# coding: ascii-8bit
# Copyright (C) 2008-2012 TOMITA Masahiro
# mailto:tommy@tmtm.org

#
class Mysql
  # @!attribute [r] number
  #   @private
  # @!attribute [r] name
  #   @return [String] charset name
  # @!attribute [r] csname
  #   @return [String] collation name
  class Charset
    # @private
    # @param [Integer] number
    # @param [String] name
    # @param [String] csname
    def initialize(number, name, csname)
      @number, @name, @csname = number, name, csname
    end

    attr_reader :number, :name, :csname

    # [[charset_number, charset_name, collation_name, default], ...]
    # @private
    CHARSETS = [
      [  1, "big5",     "big5_chinese_ci",             true ],
      [  2, "latin2",   "latin2_czech_cs",             false],
      [  3, "dec8",     "dec8_swedish_ci",             true ],
      [  4, "cp850",    "cp850_general_ci",            true ],
      [  5, "latin1",   "latin1_german1_ci",           false],
      [  6, "hp8",      "hp8_english_ci",              true ],
      [  7, "koi8r",    "koi8r_general_ci",            true ],
      [  8, "latin1",   "latin1_swedish_ci",           true ],
      [  9, "latin2",   "latin2_general_ci",           true ],
      [ 10, "swe7",     "swe7_swedish_ci",             true ],
      [ 11, "ascii",    "ascii_general_ci",            true ],
      [ 12, "ujis",     "ujis_japanese_ci",            true ],
      [ 13, "sjis",     "sjis_japanese_ci",            true ],
      [ 14, "cp1251",   "cp1251_bulgarian_ci",         false],
      [ 15, "latin1",   "latin1_danish_ci",            false],
      [ 16, "hebrew",   "hebrew_general_ci",           true ],
      [ 17, "filename", "filename",                    true ],
      [ 18, "tis620",   "tis620_thai_ci",              true ],
      [ 19, "euckr",    "euckr_korean_ci",             true ],
      [ 20, "latin7",   "latin7_estonian_cs",          false],
      [ 21, "latin2",   "latin2_hungarian_ci",         false],
      [ 22, "koi8u",    "koi8u_general_ci",            true ],
      [ 23, "cp1251",   "cp1251_ukrainian_ci",         false],
      [ 24, "gb2312",   "gb2312_chinese_ci",           true ],
      [ 25, "greek",    "greek_general_ci",            true ],
      [ 26, "cp1250",   "cp1250_general_ci",           true ],
      [ 27, "latin2",   "latin2_croatian_ci",          false],
      [ 28, "gbk",      "gbk_chinese_ci",              true ],
      [ 29, "cp1257",   "cp1257_lithuanian_ci",        false],
      [ 30, "latin5",   "latin5_turkish_ci",           true ],
      [ 31, "latin1",   "latin1_german2_ci",           false],
      [ 32, "armscii8", "armscii8_general_ci",         true ],
      [ 33, "utf8",     "utf8_general_ci",             true ],
      [ 33, "utf8mb3",  "utf8mb3_general_ci",          true ],
      [ 34, "cp1250",   "cp1250_czech_cs",             false],
      [ 35, "ucs2",     "ucs2_general_ci",             true ],
      [ 36, "cp866",    "cp866_general_ci",            true ],
      [ 37, "keybcs2",  "keybcs2_general_ci",          true ],
      [ 38, "macce",    "macce_general_ci",            true ],
      [ 39, "macroman", "macroman_general_ci",         true ],
      [ 40, "cp852",    "cp852_general_ci",            true ],
      [ 41, "latin7",   "latin7_general_ci",           true ],
      [ 42, "latin7",   "latin7_general_cs",           false],
      [ 43, "macce",    "macce_bin",                   false],
      [ 44, "cp1250",   "cp1250_croatian_ci",          false],
      [ 45, "utf8mb4",  "utf8mb4_general_ci",          false],
      [ 46, "utf8mb4",  "utf8mb4_bin",                 false],
      [ 47, "latin1",   "latin1_bin",                  false],
      [ 48, "latin1",   "latin1_general_ci",           false],
      [ 49, "latin1",   "latin1_general_cs",           false],
      [ 50, "cp1251",   "cp1251_bin",                  false],
      [ 51, "cp1251",   "cp1251_general_ci",           true ],
      [ 52, "cp1251",   "cp1251_general_cs",           false],
      [ 53, "macroman", "macroman_bin",                false],
      [ 54, "utf16",    "utf16_general_ci",            true ],
      [ 55, "utf16",    "utf16_bin",                   false],
      [ 56, "utf16le",  "utf16le_general_ci",          true ],
      [ 57, "cp1256",   "cp1256_general_ci",           true ],
      [ 58, "cp1257",   "cp1257_bin",                  false],
      [ 59, "cp1257",   "cp1257_general_ci",           true ],
      [ 60, "utf32",    "utf32_general_ci",            true ],
      [ 61, "utf32",    "utf32_bin",                   false],
      [ 62, "utf16le",  "utf16le_bin",                 false],
      [ 63, "binary",   "binary",                      true ],
      [ 64, "armscii8", "armscii8_bin",                false],
      [ 65, "ascii",    "ascii_bin",                   false],
      [ 66, "cp1250",   "cp1250_bin",                  false],
      [ 67, "cp1256",   "cp1256_bin",                  false],
      [ 68, "cp866",    "cp866_bin",                   false],
      [ 69, "dec8",     "dec8_bin",                    false],
      [ 70, "greek",    "greek_bin",                   false],
      [ 71, "hebrew",   "hebrew_bin",                  false],
      [ 72, "hp8",      "hp8_bin",                     false],
      [ 73, "keybcs2",  "keybcs2_bin",                 false],
      [ 74, "koi8r",    "koi8r_bin",                   false],
      [ 75, "koi8u",    "koi8u_bin",                   false],
      [ 76, "utf8",     "utf8_tolower_ci",             false],
      [ 76, "utf8mb3",  "utf8mb3_tolower_ci",          false],
      [ 77, "latin2",   "latin2_bin",                  false],
      [ 78, "latin5",   "latin5_bin",                  false],
      [ 79, "latin7",   "latin7_bin",                  false],
      [ 80, "cp850",    "cp850_bin",                   false],
      [ 81, "cp852",    "cp852_bin",                   false],
      [ 82, "swe7",     "swe7_bin",                    false],
      [ 83, "utf8",     "utf8_bin",                    false],
      [ 83, "utf8mb3",  "utf8mb3_bin",                 false],
      [ 84, "big5",     "big5_bin",                    false],
      [ 85, "euckr",    "euckr_bin",                   false],
      [ 86, "gb2312",   "gb2312_bin",                  false],
      [ 87, "gbk",      "gbk_bin",                     false],
      [ 88, "sjis",     "sjis_bin",                    false],
      [ 89, "tis620",   "tis620_bin",                  false],
      [ 90, "ucs2",     "ucs2_bin",                    false],
      [ 91, "ujis",     "ujis_bin",                    false],
      [ 92, "geostd8",  "geostd8_general_ci",          true ],
      [ 93, "geostd8",  "geostd8_bin",                 false],
      [ 94, "latin1",   "latin1_spanish_ci",           false],
      [ 95, "cp932",    "cp932_japanese_ci",           true ],
      [ 96, "cp932",    "cp932_bin",                   false],
      [ 97, "eucjpms",  "eucjpms_japanese_ci",         true ],
      [ 98, "eucjpms",  "eucjpms_bin",                 false],
      [ 99, "cp1250",   "cp1250_polish_ci",            false],
      [101, "utf16",    "utf16_unicode_ci",            false],
      [102, "utf16",    "utf16_icelandic_ci",          false],
      [103, "utf16",    "utf16_latvian_ci",            false],
      [104, "utf16",    "utf16_romanian_ci",           false],
      [105, "utf16",    "utf16_slovenian_ci",          false],
      [106, "utf16",    "utf16_polish_ci",             false],
      [107, "utf16",    "utf16_estonian_ci",           false],
      [108, "utf16",    "utf16_spanish_ci",            false],
      [109, "utf16",    "utf16_swedish_ci",            false],
      [110, "utf16",    "utf16_turkish_ci",            false],
      [111, "utf16",    "utf16_czech_ci",              false],
      [112, "utf16",    "utf16_danish_ci",             false],
      [113, "utf16",    "utf16_lithuanian_ci",         false],
      [114, "utf16",    "utf16_slovak_ci",             false],
      [115, "utf16",    "utf16_spanish2_ci",           false],
      [116, "utf16",    "utf16_roman_ci",              false],
      [117, "utf16",    "utf16_persian_ci",            false],
      [118, "utf16",    "utf16_esperanto_ci",          false],
      [119, "utf16",    "utf16_hungarian_ci",          false],
      [120, "utf16",    "utf16_sinhala_ci",            false],
      [121, "utf16",    "utf16_german2_ci",            false],
      [122, "utf16",    "utf16_croatian_ci",           false],
      [123, "utf16",    "utf16_unicode_520_ci",        false],
      [124, "utf16",    "utf16_vietnamese_ci",         false],
      [128, "ucs2",     "ucs2_unicode_ci",             false],
      [129, "ucs2",     "ucs2_icelandic_ci",           false],
      [130, "ucs2",     "ucs2_latvian_ci",             false],
      [131, "ucs2",     "ucs2_romanian_ci",            false],
      [132, "ucs2",     "ucs2_slovenian_ci",           false],
      [133, "ucs2",     "ucs2_polish_ci",              false],
      [134, "ucs2",     "ucs2_estonian_ci",            false],
      [135, "ucs2",     "ucs2_spanish_ci",             false],
      [136, "ucs2",     "ucs2_swedish_ci",             false],
      [137, "ucs2",     "ucs2_turkish_ci",             false],
      [138, "ucs2",     "ucs2_czech_ci",               false],
      [139, "ucs2",     "ucs2_danish_ci",              false],
      [140, "ucs2",     "ucs2_lithuanian_ci",          false],
      [141, "ucs2",     "ucs2_slovak_ci",              false],
      [142, "ucs2",     "ucs2_spanish2_ci",            false],
      [143, "ucs2",     "ucs2_roman_ci",               false],
      [144, "ucs2",     "ucs2_persian_ci",             false],
      [145, "ucs2",     "ucs2_esperanto_ci",           false],
      [146, "ucs2",     "ucs2_hungarian_ci",           false],
      [147, "ucs2",     "ucs2_sinhala_ci",             false],
      [148, "ucs2",     "ucs2_german2_ci",             false],
      [149, "ucs2",     "ucs2_croatian_ci",            false],
      [150, "ucs2",     "ucs2_unicode_520_ci",         false],
      [151, "ucs2",     "ucs2_vietnamese_ci",          false],
      [159, "ucs2",     "ucs2_general_mysql500_ci",    false],
      [160, "utf32",    "utf32_unicode_ci",            false],
      [161, "utf32",    "utf32_icelandic_ci",          false],
      [162, "utf32",    "utf32_latvian_ci",            false],
      [163, "utf32",    "utf32_romanian_ci",           false],
      [164, "utf32",    "utf32_slovenian_ci",          false],
      [165, "utf32",    "utf32_polish_ci",             false],
      [166, "utf32",    "utf32_estonian_ci",           false],
      [167, "utf32",    "utf32_spanish_ci",            false],
      [168, "utf32",    "utf32_swedish_ci",            false],
      [169, "utf32",    "utf32_turkish_ci",            false],
      [170, "utf32",    "utf32_czech_ci",              false],
      [171, "utf32",    "utf32_danish_ci",             false],
      [172, "utf32",    "utf32_lithuanian_ci",         false],
      [173, "utf32",    "utf32_slovak_ci",             false],
      [174, "utf32",    "utf32_spanish2_ci",           false],
      [175, "utf32",    "utf32_roman_ci",              false],
      [176, "utf32",    "utf32_persian_ci",            false],
      [177, "utf32",    "utf32_esperanto_ci",          false],
      [178, "utf32",    "utf32_hungarian_ci",          false],
      [179, "utf32",    "utf32_sinhala_ci",            false],
      [180, "utf32",    "utf32_german2_ci",            false],
      [181, "utf32",    "utf32_croatian_ci",           false],
      [182, "utf32",    "utf32_unicode_520_ci",        false],
      [183, "utf32",    "utf32_vietnamese_ci",         false],
      [192, "utf8",     "utf8_unicode_ci",             false],
      [193, "utf8",     "utf8_icelandic_ci",           false],
      [194, "utf8",     "utf8_latvian_ci",             false],
      [195, "utf8",     "utf8_romanian_ci",            false],
      [196, "utf8",     "utf8_slovenian_ci",           false],
      [197, "utf8",     "utf8_polish_ci",              false],
      [198, "utf8",     "utf8_estonian_ci",            false],
      [199, "utf8",     "utf8_spanish_ci",             false],
      [200, "utf8",     "utf8_swedish_ci",             false],
      [201, "utf8",     "utf8_turkish_ci",             false],
      [202, "utf8",     "utf8_czech_ci",               false],
      [203, "utf8",     "utf8_danish_ci",              false],
      [204, "utf8",     "utf8_lithuanian_ci",          false],
      [205, "utf8",     "utf8_slovak_ci",              false],
      [206, "utf8",     "utf8_spanish2_ci",            false],
      [207, "utf8",     "utf8_roman_ci",               false],
      [208, "utf8",     "utf8_persian_ci",             false],
      [209, "utf8",     "utf8_esperanto_ci",           false],
      [210, "utf8",     "utf8_hungarian_ci",           false],
      [211, "utf8",     "utf8_sinhala_ci",             false],
      [212, "utf8",     "utf8_german2_ci",             false],
      [213, "utf8",     "utf8_croatian_ci",            false],
      [214, "utf8",     "utf8_unicode_520_ci",         false],
      [215, "utf8",     "utf8_vietnamese_ci",          false],
      [223, "utf8",     "utf8_general_mysql500_ci",    false],
      [192, "utf8mb3",  "utf8mb3_unicode_ci",          false],
      [193, "utf8mb3",  "utf8mb3_icelandic_ci",        false],
      [194, "utf8mb3",  "utf8mb3_latvian_ci",          false],
      [195, "utf8mb3",  "utf8mb3_romanian_ci",         false],
      [196, "utf8mb3",  "utf8mb3_slovenian_ci",        false],
      [197, "utf8mb3",  "utf8mb3_polish_ci",           false],
      [198, "utf8mb3",  "utf8mb3_estonian_ci",         false],
      [199, "utf8mb3",  "utf8mb3_spanish_ci",          false],
      [200, "utf8mb3",  "utf8mb3_swedish_ci",          false],
      [201, "utf8mb3",  "utf8mb3_turkish_ci",          false],
      [202, "utf8mb3",  "utf8mb3_czech_ci",            false],
      [203, "utf8mb3",  "utf8mb3_danish_ci",           false],
      [204, "utf8mb3",  "utf8mb3_lithuanian_ci",       false],
      [205, "utf8mb3",  "utf8mb3_slovak_ci",           false],
      [206, "utf8mb3",  "utf8mb3_spanish2_ci",         false],
      [207, "utf8mb3",  "utf8mb3_roman_ci",            false],
      [208, "utf8mb3",  "utf8mb3_persian_ci",          false],
      [209, "utf8mb3",  "utf8mb3_esperanto_ci",        false],
      [210, "utf8mb3",  "utf8mb3_hungarian_ci",        false],
      [211, "utf8mb3",  "utf8mb3_sinhala_ci",          false],
      [212, "utf8mb3",  "utf8mb3_german2_ci",          false],
      [213, "utf8mb3",  "utf8mb3_croatian_ci",         false],
      [214, "utf8mb3",  "utf8mb3_unicode_520_ci",      false],
      [215, "utf8mb3",  "utf8mb3_vietnamese_ci",       false],
      [223, "utf8mb3",  "utf8mb3_general_mysql500_ci", false],
      [224, "utf8mb4",  "utf8mb4_unicode_ci",          false],
      [225, "utf8mb4",  "utf8mb4_icelandic_ci",        false],
      [226, "utf8mb4",  "utf8mb4_latvian_ci",          false],
      [227, "utf8mb4",  "utf8mb4_romanian_ci",         false],
      [228, "utf8mb4",  "utf8mb4_slovenian_ci",        false],
      [229, "utf8mb4",  "utf8mb4_polish_ci",           false],
      [230, "utf8mb4",  "utf8mb4_estonian_ci",         false],
      [231, "utf8mb4",  "utf8mb4_spanish_ci",          false],
      [232, "utf8mb4",  "utf8mb4_swedish_ci",          false],
      [233, "utf8mb4",  "utf8mb4_turkish_ci",          false],
      [234, "utf8mb4",  "utf8mb4_czech_ci",            false],
      [235, "utf8mb4",  "utf8mb4_danish_ci",           false],
      [236, "utf8mb4",  "utf8mb4_lithuanian_ci",       false],
      [237, "utf8mb4",  "utf8mb4_slovak_ci",           false],
      [238, "utf8mb4",  "utf8mb4_spanish2_ci",         false],
      [239, "utf8mb4",  "utf8mb4_roman_ci",            false],
      [240, "utf8mb4",  "utf8mb4_persian_ci",          false],
      [241, "utf8mb4",  "utf8mb4_esperanto_ci",        false],
      [242, "utf8mb4",  "utf8mb4_hungarian_ci",        false],
      [243, "utf8mb4",  "utf8mb4_sinhala_ci",          false],
      [244, "utf8mb4",  "utf8mb4_german2_ci",          false],
      [245, "utf8mb4",  "utf8mb4_croatian_ci",         false],
      [246, "utf8mb4",  "utf8mb4_unicode_520_ci",      false],
      [247, "utf8mb4",  "utf8mb4_vietnamese_ci",       false],
      [248, "gb18030",  "gb18030_chinese_ci",          true ],
      [249, "gb18030",  "gb18030_bin",                 false],
      [250, "gb18030",  "gb18030_unicode_520_ci",      false],
      [254, "utf8",     "utf8mb3_general_cs",          false],
      [254, "utf8mb3",  "utf8mb3_general_cs",          false],
      [255, "utf8mb4",  "utf8mb4_0900_ai_ci",          true ],
      [256, "utf8mb4",  "utf8mb4_de_pb_0900_ai_ci",    false],
      [257, "utf8mb4",  "utf8mb4_is_0900_ai_ci",       false],
      [258, "utf8mb4",  "utf8mb4_lv_0900_ai_ci",       false],
      [259, "utf8mb4",  "utf8mb4_ro_0900_ai_ci",       false],
      [260, "utf8mb4",  "utf8mb4_sl_0900_ai_ci",       false],
      [261, "utf8mb4",  "utf8mb4_pl_0900_ai_ci",       false],
      [262, "utf8mb4",  "utf8mb4_et_0900_ai_ci",       false],
      [263, "utf8mb4",  "utf8mb4_es_0900_ai_ci",       false],
      [264, "utf8mb4",  "utf8mb4_sv_0900_ai_ci",       false],
      [265, "utf8mb4",  "utf8mb4_tr_0900_ai_ci",       false],
      [266, "utf8mb4",  "utf8mb4_cs_0900_ai_ci",       false],
      [267, "utf8mb4",  "utf8mb4_da_0900_ai_ci",       false],
      [268, "utf8mb4",  "utf8mb4_lt_0900_ai_ci",       false],
      [269, "utf8mb4",  "utf8mb4_sk_0900_ai_ci",       false],
      [270, "utf8mb4",  "utf8mb4_es_trad_0900_ai_ci",  false],
      [271, "utf8mb4",  "utf8mb4_la_0900_ai_ci",       false],
      [273, "utf8mb4",  "utf8mb4_eo_0900_ai_ci",       false],
      [274, "utf8mb4",  "utf8mb4_hu_0900_ai_ci",       false],
      [275, "utf8mb4",  "utf8mb4_hr_0900_ai_ci",       false],
      [277, "utf8mb4",  "utf8mb4_vi_0900_ai_ci",       false],
      [278, "utf8mb4",  "utf8mb4_0900_as_cs",          false],
      [279, "utf8mb4",  "utf8mb4_de_pb_0900_as_cs",    false],
      [280, "utf8mb4",  "utf8mb4_is_0900_as_cs",       false],
      [281, "utf8mb4",  "utf8mb4_lv_0900_as_cs",       false],
      [282, "utf8mb4",  "utf8mb4_ro_0900_as_cs",       false],
      [283, "utf8mb4",  "utf8mb4_sl_0900_as_cs",       false],
      [284, "utf8mb4",  "utf8mb4_pl_0900_as_cs",       false],
      [285, "utf8mb4",  "utf8mb4_et_0900_as_cs",       false],
      [286, "utf8mb4",  "utf8mb4_es_0900_as_cs",       false],
      [287, "utf8mb4",  "utf8mb4_sv_0900_as_cs",       false],
      [288, "utf8mb4",  "utf8mb4_tr_0900_as_cs",       false],
      [289, "utf8mb4",  "utf8mb4_cs_0900_as_cs",       false],
      [290, "utf8mb4",  "utf8mb4_da_0900_as_cs",       false],
      [291, "utf8mb4",  "utf8mb4_lt_0900_as_cs",       false],
      [292, "utf8mb4",  "utf8mb4_sk_0900_as_cs",       false],
      [293, "utf8mb4",  "utf8mb4_es_trad_0900_as_cs",  false],
      [294, "utf8mb4",  "utf8mb4_la_0900_as_cs",       false],
      [296, "utf8mb4",  "utf8mb4_eo_0900_as_cs",       false],
      [297, "utf8mb4",  "utf8mb4_hu_0900_as_cs",       false],
      [298, "utf8mb4",  "utf8mb4_hr_0900_as_cs",       false],
      [300, "utf8mb4",  "utf8mb4_vi_0900_as_cs",       false],
      [303, "utf8mb4",  "utf8mb4_ja_0900_as_cs",       false],
      [304, "utf8mb4",  "utf8mb4_ja_0900_as_cs_ks",    false],
      [305, "utf8mb4",  "utf8mb4_0900_as_ci",          false],
      [306, "utf8mb4",  "utf8mb4_ru_0900_ai_ci",       false],
      [307, "utf8mb4",  "utf8mb4_ru_0900_as_cs",       false],
      [308, "utf8mb4",  "utf8mb4_zh_0900_as_cs",       false],
      [309, "utf8mb4",  "utf8mb4_0900_bin",            false],
    ]

    # @private
    NUMBER_TO_CHARSET = {}
    # @private
    COLLATION_TO_CHARSET = {}
    # @private
    CHARSET_DEFAULT = {}
    CHARSETS.each do |number, csname, clname, default|
      cs = Charset.new number, csname, clname
      NUMBER_TO_CHARSET[number] = cs
      COLLATION_TO_CHARSET[clname] = cs
      CHARSET_DEFAULT[csname] = cs if default
    end

    # @private
    BINARY_CHARSET_NUMBER = CHARSET_DEFAULT['binary'].number

    # @private
    # @param [Integer] n
    # @return [Mysql::Charset]
    def self.by_number(n)
      raise ClientError, "unknown charset number: #{n}" unless NUMBER_TO_CHARSET.key? n
      NUMBER_TO_CHARSET[n]
    end

    # @private
    # @param [String] str
    # @return [Mysql::Charset]
    def self.by_name(str)
      ret = COLLATION_TO_CHARSET[str] || CHARSET_DEFAULT[str]
      raise ClientError, "unknown charset: #{str}" unless ret
      ret
    end

    # @private
    # MySQL Charset -> Ruby's Encoding
    CHARSET_ENCODING = {
      "armscii8" => nil,
      "ascii"    => Encoding::US_ASCII,
      "big5"     => Encoding::Big5,
      "binary"   => Encoding::ASCII_8BIT,
      "cp1250"   => Encoding::Windows_1250,
      "cp1251"   => Encoding::Windows_1251,
      "cp1256"   => Encoding::Windows_1256,
      "cp1257"   => Encoding::Windows_1257,
      "cp850"    => Encoding::CP850,
      "cp852"    => Encoding::CP852,
      "cp866"    => Encoding::IBM866,
      "cp932"    => Encoding::Windows_31J,
      "dec8"     => nil,
      "eucjpms"  => Encoding::EucJP_ms,
      "euckr"    => Encoding::EUC_KR,
      "gb18030"  => Encoding::GB18030,
      "gb2312"   => Encoding::EUC_CN,
      "gbk"      => Encoding::GBK,
      "geostd8"  => nil,
      "greek"    => Encoding::ISO_8859_7,
      "hebrew"   => Encoding::ISO_8859_8,
      "hp8"      => nil,
      "keybcs2"  => nil,
      "koi8r"    => Encoding::KOI8_R,
      "koi8u"    => Encoding::KOI8_U,
      "latin1"   => Encoding::ISO_8859_1,
      "latin2"   => Encoding::ISO_8859_2,
      "latin5"   => Encoding::ISO_8859_9,
      "latin7"   => Encoding::ISO_8859_13,
      "macce"    => Encoding::MacCentEuro,
      "macroman" => Encoding::MacRoman,
      "sjis"     => Encoding::SHIFT_JIS,
      "swe7"     => nil,
      "tis620"   => Encoding::TIS_620,
      "ucs2"     => Encoding::UTF_16BE,
      "ujis"     => Encoding::EucJP_ms,
      "utf16"    => Encoding::UTF_16BE,
      "utf16le"  => Encoding::UTF_16LE,
      "utf32"    => Encoding::UTF_32BE,
      "utf8"     => Encoding::UTF_8,
      "utf8mb3"  => Encoding::UTF_8,
      "utf8mb4"  => Encoding::UTF_8,
    }

    # @private
    # @param [String] value
    # @return [String]
    def self.to_binary(value)
      value.force_encoding Encoding::ASCII_8BIT
    end

    # @private
    # convert raw to encoding and convert to Encoding.default_internal
    # @param [String] raw
    # @param [Encoding] encoding
    # @return [String] result
    def self.convert_encoding(raw, encoding)
      raw.force_encoding(encoding).encode
    end

    # @private
    # retrun corresponding Ruby encoding
    # @return [Encoding] encoding
    def encoding
      enc = CHARSET_ENCODING[@name.downcase]
      raise Mysql::ClientError, "unsupported charset: #{@name}" unless enc
      enc
    end

    # @private
    # convert encoding to corrensponding to MySQL charset
    # @param [String] value
    # @return [String]
    def convert(value)
      if value.is_a? String and value.encoding != Encoding::ASCII_8BIT
        value = value.encode encoding
      end
      value
    end
  end
end
