spg-engine 7.37.16

//! v7.38 (read01, T30) — single-byte encoding transcode tables, sourced from
//! live PostgreSQL 18.4. Each `*_HIGH` table covers bytes 0x80..=0xFF; low
//! bytes are ASCII (identity). `'\u{FFFF}'` marks a byte undefined in that
//! encoding. (WIN125x, with undefined bytes, keep their existing arm.)

use alloc::string::String;
use alloc::vec::Vec;

use crate::eval::EvalError;

#[rustfmt::skip]
const LATIN1_HIGH: [char; 128] = [
    '\u{0080}', '\u{0081}', '\u{0082}', '\u{0083}', '\u{0084}', '\u{0085}', '\u{0086}', '\u{0087}',
    '\u{0088}', '\u{0089}', '\u{008A}', '\u{008B}', '\u{008C}', '\u{008D}', '\u{008E}', '\u{008F}',
    '\u{0090}', '\u{0091}', '\u{0092}', '\u{0093}', '\u{0094}', '\u{0095}', '\u{0096}', '\u{0097}',
    '\u{0098}', '\u{0099}', '\u{009A}', '\u{009B}', '\u{009C}', '\u{009D}', '\u{009E}', '\u{009F}',
    '\u{00A0}', '\u{00A1}', '\u{00A2}', '\u{00A3}', '\u{00A4}', '\u{00A5}', '\u{00A6}', '\u{00A7}',
    '\u{00A8}', '\u{00A9}', '\u{00AA}', '\u{00AB}', '\u{00AC}', '\u{00AD}', '\u{00AE}', '\u{00AF}',
    '\u{00B0}', '\u{00B1}', '\u{00B2}', '\u{00B3}', '\u{00B4}', '\u{00B5}', '\u{00B6}', '\u{00B7}',
    '\u{00B8}', '\u{00B9}', '\u{00BA}', '\u{00BB}', '\u{00BC}', '\u{00BD}', '\u{00BE}', '\u{00BF}',
    '\u{00C0}', '\u{00C1}', '\u{00C2}', '\u{00C3}', '\u{00C4}', '\u{00C5}', '\u{00C6}', '\u{00C7}',
    '\u{00C8}', '\u{00C9}', '\u{00CA}', '\u{00CB}', '\u{00CC}', '\u{00CD}', '\u{00CE}', '\u{00CF}',
    '\u{00D0}', '\u{00D1}', '\u{00D2}', '\u{00D3}', '\u{00D4}', '\u{00D5}', '\u{00D6}', '\u{00D7}',
    '\u{00D8}', '\u{00D9}', '\u{00DA}', '\u{00DB}', '\u{00DC}', '\u{00DD}', '\u{00DE}', '\u{00DF}',
    '\u{00E0}', '\u{00E1}', '\u{00E2}', '\u{00E3}', '\u{00E4}', '\u{00E5}', '\u{00E6}', '\u{00E7}',
    '\u{00E8}', '\u{00E9}', '\u{00EA}', '\u{00EB}', '\u{00EC}', '\u{00ED}', '\u{00EE}', '\u{00EF}',
    '\u{00F0}', '\u{00F1}', '\u{00F2}', '\u{00F3}', '\u{00F4}', '\u{00F5}', '\u{00F6}', '\u{00F7}',
    '\u{00F8}', '\u{00F9}', '\u{00FA}', '\u{00FB}', '\u{00FC}', '\u{00FD}', '\u{00FE}', '\u{00FF}',
];

#[rustfmt::skip]
const LATIN2_HIGH: [char; 128] = [
    '\u{0080}', '\u{0081}', '\u{0082}', '\u{0083}', '\u{0084}', '\u{0085}', '\u{0086}', '\u{0087}',
    '\u{0088}', '\u{0089}', '\u{008A}', '\u{008B}', '\u{008C}', '\u{008D}', '\u{008E}', '\u{008F}',
    '\u{0090}', '\u{0091}', '\u{0092}', '\u{0093}', '\u{0094}', '\u{0095}', '\u{0096}', '\u{0097}',
    '\u{0098}', '\u{0099}', '\u{009A}', '\u{009B}', '\u{009C}', '\u{009D}', '\u{009E}', '\u{009F}',
    '\u{00A0}', '\u{0104}', '\u{02D8}', '\u{0141}', '\u{00A4}', '\u{013D}', '\u{015A}', '\u{00A7}',
    '\u{00A8}', '\u{0160}', '\u{015E}', '\u{0164}', '\u{0179}', '\u{00AD}', '\u{017D}', '\u{017B}',
    '\u{00B0}', '\u{0105}', '\u{02DB}', '\u{0142}', '\u{00B4}', '\u{013E}', '\u{015B}', '\u{02C7}',
    '\u{00B8}', '\u{0161}', '\u{015F}', '\u{0165}', '\u{017A}', '\u{02DD}', '\u{017E}', '\u{017C}',
    '\u{0154}', '\u{00C1}', '\u{00C2}', '\u{0102}', '\u{00C4}', '\u{0139}', '\u{0106}', '\u{00C7}',
    '\u{010C}', '\u{00C9}', '\u{0118}', '\u{00CB}', '\u{011A}', '\u{00CD}', '\u{00CE}', '\u{010E}',
    '\u{0110}', '\u{0143}', '\u{0147}', '\u{00D3}', '\u{00D4}', '\u{0150}', '\u{00D6}', '\u{00D7}',
    '\u{0158}', '\u{016E}', '\u{00DA}', '\u{0170}', '\u{00DC}', '\u{00DD}', '\u{0162}', '\u{00DF}',
    '\u{0155}', '\u{00E1}', '\u{00E2}', '\u{0103}', '\u{00E4}', '\u{013A}', '\u{0107}', '\u{00E7}',
    '\u{010D}', '\u{00E9}', '\u{0119}', '\u{00EB}', '\u{011B}', '\u{00ED}', '\u{00EE}', '\u{010F}',
    '\u{0111}', '\u{0144}', '\u{0148}', '\u{00F3}', '\u{00F4}', '\u{0151}', '\u{00F6}', '\u{00F7}',
    '\u{0159}', '\u{016F}', '\u{00FA}', '\u{0171}', '\u{00FC}', '\u{00FD}', '\u{0163}', '\u{02D9}',
];

#[rustfmt::skip]
const LATIN9_HIGH: [char; 128] = [
    '\u{0080}', '\u{0081}', '\u{0082}', '\u{0083}', '\u{0084}', '\u{0085}', '\u{0086}', '\u{0087}',
    '\u{0088}', '\u{0089}', '\u{008A}', '\u{008B}', '\u{008C}', '\u{008D}', '\u{008E}', '\u{008F}',
    '\u{0090}', '\u{0091}', '\u{0092}', '\u{0093}', '\u{0094}', '\u{0095}', '\u{0096}', '\u{0097}',
    '\u{0098}', '\u{0099}', '\u{009A}', '\u{009B}', '\u{009C}', '\u{009D}', '\u{009E}', '\u{009F}',
    '\u{00A0}', '\u{00A1}', '\u{00A2}', '\u{00A3}', '\u{20AC}', '\u{00A5}', '\u{0160}', '\u{00A7}',
    '\u{0161}', '\u{00A9}', '\u{00AA}', '\u{00AB}', '\u{00AC}', '\u{00AD}', '\u{00AE}', '\u{00AF}',
    '\u{00B0}', '\u{00B1}', '\u{00B2}', '\u{00B3}', '\u{017D}', '\u{00B5}', '\u{00B6}', '\u{00B7}',
    '\u{017E}', '\u{00B9}', '\u{00BA}', '\u{00BB}', '\u{0152}', '\u{0153}', '\u{0178}', '\u{00BF}',
    '\u{00C0}', '\u{00C1}', '\u{00C2}', '\u{00C3}', '\u{00C4}', '\u{00C5}', '\u{00C6}', '\u{00C7}',
    '\u{00C8}', '\u{00C9}', '\u{00CA}', '\u{00CB}', '\u{00CC}', '\u{00CD}', '\u{00CE}', '\u{00CF}',
    '\u{00D0}', '\u{00D1}', '\u{00D2}', '\u{00D3}', '\u{00D4}', '\u{00D5}', '\u{00D6}', '\u{00D7}',
    '\u{00D8}', '\u{00D9}', '\u{00DA}', '\u{00DB}', '\u{00DC}', '\u{00DD}', '\u{00DE}', '\u{00DF}',
    '\u{00E0}', '\u{00E1}', '\u{00E2}', '\u{00E3}', '\u{00E4}', '\u{00E5}', '\u{00E6}', '\u{00E7}',
    '\u{00E8}', '\u{00E9}', '\u{00EA}', '\u{00EB}', '\u{00EC}', '\u{00ED}', '\u{00EE}', '\u{00EF}',
    '\u{00F0}', '\u{00F1}', '\u{00F2}', '\u{00F3}', '\u{00F4}', '\u{00F5}', '\u{00F6}', '\u{00F7}',
    '\u{00F8}', '\u{00F9}', '\u{00FA}', '\u{00FB}', '\u{00FC}', '\u{00FD}', '\u{00FE}', '\u{00FF}',
];

#[rustfmt::skip]
const KOI8R_HIGH: [char; 128] = [
    '\u{2500}', '\u{2502}', '\u{250C}', '\u{2510}', '\u{2514}', '\u{2518}', '\u{251C}', '\u{2524}',
    '\u{252C}', '\u{2534}', '\u{253C}', '\u{2580}', '\u{2584}', '\u{2588}', '\u{258C}', '\u{2590}',
    '\u{2591}', '\u{2592}', '\u{2593}', '\u{2320}', '\u{25A0}', '\u{2219}', '\u{221A}', '\u{2248}',
    '\u{2264}', '\u{2265}', '\u{00A0}', '\u{2321}', '\u{00B0}', '\u{00B2}', '\u{00B7}', '\u{00F7}',
    '\u{2550}', '\u{2551}', '\u{2552}', '\u{0451}', '\u{2553}', '\u{2554}', '\u{2555}', '\u{2556}',
    '\u{2557}', '\u{2558}', '\u{2559}', '\u{255A}', '\u{255B}', '\u{255C}', '\u{255D}', '\u{255E}',
    '\u{255F}', '\u{2560}', '\u{2561}', '\u{0401}', '\u{2562}', '\u{2563}', '\u{2564}', '\u{2565}',
    '\u{2566}', '\u{2567}', '\u{2568}', '\u{2569}', '\u{256A}', '\u{256B}', '\u{256C}', '\u{00A9}',
    '\u{044E}', '\u{0430}', '\u{0431}', '\u{0446}', '\u{0434}', '\u{0435}', '\u{0444}', '\u{0433}',
    '\u{0445}', '\u{0438}', '\u{0439}', '\u{043A}', '\u{043B}', '\u{043C}', '\u{043D}', '\u{043E}',
    '\u{043F}', '\u{044F}', '\u{0440}', '\u{0441}', '\u{0442}', '\u{0443}', '\u{0436}', '\u{0432}',
    '\u{044C}', '\u{044B}', '\u{0437}', '\u{0448}', '\u{044D}', '\u{0449}', '\u{0447}', '\u{044A}',
    '\u{042E}', '\u{0410}', '\u{0411}', '\u{0426}', '\u{0414}', '\u{0415}', '\u{0424}', '\u{0413}',
    '\u{0425}', '\u{0418}', '\u{0419}', '\u{041A}', '\u{041B}', '\u{041C}', '\u{041D}', '\u{041E}',
    '\u{041F}', '\u{042F}', '\u{0420}', '\u{0421}', '\u{0422}', '\u{0423}', '\u{0416}', '\u{0412}',
    '\u{042C}', '\u{042B}', '\u{0417}', '\u{0428}', '\u{042D}', '\u{0429}', '\u{0427}', '\u{042A}',
];

#[rustfmt::skip]
const KOI8U_HIGH: [char; 128] = [
    '\u{2500}', '\u{2502}', '\u{250C}', '\u{2510}', '\u{2514}', '\u{2518}', '\u{251C}', '\u{2524}',
    '\u{252C}', '\u{2534}', '\u{253C}', '\u{2580}', '\u{2584}', '\u{2588}', '\u{258C}', '\u{2590}',
    '\u{2591}', '\u{2592}', '\u{2593}', '\u{2320}', '\u{25A0}', '\u{2219}', '\u{221A}', '\u{2248}',
    '\u{2264}', '\u{2265}', '\u{00A0}', '\u{2321}', '\u{00B0}', '\u{00B2}', '\u{00B7}', '\u{00F7}',
    '\u{2550}', '\u{2551}', '\u{2552}', '\u{0451}', '\u{0454}', '\u{2554}', '\u{0456}', '\u{0457}',
    '\u{2557}', '\u{2558}', '\u{2559}', '\u{255A}', '\u{255B}', '\u{0491}', '\u{255D}', '\u{255E}',
    '\u{255F}', '\u{2560}', '\u{2561}', '\u{0401}', '\u{0404}', '\u{2563}', '\u{0406}', '\u{0407}',
    '\u{2566}', '\u{2567}', '\u{2568}', '\u{2569}', '\u{256A}', '\u{0490}', '\u{256C}', '\u{00A9}',
    '\u{044E}', '\u{0430}', '\u{0431}', '\u{0446}', '\u{0434}', '\u{0435}', '\u{0444}', '\u{0433}',
    '\u{0445}', '\u{0438}', '\u{0439}', '\u{043A}', '\u{043B}', '\u{043C}', '\u{043D}', '\u{043E}',
    '\u{043F}', '\u{044F}', '\u{0440}', '\u{0441}', '\u{0442}', '\u{0443}', '\u{0436}', '\u{0432}',
    '\u{044C}', '\u{044B}', '\u{0437}', '\u{0448}', '\u{044D}', '\u{0449}', '\u{0447}', '\u{044A}',
    '\u{042E}', '\u{0410}', '\u{0411}', '\u{0426}', '\u{0414}', '\u{0415}', '\u{0424}', '\u{0413}',
    '\u{0425}', '\u{0418}', '\u{0419}', '\u{041A}', '\u{041B}', '\u{041C}', '\u{041D}', '\u{041E}',
    '\u{041F}', '\u{042F}', '\u{0420}', '\u{0421}', '\u{0422}', '\u{0423}', '\u{0416}', '\u{0412}',
    '\u{042C}', '\u{042B}', '\u{0417}', '\u{0428}', '\u{042D}', '\u{0429}', '\u{0427}', '\u{042A}',
];

/// v7.38 (T30) — WIN1250 (CP1250) high half, extracted from live PG18.4 via
/// `convert_from`. Undefined bytes [129, 131, 136, 144, 152] map to the U+FFFF sentinel
/// `single_byte_to_utf8` rejects (PG errors on them too).
const WIN1250_HIGH: [char; 128] = [
    '\u{20AC}', '\u{FFFF}', '\u{201A}', '\u{FFFF}', '\u{201E}', '\u{2026}', '\u{2020}', '\u{2021}',
    '\u{FFFF}', '\u{2030}', '\u{0160}', '\u{2039}', '\u{015A}', '\u{0164}', '\u{017D}', '\u{0179}',
    '\u{FFFF}', '\u{2018}', '\u{2019}', '\u{201C}', '\u{201D}', '\u{2022}', '\u{2013}', '\u{2014}',
    '\u{FFFF}', '\u{2122}', '\u{0161}', '\u{203A}', '\u{015B}', '\u{0165}', '\u{017E}', '\u{017A}',
    '\u{00A0}', '\u{02C7}', '\u{02D8}', '\u{0141}', '\u{00A4}', '\u{0104}', '\u{00A6}', '\u{00A7}',
    '\u{00A8}', '\u{00A9}', '\u{015E}', '\u{00AB}', '\u{00AC}', '\u{00AD}', '\u{00AE}', '\u{017B}',
    '\u{00B0}', '\u{00B1}', '\u{02DB}', '\u{0142}', '\u{00B4}', '\u{00B5}', '\u{00B6}', '\u{00B7}',
    '\u{00B8}', '\u{0105}', '\u{015F}', '\u{00BB}', '\u{013D}', '\u{02DD}', '\u{013E}', '\u{017C}',
    '\u{0154}', '\u{00C1}', '\u{00C2}', '\u{0102}', '\u{00C4}', '\u{0139}', '\u{0106}', '\u{00C7}',
    '\u{010C}', '\u{00C9}', '\u{0118}', '\u{00CB}', '\u{011A}', '\u{00CD}', '\u{00CE}', '\u{010E}',
    '\u{0110}', '\u{0143}', '\u{0147}', '\u{00D3}', '\u{00D4}', '\u{0150}', '\u{00D6}', '\u{00D7}',
    '\u{0158}', '\u{016E}', '\u{00DA}', '\u{0170}', '\u{00DC}', '\u{00DD}', '\u{0162}', '\u{00DF}',
    '\u{0155}', '\u{00E1}', '\u{00E2}', '\u{0103}', '\u{00E4}', '\u{013A}', '\u{0107}', '\u{00E7}',
    '\u{010D}', '\u{00E9}', '\u{0119}', '\u{00EB}', '\u{011B}', '\u{00ED}', '\u{00EE}', '\u{010F}',
    '\u{0111}', '\u{0144}', '\u{0148}', '\u{00F3}', '\u{00F4}', '\u{0151}', '\u{00F6}', '\u{00F7}',
    '\u{0159}', '\u{016F}', '\u{00FA}', '\u{0171}', '\u{00FC}', '\u{00FD}', '\u{0163}', '\u{02D9}',
];

/// v7.38 (T30) — WIN1251 (CP1251) high half, extracted from live PG18.4 via
/// `convert_from`. Undefined bytes [152] map to the U+FFFF sentinel
/// `single_byte_to_utf8` rejects (PG errors on them too).
const WIN1251_HIGH: [char; 128] = [
    '\u{0402}', '\u{0403}', '\u{201A}', '\u{0453}', '\u{201E}', '\u{2026}', '\u{2020}', '\u{2021}',
    '\u{20AC}', '\u{2030}', '\u{0409}', '\u{2039}', '\u{040A}', '\u{040C}', '\u{040B}', '\u{040F}',
    '\u{0452}', '\u{2018}', '\u{2019}', '\u{201C}', '\u{201D}', '\u{2022}', '\u{2013}', '\u{2014}',
    '\u{FFFF}', '\u{2122}', '\u{0459}', '\u{203A}', '\u{045A}', '\u{045C}', '\u{045B}', '\u{045F}',
    '\u{00A0}', '\u{040E}', '\u{045E}', '\u{0408}', '\u{00A4}', '\u{0490}', '\u{00A6}', '\u{00A7}',
    '\u{0401}', '\u{00A9}', '\u{0404}', '\u{00AB}', '\u{00AC}', '\u{00AD}', '\u{00AE}', '\u{0407}',
    '\u{00B0}', '\u{00B1}', '\u{0406}', '\u{0456}', '\u{0491}', '\u{00B5}', '\u{00B6}', '\u{00B7}',
    '\u{0451}', '\u{2116}', '\u{0454}', '\u{00BB}', '\u{0458}', '\u{0405}', '\u{0455}', '\u{0457}',
    '\u{0410}', '\u{0411}', '\u{0412}', '\u{0413}', '\u{0414}', '\u{0415}', '\u{0416}', '\u{0417}',
    '\u{0418}', '\u{0419}', '\u{041A}', '\u{041B}', '\u{041C}', '\u{041D}', '\u{041E}', '\u{041F}',
    '\u{0420}', '\u{0421}', '\u{0422}', '\u{0423}', '\u{0424}', '\u{0425}', '\u{0426}', '\u{0427}',
    '\u{0428}', '\u{0429}', '\u{042A}', '\u{042B}', '\u{042C}', '\u{042D}', '\u{042E}', '\u{042F}',
    '\u{0430}', '\u{0431}', '\u{0432}', '\u{0433}', '\u{0434}', '\u{0435}', '\u{0436}', '\u{0437}',
    '\u{0438}', '\u{0439}', '\u{043A}', '\u{043B}', '\u{043C}', '\u{043D}', '\u{043E}', '\u{043F}',
    '\u{0440}', '\u{0441}', '\u{0442}', '\u{0443}', '\u{0444}', '\u{0445}', '\u{0446}', '\u{0447}',
    '\u{0448}', '\u{0449}', '\u{044A}', '\u{044B}', '\u{044C}', '\u{044D}', '\u{044E}', '\u{044F}',
];

/// v7.38 (T30) — WIN1253 (CP1253) high half, extracted from live PG18.4 via
/// `convert_from`. Undefined bytes [129, 136, 138, 140, 141, 142, 143, 144, 152, 154, 156, 157, 158, 159, 170, 210, 255] map to the U+FFFF sentinel
/// `single_byte_to_utf8` rejects (PG errors on them too).
const WIN1253_HIGH: [char; 128] = [
    '\u{20AC}', '\u{FFFF}', '\u{201A}', '\u{0192}', '\u{201E}', '\u{2026}', '\u{2020}', '\u{2021}',
    '\u{FFFF}', '\u{2030}', '\u{FFFF}', '\u{2039}', '\u{FFFF}', '\u{FFFF}', '\u{FFFF}', '\u{FFFF}',
    '\u{FFFF}', '\u{2018}', '\u{2019}', '\u{201C}', '\u{201D}', '\u{2022}', '\u{2013}', '\u{2014}',
    '\u{FFFF}', '\u{2122}', '\u{FFFF}', '\u{203A}', '\u{FFFF}', '\u{FFFF}', '\u{FFFF}', '\u{FFFF}',
    '\u{00A0}', '\u{0385}', '\u{0386}', '\u{00A3}', '\u{00A4}', '\u{00A5}', '\u{00A6}', '\u{00A7}',
    '\u{00A8}', '\u{00A9}', '\u{FFFF}', '\u{00AB}', '\u{00AC}', '\u{00AD}', '\u{00AE}', '\u{2015}',
    '\u{00B0}', '\u{00B1}', '\u{00B2}', '\u{00B3}', '\u{0384}', '\u{00B5}', '\u{00B6}', '\u{00B7}',
    '\u{0388}', '\u{0389}', '\u{038A}', '\u{00BB}', '\u{038C}', '\u{00BD}', '\u{038E}', '\u{038F}',
    '\u{0390}', '\u{0391}', '\u{0392}', '\u{0393}', '\u{0394}', '\u{0395}', '\u{0396}', '\u{0397}',
    '\u{0398}', '\u{0399}', '\u{039A}', '\u{039B}', '\u{039C}', '\u{039D}', '\u{039E}', '\u{039F}',
    '\u{03A0}', '\u{03A1}', '\u{FFFF}', '\u{03A3}', '\u{03A4}', '\u{03A5}', '\u{03A6}', '\u{03A7}',
    '\u{03A8}', '\u{03A9}', '\u{03AA}', '\u{03AB}', '\u{03AC}', '\u{03AD}', '\u{03AE}', '\u{03AF}',
    '\u{03B0}', '\u{03B1}', '\u{03B2}', '\u{03B3}', '\u{03B4}', '\u{03B5}', '\u{03B6}', '\u{03B7}',
    '\u{03B8}', '\u{03B9}', '\u{03BA}', '\u{03BB}', '\u{03BC}', '\u{03BD}', '\u{03BE}', '\u{03BF}',
    '\u{03C0}', '\u{03C1}', '\u{03C2}', '\u{03C3}', '\u{03C4}', '\u{03C5}', '\u{03C6}', '\u{03C7}',
    '\u{03C8}', '\u{03C9}', '\u{03CA}', '\u{03CB}', '\u{03CC}', '\u{03CD}', '\u{03CE}', '\u{FFFF}',
];

/// v7.38 (T30) — WIN1254 (CP1254) high half, extracted from live PG18.4 via
/// `convert_from`. Undefined bytes [129, 141, 142, 143, 144, 157, 158] map to the U+FFFF sentinel
/// `single_byte_to_utf8` rejects (PG errors on them too).
const WIN1254_HIGH: [char; 128] = [
    '\u{20AC}', '\u{FFFF}', '\u{201A}', '\u{0192}', '\u{201E}', '\u{2026}', '\u{2020}', '\u{2021}',
    '\u{02C6}', '\u{2030}', '\u{0160}', '\u{2039}', '\u{0152}', '\u{FFFF}', '\u{FFFF}', '\u{FFFF}',
    '\u{FFFF}', '\u{2018}', '\u{2019}', '\u{201C}', '\u{201D}', '\u{2022}', '\u{2013}', '\u{2014}',
    '\u{02DC}', '\u{2122}', '\u{0161}', '\u{203A}', '\u{0153}', '\u{FFFF}', '\u{FFFF}', '\u{0178}',
    '\u{00A0}', '\u{00A1}', '\u{00A2}', '\u{00A3}', '\u{00A4}', '\u{00A5}', '\u{00A6}', '\u{00A7}',
    '\u{00A8}', '\u{00A9}', '\u{00AA}', '\u{00AB}', '\u{00AC}', '\u{00AD}', '\u{00AE}', '\u{00AF}',
    '\u{00B0}', '\u{00B1}', '\u{00B2}', '\u{00B3}', '\u{00B4}', '\u{00B5}', '\u{00B6}', '\u{00B7}',
    '\u{00B8}', '\u{00B9}', '\u{00BA}', '\u{00BB}', '\u{00BC}', '\u{00BD}', '\u{00BE}', '\u{00BF}',
    '\u{00C0}', '\u{00C1}', '\u{00C2}', '\u{00C3}', '\u{00C4}', '\u{00C5}', '\u{00C6}', '\u{00C7}',
    '\u{00C8}', '\u{00C9}', '\u{00CA}', '\u{00CB}', '\u{00CC}', '\u{00CD}', '\u{00CE}', '\u{00CF}',
    '\u{011E}', '\u{00D1}', '\u{00D2}', '\u{00D3}', '\u{00D4}', '\u{00D5}', '\u{00D6}', '\u{00D7}',
    '\u{00D8}', '\u{00D9}', '\u{00DA}', '\u{00DB}', '\u{00DC}', '\u{0130}', '\u{015E}', '\u{00DF}',
    '\u{00E0}', '\u{00E1}', '\u{00E2}', '\u{00E3}', '\u{00E4}', '\u{00E5}', '\u{00E6}', '\u{00E7}',
    '\u{00E8}', '\u{00E9}', '\u{00EA}', '\u{00EB}', '\u{00EC}', '\u{00ED}', '\u{00EE}', '\u{00EF}',
    '\u{011F}', '\u{00F1}', '\u{00F2}', '\u{00F3}', '\u{00F4}', '\u{00F5}', '\u{00F6}', '\u{00F7}',
    '\u{00F8}', '\u{00F9}', '\u{00FA}', '\u{00FB}', '\u{00FC}', '\u{0131}', '\u{015F}', '\u{00FF}',
];

/// Look up a single-byte encoding's high-half table by PG name (already
/// upper-cased with separators stripped).
pub(super) fn encoding_table(enc: &str) -> Option<&'static [char; 128]> {
    Some(match enc {
        "LATIN1" | "ISO88591" => &LATIN1_HIGH,
        "LATIN2" | "ISO88592" => &LATIN2_HIGH,
        "LATIN9" | "ISO885915" => &LATIN9_HIGH,
        "KOI8R" | "KOI8" => &KOI8R_HIGH,
        "KOI8U" => &KOI8U_HIGH,
        // v7.38 (T30) — Windows code pages, tables extracted from live PG18.4.
        "WIN1250" | "WINDOWS1250" => &WIN1250_HIGH,
        "WIN1251" | "WINDOWS1251" => &WIN1251_HIGH,
        "WIN1253" | "WINDOWS1253" => &WIN1253_HIGH,
        "WIN1254" | "WINDOWS1254" => &WIN1254_HIGH,
        _ => return None,
    })
}

/// Decode single-byte-encoded bytes to UTF-8 via the high table.
pub(super) fn single_byte_to_utf8(
    bytes: &[u8],
    high: &[char; 128],
    enc: &str,
) -> Result<String, EvalError> {
    let mut out = String::with_capacity(bytes.len());
    for &b in bytes {
        if b < 0x80 {
            out.push(b as char);
        } else {
            let ch = high[(b - 0x80) as usize];
            if ch == '\u{FFFF}' {
                return Err(EvalError::TypeMismatch {
                    detail: alloc::format!("byte {b:#04x} is not defined in encoding {enc}"),
                });
            }
            out.push(ch);
        }
    }
    Ok(out)
}

/// Encode a UTF-8 string to single-byte bytes via a reverse table lookup.
pub(super) fn utf8_to_single_byte(
    s: &str,
    high: &[char; 128],
    enc: &str,
) -> Result<Vec<u8>, EvalError> {
    let mut out = Vec::with_capacity(s.len());
    for c in s.chars() {
        if (c as u32) < 0x80 {
            out.push(c as u8);
        } else if let Some(i) = high.iter().position(|&h| h == c) {
            out.push((i + 0x80) as u8);
        } else {
            return Err(EvalError::TypeMismatch {
                detail: alloc::format!("character {c:?} has no representation in encoding {enc}"),
            });
        }
    }
    Ok(out)
}