icuSources/layout/ThaiShaping.h

   1 /*
   2  *
   3  * (C) Copyright IBM Corp. 1998-2004 - All Rights Reserved
   4  *
   5  */
   6
   7 #ifndef __THAISHAPING_H
   8 #define __THAISHAPING_H
   9
  10 /**
  11  * \file
  12  * \internal
  13  */
  14
  15 #include "LETypes.h"
  16 #include "LEGlyphFilter.h"
  17 #include "OpenTypeTables.h"
  18
  19 U_NAMESPACE_BEGIN
  20
  21 class LEGlyphStorage;
  22
  23 class ThaiShaping /* not : public UObject because all methods are static */ {
  24 public:
  25
  26     enum {
  27         // Character classes
  28         NON =  0,
  29         CON =  1,
  30         COA =  2,
  31         COD =  3,
  32         LVO =  4,
  33         FV1 =  5,
  34         FV2 =  6,
  35         FV3 =  7,
  36         BV1 =  8,
  37         BV2 =  9,
  38         BDI = 10,
  39         TON = 11,
  40         AD1 = 12,
  41         AD2 = 13,
  42         AD3 = 14,
  43         NIK = 15,
  44         AV1 = 16,
  45         AV2 = 17,
  46         AV3 = 18,
  47         classCount = 19,
  48
  49         // State Transition actions
  50         tA  =  0,
  51         tC  =  1,
  52         tD  =  2,
  53         tE  =  3,
  54         tF  =  4,
  55         tG  =  5,
  56         tH  =  6,
  57         tR  =  7,
  58         tS  =  8
  59     };
  60
  61     struct StateTransition
  62     {
  63         le_uint8 nextState;
  64         le_uint8 action;
  65
  66         le_uint8 getNextState() { return nextState; };
  67         le_uint8 getAction() { return action; };
  68     };
  69
  70     static le_int32 compose(const LEUnicode *input, le_int32 offset, le_int32 charCount, le_uint8 glyphSet,
  71         LEUnicode errorChar, LEUnicode *output, LEGlyphStorage &glyphStorage);
  72
  73 private:
  74     // forbid instantiation
  75     ThaiShaping();
  76
  77     static const le_uint8 classTable[];
  78     static const StateTransition thaiStateTable[][classCount];
  79
  80     static StateTransition getTransition(le_uint8 state, le_uint8 currClass);
  81     static le_uint8 doTransition(StateTransition transition, LEUnicode currChar, le_int32 inputIndex, le_uint8 glyphSet,
  82         LEUnicode errorChar, LEUnicode *outputBuffer, LEGlyphStorage &glyphStorage, le_int32 &outputIndex);
  83
  84     static le_uint8 getNextState(LEUnicode ch, le_uint8 state, le_int32 inputIndex, le_uint8 glyphSet, LEUnicode errorChar,
  85         le_uint8 &charClass, LEUnicode *output, LEGlyphStorage &glyphStorage, le_int32 &outputIndex);
  86
  87     static le_bool isLegalHere(LEUnicode ch, le_uint8 prevState);
  88     static le_uint8 getCharClass(LEUnicode ch);
  89
  90     static LEUnicode noDescenderCOD(LEUnicode cod, le_uint8 glyphSet);
  91     static LEUnicode leftAboveVowel(LEUnicode vowel, le_uint8 glyphSet);
  92     static LEUnicode lowerBelowVowel(LEUnicode vowel, le_uint8 glyphSet);
  93     static LEUnicode lowerRightTone(LEUnicode tone, le_uint8 glyphSet);
  94     static LEUnicode lowerLeftTone(LEUnicode tone, le_uint8 glyphSet);
  95     static LEUnicode upperLeftTone(LEUnicode tone, le_uint8 glyphSet);
  96
  97 };
  98
  99 inline ThaiShaping::StateTransition ThaiShaping::getTransition(le_uint8 state, le_uint8 currClass)
 100 {
 101     return thaiStateTable[state][currClass];
 102 }
 103
 104 U_NAMESPACE_END
 105 #endif
 106
 107