Everywhere: Hoist the Libraries folder to the top-level

Author: https://github.com/trflynn89 Commit: 93712b24bf Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2256 Reviewed-by: https://github.com/sideshowbarker
2025-07-31 13:19:05 +00:00 · 2024-11-09 12:25:08 -05:00 · 2024-11-09 12:25:08 -05:00 · 93712b24bf · 2024-11-10 11:51:52 +00:00
commit 93712b24bf
parent 950e819ee7
4547 changed files with 104 additions and 113 deletions
--- a/Libraries/LibTextCodec/Encoder.cpp
+++ b/Libraries/LibTextCodec/Encoder.cpp
@ -0,0 +1,669 @@
+/*
+ * Copyright (c) 2024, Ben Jilks <benjyjilks@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/BinarySearch.h>
+#include <AK/Error.h>
+#include <AK/Utf8View.h>
+#include <LibTextCodec/Decoder.h>
+#include <LibTextCodec/Encoder.h>
+#include <LibTextCodec/LookupTables.h>
+
+namespace TextCodec {
+
+namespace {
+UTF8Encoder s_utf8_encoder;
+GB18030Encoder s_gb18030_encoder;
+GB18030Encoder s_gbk_encoder(GB18030Encoder::IsGBK::Yes);
+Big5Encoder s_big5_encoder;
+EUCJPEncoder s_euc_jp_encoder;
+ISO2022JPEncoder s_iso_2022_jp_encoder;
+ShiftJISEncoder s_shift_jis_encoder;
+EUCKREncoder s_euc_kr_encoder;
+
+// s_{encoding}_index is generated from https://encoding.spec.whatwg.org/indexes.json
+// Found separately in https://encoding.spec.whatwg.org/index-{encoding}.txt
+SingleByteEncoder s_ibm866_encoder { s_ibm866_index };
+SingleByteEncoder s_latin2_encoder { s_iso_8859_2_index };
+SingleByteEncoder s_latin3_encoder { s_iso_8859_3_index };
+SingleByteEncoder s_latin4_encoder { s_iso_8859_4_index };
+SingleByteEncoder s_latin_cyrillic_encoder { s_iso_8859_5_index };
+SingleByteEncoder s_latin_arabic_encoder { s_iso_8859_6_index };
+SingleByteEncoder s_latin_greek_encoder { s_iso_8859_7_index };
+SingleByteEncoder s_latin_hebrew_encoder { s_iso_8859_8_index };
+SingleByteEncoder s_latin6_encoder { s_iso_8859_10_index };
+SingleByteEncoder s_latin7_encoder { s_iso_8859_13_index };
+SingleByteEncoder s_latin8_encoder { s_iso_8859_14_index };
+SingleByteEncoder s_latin9_encoder { s_iso_8859_15_index };
+SingleByteEncoder s_latin10_encoder { s_iso_8859_16_index };
+SingleByteEncoder s_centraleurope_encoder { s_windows_1250_index };
+SingleByteEncoder s_cyrillic_encoder { s_windows_1251_index };
+SingleByteEncoder s_hebrew_encoder { s_windows_1255_index };
+SingleByteEncoder s_koi8r_encoder { s_koi8_r_index };
+SingleByteEncoder s_koi8u_encoder { s_koi8_u_index };
+SingleByteEncoder s_mac_roman_encoder { s_macintosh_index };
+SingleByteEncoder s_windows874_encoder { s_windows_874_index };
+SingleByteEncoder s_windows1252_encoder { s_windows_1252_index };
+SingleByteEncoder s_windows1253_encoder { s_windows_1253_index };
+SingleByteEncoder s_turkish_encoder { s_windows_1254_index };
+SingleByteEncoder s_windows1256_encoder { s_windows_1256_index };
+SingleByteEncoder s_windows1257_encoder { s_windows_1257_index };
+SingleByteEncoder s_windows1258_encoder { s_windows_1258_index };
+SingleByteEncoder s_mac_cyrillic_encoder { s_x_mac_cyrillic_index };
+
+}
+
+Optional<Encoder&> encoder_for_exact_name(StringView encoding)
+{
+    if (encoding.equals_ignoring_ascii_case("utf-8"sv))
+        return s_utf8_encoder;
+    if (encoding.equals_ignoring_ascii_case("big5"sv))
+        return s_big5_encoder;
+    if (encoding.equals_ignoring_ascii_case("euc-jp"sv))
+        return s_euc_jp_encoder;
+    if (encoding.equals_ignoring_ascii_case("iso-2022-jp"sv))
+        return s_iso_2022_jp_encoder;
+    if (encoding.equals_ignoring_ascii_case("shift_jis"sv))
+        return s_shift_jis_encoder;
+    if (encoding.equals_ignoring_ascii_case("euc-kr"sv))
+        return s_euc_kr_encoder;
+    if (encoding.equals_ignoring_ascii_case("gb18030"sv))
+        return s_gb18030_encoder;
+    if (encoding.equals_ignoring_ascii_case("gbk"sv))
+        return s_gbk_encoder;
+    if (encoding.equals_ignoring_ascii_case("ibm866"sv))
+        return s_ibm866_encoder;
+    if (encoding.equals_ignoring_ascii_case("iso-8859-2"sv))
+        return s_latin2_encoder;
+    if (encoding.equals_ignoring_ascii_case("iso-8859-3"sv))
+        return s_latin3_encoder;
+    if (encoding.equals_ignoring_ascii_case("iso-8859-4"sv))
+        return s_latin4_encoder;
+    if (encoding.equals_ignoring_ascii_case("iso-8859-5"sv))
+        return s_latin_cyrillic_encoder;
+    if (encoding.equals_ignoring_ascii_case("iso-8859-6"sv))
+        return s_latin_arabic_encoder;
+    if (encoding.equals_ignoring_ascii_case("iso-8859-7"sv))
+        return s_latin_greek_encoder;
+    if (encoding.is_one_of_ignoring_ascii_case("iso-8859-8"sv, "iso-8859-8-i"sv))
+        return s_latin_hebrew_encoder;
+    if (encoding.equals_ignoring_ascii_case("iso-8859-10"sv))
+        return s_latin6_encoder;
+    if (encoding.equals_ignoring_ascii_case("iso-8859-13"sv))
+        return s_latin7_encoder;
+    if (encoding.equals_ignoring_ascii_case("iso-8859-14"sv))
+        return s_latin8_encoder;
+    if (encoding.equals_ignoring_ascii_case("iso-8859-15"sv))
+        return s_latin9_encoder;
+    if (encoding.equals_ignoring_ascii_case("iso-8859-16"sv))
+        return s_latin10_encoder;
+    if (encoding.equals_ignoring_ascii_case("koi8-r"sv))
+        return s_koi8r_encoder;
+    if (encoding.equals_ignoring_ascii_case("koi8-u"sv))
+        return s_koi8u_encoder;
+    if (encoding.equals_ignoring_ascii_case("macintosh"sv))
+        return s_mac_roman_encoder;
+    if (encoding.equals_ignoring_ascii_case("windows-874"sv))
+        return s_windows874_encoder;
+    if (encoding.equals_ignoring_ascii_case("windows-1250"sv))
+        return s_centraleurope_encoder;
+    if (encoding.equals_ignoring_ascii_case("windows-1251"sv))
+        return s_cyrillic_encoder;
+    if (encoding.equals_ignoring_ascii_case("windows-1252"sv))
+        return s_windows1252_encoder;
+    if (encoding.equals_ignoring_ascii_case("windows-1253"sv))
+        return s_windows1253_encoder;
+    if (encoding.equals_ignoring_ascii_case("windows-1254"sv))
+        return s_turkish_encoder;
+    if (encoding.equals_ignoring_ascii_case("windows-1255"sv))
+        return s_hebrew_encoder;
+    if (encoding.equals_ignoring_ascii_case("windows-1256"sv))
+        return s_windows1256_encoder;
+    if (encoding.equals_ignoring_ascii_case("windows-1257"sv))
+        return s_windows1257_encoder;
+    if (encoding.equals_ignoring_ascii_case("windows-1258"sv))
+        return s_windows1258_encoder;
+    if (encoding.equals_ignoring_ascii_case("x-mac-cyrillic"sv))
+        return s_mac_cyrillic_encoder;
+    dbgln("TextCodec: No encoder implemented for encoding '{}'", encoding);
+    return {};
+}
+
+Optional<Encoder&> encoder_for(StringView label)
+{
+    auto encoding = get_standardized_encoding(label);
+    return encoding.has_value() ? encoder_for_exact_name(encoding.value()) : Optional<Encoder&> {};
+}
+
+// https://encoding.spec.whatwg.org/#utf-8-encoder
+ErrorOr<void> UTF8Encoder::process(Utf8View input, Function<ErrorOr<void>(u8)> on_byte, Function<ErrorOr<void>(u32)>)
+{
+    ReadonlyBytes bytes { input.bytes(), input.byte_length() };
+    for (auto byte : bytes)
+        TRY(on_byte(byte));
+    return {};
+}
+
+// https://encoding.spec.whatwg.org/#euc-jp-encoder
+ErrorOr<void> EUCJPEncoder::process(Utf8View input, Function<ErrorOr<void>(u8)> on_byte, Function<ErrorOr<void>(u32)> on_error)
+{
+    for (auto item : input) {
+        // 1. If code point is end-of-queue, return finished.
+
+        // 2. If code point is an ASCII code point, return a byte whose value is code point.
+        if (is_ascii(item)) {
+            TRY(on_byte(static_cast<u8>(item)));
+            continue;
+        }
+
+        // 3. If code point is U+00A5, return byte 0x5C.
+        if (item == 0x00A5) {
+            TRY(on_byte(static_cast<u8>(0x5C)));
+            continue;
+        }
+
+        // 4. If code point is U+203E, return byte 0x7E.
+        if (item == 0x203E) {
+            TRY(on_byte(static_cast<u8>(0x7E)));
+            continue;
+        }
+
+        // 5. If code point is in the range U+FF61 to U+FF9F, inclusive, return two bytes whose values are 0x8E and code point − 0xFF61 + 0xA1.
+        if (item >= 0xFF61 && item <= 0xFF9F) {
+            TRY(on_byte(0x8E));
+            TRY(on_byte(static_cast<u8>(item - 0xFF61 + 0xA1)));
+            continue;
+        }
+
+        // 6. If code point is U+2212, set it to U+FF0D.
+        if (item == 0x2212)
+            item = 0xFF0D;
+
+        // 7. Let pointer be the index pointer for code point in index jis0208.
+        auto pointer = code_point_jis0208_index(item);
+
+        // 8. If pointer is null, return error with code point.
+        if (!pointer.has_value()) {
+            TRY(on_error(item));
+            continue;
+        }
+
+        // 9. Let lead be pointer / 94 + 0xA1.
+        auto lead = *pointer / 94 + 0xA1;
+
+        // 10. Let trail be pointer % 94 + 0xA1.
+        auto trail = *pointer % 94 + 0xA1;
+
+        // 11. Return two bytes whose values are lead and trail.
+        TRY(on_byte(static_cast<u8>(lead)));
+        TRY(on_byte(static_cast<u8>(trail)));
+    }
+
+    return {};
+}
+
+// https://encoding.spec.whatwg.org/#iso-2022-jp-encoder
+ErrorOr<ISO2022JPEncoder::State> ISO2022JPEncoder::process_item(u32 item, State state, Function<ErrorOr<void>(u8)>& on_byte, Function<ErrorOr<void>(u32)>& on_error)
+{
+    // 3. If ISO-2022-JP encoder state is ASCII or Roman, and code point is U+000E, U+000F, or U+001B, return error with U+FFFD.
+    if (state == State::ASCII || state == State::Roman) {
+        if (item == 0x000E || item == 0x000F || item == 0x001B) {
+            TRY(on_error(0xFFFD));
+            return state;
+        }
+    }
+
+    // 4. If ISO-2022-JP encoder state is ASCII and code point is an ASCII code point, return a byte whose value is code point.
+    if (state == State::ASCII && is_ascii(item)) {
+        TRY(on_byte(static_cast<u8>(item)));
+        return state;
+    }
+
+    // 5. If ISO-2022-JP encoder state is Roman and code point is an ASCII code point, excluding U+005C and U+007E, or is U+00A5 or U+203E, then:
+    if (state == State::Roman && ((is_ascii(item) && item != 0x005C && item != 0x007E) || (item == 0x00A5 || item == 0x203E))) {
+        // 1. If code point is an ASCII code point, return a byte whose value is code point.
+        if (is_ascii(item)) {
+            TRY(on_byte(static_cast<u8>(item)));
+            return state;
+        }
+
+        // 2. If code point is U+00A5, return byte 0x5C.
+        if (item == 0x00A5) {
+            TRY(on_byte(0x5C));
+            return state;
+        }
+
+        // 3. If code point is U+203E, return byte 0x7E.
+        if (item == 0x203E) {
+            TRY(on_byte(0x7E));
+            return state;
+        }
+    }
+
+    // 6. If code point is an ASCII code point, and ISO-2022-JP encoder state is not ASCII, restore code point to ioQueue, set
+    //    ISO-2022-JP encoder state to ASCII, and return three bytes 0x1B 0x28 0x42.
+    if (is_ascii(item) && state != State::ASCII) {
+        TRY(on_byte(0x1B));
+        TRY(on_byte(0x28));
+        TRY(on_byte(0x42));
+        return process_item(item, State::ASCII, on_byte, on_error);
+    }
+
+    // 7. If code point is either U+00A5 or U+203E, and ISO-2022-JP encoder state is not Roman, restore code point to ioQueue,
+    //    set ISO-2022-JP encoder state to Roman, and return three bytes 0x1B 0x28 0x4A.
+    if ((item == 0x00A5 || item == 0x203E) && state != State::Roman) {
+        TRY(on_byte(0x1B));
+        TRY(on_byte(0x28));
+        TRY(on_byte(0x4A));
+        return process_item(item, State::Roman, on_byte, on_error);
+    }
+
+    // 8. If code point is U+2212, set it to U+FF0D.
+    if (item == 0x2212)
+        item = 0xFF0D;
+
+    // 9. If code point is in the range U+FF61 to U+FF9F, inclusive, set it to the index code point for code point − 0xFF61
+    //    in index ISO-2022-JP katakana.
+    if (item >= 0xFF61 && item <= 0xFF9F) {
+        item = *index_iso_2022_jp_katakana_code_point(item - 0xFF61);
+    }
+
+    // 10. Let pointer be the index pointer for code point in index jis0208.
+    auto pointer = code_point_jis0208_index(item);
+
+    // 11. If pointer is null, then:
+    if (!pointer.has_value()) {
+        // 1. If ISO-2022-JP encoder state is jis0208, then restore code point to ioQueue, set ISO-2022-JP encoder state to
+        //    ASCII, and return three bytes 0x1B 0x28 0x42.
+        if (state == State::jis0208) {
+            TRY(on_byte(0x1B));
+            TRY(on_byte(0x28));
+            TRY(on_byte(0x4A));
+            return process_item(item, State::ASCII, on_byte, on_error);
+        }
+
+        // 2. Return error with code point.
+        TRY(on_error(item));
+        return state;
+    }
+
+    // 12. If ISO-2022-JP encoder state is not jis0208, restore code point to ioQueue, set ISO-2022-JP encoder state to
+    //     jis0208, and return three bytes 0x1B 0x24 0x42.
+    if (state != State::jis0208) {
+        TRY(on_byte(0x1B));
+        TRY(on_byte(0x24));
+        TRY(on_byte(0x42));
+        return process_item(item, State::jis0208, on_byte, on_error);
+    }
+
+    // 13. Let lead be pointer / 94 + 0x21.
+    auto lead = *pointer / 94 + 0x21;
+
+    // 14. Let trail be pointer % 94 + 0x21.
+    auto trail = *pointer % 94 + 0x21;
+
+    // 15. Return two bytes whose values are lead and trail.
+    TRY(on_byte(static_cast<u8>(lead)));
+    TRY(on_byte(static_cast<u8>(trail)));
+    return state;
+}
+
+// https://encoding.spec.whatwg.org/#iso-2022-jp-encoder
+ErrorOr<void> ISO2022JPEncoder::process(Utf8View input, Function<ErrorOr<void>(u8)> on_byte, Function<ErrorOr<void>(u32)> on_error)
+{
+    // ISO-2022-JP’s encoder has an associated ISO-2022-JP encoder state which is ASCII, Roman, or jis0208 (initially ASCII).
+    auto state = State::ASCII;
+
+    for (u32 item : input) {
+        state = TRY(process_item(item, state, on_byte, on_error));
+    }
+
+    // 1. If code point is end-of-queue and ISO-2022-JP encoder state is not ASCII, set ISO-2022-JP
+    //    encoder state to ASCII, and return three bytes 0x1B 0x28 0x42.
+    if (state != State::ASCII) {
+        state = State::ASCII;
+        TRY(on_byte(0x1B));
+        TRY(on_byte(0x28));
+        TRY(on_byte(0x42));
+        return {};
+    }
+
+    // 2. If code point is end-of-queue and ISO-2022-JP encoder state is ASCII, return finished.
+    return {};
+}
+
+static Optional<u32> code_point_jis0208_index_skipping_range(u32 code_point, u32 skip_from, u32 skip_to)
+{
+    VERIFY(skip_to >= skip_from);
+    for (u32 i = 0; i < s_jis0208_index.size(); ++i) {
+        if (i >= skip_from && i <= skip_to)
+            continue;
+        if (s_jis0208_index[i] == code_point)
+            return i;
+    }
+    return {};
+}
+
+// https://encoding.spec.whatwg.org/#index-shift_jis-pointer
+static Optional<u32> index_shift_jis_pointer(u32 code_point)
+{
+    // 1. Let index be index jis0208 excluding all entries whose pointer is in the range 8272 to 8835, inclusive.
+    auto pointer = code_point_jis0208_index_skipping_range(code_point, 8272, 8835);
+    if (!pointer.has_value())
+        return {};
+
+    // 2. Return the index pointer for code point in index.
+    return *pointer;
+}
+
+// https://encoding.spec.whatwg.org/#shift_jis-encoder
+ErrorOr<void> ShiftJISEncoder::process(Utf8View input, Function<ErrorOr<void>(u8)> on_byte, Function<ErrorOr<void>(u32)> on_error)
+{
+    for (u32 item : input) {
+        // 1. If code point is end-of-queue, return finished.
+
+        // 2. If code point is an ASCII code point or U+0080, return a byte whose value is code point.
+        if (is_ascii(item) || item == 0x0080) {
+            TRY(on_byte(static_cast<u8>(item)));
+            continue;
+        }
+
+        // 3. If code point is U+00A5, return byte 0x5C.
+        if (item == 0x00A5) {
+            TRY(on_byte(0x5C));
+            continue;
+        }
+
+        // 4. If code point is U+203E, return byte 0x7E.
+        if (item == 0x203E) {
+            TRY(on_byte(0x7E));
+            continue;
+        }
+
+        // 5. If code point is in the range U+FF61 to U+FF9F, inclusive, return a byte whose value is code point − 0xFF61 + 0xA1.
+        if (item >= 0xFF61 && item <= 0xFF9F) {
+            TRY(on_byte(static_cast<u8>(item - 0xFF61 + 0xA1)));
+            continue;
+        }
+
+        // 6. If code point is U+2212, set it to U+FF0D.
+        if (item == 0x2212)
+            item = 0xFF0D;
+
+        // 7. Let pointer be the index Shift_JIS pointer for code point.
+        auto pointer = index_shift_jis_pointer(item);
+
+        // 8. If pointer is null, return error with code point.
+        if (!pointer.has_value()) {
+            TRY(on_error(item));
+            continue;
+        }
+
+        // 9. Let lead be pointer / 188.
+        auto lead = *pointer / 188;
+
+        // 10. Let lead offset be 0x81 if lead is less than 0x1F, otherwise 0xC1.
+        auto lead_offset = 0xC1;
+        if (lead < 0x1F)
+            lead_offset = 0x81;
+
+        // 11. Let trail be pointer % 188.
+        auto trail = *pointer % 188;
+
+        // 12. Let offset be 0x40 if trail is less than 0x3F, otherwise 0x41.
+        auto offset = 0x41;
+        if (trail < 0x3F)
+            offset = 0x40;
+
+        // 13. Return two bytes whose values are lead + lead offset and trail + offset.
+        TRY(on_byte(static_cast<u8>(lead + lead_offset)));
+        TRY(on_byte(static_cast<u8>(trail + offset)));
+    }
+
+    return {};
+}
+
+// https://encoding.spec.whatwg.org/#euc-kr-encoder
+ErrorOr<void> EUCKREncoder::process(Utf8View input, Function<ErrorOr<void>(u8)> on_byte, Function<ErrorOr<void>(u32)> on_error)
+{
+    for (u32 item : input) {
+        // 1. If code point is end-of-queue, return finished.
+
+        // 2. If code point is an ASCII code point, return a byte whose value is code point.
+        if (is_ascii(item)) {
+            TRY(on_byte(static_cast<u8>(item)));
+            continue;
+        }
+
+        // 3. Let pointer be the index pointer for code point in index EUC-KR.
+        auto pointer = code_point_euc_kr_index(item);
+
+        // 4. If pointer is null, return error with code point.
+        if (!pointer.has_value()) {
+            TRY(on_error(item));
+            continue;
+        }
+
+        // 5. Let lead be pointer / 190 + 0x81.
+        auto lead = *pointer / 190 + 0x81;
+
+        // 6. Let trail be pointer % 190 + 0x41.
+        auto trail = *pointer % 190 + 0x41;
+
+        // 7. Return two bytes whose values are lead and trail.
+        TRY(on_byte(static_cast<u8>(lead)));
+        TRY(on_byte(static_cast<u8>(trail)));
+    }
+
+    return {};
+}
+
+// https://encoding.spec.whatwg.org/#index-big5-pointer
+static Optional<u32> index_big5_pointer(u32 code_point)
+{
+    // 1. Let index be index Big5 excluding all entries whose pointer is less than (0xA1 - 0x81) × 157.
+    auto start_index = (0xA1 - 0x81) * 157 - s_big5_index_first_pointer;
+
+    // 2. If code point is U+2550, U+255E, U+2561, U+256A, U+5341, or U+5345, return the last pointer
+    //    corresponding to code point in index.
+    if (Array<u32, 6> { 0x2550, 0x255E, 0x2561, 0x256A, 0x5341, 0x5345 }.contains_slow(code_point)) {
+        for (u32 i = s_big5_index.size() - 1; i >= start_index; --i) {
+            if (s_big5_index[i] == code_point) {
+                return s_big5_index_first_pointer + i;
+            }
+        }
+        return {};
+    }
+
+    // 3. Return the index pointer for code point in index.
+    for (u32 i = start_index; i < s_big5_index.size(); ++i) {
+        if (s_big5_index[i] == code_point) {
+            return s_big5_index_first_pointer + i;
+        }
+    }
+    return {};
+}
+
+// https://encoding.spec.whatwg.org/#big5-encoder
+ErrorOr<void> Big5Encoder::process(Utf8View input, Function<ErrorOr<void>(u8)> on_byte, Function<ErrorOr<void>(u32)> on_error)
+{
+    for (u32 item : input) {
+        // 1. If code point is end-of-queue, return finished.
+
+        // 2. If code point is an ASCII code point, return a byte whose value is code point.
+        if (is_ascii(item)) {
+            TRY(on_byte(static_cast<u8>(item)));
+            continue;
+        }
+
+        // 3. Let pointer be the index Big5 pointer for code point.
+        auto pointer = index_big5_pointer(item);
+
+        // 4. If pointer is null, return error with code point.
+        if (!pointer.has_value()) {
+            TRY(on_error(item));
+            continue;
+        }
+
+        // 5. Let lead be pointer / 157 + 0x81.
+        auto lead = *pointer / 157 + 0x81;
+
+        // 6. Let trail be pointer % 157.
+        auto trail = *pointer % 157;
+
+        // 7. Let offset be 0x40 if trail is less than 0x3F, otherwise 0x62.
+        auto offset = 0x62;
+        if (trail < 0x3f)
+            offset = 0x40;
+
+        // 8. Return two bytes whose values are lead and trail + offset.
+        TRY(on_byte(static_cast<u8>(lead)));
+        TRY(on_byte(static_cast<u8>(trail + offset)));
+    }
+
+    return {};
+}
+
+// https://encoding.spec.whatwg.org/#index-gb18030-ranges-pointer
+static u32 index_gb18030_ranges_pointer(u32 code_point)
+{
+    // 1. If code point is U+E7C7, return pointer 7457.
+    if (code_point == 0xe7c7)
+        return 7457;
+
+    // 2. Let offset be the last code point in index gb18030 ranges that is less than
+    //    or equal to code point and let pointer offset be its corresponding pointer.
+    size_t last_index;
+    binary_search(s_gb18030_ranges, code_point, &last_index, [](auto const code_point, auto const& entry) {
+        return code_point - entry.code_point;
+    });
+    auto offset = s_gb18030_ranges[last_index].code_point;
+    auto pointer_offset = s_gb18030_ranges[last_index].pointer;
+
+    // 3. Return a pointer whose value is pointer offset + code point − offset.
+    return pointer_offset + code_point - offset;
+}
+
+GB18030Encoder::GB18030Encoder(IsGBK is_gbk)
+    : m_is_gbk(is_gbk)
+{
+}
+
+// https://encoding.spec.whatwg.org/#gb18030-encoder
+ErrorOr<void> GB18030Encoder::process(Utf8View input, Function<ErrorOr<void>(u8)> on_byte, Function<ErrorOr<void>(u32)> on_error)
+{
+    bool gbk = (m_is_gbk == IsGBK::Yes);
+
+    for (u32 item : input) {
+        // 1. If code point is end-of-queue, return finished.
+
+        // 2. If code point is an ASCII code point, return a byte whose value is code point.
+        if (is_ascii(item)) {
+            TRY(on_byte(static_cast<u8>(item)));
+            continue;
+        }
+
+        // 3. If code point is U+E5E5, return error with code point.
+        if (item == 0xE5E5) {
+            TRY(on_error(item));
+            continue;
+        }
+
+        // 4. If is GBK is true and code point is U+20AC, return byte 0x80.
+        if (gbk && item == 0x20AC) {
+            TRY(on_byte(0x80));
+            continue;
+        }
+
+        // 5. Let pointer be the index pointer for code point in index gb18030.
+        auto pointer = code_point_gb18030_index(item);
+
+        // 6. If pointer is non-null, then:
+        if (pointer.has_value()) {
+            // 1. Let lead be pointer / 190 + 0x81.
+            auto lead = *pointer / 190 + 0x81;
+
+            // 2. Let trail be pointer % 190.
+            auto trail = *pointer % 190;
+
+            // 3. Let offset be 0x40 if trail is less than 0x3F, otherwise 0x41.
+            auto offset = 0x41;
+            if (trail < 0x3f)
+                offset = 0x40;
+
+            // 4. Return two bytes whose values are lead and trail + offset.
+            TRY(on_byte(static_cast<u8>(lead)));
+            TRY(on_byte(static_cast<u8>(trail + offset)));
+            continue;
+        }
+
+        // 7. If is GBK is true, return error with code point.
+        if (gbk) {
+            TRY(on_error(item));
+            continue;
+        }
+
+        // 8. Set pointer to the index gb18030 ranges pointer for code point.
+        pointer = index_gb18030_ranges_pointer(item);
+
+        // 9. Let byte1 be pointer / (10 × 126 × 10).
+        auto byte1 = *pointer / (10 * 126 * 10);
+
+        // 10. Set pointer to pointer % (10 × 126 × 10).
+        pointer = *pointer % (10 * 126 * 10);
+
+        // 11. Let byte2 be pointer / (10 × 126).
+        auto byte2 = *pointer / (10 * 126);
+
+        // 12. Set pointer to pointer % (10 × 126).
+        pointer = *pointer % (10 * 126);
+
+        // 13. Let byte3 be pointer / 10.
+        auto byte3 = *pointer / 10;
+
+        // 14. Let byte4 be pointer % 10.
+        auto byte4 = *pointer % 10;
+
+        // 15. Return four bytes whose values are byte1 + 0x81, byte2 + 0x30, byte3 + 0x81, byte4 + 0x30.
+        TRY(on_byte(static_cast<u8>(byte1 + 0x81)));
+        TRY(on_byte(static_cast<u8>(byte2 + 0x30)));
+        TRY(on_byte(static_cast<u8>(byte3 + 0x81)));
+        TRY(on_byte(static_cast<u8>(byte4 + 0x30)));
+    }
+
+    return {};
+}
+
+// https://encoding.spec.whatwg.org/#single-byte-encoder
+template<Integral ArrayType>
+ErrorOr<void> SingleByteEncoder<ArrayType>::process(Utf8View input, Function<ErrorOr<void>(u8)> on_byte, Function<ErrorOr<void>(u32)> on_error)
+{
+    for (u32 const code_point : input) {
+        if (code_point < 0x80) {
+            // 2. If code point is an ASCII code point, return a byte whose value is code point.
+            TRY(on_byte(static_cast<u8>(code_point)));
+        } else {
+            Optional<u8> pointer = {};
+            for (u8 i = 0; i < m_translation_table.size(); i++) {
+                if (m_translation_table[i] == code_point) {
+                    // 3. Let pointer be the index pointer for code point in index single-byte.
+                    pointer = i;
+                    break;
+                }
+            }
+            if (pointer.has_value()) {
+                // 5. Return a byte whose value is pointer + 0x80.
+                TRY(on_byte(pointer.value() + 0x80));
+            } else {
+                // 4. If pointer is null, return error with code point.
+                TRY(on_error(code_point));
+            }
+        }
+    }
+    // 1. If code point is end-of-queue, return finished.
+    return {};
+}
+
+}