/Modules/cjkcodecs/README

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  1. To generate or modify mapping headers
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  2. -------------------------------------
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  3. Mapping headers are imported from CJKCodecs as pre-generated form.
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  4. If you need to tweak or add something on it, please look at tools/
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  5. subdirectory of CJKCodecs' distribution.
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    7. 

  7. 

  8. 

  9. Notes on implmentation characteristics of each codecs
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  10. -----------------------------------------------------
    11. 

  11. 

  12. 1) Big5 codec
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  13. 

  14.   The big5 codec maps the following characters as cp950 does rather
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  15.   than conforming Unicode.org's that maps to 0xFFFD.
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    17. 

  17.     BIG5        Unicode     Description
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  18. 

  19.     0xA15A      0x2574      SPACING UNDERSCORE
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  20.     0xA1C3      0xFFE3      SPACING HEAVY OVERSCORE
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  21.     0xA1C5      0x02CD      SPACING HEAVY UNDERSCORE
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  22.     0xA1FE      0xFF0F      LT DIAG UP RIGHT TO LOW LEFT
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  23.     0xA240      0xFF3C      LT DIAG UP LEFT TO LOW RIGHT
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  24.     0xA2CC      0x5341      HANGZHOU NUMERAL TEN
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  25.     0xA2CE      0x5345      HANGZHOU NUMERAL THIRTY
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  26. 

  27.   Because unicode 0x5341, 0x5345, 0xFF0F, 0xFF3C is mapped to another
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  28.   big5 codes already, a roundtrip compatibility is not guaranteed for
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  29.   them.
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  30. 

  31. 

  32. 2) cp932 codec
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  33. 

  34.   To conform to Windows's real mapping, cp932 codec maps the following
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  35.   codepoints in addition of the official cp932 mapping.
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  36. 

  37.     CP932     Unicode     Description
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  38. 

  39.     0x80      0x80        UNDEFINED
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  40.     0xA0      0xF8F0      UNDEFINED
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  41.     0xFD      0xF8F1      UNDEFINED
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  42.     0xFE      0xF8F2      UNDEFINED
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  43.     0xFF      0xF8F3      UNDEFINED
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  44. 

  45. 

  46. 3) euc-jisx0213 codec
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  47. 

  48.   The euc-jisx0213 codec maps JIS X 0213 Plane 1 code 0x2140 into
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  49.   unicode U+FF3C instead of U+005C as on unicode.org's mapping.
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  50.   Because euc-jisx0213 has REVERSE SOLIDUS on 0x5c already and A140
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  51.   is shown as a full width character, mapping to U+FF3C can make
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  52.   more sense.
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  53. 

  54.   The euc-jisx0213 codec is enabled to decode JIS X 0212 codes on
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  55.   codeset 2. Because JIS X 0212 and JIS X 0213 Plane 2 don't have
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  56.   overlapped by each other, it doesn't bother standard conformations
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  57.   (and JIS X 0213 Plane 2 is intended to use so.) On encoding
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  58.   sessions, the codec will try to encode kanji characters in this
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  59.   order:
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  60. 

  61.     JIS X 0213 Plane 1 -> JIS X 0213 Plane 2 -> JIS X 0212
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  62. 

  63. 

  64. 4) euc-jp codec
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  65. 

  66.   The euc-jp codec is a compatibility instance on these points:
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  67.    - U+FF3C FULLWIDTH REVERSE SOLIDUS is mapped to EUC-JP A1C0 (vice versa)
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  68.    - U+00A5 YEN SIGN is mapped to EUC-JP 0x5c. (one way)
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  69.    - U+203E OVERLINE is mapped to EUC-JP 0x7e. (one way)
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  70. 

  71. 

  72. 5) shift-jis codec
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  73. 

  74.   The shift-jis codec is mapping 0x20-0x7e area to U+20-U+7E directly
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  75.   instead of using JIS X 0201 for compatibility. The differences are:
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  76.    - U+005C REVERSE SOLIDUS is mapped to SHIFT-JIS 0x5c.
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  77.    - U+007E TILDE is mapped to SHIFT-JIS 0x7e.
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  78.    - U+FF3C FULL-WIDTH REVERSE SOLIDUS is mapped to SHIFT-JIS 815f.
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