/* ----------------------------------------------------------------------------
 * conv.c
 * convert sjis <=> utf8
 * ----------------------------------------------------------------------------
 * Mastering programed by YAMASHINA Hio
 * ----------------------------------------------------------------------------
 * $Id: conv.c 4697 2007-09-14 06:17:00Z pho $
 * ------------------------------------------------------------------------- */

#ifdef _MSC_VER
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include <windows.h>
#include <winsock.h>
#define snprintf _snprintf
#endif

#include "Japanese.h"
#include <stdio.h>

#define DISP_S2U 0
#define DISP_U2S 0

#if DISP_U2S
#define ECHO_U2S(arg) fprintf arg
#define ON_U2S(cmd) cmd
#else
#define ECHO_U2S(arg)
#define ON_U2S(cmd)
#endif

#ifndef __cplusplus
#if __STDC_VERSION__ >= 202311L
	/* bool is part of the C23 standard */
#else
#undef bool
#undef true
#undef false
typedef enum bool { false, true, } bool;
#endif
#endif

/* ----------------------------------------------------------------------------
 * SV* sv_utf8 = xs_sjis_utf8(SV* sv_sjis)
 * convert string from sjis to utf8.
 * ------------------------------------------------------------------------- */
EXTERN_C
SV*
xs_sjis_utf8(SV* sv_str)
{
  UJ_UINT8* src;
  STRLEN len;
  
  SV_Buf result;
  const UJ_UINT8* src_end;
  
  if( sv_str==&PL_sv_undef )
  {
    return newSVsv(&PL_sv_undef);
  }
  if( SvGMAGICAL(sv_str) )
  {
    mg_get(sv_str);
  }
  if( !SvOK(sv_str) )
  {
    return newSVsv(&PL_sv_undef);
  }
  
  src = (UJ_UINT8*)SvPV(sv_str, len);
#if DISP_S2U
  fprintf(stderr,"Unicode::Japanese::(xs)sjis_utf8\n");
  bin_dump("in ",src,len);
#endif
  SV_Buf_init(&result,len*3/2+4);
  src_end = src+len;

  while( src<src_end )
  {
    const UJ_UINT8* ptr;
    if( src[0]<0x80 )
    { /* ASCII */
      ECHO_U2S((stderr,"ascii: %02x\n",src[0]));
      SV_Buf_append_ch(&result,*src);
      ++src;
      continue;
    }else if( 0xa1<=src[0] && src[0]<=0xdf )
    { /* half-width katakana (ja:Ⱦѥ) */
      ECHO_U2S((stderr,"kana: %02x\n",src[0]));
      ptr = (UJ_UINT8*)&g_s2u_table[(src[0]-0xa1)*3];
      ++src;
    }else if( src+1<src_end && 0x81<=src[0] && src[0]<=0x9f )
    { /* a two-bytes letter (ja:2Хʸ) */
      const UJ_UINT16 sjis = (src[0]<<8)+src[1]; /* ntohs */
      ECHO_U2S((stderr,"sjis.dbcs#1: %04x\n",sjis));
      ptr = (UJ_UINT8*)&g_s2u_table[(sjis - 0x8100 + 0x3f)*3];
      src += 2;
    }else if( src+1<src_end && 0xe0<=src[0] && src[0]<=0xfc )
    { /* a two-bytes letter (ja:2Хʸ) */
      const UJ_UINT16 sjis = (src[0]<<8)+src[1]; /* ntohs */
      ECHO_U2S((stderr,"sjis.dbcs#2: %04x\n",sjis));
      ptr = (UJ_UINT8*)&g_s2u_table[(sjis- 0xe000 + 0x1f3f)*3];
      src += 2;
    }else
    { /* unknown */
      /*fprintf(stderr,"unknown: %02x\n",src[0]); */
      SV_Buf_append_ch(&result,'?');
      ++src;
      continue;
    }

    ECHO_U2S((stderr,"offset: 0x%04x\n",(int)(ptr-g_s2u_table)));
    ECHO_U2S((stderr,"utf8-char : %02x %02x %02x\n",ptr[0],ptr[1],ptr[2]));
    if( ptr[2] )
    {
      /*fprintf(stderr,"utf8-len: [%d]\n",3); */
      SV_Buf_append_mem(&result, ptr, 3);
    }else if( ptr[1] )
    {
      /*fprintf(stderr,"utf8-len: [%d]\n",2); */
      SV_Buf_append_mem(&result, ptr, 2);
    }else if( ptr[0] )
    {
      /*fprintf(stderr,"utf8-len: [%d]\n",1); */
      SV_Buf_append_ch(&result,*ptr);
    }else
    {
      SV_Buf_append_ch(&result,'?');
    }
  }
#if DISP_S2U
  bin_dump("out",SV_Buf_getBegin(&result),SV_Buf_getLength(&result));
#endif
  SV_Buf_setLength(&result);

  return SV_Buf_getSv(&result);
}

/* ----------------------------------------------------------------------------
 * SV* sv_sjis = xs_utf8_sjis(SV* sv_utf8)
 * convert from utf8 to sjis.
 * ------------------------------------------------------------------------- */
EXTERN_C
SV*
xs_utf8_sjis(SV* sv_str)
{
  const UJ_UINT8* src;
  STRLEN len;
  SV_Buf result;
  const UJ_UINT8* src_end;
  static const UJ_UINT8 char_null[2]    = { '\0', '\0' };
  static const UJ_UINT8 char_unknown[2] = { '?',  '\0' };
  
  if( sv_str==&PL_sv_undef )
  {
    return newSVsv(&PL_sv_undef);
  }
  if( SvGMAGICAL(sv_str) )
  {
    mg_get(sv_str);
  }
  if( !SvOK(sv_str) )
  {
    return newSVsv(&PL_sv_undef);
  }
  
  src = (UJ_UINT8*)SvPV(sv_str, len);


  ECHO_U2S((stderr,"Unicode::Japanese::(xs)utf8_sjis (%p:%ld)\n",src,len));
  ON_U2S( bin_dump("in ",src,len) );

  SV_Buf_init(&result,len+4);
  src_end = src+len;

  while( src<src_end )
  {
    UJ_UINT32 ucs;
    const UJ_UINT8* sjis_ptr;
    
    if( *src<=0x7f )
    {
      /* append the block of contiguous ascii chars (ja:ASCIIϤޤȤɲá) */
      int len = 1;
      while( src+len<src_end && src[len]<=0x7f )
      {
        ++len;
      }
      SV_Buf_append_mem(&result,src,len);
      src+=len;
      continue;
    }
    
    /* non-ascii */
    if( 0xe0<=*src && *src<=0xef )
    { /* 3-bytes letters. most letters are 3-bytes. */
      const int       utf8_len = 3;
      const UJ_UINT32 ucs_min  = 0x800;
      const UJ_UINT32 ucs_max  = 0xffff;
      ECHO_U2S((stderr,"utf8-len: [%d]\n",utf8_len));
      /* check the length */
      if( src+utf8_len<=src_end )
      { /* noop */
      }else
      { /* no enough space in the buffer */
        SV_Buf_append_ch(&result,'?');
        ++src;
        continue;
      }
      /* check successive bytes */
      if( 0x80<=src[1] && src[1]<=0xbf && 0x80<=src[2] && src[2]<=0xbf )
      { /* noop */
      }else
      {
        SV_Buf_append_ch(&result,'?');
        ++src;
        continue;
      }
      
      /* compute the code point */
      ucs = ((src[0] & 0x0F)<<12)|((src[1] & 0x3F)<<6)|(src[2] & 0x3F);
      src += utf8_len;
      if( ucs_min<=ucs && ucs<=ucs_max )
      { /* noop */
      }else
      { /* illegal sequence */
        SV_Buf_append_ch(&result,'?');
        continue;
      }
      /* ok. */
    }else if( 0xf0<=*src && *src<=0xf7 )
    {
      const int       utf8_len = 4;
      const UJ_UINT32 ucs_min  = 0x010000;
      const UJ_UINT32 ucs_max  = 0x10ffff;
      ECHO_U2S((stderr,"utf8-len: [%d]\n",utf8_len));
      /* check the length */
      if( src+utf8_len<=src_end )
      { /* noop */
      }else
      { /* no enough space in the buffer */
        SV_Buf_append_ch(&result,'?');
        ++src;
        continue;
      }
      /* check successive bytes */
      if( 0x80<=src[1] && src[1]<=0xbf && 0x80<=src[2] && src[2]<=0xbf
          && 0x80<=src[3] && src[3]<=0xbf )
      { /* noop */
      }else
      {
        SV_Buf_append_ch(&result,'?');
        ++src;
        continue;
      }
      
      /* compute the code point */
      ucs = ((src[0] & 0x07)<<18)|((src[1] & 0x3F)<<12)|
        ((src[2] & 0x3f) << 6)|(src[3] & 0x3F);
      src += utf8_len;
      if( ucs_min<=ucs && ucs<=ucs_max )
      { /* noop */
      }else
      { /* illegal sequence */
        SV_Buf_append_ch(&result,'?');
        continue;
      }
      /* private area (emoji) */ 
      if( 0x0f0000<=ucs && ucs<=0x0fffff )
      { 
        SV_Buf_append_ch(&result,'?');
        continue;
      }
      
      /* > U+10FFFF isn't representable in UTF-8 (RFC 3629). */
      if( ucs>0x10FFFF )
      {
        SV_Buf_append_ch(&result,'?');
        continue;
      }
    }else if( 0xc0<=*src && *src<=0xdf )
    {
      const int       utf8_len = 2;
      const UJ_UINT32 ucs_min  =  0x80;
      const UJ_UINT32 ucs_max  = 0x7ff;
      ECHO_U2S((stderr,"utf8-len: [%d]\n",utf8_len));
      /* check the length */
      if( src+utf8_len<=src_end )
      { /* noop */
      }else
      { /* no enough space in the buffer */
        SV_Buf_append_ch(&result,'?');
        ++src;
        continue;
      }
      /* check follow sequences */
      if( 0x80<=src[1] && src[1]<=0xbf )
      { /* noop */
      }else
      {
        SV_Buf_append_ch(&result,'?');
        ++src;
        continue;
      }
      
      /* compute the code point */
      ucs = ((src[0] & 0x1F)<<6)|(src[1] & 0x3F);
      src += utf8_len;
      if( ucs_min<=ucs && ucs<=ucs_max )
      { /* noop */
      }else
      { /* illegal sequence */
        SV_Buf_append_ch(&result,'?');
        continue;
      }
      
      /* ok. */
    }else if( 0xf8<=*src && *src<=0xfb )
    {
      const int          utf8_len = 5;
      ECHO_U2S((stderr,"utf8-len: [%d]\n",utf8_len));
      /* check the length */
      if( src+utf8_len<=src_end )
      { /* noop */
      }else
      { /* no enough space in the buffer */
        SV_Buf_append_ch(&result,'?');
        ++src;
        continue;
      }
      /* check successive bytes */
      if( 0x80<=src[1] && src[1]<=0xbf && 0x80<=src[2] && src[2]<=0xbf
          && 0x80<=src[3] && src[3]<=0xbf && 0x80<=src[4] && src[4]<=0xbf )
      { /* noop */
      }else
      {
        SV_Buf_append_ch(&result,'?');
        ++src;
        continue;
      }
      
      /* compute the code point */
      /* > U+10FFFF isn't representable in UTF-8 (RFC 3629). */
      src += utf8_len;
      SV_Buf_append_ch(&result,'?');
      continue;
    }else if( 0xfc<=*src && *src<=0xfd )
    {
      const int          utf8_len = 6;
      ECHO_U2S((stderr,"utf8-len: [%d]\n",utf8_len));
      /* check the length */
      if( src+utf8_len<=src_end )
      { /* noop */
      }else
      { /* no enough space in the buffer */
        SV_Buf_append_ch(&result,'?');
        ++src;
        continue;
      }
      /* check successive bytes */
      if( 0x80<=src[1] && src[1]<=0xbf && 0x80<=src[2] && src[2]<=0xbf
          && 0x80<=src[3] && src[3]<=0xbf && 0x80<=src[4] && src[4]<=0xbf
          && 0x80<=src[5] && src[5]<=0xbf )
      { /* noop */
      }else
      {
        SV_Buf_append_ch(&result,'?');
        ++src;
        continue;
      }
      
      /* compute the code point */
      /* > U+10FFFF isn't representable in UTF-8 (RFC 3629). */
      src += utf8_len;
      SV_Buf_append_ch(&result,'?');
      continue;
    }else
    {
      SV_Buf_append_ch(&result,'?');
      ++src;
      continue;
    }
    
    /* ucs => sjis */
    ECHO_U2S((stderr,"ucs [%04x]\n",ucs));
    if( ucs<=0x9FFF ) 
    {
      sjis_ptr = g_u2s_table + ucs*2;
    }else if( 0xF900<=ucs && ucs<=0xFFFF )
    {
      sjis_ptr = g_u2s_table + (ucs - 0xF900 + 0xA000)*2;
    }else if( 0x0FE000<=ucs && ucs<=0x0FFFFF )
    { /* emoji. */
      sjis_ptr = char_unknown; /* "?\0" */
    }else
    {
      sjis_ptr = char_null; /* "\0\0" */
    }
    if( sjis_ptr[0]!=0 || sjis_ptr[1]!=0 )
    { /* this letter can actually be mapped. */
      if( sjis_ptr[1]!=0 )
      {
        SV_Buf_append_mem(&result, sjis_ptr, 2);
      }else
      {
        SV_Buf_append_ch(&result, *sjis_ptr);
      }
    }else if( ucs<=0x7F )
    {
      SV_Buf_append_ch(&result,(UJ_UINT8)ucs);
    }else
    {
      SV_Buf_append_entityref(&result,ucs);
    }
  } /* while */

  ON_U2S( bin_dump("out",SV_Buf_getBegin(&result),SV_Buf_getLength(&result)) );
  SV_Buf_setLength(&result);

  return SV_Buf_getSv(&result);
}

/* ----------------------------------------------------------------------------
 * End Of File.
 * ------------------------------------------------------------------------- */