASCII characters written.
+///
+/// The output is not null-terminated.
+///
+/// The caller _MUST_ ensure that `name_out` points to a buffer whose length
+/// is at least `ENCODING_NAME_MAX_LENGTH` bytes.
+///
+/// # Undefined behavior
+///
+/// UB ensues if either argument is `NULL` or if `name_out` doesn't point to
+/// a valid block of memory whose length is at least
+/// `ENCODING_NAME_MAX_LENGTH` bytes.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_name(encoding: *const Encoding, name_out: *mut u8) -> usize {
+    let bytes = (*encoding).name().as_bytes();
+    ::std::ptr::copy_nonoverlapping(bytes.as_ptr(), name_out, bytes.len());
+    bytes.len()
+}
+
+/// Checks whether the _output encoding_ of this encoding can encode every
+/// Unicode scalar. (Only true if the output encoding is UTF-8.)
+///
+/// # Undefined behavior
+///
+/// UB ensues if the argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_can_encode_everything(encoding: *const Encoding) -> bool {
+    (*encoding).can_encode_everything()
+}
+
+/// Checks whether the bytes 0x00...0x7F map exclusively to the characters
+/// U+0000...U+007F and vice versa.
+///
+/// # Undefined behavior
+///
+/// UB ensues if the argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_is_ascii_compatible(encoding: *const Encoding) -> bool {
+    (*encoding).is_ascii_compatible()
+}
+
+/// Checks whether this encoding maps one byte to one Basic Multilingual
+/// Plane code point (i.e. byte length equals decoded UTF-16 length) and
+/// vice versa (for mappable characters).
+///
+/// `true` iff this encoding is on the list of [Legacy single-byte
+/// encodings](https://encoding.spec.whatwg.org/#legacy-single-byte-encodings)
+/// in the spec or x-user-defined.
+///
+/// # Undefined behavior
+///
+/// UB ensues if the argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_is_single_byte(encoding: *const Encoding) -> bool {
+    (*encoding).is_single_byte()
+}
+
+/// Returns the _output encoding_ of this encoding. This is UTF-8 for
+/// UTF-16BE, UTF-16LE and replacement and the encoding itself otherwise.
+///
+/// # Undefined behavior
+///
+/// UB ensues if the argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_output_encoding(encoding: *const Encoding) -> *const Encoding {
+    (*encoding).output_encoding()
+}
+
+/// Allocates a new `Decoder` for the given `Encoding` on the heap with BOM
+/// sniffing enabled and returns a pointer to the newly-allocated `Decoder`.
+///
+/// BOM sniffing may cause the returned decoder to morph into a decoder
+/// for UTF-8, UTF-16LE or UTF-16BE instead of this encoding.
+///
+/// Once the allocated `Decoder` is no longer needed, the caller _MUST_
+/// deallocate it by passing the pointer returned by this function to
+/// `decoder_free()`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if the argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_new_decoder(encoding: *const Encoding) -> *mut Decoder {
+    Box::into_raw(Box::new((*encoding).new_decoder()))
+}
+
+/// Allocates a new `Decoder` for the given `Encoding` on the heap with BOM
+/// removal and returns a pointer to the newly-allocated `Decoder`.
+///
+/// If the input starts with bytes that are the BOM for this encoding,
+/// those bytes are removed. However, the decoder never morphs into a
+/// decoder for another encoding: A BOM for another encoding is treated as
+/// (potentially malformed) input to the decoding algorithm for this
+/// encoding.
+///
+/// Once the allocated `Decoder` is no longer needed, the caller _MUST_
+/// deallocate it by passing the pointer returned by this function to
+/// `decoder_free()`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if the argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_new_decoder_with_bom_removal(
+    encoding: *const Encoding,
+) -> *mut Decoder {
+    Box::into_raw(Box::new((*encoding).new_decoder_with_bom_removal()))
+}
+
+/// Allocates a new `Decoder` for the given `Encoding` on the heap with BOM
+/// handling disabled and returns a pointer to the newly-allocated `Decoder`.
+///
+/// If the input starts with bytes that look like a BOM, those bytes are
+/// not treated as a BOM. (Hence, the decoder never morphs into a decoder
+/// for another encoding.)
+///
+/// _Note:_ If the caller has performed BOM sniffing on its own but has not
+/// removed the BOM, the caller should use
+/// `encoding_new_decoder_with_bom_removal()` instead of this function to cause
+/// the BOM to be removed.
+///
+/// Once the allocated `Decoder` is no longer needed, the caller _MUST_
+/// deallocate it by passing the pointer returned by this function to
+/// `decoder_free()`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if the argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_new_decoder_without_bom_handling(
+    encoding: *const Encoding,
+) -> *mut Decoder {
+    Box::into_raw(Box::new((*encoding).new_decoder_without_bom_handling()))
+}
+
+/// Allocates a new `Decoder` for the given `Encoding` into memory provided by
+/// the caller with BOM sniffing enabled. (In practice, the target should
+/// likely be a pointer previously returned by `encoding_new_decoder()`.)
+///
+/// Note: If the caller has already performed BOM sniffing but has
+/// not removed the BOM, the caller should still use this function in
+/// order to cause the BOM to be ignored.
+///
+/// # Undefined behavior
+///
+/// UB ensues if either argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_new_decoder_into(
+    encoding: *const Encoding,
+    decoder: *mut Decoder,
+) {
+    *decoder = (*encoding).new_decoder();
+}
+
+/// Allocates a new `Decoder` for the given `Encoding` into memory provided by
+/// the caller with BOM removal.
+///
+/// If the input starts with bytes that are the BOM for this encoding,
+/// those bytes are removed. However, the decoder never morphs into a
+/// decoder for another encoding: A BOM for another encoding is treated as
+/// (potentially malformed) input to the decoding algorithm for this
+/// encoding.
+///
+/// Once the allocated `Decoder` is no longer needed, the caller _MUST_
+/// deallocate it by passing the pointer returned by this function to
+/// `decoder_free()`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if either argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_new_decoder_with_bom_removal_into(
+    encoding: *const Encoding,
+    decoder: *mut Decoder,
+) {
+    *decoder = (*encoding).new_decoder_with_bom_removal();
+}
+
+/// Allocates a new `Decoder` for the given `Encoding` into memory provided by
+/// the caller with BOM handling disabled.
+///
+/// If the input starts with bytes that look like a BOM, those bytes are
+/// not treated as a BOM. (Hence, the decoder never morphs into a decoder
+/// for another encoding.)
+///
+/// _Note:_ If the caller has performed BOM sniffing on its own but has not
+/// removed the BOM, the caller should use
+/// `encoding_new_decoder_with_bom_removal_into()` instead of this function to
+/// cause the BOM to be removed.
+///
+/// # Undefined behavior
+///
+/// UB ensues if either argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_new_decoder_without_bom_handling_into(
+    encoding: *const Encoding,
+    decoder: *mut Decoder,
+) {
+    *decoder = (*encoding).new_decoder_without_bom_handling();
+}
+
+/// Allocates a new `Encoder` for the given `Encoding` on the heap and returns a
+/// pointer to the newly-allocated `Encoder`. (Exception, if the `Encoding` is
+/// `replacement`, a new `Decoder` for UTF-8 is instantiated (and that
+/// `Decoder` reports `UTF_8` as its `Encoding`).
+///
+/// Once the allocated `Encoder` is no longer needed, the caller _MUST_
+/// deallocate it by passing the pointer returned by this function to
+/// `encoder_free()`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if the argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_new_encoder(encoding: *const Encoding) -> *mut Encoder {
+    Box::into_raw(Box::new((*encoding).new_encoder()))
+}
+
+/// Allocates a new `Encoder` for the given `Encoding` into memory provided by
+/// the caller. (In practice, the target should likely be a pointer previously
+/// returned by `encoding_new_encoder()`.)
+///
+/// # Undefined behavior
+///
+/// UB ensues if either argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_new_encoder_into(
+    encoding: *const Encoding,
+    encoder: *mut Encoder,
+) {
+    *encoder = (*encoding).new_encoder();
+}
+
+/// Validates UTF-8.
+///
+/// Returns the index of the first byte that makes the input malformed as
+/// UTF-8 or `buffer_len` if `buffer` is entirely valid.
+///
+/// `buffer` must be non-`NULL` even if `buffer_len` is zero. When
+/// `buffer_len` is zero, it is OK for `buffer` to be something
+/// non-dereferencable, such as `0x1`. This is required due to Rust's
+/// optimization for slices within `Option`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if `buffer` and `buffer_len` don't designate a valid memory
+/// block of if `buffer` is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_utf8_valid_up_to(buffer: *const u8, buffer_len: usize) -> usize {
+    let buffer_slice = ::std::slice::from_raw_parts(buffer, buffer_len);
+    Encoding::utf8_valid_up_to(buffer_slice)
+}
+
+/// Validates ASCII.
+///
+/// Returns the index of the first byte that makes the input malformed as
+/// ASCII or `buffer_len` if `buffer` is entirely valid.
+///
+/// `buffer` must be non-`NULL` even if `buffer_len` is zero. When
+/// `buffer_len` is zero, it is OK for `buffer` to be something
+/// non-dereferencable, such as `0x1`. This is required due to Rust's
+/// optimization for slices within `Option`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if `buffer` and `buffer_len` don't designate a valid memory
+/// block of if `buffer` is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_ascii_valid_up_to(buffer: *const u8, buffer_len: usize) -> usize {
+    let buffer_slice = ::std::slice::from_raw_parts(buffer, buffer_len);
+    Encoding::ascii_valid_up_to(buffer_slice)
+}
+
+/// Validates ISO-2022-JP ASCII-state data.
+///
+/// Returns the index of the first byte that makes the input not representable
+/// in the ASCII state of ISO-2022-JP or `buffer_len` if `buffer` is entirely
+/// representable in the ASCII state of ISO-2022-JP.
+///
+/// `buffer` must be non-`NULL` even if `buffer_len` is zero. When
+/// `buffer_len` is zero, it is OK for `buffer` to be something
+/// non-dereferencable, such as `0x1`. This is required due to Rust's
+/// optimization for slices within `Option`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if `buffer` and `buffer_len` don't designate a valid memory
+/// block of if `buffer` is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoding_iso_2022_jp_ascii_valid_up_to(
+    buffer: *const u8,
+    buffer_len: usize,
+) -> usize {
+    let buffer_slice = ::std::slice::from_raw_parts(buffer, buffer_len);
+    Encoding::iso_2022_jp_ascii_valid_up_to(buffer_slice)
+}
+
+/// Deallocates a `Decoder` previously allocated by `encoding_new_decoder()`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if the argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn decoder_free(decoder: *mut Decoder) {
+    let _ = Box::from_raw(decoder);
+}
+
+/// The `Encoding` this `Decoder` is for.
+///
+/// BOM sniffing can change the return value of this method during the life
+/// of the decoder.
+///
+/// # Undefined behavior
+///
+/// UB ensues if the argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn decoder_encoding(decoder: *const Decoder) -> *const Encoding {
+    (*decoder).encoding()
+}
+
+/// Query the worst-case UTF-8 output size _with replacement_.
+///
+/// Returns the size of the output buffer in UTF-8 code units (`uint8_t`)
+/// that will not overflow given the current state of the decoder and
+/// `byte_length` number of additional input bytes when decoding with
+/// errors handled by outputting a REPLACEMENT CHARACTER for each malformed
+/// sequence or `SIZE_MAX` if `size_t` would overflow.
+///
+/// # Undefined behavior
+///
+/// UB ensues if `decoder` is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn decoder_max_utf8_buffer_length(
+    decoder: *const Decoder,
+    byte_length: usize,
+) -> usize {
+    (*decoder)
+        .max_utf8_buffer_length(byte_length)
+        .unwrap_or(::std::usize::MAX)
+}
+
+/// Query the worst-case UTF-8 output size _without replacement_.
+///
+/// Returns the size of the output buffer in UTF-8 code units (`uint8_t`)
+/// that will not overflow given the current state of the decoder and
+/// `byte_length` number of additional input bytes when decoding without
+/// replacement error handling or `SIZE_MAX` if `size_t` would overflow.
+///
+/// Note that this value may be too small for the `_with_replacement` case.
+/// Use `decoder_max_utf8_buffer_length()` for that case.
+///
+/// # Undefined behavior
+///
+/// UB ensues if `decoder` is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn decoder_max_utf8_buffer_length_without_replacement(
+    decoder: *const Decoder,
+    byte_length: usize,
+) -> usize {
+    (*decoder)
+        .max_utf8_buffer_length_without_replacement(byte_length)
+        .unwrap_or(::std::usize::MAX)
+}
+
+/// Incrementally decode a byte stream into UTF-8 with malformed sequences
+/// replaced with the REPLACEMENT CHARACTER.
+///
+/// See the top-level FFI documentation for documentation for how the
+/// `decoder_decode_*` functions are mapped from Rust and the documentation
+/// for the [`Decoder`][1] struct for the semantics.
+///
+/// `src` must be non-`NULL` even if `src_len` is zero. When`src_len` is zero,
+/// it is OK for `src` to be something non-dereferencable, such as `0x1`.
+/// Likewise for `dst` when `dst_len` is zero. This is required due to Rust's
+/// optimization for slices within `Option`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if any of the pointer arguments is `NULL`, `src` and `src_len`
+/// don't designate a valid block of memory or `dst` and `dst_len` don't
+/// designate a valid block of memory.
+///
+/// [1]: https://docs.rs/encoding_rs/0.6.10/encoding_rs/struct.Decoder.html
+#[no_mangle]
+pub unsafe extern "C" fn decoder_decode_to_utf8(
+    decoder: *mut Decoder,
+    src: *const u8,
+    src_len: *mut usize,
+    dst: *mut u8,
+    dst_len: *mut usize,
+    last: bool,
+    had_replacements: *mut bool,
+) -> u32 {
+    let src_slice = ::std::slice::from_raw_parts(src, *src_len);
+    let dst_slice = ::std::slice::from_raw_parts_mut(dst, *dst_len);
+    let (result, read, written, replaced) = (*decoder).decode_to_utf8(src_slice, dst_slice, last);
+    *src_len = read;
+    *dst_len = written;
+    *had_replacements = replaced;
+    coder_result_to_u32(result)
+}
+
+/// Incrementally decode a byte stream into UTF-8 _without replacement_.
+///
+/// See the top-level FFI documentation for documentation for how the
+/// `decoder_decode_*` functions are mapped from Rust and the documentation
+/// for the [`Decoder`][1] struct for the semantics.
+///
+/// `src` must be non-`NULL` even if `src_len` is zero. When`src_len` is zero,
+/// it is OK for `src` to be something non-dereferencable, such as `0x1`.
+/// Likewise for `dst` when `dst_len` is zero. This is required due to Rust's
+/// optimization for slices within `Option`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if any of the pointer arguments is `NULL`, `src` and `src_len`
+/// don't designate a valid block of memory or `dst` and `dst_len` don't
+/// designate a valid block of memory.
+///
+/// [1]: https://docs.rs/encoding_rs/0.6.10/encoding_rs/struct.Decoder.html
+#[no_mangle]
+pub unsafe extern "C" fn decoder_decode_to_utf8_without_replacement(
+    decoder: *mut Decoder,
+    src: *const u8,
+    src_len: *mut usize,
+    dst: *mut u8,
+    dst_len: *mut usize,
+    last: bool,
+) -> u32 {
+    let src_slice = ::std::slice::from_raw_parts(src, *src_len);
+    let dst_slice = ::std::slice::from_raw_parts_mut(dst, *dst_len);
+    let (result, read, written) =
+        (*decoder).decode_to_utf8_without_replacement(src_slice, dst_slice, last);
+    *src_len = read;
+    *dst_len = written;
+    decoder_result_to_u32(result)
+}
+
+/// Query the worst-case UTF-16 output size (with or without replacement).
+///
+/// Returns the size of the output buffer in UTF-16 code units (`char16_t`)
+/// that will not overflow given the current state of the decoder and
+/// `byte_length` number of additional input bytes or `SIZE_MAX` if `size_t`
+/// would overflow.
+///
+/// Since the REPLACEMENT CHARACTER fits into one UTF-16 code unit, the
+/// return value of this method applies also in the
+/// `_without_replacement` case.
+///
+/// # Undefined behavior
+///
+/// UB ensues if `decoder` is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn decoder_max_utf16_buffer_length(
+    decoder: *const Decoder,
+    u16_length: usize,
+) -> usize {
+    (*decoder)
+        .max_utf16_buffer_length(u16_length)
+        .unwrap_or(::std::usize::MAX)
+}
+
+/// Incrementally decode a byte stream into UTF-16 with malformed sequences
+/// replaced with the REPLACEMENT CHARACTER.
+///
+/// See the top-level FFI documentation for documentation for how the
+/// `decoder_decode_*` functions are mapped from Rust and the documentation
+/// for the [`Decoder`][1] struct for the semantics.
+///
+/// `src` must be non-`NULL` even if `src_len` is zero. When`src_len` is zero,
+/// it is OK for `src` to be something non-dereferencable, such as `0x1`.
+/// Likewise for `dst` when `dst_len` is zero. This is required due to Rust's
+/// optimization for slices within `Option`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if any of the pointer arguments is `NULL`, `src` and `src_len`
+/// don't designate a valid block of memory or `dst` and `dst_len` don't
+/// designate a valid block of memory.
+///
+/// [1]: https://docs.rs/encoding_rs/0.6.10/encoding_rs/struct.Decoder.html
+#[no_mangle]
+pub unsafe extern "C" fn decoder_decode_to_utf16(
+    decoder: *mut Decoder,
+    src: *const u8,
+    src_len: *mut usize,
+    dst: *mut u16,
+    dst_len: *mut usize,
+    last: bool,
+    had_replacements: *mut bool,
+) -> u32 {
+    let src_slice = ::std::slice::from_raw_parts(src, *src_len);
+    let dst_slice = ::std::slice::from_raw_parts_mut(dst, *dst_len);
+    let (result, read, written, replaced) = (*decoder).decode_to_utf16(src_slice, dst_slice, last);
+    *src_len = read;
+    *dst_len = written;
+    *had_replacements = replaced;
+    coder_result_to_u32(result)
+}
+
+/// Incrementally decode a byte stream into UTF-16 _without replacement_.
+///
+/// See the top-level FFI documentation for documentation for how the
+/// `decoder_decode_*` functions are mapped from Rust and the documentation
+/// for the [`Decoder`][1] struct for the semantics.
+///
+/// `src` must be non-`NULL` even if `src_len` is zero. When`src_len` is zero,
+/// it is OK for `src` to be something non-dereferencable, such as `0x1`.
+/// Likewise for `dst` when `dst_len` is zero. This is required due to Rust's
+/// optimization for slices within `Option`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if any of the pointer arguments is `NULL`, `src` and `src_len`
+/// don't designate a valid block of memory or `dst` and `dst_len` don't
+/// designate a valid block of memory.
+///
+/// [1]: https://docs.rs/encoding_rs/0.6.10/encoding_rs/struct.Decoder.html
+#[no_mangle]
+pub unsafe extern "C" fn decoder_decode_to_utf16_without_replacement(
+    decoder: *mut Decoder,
+    src: *const u8,
+    src_len: *mut usize,
+    dst: *mut u16,
+    dst_len: *mut usize,
+    last: bool,
+) -> u32 {
+    let src_slice = ::std::slice::from_raw_parts(src, *src_len);
+    let dst_slice = ::std::slice::from_raw_parts_mut(dst, *dst_len);
+    let (result, read, written) =
+        (*decoder).decode_to_utf16_without_replacement(src_slice, dst_slice, last);
+    *src_len = read;
+    *dst_len = written;
+    decoder_result_to_u32(result)
+}
+
+/// Checks for compatibility with storing Unicode scalar values as unsigned
+/// bytes taking into account the state of the decoder.
+///
+/// Returns `SIZE_MAX` if the decoder is not in a neutral state, including waiting
+/// for the BOM, or if the encoding is never Latin1-byte-compatible.
+///
+/// Otherwise returns the index of the first byte whose unsigned value doesn't
+/// directly correspond to the decoded Unicode scalar value, or the length
+/// of the input if all bytes in the input decode directly to scalar values
+/// corresponding to the unsigned byte values.
+///
+/// Does not change the state of the decoder.
+///
+/// Do not use this unless you are supporting SpiderMonkey/V8-style string
+/// storage optimizations.
+///
+/// # Undefined behavior
+///
+/// UB ensues if `buffer` and `*buffer_len` don't designate a valid memory
+/// block of if `buffer` is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn decoder_latin1_byte_compatible_up_to(
+    decoder: *const Decoder,
+    buffer: *const u8,
+    buffer_len: usize,
+) -> usize {
+    (*decoder)
+        .latin1_byte_compatible_up_to(::std::slice::from_raw_parts(buffer, buffer_len))
+        .unwrap_or(::std::usize::MAX)
+}
+
+/// Deallocates an `Encoder` previously allocated by `encoding_new_encoder()`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if the argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoder_free(encoder: *mut Encoder) {
+    let _ = Box::from_raw(encoder);
+}
+
+/// The `Encoding` this `Encoder` is for.
+///
+/// # Undefined behavior
+///
+/// UB ensues if the argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoder_encoding(encoder: *const Encoder) -> *const Encoding {
+    (*encoder).encoding()
+}
+
+/// Returns `true` if this is an ISO-2022-JP encoder that's not in the
+/// ASCII state and `false` otherwise.
+///
+/// # Undefined behavior
+///
+/// UB ensues if the argument is `NULL`.
+#[no_mangle]
+pub unsafe extern "C" fn encoder_has_pending_state(encoder: *const Encoder) -> bool {
+    (*encoder).has_pending_state()
+}
+
+/// Query the worst-case output size when encoding from UTF-8 with
+/// replacement.
+///
+/// Returns the size of the output buffer in bytes that will not overflow
+/// given the current state of the encoder and `byte_length` number of
+/// additional input code units if there are no unmappable characters in
+/// the input or `SIZE_MAX` if `size_t` would overflow.
+#[no_mangle]
+pub unsafe extern "C" fn encoder_max_buffer_length_from_utf8_if_no_unmappables(
+    encoder: *const Encoder,
+    byte_length: usize,
+) -> usize {
+    (*encoder)
+        .max_buffer_length_from_utf8_if_no_unmappables(byte_length)
+        .unwrap_or(::std::usize::MAX)
+}
+
+/// Query the worst-case output size when encoding from UTF-8 without
+/// replacement.
+///
+/// Returns the size of the output buffer in bytes that will not overflow
+/// given the current state of the encoder and `byte_length` number of
+/// additional input code units or `SIZE_MAX` if `size_t` would overflow.
+#[no_mangle]
+pub unsafe extern "C" fn encoder_max_buffer_length_from_utf8_without_replacement(
+    encoder: *const Encoder,
+    byte_length: usize,
+) -> usize {
+    (*encoder)
+        .max_buffer_length_from_utf8_without_replacement(byte_length)
+        .unwrap_or(::std::usize::MAX)
+}
+
+/// Incrementally encode into byte stream from UTF-8 with unmappable
+/// characters replaced with HTML (decimal) numeric character references.
+///
+/// The input absolutely _MUST_ be valid UTF-8 or the behavior is memory-unsafe!
+/// If in doubt, check the validity of input before using!
+///
+/// See the top-level FFI documentation for documentation for how the
+/// `encoder_encode_*` functions are mapped from Rust and the documentation
+/// for the [`Encoder`][1] struct for the semantics.
+///
+/// `src` must be non-`NULL` even if `src_len` is zero. When`src_len` is zero,
+/// it is OK for `src` to be something non-dereferencable, such as `0x1`.
+/// Likewise for `dst` when `dst_len` is zero. This is required due to Rust's
+/// optimization for slices within `Option`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if any of the pointer arguments is `NULL`, `src` and `src_len`
+/// don't designate a valid block of memory or `dst` and `dst_len` don't
+/// designate a valid block of memory.
+///
+/// [1]: https://docs.rs/encoding_rs/0.6.10/encoding_rs/struct.Encoder.html
+#[no_mangle]
+pub unsafe extern "C" fn encoder_encode_from_utf8(
+    encoder: *mut Encoder,
+    src: *const u8,
+    src_len: *mut usize,
+    dst: *mut u8,
+    dst_len: *mut usize,
+    last: bool,
+    had_replacements: *mut bool,
+) -> u32 {
+    let src_slice = ::std::slice::from_raw_parts(src, *src_len);
+    let string = ::std::str::from_utf8_unchecked(src_slice);
+    let dst_slice = ::std::slice::from_raw_parts_mut(dst, *dst_len);
+    let (result, read, written, replaced) = (*encoder).encode_from_utf8(string, dst_slice, last);
+    *src_len = read;
+    *dst_len = written;
+    *had_replacements = replaced;
+    coder_result_to_u32(result)
+}
+
+/// Incrementally encode into byte stream from UTF-8 _without replacement_.
+///
+/// See the top-level FFI documentation for documentation for how the
+/// `encoder_encode_*` functions are mapped from Rust and the documentation
+/// for the [`Encoder`][1] struct for the semantics.
+///
+/// The input absolutely _MUST_ be valid UTF-8 or the behavior is memory-unsafe!
+/// If in doubt, check the validity of input before using!
+///
+/// `src` must be non-`NULL` even if `src_len` is zero. When`src_len` is zero,
+/// it is OK for `src` to be something non-dereferencable, such as `0x1`.
+/// Likewise for `dst` when `dst_len` is zero. This is required due to Rust's
+/// optimization for slices within `Option`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if any of the pointer arguments is `NULL`, `src` and `src_len`
+/// don't designate a valid block of memory or `dst` and `dst_len` don't
+/// designate a valid block of memory.
+///
+/// [1]: https://docs.rs/encoding_rs/0.6.10/encoding_rs/struct.Encoder.html
+#[no_mangle]
+pub unsafe extern "C" fn encoder_encode_from_utf8_without_replacement(
+    encoder: *mut Encoder,
+    src: *const u8,
+    src_len: *mut usize,
+    dst: *mut u8,
+    dst_len: *mut usize,
+    last: bool,
+) -> u32 {
+    let src_slice = ::std::slice::from_raw_parts(src, *src_len);
+    let string = ::std::str::from_utf8_unchecked(src_slice);
+    let dst_slice = ::std::slice::from_raw_parts_mut(dst, *dst_len);
+    let (result, read, written) =
+        (*encoder).encode_from_utf8_without_replacement(string, dst_slice, last);
+    *src_len = read;
+    *dst_len = written;
+    encoder_result_to_u32(result)
+}
+
+/// Query the worst-case output size when encoding from UTF-16 with
+/// replacement.
+///
+/// Returns the size of the output buffer in bytes that will not overflow
+/// given the current state of the encoder and `u16_length` number of
+/// additional input code units if there are no unmappable characters in
+/// the input or `SIZE_MAX` if `size_t` would overflow.
+#[no_mangle]
+pub unsafe extern "C" fn encoder_max_buffer_length_from_utf16_if_no_unmappables(
+    encoder: *const Encoder,
+    u16_length: usize,
+) -> usize {
+    (*encoder)
+        .max_buffer_length_from_utf16_if_no_unmappables(u16_length)
+        .unwrap_or(::std::usize::MAX)
+}
+
+/// Query the worst-case output size when encoding from UTF-16 without
+/// replacement.
+///
+/// Returns the size of the output buffer in bytes that will not overflow
+/// given the current state of the encoder and `u16_length` number of
+/// additional input code units or `SIZE_MAX` if `size_t` would overflow.
+#[no_mangle]
+pub unsafe extern "C" fn encoder_max_buffer_length_from_utf16_without_replacement(
+    encoder: *const Encoder,
+    u16_length: usize,
+) -> usize {
+    (*encoder)
+        .max_buffer_length_from_utf16_without_replacement(u16_length)
+        .unwrap_or(::std::usize::MAX)
+}
+
+/// Incrementally encode into byte stream from UTF-16 with unmappable
+/// characters replaced with HTML (decimal) numeric character references.
+///
+/// See the top-level FFI documentation for documentation for how the
+/// `encoder_encode_*` functions are mapped from Rust and the documentation
+/// for the [`Encoder`][1] struct for the semantics.
+///
+/// `src` must be non-`NULL` even if `src_len` is zero. When`src_len` is zero,
+/// it is OK for `src` to be something non-dereferencable, such as `0x1`.
+/// Likewise for `dst` when `dst_len` is zero. This is required due to Rust's
+/// optimization for slices within `Option`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if any of the pointer arguments is `NULL`, `src` and `src_len`
+/// don't designate a valid block of memory or `dst` and `dst_len` don't
+/// designate a valid block of memory.
+///
+/// [1]: https://docs.rs/encoding_rs/0.6.10/encoding_rs/struct.Encoder.html
+#[no_mangle]
+pub unsafe extern "C" fn encoder_encode_from_utf16(
+    encoder: *mut Encoder,
+    src: *const u16,
+    src_len: *mut usize,
+    dst: *mut u8,
+    dst_len: *mut usize,
+    last: bool,
+    had_replacements: *mut bool,
+) -> u32 {
+    let src_slice = ::std::slice::from_raw_parts(src, *src_len);
+    let dst_slice = ::std::slice::from_raw_parts_mut(dst, *dst_len);
+    let (result, read, written, replaced) =
+        (*encoder).encode_from_utf16(src_slice, dst_slice, last);
+    *src_len = read;
+    *dst_len = written;
+    *had_replacements = replaced;
+    coder_result_to_u32(result)
+}
+
+/// Incrementally encode into byte stream from UTF-16 _without replacement_.
+///
+/// See the top-level FFI documentation for documentation for how the
+/// `encoder_encode_*` functions are mapped from Rust and the documentation
+/// for the [`Encoder`][1] struct for the semantics.
+///
+/// `src` must be non-`NULL` even if `src_len` is zero. When`src_len` is zero,
+/// it is OK for `src` to be something non-dereferencable, such as `0x1`.
+/// Likewise for `dst` when `dst_len` is zero. This is required due to Rust's
+/// optimization for slices within `Option`.
+///
+/// # Undefined behavior
+///
+/// UB ensues if any of the pointer arguments is `NULL`, `src` and `src_len`
+/// don't designate a valid block of memory or `dst` and `dst_len` don't
+/// designate a valid block of memory.
+///
+/// [1]: https://docs.rs/encoding_rs/0.6.10/encoding_rs/struct.Encoder.html
+#[no_mangle]
+pub unsafe extern "C" fn encoder_encode_from_utf16_without_replacement(
+    encoder: *mut Encoder,
+    src: *const u16,
+    src_len: *mut usize,
+    dst: *mut u8,
+    dst_len: *mut usize,
+    last: bool,
+) -> u32 {
+    let src_slice = ::std::slice::from_raw_parts(src, *src_len);
+    let dst_slice = ::std::slice::from_raw_parts_mut(dst, *dst_len);
+    let (result, read, written) =
+        (*encoder).encode_from_utf16_without_replacement(src_slice, dst_slice, last);
+    *src_len = read;
+    *dst_len = written;
+    encoder_result_to_u32(result)
+}