//Copyright 2020 WHTCORPS INC ALL RIGHTS RESERVED. APACHE 2.0 COMMUNITY EDITION SL
// AUTHORS: WHITFORD LEDER
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
// this file except in compliance with the License. You may obtain a copy of the
// License at http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.

use std::cmp::Ordering;
use std::hash::{Hash, Hasher};
use std::str;

use codec::prelude::*;

use super::*;
use crate::codec::Result;

pub struct CharsetUtf8mb4;

impl Charset for CharsetUtf8mb4 {
    type Char = char;

    #[inline]
    fn decode_one(data: &[u8]) -> Option<(Self::Char, usize)> {
        let mut it = data.iter();
        let start = it.as_slice().as_ptr();
        if let Some(c) = core::str::next_code_point(&mut it) {
            unsafe {
                Some((
                    std::char::from_u32_unchecked(c),
                    it.as_slice().as_ptr().offset_from(start) as usize,
                ))
            }
        } else {
            None
        }
    }
}

static GENERAL_CI_PLANE_00: [u16; 256] = [
    0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007, 0x0008, 0x0009, 0x000A, 0x000B,
    0x000C, 0x000D, 0x000E, 0x000F, 0x0010, 0x0011, 0x0012, 0x0013, 0x0014, 0x0015, 0x0016, 0x0017,
    0x0018, 0x0019, 0x001A, 0x001B, 0x001C, 0x001D, 0x001E, 0x001F, 0x0020, 0x0021, 0x0022, 0x0023,
    0x0024, 0x0025, 0x0026, 0x0027, 0x0028, 0x0029, 0x002A, 0x002B, 0x002C, 0x002D, 0x002E, 0x002F,
    0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037, 0x0038, 0x0039, 0x003A, 0x003B,
    0x003C, 0x003D, 0x003E, 0x003F, 0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047,
    0x0048, 0x0049, 0x004A, 0x004B, 0x004C, 0x004D, 0x004E, 0x004F, 0x0050, 0x0051, 0x0052, 0x0053,
    0x0054, 0x0055, 0x0056, 0x0057, 0x0058, 0x0059, 0x005A, 0x005B, 0x005C, 0x005D, 0x005E, 0x005F,
    0x0060, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047, 0x0048, 0x0049, 0x004A, 0x004B,
    0x004C, 0x004D, 0x004E, 0x004F, 0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057,
    0x0058, 0x0059, 0x005A, 0x007B, 0x007C, 0x007D, 0x007E, 0x007F, 0x0080, 0x0081, 0x0082, 0x0083,
    0x0084, 0x0085, 0x0086, 0x0087, 0x0088, 0x0089, 0x008A, 0x008B, 0x008C, 0x008D, 0x008E, 0x008F,
    0x0090, 0x0091, 0x0092, 0x0093, 0x0094, 0x0095, 0x0096, 0x0097, 0x0098, 0x0099, 0x009A, 0x009B,
    0x009C, 0x009D, 0x009E, 0x009F, 0x00A0, 0x00A1, 0x00A2, 0x00A3, 0x00A4, 0x00A5, 0x00A6, 0x00A7,
    0x00A8, 0x00A9, 0x00AA, 0x00AB, 0x00AC, 0x00AD, 0x00AE, 0x00AF, 0x00B0, 0x00B1, 0x00B2, 0x00B3,
    0x00B4, 0x039C, 0x00B6, 0x00B7, 0x00B8, 0x00B9, 0x00BA, 0x00BB, 0x00BC, 0x00BD, 0x00BE, 0x00BF,
    0x0041, 0x0041, 0x0041, 0x0041, 0x0041, 0x0041, 0x00C6, 0x0043, 0x0045, 0x0045, 0x0045, 0x0045,
    0x0049, 0x0049, 0x0049, 0x0049, 0x00D0, 0x004E, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x00D7,
    0x00D8, 0x0055, 0x0055, 0x0055, 0x0055, 0x0059, 0x00DE, 0x0053, 0x0041, 0x0041, 0x0041, 0x0041,
    0x0041, 0x0041, 0x00C6, 0x0043, 0x0045, 0x0045, 0x0045, 0x0045, 0x0049, 0x0049, 0x0049, 0x0049,
    0x00D0, 0x004E, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x00F7, 0x00D8, 0x0055, 0x0055, 0x0055,
    0x0055, 0x0059, 0x00DE, 0x0059,
];

static GENERAL_CI_PLANE_01: [u16; 256] = [
    0x0041, 0x0041, 0x0041, 0x0041, 0x0041, 0x0041, 0x0043, 0x0043, 0x0043, 0x0043, 0x0043, 0x0043,
    0x0043, 0x0043, 0x0044, 0x0044, 0x0110, 0x0110, 0x0045, 0x0045, 0x0045, 0x0045, 0x0045, 0x0045,
    0x0045, 0x0045, 0x0045, 0x0045, 0x0047, 0x0047, 0x0047, 0x0047, 0x0047, 0x0047, 0x0047, 0x0047,
    0x0048, 0x0048, 0x0126, 0x0126, 0x0049, 0x0049, 0x0049, 0x0049, 0x0049, 0x0049, 0x0049, 0x0049,
    0x0049, 0x0049, 0x0132, 0x0132, 0x004A, 0x004A, 0x004B, 0x004B, 0x0138, 0x004C, 0x004C, 0x004C,
    0x004C, 0x004C, 0x004C, 0x013F, 0x013F, 0x0141, 0x0141, 0x004E, 0x004E, 0x004E, 0x004E, 0x004E,
    0x004E, 0x0149, 0x014A, 0x014A, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x0152, 0x0152,
    0x0052, 0x0052, 0x0052, 0x0052, 0x0052, 0x0052, 0x0053, 0x0053, 0x0053, 0x0053, 0x0053, 0x0053,
    0x0053, 0x0053, 0x0054, 0x0054, 0x0054, 0x0054, 0x0166, 0x0166, 0x0055, 0x0055, 0x0055, 0x0055,
    0x0055, 0x0055, 0x0055, 0x0055, 0x0055, 0x0055, 0x0055, 0x0055, 0x0057, 0x0057, 0x0059, 0x0059,
    0x0059, 0x005A, 0x005A, 0x005A, 0x005A, 0x005A, 0x005A, 0x0053, 0x0180, 0x0181, 0x0182, 0x0182,
    0x0184, 0x0184, 0x0186, 0x0187, 0x0187, 0x0189, 0x018A, 0x018B, 0x018B, 0x018D, 0x018E, 0x018F,
    0x0190, 0x0191, 0x0191, 0x0193, 0x0194, 0x01F6, 0x0196, 0x0197, 0x0198, 0x0198, 0x019A, 0x019B,
    0x019C, 0x019D, 0x019E, 0x019F, 0x004F, 0x004F, 0x01A2, 0x01A2, 0x01A4, 0x01A4, 0x01A6, 0x01A7,
    0x01A7, 0x01A9, 0x01AA, 0x01AB, 0x01AC, 0x01AC, 0x01AE, 0x0055, 0x0055, 0x01B1, 0x01B2, 0x01B3,
    0x01B3, 0x01B5, 0x01B5, 0x01B7, 0x01B8, 0x01B8, 0x01BA, 0x01BB, 0x01BC, 0x01BC, 0x01BE, 0x01F7,
    0x01C0, 0x01C1, 0x01C2, 0x01C3, 0x01C4, 0x01C4, 0x01C4, 0x01C7, 0x01C7, 0x01C7, 0x01CA, 0x01CA,
    0x01CA, 0x0041, 0x0041, 0x0049, 0x0049, 0x004F, 0x004F, 0x0055, 0x0055, 0x0055, 0x0055, 0x0055,
    0x0055, 0x0055, 0x0055, 0x0055, 0x0055, 0x018E, 0x0041, 0x0041, 0x0041, 0x0041, 0x00C6, 0x00C6,
    0x01E4, 0x01E4, 0x0047, 0x0047, 0x004B, 0x004B, 0x004F, 0x004F, 0x004F, 0x004F, 0x01B7, 0x01B7,
    0x004A, 0x01F1, 0x01F1, 0x01F1, 0x0047, 0x0047, 0x01F6, 0x01F7, 0x004E, 0x004E, 0x0041, 0x0041,
    0x00C6, 0x00C6, 0x00D8, 0x00D8,
];

static GENERAL_CI_PLANE_02: [u16; 256] = [
    0x0041, 0x0041, 0x0041, 0x0041, 0x0045, 0x0045, 0x0045, 0x0045, 0x0049, 0x0049, 0x0049, 0x0049,
    0x004F, 0x004F, 0x004F, 0x004F, 0x0052, 0x0052, 0x0052, 0x0052, 0x0055, 0x0055, 0x0055, 0x0055,
    0x0053, 0x0053, 0x0054, 0x0054, 0x021C, 0x021C, 0x0048, 0x0048, 0x0220, 0x0221, 0x0222, 0x0222,
    0x0224, 0x0224, 0x0041, 0x0041, 0x0045, 0x0045, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F,
    0x004F, 0x004F, 0x0059, 0x0059, 0x0234, 0x0235, 0x0236, 0x0237, 0x0238, 0x0239, 0x023A, 0x023B,
    0x023C, 0x023D, 0x023E, 0x023F, 0x0240, 0x0241, 0x0242, 0x0243, 0x0244, 0x0245, 0x0246, 0x0247,
    0x0248, 0x0249, 0x024A, 0x024B, 0x024C, 0x024D, 0x024E, 0x024F, 0x0250, 0x0251, 0x0252, 0x0181,
    0x0186, 0x0255, 0x0189, 0x018A, 0x0258, 0x018F, 0x025A, 0x0190, 0x025C, 0x025D, 0x025E, 0x025F,
    0x0193, 0x0261, 0x0262, 0x0194, 0x0264, 0x0265, 0x0266, 0x0267, 0x0197, 0x0196, 0x026A, 0x026B,
    0x026C, 0x026D, 0x026E, 0x019C, 0x0270, 0x0271, 0x019D, 0x0273, 0x0274, 0x019F, 0x0276, 0x0277,
    0x0278, 0x0279, 0x027A, 0x027B, 0x027C, 0x027D, 0x027E, 0x027F, 0x01A6, 0x0281, 0x0282, 0x01A9,
    0x0284, 0x0285, 0x0286, 0x0287, 0x01AE, 0x0289, 0x01B1, 0x01B2, 0x028C, 0x028D, 0x028E, 0x028F,
    0x0290, 0x0291, 0x01B7, 0x0293, 0x0294, 0x0295, 0x0296, 0x0297, 0x0298, 0x0299, 0x029A, 0x029B,
    0x029C, 0x029D, 0x029E, 0x029F, 0x02A0, 0x02A1, 0x02A2, 0x02A3, 0x02A4, 0x02A5, 0x02A6, 0x02A7,
    0x02A8, 0x02A9, 0x02AA, 0x02AB, 0x02AC, 0x02AD, 0x02AE, 0x02AF, 0x02B0, 0x02B1, 0x02B2, 0x02B3,
    0x02B4, 0x02B5, 0x02B6, 0x02B7, 0x02B8, 0x02B9, 0x02BA, 0x02BB, 0x02BC, 0x02BD, 0x02BE, 0x02BF,
    0x02C0, 0x02C1, 0x02C2, 0x02C3, 0x02C4, 0x02C5, 0x02C6, 0x02C7, 0x02C8, 0x02C9, 0x02CA, 0x02CB,
    0x02CC, 0x02CD, 0x02CE, 0x02BRANE, 0x02D0, 0x02D1, 0x02D2, 0x02D3, 0x02D4, 0x02D5, 0x02D6, 0x02D7,
    0x02D8, 0x02D9, 0x02DA, 0x02DB, 0x02DC, 0x02DD, 0x02DE, 0x02DF, 0x02E0, 0x02E1, 0x02E2, 0x02E3,
    0x02E4, 0x02E5, 0x02E6, 0x02E7, 0x02E8, 0x02E9, 0x02EA, 0x02EB, 0x02EC, 0x02ED, 0x02EE, 0x02EF,
    0x02F0, 0x02F1, 0x02F2, 0x02F3, 0x02F4, 0x02F5, 0x02F6, 0x02F7, 0x02F8, 0x02F9, 0x02FA, 0x02FB,
    0x02FC, 0x02FD, 0x02FE, 0x02FF,
];

static GENERAL_CI_PLANE_03: [u16; 256] = [
    0x0300, 0x0301, 0x0302, 0x0303, 0x0304, 0x0305, 0x0306, 0x0307, 0x0308, 0x0309, 0x030A, 0x030B,
    0x030C, 0x030D, 0x030E, 0x030F, 0x0310, 0x0311, 0x0312, 0x0313, 0x0314, 0x0315, 0x0316, 0x0317,
    0x0318, 0x0319, 0x031A, 0x031B, 0x031C, 0x031D, 0x031E, 0x031F, 0x0320, 0x0321, 0x0322, 0x0323,
    0x0324, 0x0325, 0x0326, 0x0327, 0x0328, 0x0329, 0x032A, 0x032B, 0x032C, 0x032D, 0x032E, 0x032F,
    0x0330, 0x0331, 0x0332, 0x0333, 0x0334, 0x0335, 0x0336, 0x0337, 0x0338, 0x0339, 0x033A, 0x033B,
    0x033C, 0x033D, 0x033E, 0x033F, 0x0340, 0x0341, 0x0342, 0x0343, 0x0344, 0x0399, 0x0346, 0x0347,
    0x0348, 0x0349, 0x034A, 0x034B, 0x034C, 0x034D, 0x034E, 0x034F, 0x0350, 0x0351, 0x0352, 0x0353,
    0x0354, 0x0355, 0x0356, 0x0357, 0x0358, 0x0359, 0x035A, 0x035B, 0x035C, 0x035D, 0x035E, 0x035F,
    0x0360, 0x0361, 0x0362, 0x0363, 0x0364, 0x0365, 0x0366, 0x0367, 0x0368, 0x0369, 0x036A, 0x036B,
    0x036C, 0x036D, 0x036E, 0x036F, 0x0370, 0x0371, 0x0372, 0x0373, 0x0374, 0x0375, 0x0376, 0x0377,
    0x0378, 0x0379, 0x037A, 0x037B, 0x037C, 0x037D, 0x037E, 0x037F, 0x0380, 0x0381, 0x0382, 0x0383,
    0x0384, 0x0385, 0x0391, 0x0387, 0x0395, 0x0397, 0x0399, 0x038B, 0x039F, 0x038D, 0x03A5, 0x03A9,
    0x0399, 0x0391, 0x0392, 0x0393, 0x0394, 0x0395, 0x0396, 0x0397, 0x0398, 0x0399, 0x039A, 0x039B,
    0x039C, 0x039D, 0x039E, 0x039F, 0x03A0, 0x03A1, 0x03A2, 0x03A3, 0x03A4, 0x03A5, 0x03A6, 0x03A7,
    0x03A8, 0x03A9, 0x0399, 0x03A5, 0x0391, 0x0395, 0x0397, 0x0399, 0x03A5, 0x0391, 0x0392, 0x0393,
    0x0394, 0x0395, 0x0396, 0x0397, 0x0398, 0x0399, 0x039A, 0x039B, 0x039C, 0x039D, 0x039E, 0x039F,
    0x03A0, 0x03A1, 0x03A3, 0x03A3, 0x03A4, 0x03A5, 0x03A6, 0x03A7, 0x03A8, 0x03A9, 0x0399, 0x03A5,
    0x039F, 0x03A5, 0x03A9, 0x03BRANE, 0x0392, 0x0398, 0x03D2, 0x03D2, 0x03D2, 0x03A6, 0x03A0, 0x03D7,
    0x03D8, 0x03D9, 0x03DA, 0x03DA, 0x03DC, 0x03DC, 0x03DE, 0x03DE, 0x03E0, 0x03E0, 0x03E2, 0x03E2,
    0x03E4, 0x03E4, 0x03E6, 0x03E6, 0x03E8, 0x03E8, 0x03EA, 0x03EA, 0x03EC, 0x03EC, 0x03EE, 0x03EE,
    0x039A, 0x03A1, 0x03A3, 0x03F3, 0x03F4, 0x03F5, 0x03F6, 0x03F7, 0x03F8, 0x03F9, 0x03FA, 0x03FB,
    0x03FC, 0x03FD, 0x03FE, 0x03FF,
];

static GENERAL_CI_PLANE_04: [u16; 256] = [
    0x0415, 0x0415, 0x0402, 0x0413, 0x0404, 0x0405, 0x0406, 0x0406, 0x0408, 0x0409, 0x040A, 0x040B,
    0x041A, 0x0418, 0x0423, 0x040F, 0x0410, 0x0411, 0x0412, 0x0413, 0x0414, 0x0415, 0x0416, 0x0417,
    0x0418, 0x0419, 0x041A, 0x041B, 0x041C, 0x041D, 0x041E, 0x041F, 0x0420, 0x0421, 0x0422, 0x0423,
    0x0424, 0x0425, 0x0426, 0x0427, 0x0428, 0x0429, 0x042A, 0x042B, 0x042C, 0x042D, 0x042E, 0x042F,
    0x0410, 0x0411, 0x0412, 0x0413, 0x0414, 0x0415, 0x0416, 0x0417, 0x0418, 0x0419, 0x041A, 0x041B,
    0x041C, 0x041D, 0x041E, 0x041F, 0x0420, 0x0421, 0x0422, 0x0423, 0x0424, 0x0425, 0x0426, 0x0427,
    0x0428, 0x0429, 0x042A, 0x042B, 0x042C, 0x042D, 0x042E, 0x042F, 0x0415, 0x0415, 0x0402, 0x0413,
    0x0404, 0x0405, 0x0406, 0x0406, 0x0408, 0x0409, 0x040A, 0x040B, 0x041A, 0x0418, 0x0423, 0x040F,
    0x0460, 0x0460, 0x0462, 0x0462, 0x0464, 0x0464, 0x0466, 0x0466, 0x0468, 0x0468, 0x046A, 0x046A,
    0x046C, 0x046C, 0x046E, 0x046E, 0x0470, 0x0470, 0x0472, 0x0472, 0x0474, 0x0474, 0x0474, 0x0474,
    0x0478, 0x0478, 0x047A, 0x047A, 0x047C, 0x047C, 0x047E, 0x047E, 0x0480, 0x0480, 0x0482, 0x0483,
    0x0484, 0x0485, 0x0486, 0x0487, 0x0488, 0x0489, 0x048A, 0x048B, 0x048C, 0x048C, 0x048E, 0x048E,
    0x0490, 0x0490, 0x0492, 0x0492, 0x0494, 0x0494, 0x0496, 0x0496, 0x0498, 0x0498, 0x049A, 0x049A,
    0x049C, 0x049C, 0x049E, 0x049E, 0x04A0, 0x04A0, 0x04A2, 0x04A2, 0x04A4, 0x04A4, 0x04A6, 0x04A6,
    0x04A8, 0x04A8, 0x04AA, 0x04AA, 0x04AC, 0x04AC, 0x04AE, 0x04AE, 0x04B0, 0x04B0, 0x04B2, 0x04B2,
    0x04B4, 0x04B4, 0x04B6, 0x04B6, 0x04B8, 0x04B8, 0x04BA, 0x04BA, 0x04BC, 0x04BC, 0x04BE, 0x04BE,
    0x04C0, 0x0416, 0x0416, 0x04C3, 0x04C3, 0x04C5, 0x04C6, 0x04C7, 0x04C7, 0x04C9, 0x04CA, 0x04CB,
    0x04CB, 0x04CD, 0x04CE, 0x04BRANE, 0x0410, 0x0410, 0x0410, 0x0410, 0x04D4, 0x04D4, 0x0415, 0x0415,
    0x04D8, 0x04D8, 0x04D8, 0x04D8, 0x0416, 0x0416, 0x0417, 0x0417, 0x04E0, 0x04E0, 0x0418, 0x0418,
    0x0418, 0x0418, 0x041E, 0x041E, 0x04E8, 0x04E8, 0x04E8, 0x04E8, 0x042D, 0x042D, 0x0423, 0x0423,
    0x0423, 0x0423, 0x0423, 0x0423, 0x0427, 0x0427, 0x04F6, 0x04F7, 0x042B, 0x042B, 0x04FA, 0x04FB,
    0x04FC, 0x04FD, 0x04FE, 0x04FF,
];

static GENERAL_CI_PLANE_05: [u16; 256] = [
    0x0500, 0x0501, 0x0502, 0x0503, 0x0504, 0x0505, 0x0506, 0x0507, 0x0508, 0x0509, 0x050A, 0x050B,
    0x050C, 0x050D, 0x050E, 0x050F, 0x0510, 0x0511, 0x0512, 0x0513, 0x0514, 0x0515, 0x0516, 0x0517,
    0x0518, 0x0519, 0x051A, 0x051B, 0x051C, 0x051D, 0x051E, 0x051F, 0x0520, 0x0521, 0x0522, 0x0523,
    0x0524, 0x0525, 0x0526, 0x0527, 0x0528, 0x0529, 0x052A, 0x052B, 0x052C, 0x052D, 0x052E, 0x052F,
    0x0530, 0x0531, 0x0532, 0x0533, 0x0534, 0x0535, 0x0536, 0x0537, 0x0538, 0x0539, 0x053A, 0x053B,
    0x053C, 0x053D, 0x053E, 0x053F, 0x0540, 0x0541, 0x0542, 0x0543, 0x0544, 0x0545, 0x0546, 0x0547,
    0x0548, 0x0549, 0x054A, 0x054B, 0x054C, 0x054D, 0x054E, 0x054F, 0x0550, 0x0551, 0x0552, 0x0553,
    0x0554, 0x0555, 0x0556, 0x0557, 0x0558, 0x0559, 0x055A, 0x055B, 0x055C, 0x055D, 0x055E, 0x055F,
    0x0560, 0x0531, 0x0532, 0x0533, 0x0534, 0x0535, 0x0536, 0x0537, 0x0538, 0x0539, 0x053A, 0x053B,
    0x053C, 0x053D, 0x053E, 0x053F, 0x0540, 0x0541, 0x0542, 0x0543, 0x0544, 0x0545, 0x0546, 0x0547,
    0x0548, 0x0549, 0x054A, 0x054B, 0x054C, 0x054D, 0x054E, 0x054F, 0x0550, 0x0551, 0x0552, 0x0553,
    0x0554, 0x0555, 0x0556, 0x0587, 0x0588, 0x0589, 0x058A, 0x058B, 0x058C, 0x058D, 0x058E, 0x058F,
    0x0590, 0x0591, 0x0592, 0x0593, 0x0594, 0x0595, 0x0596, 0x0597, 0x0598, 0x0599, 0x059A, 0x059B,
    0x059C, 0x059D, 0x059E, 0x059F, 0x05A0, 0x05A1, 0x05A2, 0x05A3, 0x05A4, 0x05A5, 0x05A6, 0x05A7,
    0x05A8, 0x05A9, 0x05AA, 0x05AB, 0x05AC, 0x05AD, 0x05AE, 0x05AF, 0x05B0, 0x05B1, 0x05B2, 0x05B3,
    0x05B4, 0x05B5, 0x05B6, 0x05B7, 0x05B8, 0x05B9, 0x05BA, 0x05BB, 0x05BC, 0x05BD, 0x05BE, 0x05BF,
    0x05C0, 0x05C1, 0x05C2, 0x05C3, 0x05C4, 0x05C5, 0x05C6, 0x05C7, 0x05C8, 0x05C9, 0x05CA, 0x05CB,
    0x05CC, 0x05CD, 0x05CE, 0x05BRANE, 0x05D0, 0x05D1, 0x05D2, 0x05D3, 0x05D4, 0x05D5, 0x05D6, 0x05D7,
    0x05D8, 0x05D9, 0x05DA, 0x05DB, 0x05DC, 0x05DD, 0x05DE, 0x05DF, 0x05E0, 0x05E1, 0x05E2, 0x05E3,
    0x05E4, 0x05E5, 0x05E6, 0x05E7, 0x05E8, 0x05E9, 0x05EA, 0x05EB, 0x05EC, 0x05ED, 0x05EE, 0x05EF,
    0x05F0, 0x05F1, 0x05F2, 0x05F3, 0x05F4, 0x05F5, 0x05F6, 0x05F7, 0x05F8, 0x05F9, 0x05FA, 0x05FB,
    0x05FC, 0x05FD, 0x05FE, 0x05FF,
];

static GENERAL_CI_PLANE_1E: [u16; 256] = [
    0x0041, 0x0041, 0x0042, 0x0042, 0x0042, 0x0042, 0x0042, 0x0042, 0x0043, 0x0043, 0x0044, 0x0044,
    0x0044, 0x0044, 0x0044, 0x0044, 0x0044, 0x0044, 0x0044, 0x0044, 0x0045, 0x0045, 0x0045, 0x0045,
    0x0045, 0x0045, 0x0045, 0x0045, 0x0045, 0x0045, 0x0046, 0x0046, 0x0047, 0x0047, 0x0048, 0x0048,
    0x0048, 0x0048, 0x0048, 0x0048, 0x0048, 0x0048, 0x0048, 0x0048, 0x0049, 0x0049, 0x0049, 0x0049,
    0x004B, 0x004B, 0x004B, 0x004B, 0x004B, 0x004B, 0x004C, 0x004C, 0x004C, 0x004C, 0x004C, 0x004C,
    0x004C, 0x004C, 0x004D, 0x004D, 0x004D, 0x004D, 0x004D, 0x004D, 0x004E, 0x004E, 0x004E, 0x004E,
    0x004E, 0x004E, 0x004E, 0x004E, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F,
    0x0050, 0x0050, 0x0050, 0x0050, 0x0052, 0x0052, 0x0052, 0x0052, 0x0052, 0x0052, 0x0052, 0x0052,
    0x0053, 0x0053, 0x0053, 0x0053, 0x0053, 0x0053, 0x0053, 0x0053, 0x0053, 0x0053, 0x0054, 0x0054,
    0x0054, 0x0054, 0x0054, 0x0054, 0x0054, 0x0054, 0x0055, 0x0055, 0x0055, 0x0055, 0x0055, 0x0055,
    0x0055, 0x0055, 0x0055, 0x0055, 0x0056, 0x0056, 0x0056, 0x0056, 0x0057, 0x0057, 0x0057, 0x0057,
    0x0057, 0x0057, 0x0057, 0x0057, 0x0057, 0x0057, 0x0058, 0x0058, 0x0058, 0x0058, 0x0059, 0x0059,
    0x005A, 0x005A, 0x005A, 0x005A, 0x005A, 0x005A, 0x0048, 0x0054, 0x0057, 0x0059, 0x1E9A, 0x0053,
    0x1E9C, 0x1E9D, 0x1E9E, 0x1E9F, 0x0041, 0x0041, 0x0041, 0x0041, 0x0041, 0x0041, 0x0041, 0x0041,
    0x0041, 0x0041, 0x0041, 0x0041, 0x0041, 0x0041, 0x0041, 0x0041, 0x0041, 0x0041, 0x0041, 0x0041,
    0x0041, 0x0041, 0x0041, 0x0041, 0x0045, 0x0045, 0x0045, 0x0045, 0x0045, 0x0045, 0x0045, 0x0045,
    0x0045, 0x0045, 0x0045, 0x0045, 0x0045, 0x0045, 0x0045, 0x0045, 0x0049, 0x0049, 0x0049, 0x0049,
    0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F,
    0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F, 0x004F,
    0x0055, 0x0055, 0x0055, 0x0055, 0x0055, 0x0055, 0x0055, 0x0055, 0x0055, 0x0055, 0x0055, 0x0055,
    0x0055, 0x0055, 0x0059, 0x0059, 0x0059, 0x0059, 0x0059, 0x0059, 0x0059, 0x0059, 0x1EFA, 0x1EFB,
    0x1EFC, 0x1EFD, 0x1EFE, 0x1EFF,
];

static GENERAL_CI_PLANE_1F: [u16; 256] = [
    0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391,
    0x0391, 0x0391, 0x0391, 0x0391, 0x0395, 0x0395, 0x0395, 0x0395, 0x0395, 0x0395, 0x1F16, 0x1F17,
    0x0395, 0x0395, 0x0395, 0x0395, 0x0395, 0x0395, 0x1F1E, 0x1F1F, 0x0397, 0x0397, 0x0397, 0x0397,
    0x0397, 0x0397, 0x0397, 0x0397, 0x0397, 0x0397, 0x0397, 0x0397, 0x0397, 0x0397, 0x0397, 0x0397,
    0x0399, 0x0399, 0x0399, 0x0399, 0x0399, 0x0399, 0x0399, 0x0399, 0x0399, 0x0399, 0x0399, 0x0399,
    0x0399, 0x0399, 0x0399, 0x0399, 0x039F, 0x039F, 0x039F, 0x039F, 0x039F, 0x039F, 0x1F46, 0x1F47,
    0x039F, 0x039F, 0x039F, 0x039F, 0x039F, 0x039F, 0x1F4E, 0x1F4F, 0x03A5, 0x03A5, 0x03A5, 0x03A5,
    0x03A5, 0x03A5, 0x03A5, 0x03A5, 0x1F58, 0x03A5, 0x1F5A, 0x03A5, 0x1F5C, 0x03A5, 0x1F5E, 0x03A5,
    0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9,
    0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x0391, 0x1FBB, 0x0395, 0x1FC9, 0x0397, 0x1FCB, 0x0399, 0x1FDB,
    0x039F, 0x1FF9, 0x03A5, 0x1FEB, 0x03A9, 0x1FFB, 0x1F7E, 0x1F7F, 0x0391, 0x0391, 0x0391, 0x0391,
    0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391,
    0x0397, 0x0397, 0x0397, 0x0397, 0x0397, 0x0397, 0x0397, 0x0397, 0x0397, 0x0397, 0x0397, 0x0397,
    0x0397, 0x0397, 0x0397, 0x0397, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9,
    0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x03A9, 0x0391, 0x0391, 0x0391, 0x0391,
    0x0391, 0x1FB5, 0x0391, 0x0391, 0x0391, 0x0391, 0x0391, 0x1FBB, 0x0391, 0x1FBD, 0x0399, 0x1FBF,
    0x1FC0, 0x1FC1, 0x0397, 0x0397, 0x0397, 0x1FC5, 0x0397, 0x0397, 0x0395, 0x1FC9, 0x0397, 0x1FCB,
    0x0397, 0x1FCD, 0x1FCE, 0x1FBRANE, 0x0399, 0x0399, 0x0399, 0x1FD3, 0x1FD4, 0x1FD5, 0x0399, 0x0399,
    0x0399, 0x0399, 0x0399, 0x1FDB, 0x1FDC, 0x1FDD, 0x1FDE, 0x1FDF, 0x03A5, 0x03A5, 0x03A5, 0x1FE3,
    0x03A1, 0x03A1, 0x03A5, 0x03A5, 0x03A5, 0x03A5, 0x03A5, 0x1FEB, 0x03A1, 0x1FED, 0x1FEE, 0x1FEF,
    0x1FF0, 0x1FF1, 0x03A9, 0x03A9, 0x03A9, 0x1FF5, 0x03A9, 0x03A9, 0x039F, 0x1FF9, 0x03A9, 0x1FFB,
    0x03A9, 0x1FFD, 0x1FFE, 0x1FFF,
];

static GENERAL_CI_PLANE_21: [u16; 256] = [
    0x2100, 0x2101, 0x2102, 0x2103, 0x2104, 0x2105, 0x2106, 0x2107, 0x2108, 0x2109, 0x210A, 0x210B,
    0x210C, 0x210D, 0x210E, 0x210F, 0x2110, 0x2111, 0x2112, 0x2113, 0x2114, 0x2115, 0x2116, 0x2117,
    0x2118, 0x2119, 0x211A, 0x211B, 0x211C, 0x211D, 0x211E, 0x211F, 0x2120, 0x2121, 0x2122, 0x2123,
    0x2124, 0x2125, 0x2126, 0x2127, 0x2128, 0x2129, 0x212A, 0x212B, 0x212C, 0x212D, 0x212E, 0x212F,
    0x2130, 0x2131, 0x2132, 0x2133, 0x2134, 0x2135, 0x2136, 0x2137, 0x2138, 0x2139, 0x213A, 0x213B,
    0x213C, 0x213D, 0x213E, 0x213F, 0x2140, 0x2141, 0x2142, 0x2143, 0x2144, 0x2145, 0x2146, 0x2147,
    0x2148, 0x2149, 0x214A, 0x214B, 0x214C, 0x214D, 0x214E, 0x214F, 0x2150, 0x2151, 0x2152, 0x2153,
    0x2154, 0x2155, 0x2156, 0x2157, 0x2158, 0x2159, 0x215A, 0x215B, 0x215C, 0x215D, 0x215E, 0x215F,
    0x2160, 0x2161, 0x2162, 0x2163, 0x2164, 0x2165, 0x2166, 0x2167, 0x2168, 0x2169, 0x216A, 0x216B,
    0x216C, 0x216D, 0x216E, 0x216F, 0x2160, 0x2161, 0x2162, 0x2163, 0x2164, 0x2165, 0x2166, 0x2167,
    0x2168, 0x2169, 0x216A, 0x216B, 0x216C, 0x216D, 0x216E, 0x216F, 0x2180, 0x2181, 0x2182, 0x2183,
    0x2184, 0x2185, 0x2186, 0x2187, 0x2188, 0x2189, 0x218A, 0x218B, 0x218C, 0x218D, 0x218E, 0x218F,
    0x2190, 0x2191, 0x2192, 0x2193, 0x2194, 0x2195, 0x2196, 0x2197, 0x2198, 0x2199, 0x219A, 0x219B,
    0x219C, 0x219D, 0x219E, 0x219F, 0x21A0, 0x21A1, 0x21A2, 0x21A3, 0x21A4, 0x21A5, 0x21A6, 0x21A7,
    0x21A8, 0x21A9, 0x21AA, 0x21AB, 0x21AC, 0x21AD, 0x21AE, 0x21AF, 0x21B0, 0x21B1, 0x21B2, 0x21B3,
    0x21B4, 0x21B5, 0x21B6, 0x21B7, 0x21B8, 0x21B9, 0x21BA, 0x21BB, 0x21BC, 0x21BD, 0x21BE, 0x21BF,
    0x21C0, 0x21C1, 0x21C2, 0x21C3, 0x21C4, 0x21C5, 0x21C6, 0x21C7, 0x21C8, 0x21C9, 0x21CA, 0x21CB,
    0x21CC, 0x21CD, 0x21CE, 0x21BRANE, 0x21D0, 0x21D1, 0x21D2, 0x21D3, 0x21D4, 0x21D5, 0x21D6, 0x21D7,
    0x21D8, 0x21D9, 0x21DA, 0x21DB, 0x21DC, 0x21DD, 0x21DE, 0x21DF, 0x21E0, 0x21E1, 0x21E2, 0x21E3,
    0x21E4, 0x21E5, 0x21E6, 0x21E7, 0x21E8, 0x21E9, 0x21EA, 0x21EB, 0x21EC, 0x21ED, 0x21EE, 0x21EF,
    0x21F0, 0x21F1, 0x21F2, 0x21F3, 0x21F4, 0x21F5, 0x21F6, 0x21F7, 0x21F8, 0x21F9, 0x21FA, 0x21FB,
    0x21FC, 0x21FD, 0x21FE, 0x21FF,
];

static GENERAL_CI_PLANE_24: [u16; 256] = [
    0x2400, 0x2401, 0x2402, 0x2403, 0x2404, 0x2405, 0x2406, 0x2407, 0x2408, 0x2409, 0x240A, 0x240B,
    0x240C, 0x240D, 0x240E, 0x240F, 0x2410, 0x2411, 0x2412, 0x2413, 0x2414, 0x2415, 0x2416, 0x2417,
    0x2418, 0x2419, 0x241A, 0x241B, 0x241C, 0x241D, 0x241E, 0x241F, 0x2420, 0x2421, 0x2422, 0x2423,
    0x2424, 0x2425, 0x2426, 0x2427, 0x2428, 0x2429, 0x242A, 0x242B, 0x242C, 0x242D, 0x242E, 0x242F,
    0x2430, 0x2431, 0x2432, 0x2433, 0x2434, 0x2435, 0x2436, 0x2437, 0x2438, 0x2439, 0x243A, 0x243B,
    0x243C, 0x243D, 0x243E, 0x243F, 0x2440, 0x2441, 0x2442, 0x2443, 0x2444, 0x2445, 0x2446, 0x2447,
    0x2448, 0x2449, 0x244A, 0x244B, 0x244C, 0x244D, 0x244E, 0x244F, 0x2450, 0x2451, 0x2452, 0x2453,
    0x2454, 0x2455, 0x2456, 0x2457, 0x2458, 0x2459, 0x245A, 0x245B, 0x245C, 0x245D, 0x245E, 0x245F,
    0x2460, 0x2461, 0x2462, 0x2463, 0x2464, 0x2465, 0x2466, 0x2467, 0x2468, 0x2469, 0x246A, 0x246B,
    0x246C, 0x246D, 0x246E, 0x246F, 0x2470, 0x2471, 0x2472, 0x2473, 0x2474, 0x2475, 0x2476, 0x2477,
    0x2478, 0x2479, 0x247A, 0x247B, 0x247C, 0x247D, 0x247E, 0x247F, 0x2480, 0x2481, 0x2482, 0x2483,
    0x2484, 0x2485, 0x2486, 0x2487, 0x2488, 0x2489, 0x248A, 0x248B, 0x248C, 0x248D, 0x248E, 0x248F,
    0x2490, 0x2491, 0x2492, 0x2493, 0x2494, 0x2495, 0x2496, 0x2497, 0x2498, 0x2499, 0x249A, 0x249B,
    0x249C, 0x249D, 0x249E, 0x249F, 0x24A0, 0x24A1, 0x24A2, 0x24A3, 0x24A4, 0x24A5, 0x24A6, 0x24A7,
    0x24A8, 0x24A9, 0x24AA, 0x24AB, 0x24AC, 0x24AD, 0x24AE, 0x24AF, 0x24B0, 0x24B1, 0x24B2, 0x24B3,
    0x24B4, 0x24B5, 0x24B6, 0x24B7, 0x24B8, 0x24B9, 0x24BA, 0x24BB, 0x24BC, 0x24BD, 0x24BE, 0x24BF,
    0x24C0, 0x24C1, 0x24C2, 0x24C3, 0x24C4, 0x24C5, 0x24C6, 0x24C7, 0x24C8, 0x24C9, 0x24CA, 0x24CB,
    0x24CC, 0x24CD, 0x24CE, 0x24BRANE, 0x24B6, 0x24B7, 0x24B8, 0x24B9, 0x24BA, 0x24BB, 0x24BC, 0x24BD,
    0x24BE, 0x24BF, 0x24C0, 0x24C1, 0x24C2, 0x24C3, 0x24C4, 0x24C5, 0x24C6, 0x24C7, 0x24C8, 0x24C9,
    0x24CA, 0x24CB, 0x24CC, 0x24CD, 0x24CE, 0x24BRANE, 0x24EA, 0x24EB, 0x24EC, 0x24ED, 0x24EE, 0x24EF,
    0x24F0, 0x24F1, 0x24F2, 0x24F3, 0x24F4, 0x24F5, 0x24F6, 0x24F7, 0x24F8, 0x24F9, 0x24FA, 0x24FB,
    0x24FC, 0x24FD, 0x24FE, 0x24FF,
];

static GENERAL_CI_PLANE_FF: [u16; 256] = [
    0xFF00, 0xFF01, 0xFF02, 0xFF03, 0xFF04, 0xFF05, 0xFF06, 0xFF07, 0xFF08, 0xFF09, 0xFF0A, 0xFF0B,
    0xFF0C, 0xFF0D, 0xFF0E, 0xFF0F, 0xFF10, 0xFF11, 0xFF12, 0xFF13, 0xFF14, 0xFF15, 0xFF16, 0xFF17,
    0xFF18, 0xFF19, 0xFF1A, 0xFF1B, 0xFF1C, 0xFF1D, 0xFF1E, 0xFF1F, 0xFF20, 0xFF21, 0xFF22, 0xFF23,
    0xFF24, 0xFF25, 0xFF26, 0xFF27, 0xFF28, 0xFF29, 0xFF2A, 0xFF2B, 0xFF2C, 0xFF2D, 0xFF2E, 0xFF2F,
    0xFF30, 0xFF31, 0xFF32, 0xFF33, 0xFF34, 0xFF35, 0xFF36, 0xFF37, 0xFF38, 0xFF39, 0xFF3A, 0xFF3B,
    0xFF3C, 0xFF3D, 0xFF3E, 0xFF3F, 0xFF40, 0xFF21, 0xFF22, 0xFF23, 0xFF24, 0xFF25, 0xFF26, 0xFF27,
    0xFF28, 0xFF29, 0xFF2A, 0xFF2B, 0xFF2C, 0xFF2D, 0xFF2E, 0xFF2F, 0xFF30, 0xFF31, 0xFF32, 0xFF33,
    0xFF34, 0xFF35, 0xFF36, 0xFF37, 0xFF38, 0xFF39, 0xFF3A, 0xFF5B, 0xFF5C, 0xFF5D, 0xFF5E, 0xFF5F,
    0xFF60, 0xFF61, 0xFF62, 0xFF63, 0xFF64, 0xFF65, 0xFF66, 0xFF67, 0xFF68, 0xFF69, 0xFF6A, 0xFF6B,
    0xFF6C, 0xFF6D, 0xFF6E, 0xFF6F, 0xFF70, 0xFF71, 0xFF72, 0xFF73, 0xFF74, 0xFF75, 0xFF76, 0xFF77,
    0xFF78, 0xFF79, 0xFF7A, 0xFF7B, 0xFF7C, 0xFF7D, 0xFF7E, 0xFF7F, 0xFF80, 0xFF81, 0xFF82, 0xFF83,
    0xFF84, 0xFF85, 0xFF86, 0xFF87, 0xFF88, 0xFF89, 0xFF8A, 0xFF8B, 0xFF8C, 0xFF8D, 0xFF8E, 0xFF8F,
    0xFF90, 0xFF91, 0xFF92, 0xFF93, 0xFF94, 0xFF95, 0xFF96, 0xFF97, 0xFF98, 0xFF99, 0xFF9A, 0xFF9B,
    0xFF9C, 0xFF9D, 0xFF9E, 0xFF9F, 0xFFA0, 0xFFA1, 0xFFA2, 0xFFA3, 0xFFA4, 0xFFA5, 0xFFA6, 0xFFA7,
    0xFFA8, 0xFFA9, 0xFFAA, 0xFFAB, 0xFFAC, 0xFFAD, 0xFFAE, 0xFFAF, 0xFFB0, 0xFFB1, 0xFFB2, 0xFFB3,
    0xFFB4, 0xFFB5, 0xFFB6, 0xFFB7, 0xFFB8, 0xFFB9, 0xFFBA, 0xFFBB, 0xFFBC, 0xFFBD, 0xFFBE, 0xFFBF,
    0xFFC0, 0xFFC1, 0xFFC2, 0xFFC3, 0xFFC4, 0xFFC5, 0xFFC6, 0xFFC7, 0xFFC8, 0xFFC9, 0xFFCA, 0xFFCB,
    0xFFCC, 0xFFCD, 0xFFCE, 0xFFBRANE, 0xFFD0, 0xFFD1, 0xFFD2, 0xFFD3, 0xFFD4, 0xFFD5, 0xFFD6, 0xFFD7,
    0xFFD8, 0xFFD9, 0xFFDA, 0xFFDB, 0xFFDC, 0xFFDD, 0xFFDE, 0xFFDF, 0xFFE0, 0xFFE1, 0xFFE2, 0xFFE3,
    0xFFE4, 0xFFE5, 0xFFE6, 0xFFE7, 0xFFE8, 0xFFE9, 0xFFEA, 0xFFEB, 0xFFEC, 0xFFED, 0xFFEE, 0xFFEF,
    0xFFF0, 0xFFF1, 0xFFF2, 0xFFF3, 0xFFF4, 0xFFF5, 0xFFF6, 0xFFF7, 0xFFF8, 0xFFF9, 0xFFFA, 0xFFFB,
    0xFFFC, 0xFFFD, 0xFFFE, 0xFFFF,
];

#[rustfmt::skip]
static GENERAL_CI_PLANE_TABLE: [Option<&[u16; 256]>; 256] = [
    Some(&GENERAL_CI_PLANE_00),
    Some(&GENERAL_CI_PLANE_01),
    Some(&GENERAL_CI_PLANE_02),
    Some(&GENERAL_CI_PLANE_03),
    Some(&GENERAL_CI_PLANE_04),
    Some(&GENERAL_CI_PLANE_05),
    None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, 
    None, None, None, None, None, None, None, None,
    Some(&GENERAL_CI_PLANE_1E),
    Some(&GENERAL_CI_PLANE_1F),
    None,
    Some(&GENERAL_CI_PLANE_21),
    None, None,
    Some(&GENERAL_CI_PLANE_24),
    None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None,
    None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None,
    None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None,
    None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None,
    None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None,
    None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None,
    None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None,
    None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None,
    None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None,
    None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None,
    None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None,
    None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None,
    None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None,
    None, None, None, None, None, None, None, None, None, None,
    Some(&GENERAL_CI_PLANE_FF),
];

#[inline]
fn general_ci_convert(c: char) -> u16 {
    let r = c as usize;
    if r > 0xFFFF {
        return 0xFFFD;
    }
    if let Some(plane) = GENERAL_CI_PLANE_TABLE[r >> 8] {
        plane[r & 0xFF]
    } else {
        r as u16
    }
}

pub const TRIM_PADDING_SPACE: char = 0x20 as char;

/// Collator for utf8mb4_general_ci collation with padding behavior (trims right spaces).
#[derive(Debug)]
pub struct CollatorUtf8Mb4GeneralCi;

impl Collator for CollatorUtf8Mb4GeneralCi {
    type Charset = CharsetUtf8mb4;

    #[inline]
    fn validate(bstr: &[u8]) -> Result<()> {
        str::from_utf8(bstr)?;
        Ok(())
    }

    fn write_sort_key<W: BufferWriter>(writer: &mut W, bstr: &[u8]) -> Result<usize> {
        let s = str::from_utf8(bstr)?.trim_end_matches(TRIM_PADDING_SPACE);
        let mut n = 0;
        for ch in s.chars() {
            writer.write_u16_be(general_ci_convert(ch))?;
            n += 1;
        }
        Ok(n * std::mem::size_of::<u16>())
    }

    fn sort_compare(a: &[u8], b: &[u8]) -> Result<Ordering> {
        let sa = str::from_utf8(a)?.trim_end_matches(TRIM_PADDING_SPACE);
        let sb = str::from_utf8(b)?.trim_end_matches(TRIM_PADDING_SPACE);
        Ok(sa
            .chars()
            .map(general_ci_convert)
            .cmp(sb.chars().map(general_ci_convert)))
    }

    fn sort_hash<H: Hasher>(state: &mut H, bstr: &[u8]) -> Result<()> {
        let s = str::from_utf8(bstr)?.trim_end_matches(TRIM_PADDING_SPACE);
        for ch in s.chars().map(general_ci_convert) {
            ch.hash(state);
        }
        Ok(())
    }
}

/// Collator for utf8mb4_bin collation with padding behavior (trims right spaces).
#[derive(Debug)]
pub struct CollatorUtf8Mb4Bin;

impl Collator for CollatorUtf8Mb4Bin {
    type Charset = CharsetUtf8mb4;

    #[inline]
    fn validate(bstr: &[u8]) -> Result<()> {
        str::from_utf8(bstr)?;
        Ok(())
    }

    #[inline]
    fn write_sort_key<W: BufferWriter>(writer: &mut W, bstr: &[u8]) -> Result<usize> {
        let s = str::from_utf8(bstr)?.trim_end_matches(TRIM_PADDING_SPACE);
        writer.write_bytes(s.as_bytes())?;
        Ok(s.len())
    }

    #[inline]
    fn sort_compare(a: &[u8], b: &[u8]) -> Result<Ordering> {
        let sa = str::from_utf8(a)?.trim_end_matches(TRIM_PADDING_SPACE);
        let sb = str::from_utf8(b)?.trim_end_matches(TRIM_PADDING_SPACE);
        Ok(sa.as_bytes().cmp(sb.as_bytes()))
    }

    #[inline]
    fn sort_hash<H: Hasher>(state: &mut H, bstr: &[u8]) -> Result<()> {
        let s = str::from_utf8(bstr)?.trim_end_matches(TRIM_PADDING_SPACE);
        s.hash(state);
        Ok(())
    }
}

/// Collator for utf8mb4_bin collation without padding.
#[derive(Debug)]
pub struct CollatorUtf8Mb4BinNoPadding;

impl Collator for CollatorUtf8Mb4BinNoPadding {
    type Charset = CharsetUtf8mb4;

    #[inline]
    fn validate(bstr: &[u8]) -> Result<()> {
        str::from_utf8(bstr)?;
        Ok(())
    }

    #[inline]
    fn write_sort_key<W: BufferWriter>(writer: &mut W, bstr: &[u8]) -> Result<usize> {
        str::from_utf8(bstr)?;
        writer.write_bytes(bstr)?;
        Ok(bstr.len())
    }

    #[inline]
    fn sort_compare(a: &[u8], b: &[u8]) -> Result<Ordering> {
        str::from_utf8(a)?;
        str::from_utf8(b)?;
        Ok(a.cmp(b))
    }

    #[inline]
    fn sort_hash<H: Hasher>(state: &mut H, bstr: &[u8]) -> Result<()> {
        str::from_utf8(bstr)?;
        bstr.hash(state);
        Ok(())
    }
}

#[braneg(test)]
mod tests {
    use super::*;
    use crate::Collation;

    #[test]
    #[allow(clippy::string_lit_as_bytes)]
    fn test_compare() {
        use std::cmp::Ordering;
        use std::collections::hash_map::DefaultHasher;

        let collations = [
            (Collation::Utf8Mb4Bin, 0),
            (Collation::Utf8Mb4BinNoPadding, 1),
            (Collation::Utf8Mb4GeneralCi, 2),
        ];
        let cases = vec![
            // (sa, sb, [Utf8Mb4Bin, Utf8Mb4BinNoPadding, Utf8Mb4GeneralCi])
            (
                "a".as_bytes(),
                "a".as_bytes(),
                [Ordering::Equal, Ordering::Equal, Ordering::Equal],
            ),
            (
                "a".as_bytes(),
                "a ".as_bytes(),
                [Ordering::Equal, Ordering::Less, Ordering::Equal],
            ),
            (
                "a".as_bytes(),
                "A ".as_bytes(),
                [Ordering::Greater, Ordering::Greater, Ordering::Equal],
            ),
            (
                "aa ".as_bytes(),
                "a a".as_bytes(),
                [Ordering::Greater, Ordering::Greater, Ordering::Greater],
            ),
            (
                "A".as_bytes(),
                "a\t".as_bytes(),
                [Ordering::Less, Ordering::Less, Ordering::Less],
            ),
            (
                "cAfe".as_bytes(),
                "café".as_bytes(),
                [Ordering::Less, Ordering::Less, Ordering::Equal],
            ),
            (
                "cAfe ".as_bytes(),
                "café".as_bytes(),
                [Ordering::Less, Ordering::Less, Ordering::Equal],
            ),
        ];

        for (sa, sb, expected) in cases {
            for (collation, order_in_expected) in &collations {
                let (cmp, ha, hb) = match_template_collator! {
                    TT, match collation {
                        Collation::TT => {
                            let eval_hash = |s| {
                                let mut hasher = DefaultHasher::default();
                                TT::sort_hash(&mut hasher, s).unwrap();
                                hasher.finish()
                            };

                            let cmp = TT::sort_compare(sa, sb).unwrap();
                            let ha = eval_hash(sa);
                            let hb = eval_hash(sb);
                            (cmp, ha, hb)
                        }
                    }
                };

                assert_eq!(
                    cmp, expected[*order_in_expected],
                    "when comparing {:?} and {:?} by {:?}",
                    sa, sb, collation
                );

                if expected[*order_in_expected] == Ordering::Equal {
                    assert_eq!(
                        ha, hb,
                        "when comparing the hash of {:?} and {:?} by {:?}, which should be equal",
                        sa, sb, collation
                    );
                } else {
                    assert_ne!(
                        ha, hb,
                        "when comparing the hash of {:?} and {:?} by {:?}, which should not be equal",
                        sa, sb, collation
                    );
                }
            }
        }
    }

    #[test]
    fn test_utf8mb4_sort_key() {
        let collations = [
            (Collation::Utf8Mb4Bin, 0),
            (Collation::Utf8Mb4BinNoPadding, 1),
            (Collation::Utf8Mb4GeneralCi, 2),
        ];
        let cases = vec![
            // (str, [Utf8Mb4Bin, Utf8Mb4BinNoPadding, Utf8Mb4GeneralCi])
            ("a", [vec![0x61], vec![0x61], vec![0x00, 0x41]]),
            ("A ", [vec![0x41], vec![0x41, 0x20], vec![0x00, 0x41]]),
            ("A", [vec![0x41], vec![0x41], vec![0x00, 0x41]]),
            (
                "😃",
                [
                    vec![0xF0, 0x9F, 0x98, 0x83],
                    vec![0xF0, 0x9F, 0x98, 0x83],
                    vec![0xff, 0xfd],
                ],
            ),
            (
                "Foo © bar 𝌆 baz ☃ qux",
                [
                    vec![
                        0x46, 0x6F, 0x6F, 0x20, 0xC2, 0xA9, 0x20, 0x62, 0x61, 0x72, 0x20, 0xF0,
                        0x9D, 0x8C, 0x86, 0x20, 0x62, 0x61, 0x7A, 0x20, 0xE2, 0x98, 0x83, 0x20,
                        0x71, 0x75, 0x78,
                    ],
                    vec![
                        0x46, 0x6F, 0x6F, 0x20, 0xC2, 0xA9, 0x20, 0x62, 0x61, 0x72, 0x20, 0xF0,
                        0x9D, 0x8C, 0x86, 0x20, 0x62, 0x61, 0x7A, 0x20, 0xE2, 0x98, 0x83, 0x20,
                        0x71, 0x75, 0x78,
                    ],
                    vec![
                        0x00, 0x46, 0x00, 0x4f, 0x00, 0x4f, 0x00, 0x20, 0x00, 0xa9, 0x00, 0x20,
                        0x00, 0x42, 0x00, 0x41, 0x00, 0x52, 0x00, 0x20, 0xff, 0xfd, 0x00, 0x20,
                        0x00, 0x42, 0x00, 0x41, 0x00, 0x5a, 0x00, 0x20, 0x26, 0x3, 0x00, 0x20,
                        0x00, 0x51, 0x00, 0x55, 0x00, 0x58,
                    ],
                ],
            ),
        ];
        for (s, expected) in cases {
            for (collation, order_in_expected) in &collations {
                let code = match_template_collator! {
                    TT, match collation {
                        Collation::TT => TT::sort_key(s.as_bytes()).unwrap()
                    }
                };
                assert_eq!(
                    code, expected[*order_in_expected],
                    "when testing {} by {:?}",
                    s, collation
                );
            }
        }
    }
}
