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)
  13         {
  14                 char buf[2]={jis>>8, jis};
  15                 append(buf, 2);
  16         }
  17         else
  18                 error("Can't express character in JIS X 0208");
  19 }
  20
  21
  22 void JisX0208::Decoder::decode_char(const string &str, string::const_iterator &i)
  23 {
  24         if(i==str.end())
  25                 return;
  26
  27         if(!high)
  28                 high=*i++;
  29
  30         if(i==str.end())
  31                 return;
  32
  33         wchar_t ucs=jisx0208_to_ucs(high<<8 | *i++);
  34         high=0;
  35
  36         if(ucs)
  37                 append(ucs);
  38         else
  39                 error("Invalid JIS X 0208 string (undefined character)");
  40 }
  41
  42 void JisX0208::Decoder::sync()
  43 {
  44         if(high)
  45         {
  46                 error("Sync in middle of JIS X 0208 character");
  47                 high=0;
  48         }
  49 }
  50
  51 wchar_t jisx0208_to_ucs(unsigned short jis)
  52 {
  53         if((jis&0xFF)<0x21 || (jis&0xFF)>0x7E || (jis&0xFF00)<0x2100 || (jis&0xFF00)>0x7E00)
  54                 return 0;
  55
  56         return jisx0208_to_ucs_table[((jis>>8)&0xFF)*94 + (jis&0xFF)-0x21*95];
  57 }
  58
  59 unsigned short ucs_to_jisx0208(wchar_t c)
  60 {
  61         if(c&0xFFFF0000) return 0;
  62
  63         unsigned i=0;
  64         for(unsigned bit=0x1000; bit; bit>>=1)
  65         {
  66                 if(i+bit>=ucs_to_jisx0208_table_size)
  67                         continue;
  68                 if(ucs_to_jisx0208_table[i+bit].ucs<=static_cast<unsigned short>(c))
  69                         i+=bit;
  70         }
  71
  72         if(ucs_to_jisx0208_table[i].ucs==static_cast<unsigned short>(c))
  73                 return ucs_to_jisx0208_table[i].jis;
  74         return 0;
  75 }
  76
  77 } // namespace Msp