source/jisx0208.cpp

   1 #include "jisx0208.h"
   2
   3 #include "jisx0208.table"
   4
   5 using namespace std;
   6
   7 namespace Msp {
   8
   9 void JisX0208::Encoder::encode_char(wchar_t ucs)
  10 {
  11         unsigned short jis=ucs_to_jisx0208(ucs);
  12         if(!jis) throw CodecError("Can't express character in JIS X 0208");
  13
  14         char buf[2]={jis>>8, jis};
  15         append(buf, 2);
  16 }
  17
  18
  19 void JisX0208::Decoder::decode_char(const string &str, string::const_iterator &i)
  20 {
  21         if(i==str.end())
  22                 return;
  23
  24         if(!high)
  25                 high=*i++;
  26
  27         if(i==str.end())
  28                 return;
  29
  30         wchar_t ucs=jisx0208_to_ucs(high<<8 | *i++);
  31         high=0;
  32
  33         if(!ucs)
  34                 throw CodecError("Invalid JIS X 0208 string (undefined character)");
  35
  36         append(ucs);
  37 }
  38
  39 void JisX0208::Decoder::sync()
  40 {
  41         if(high)
  42                 throw CodecError("Sync in middle of JIS X 0208 character");
  43 }
  44
  45
  46 wchar_t jisx0208_to_ucs(unsigned short jis)
  47 {
  48         if((jis&0xFF)<0x21 || (jis&0xFF)>0x7E || (jis&0xFF00)<0x2100 || (jis&0xFF00)>0x7E00)
  49                 return 0;
  50
  51         return jisx0208_to_ucs_table[((jis>>8)&0xFF)*94 + (jis&0xFF)-0x21*95];
  52 }
  53
  54 unsigned short ucs_to_jisx0208(wchar_t c)
  55 {
  56         if(c&0xFFFF0000) return 0;
  57
  58         unsigned i=0;
  59         for(unsigned bit=0x1000; bit; bit>>=1)
  60         {
  61                 if(i+bit>=ucs_to_jisx0208_table_size)
  62                         continue;
  63                 if(ucs_to_jisx0208_table[i+bit].ucs<=(unsigned short)c)
  64                         i+=bit;
  65         }
  66
  67         if(ucs_to_jisx0208_table[i].ucs==(unsigned short)c)
  68                 return ucs_to_jisx0208_table[i].jis;
  69         return 0;
  70 }
  71
  72 } // namespace Msp