/* ------------------------------------------------------------------------ */
/*                                                                          */
/* [StyxI18NLit.C]      Charset Conversion & Literals Implementation (C++)  */
/*                                                                          */
/*                This file belongs to the Styx Scanner & parser generator. */
/*                                                                          */
/* Copyright (c) 2003 by Doelle, Manns                                      */
/* ------------------------------------------------------------------------ */


#include "StyxI18NLit.h"
#include <iconv.h>
#include <errno.h>

using namespace styx;

CStyxCharConv::CStyxCharConv()
{
  s_endian = 0;
  t_endian = 0;
  icd      = 0;
}

CStyxCharConv::CStyxCharConv(string cs_src, string cs_dst)
{
  init(cs_src,cs_dst);
}

CStyxCharConv::~CStyxCharConv()
{
  quit();
}


bool CStyxCharConv::init(string cs_src, string cs_dst)
{ iconv_t cd = iconv_open(cs_dst.c_str(),cs_src.c_str());
  if( cd == (iconv_t)-1 ) // error
  { char buf[1024+1];
    errmsg = strerror_r(errno,buf,1024);
    return false;
  }
  else
  {
    icd      = cd;
    ics_dst  = cs_dst;
    ics_src  = cs_src;
    s_endian = 0;
    t_endian = 0;
    if( cs_src == CS_ID_WCHAR )
    {
      for( size_t i=0, j=0; i < sizeof(wchar_t); ++i, j+=8 )
      {
        s_endian |= ((wchar_t)i+1) << j;
      }
    }
    if( cs_dst == CS_ID_WCHAR )
    {
      for( size_t i=0, j=0; i < sizeof(wchar_t); ++i, j+=8 )
      {
        t_endian |= ((wchar_t)i+1) << j;
      }
    }
  }
  return true;
}

bool CStyxCharConv::quit()
{
  if( icd ) 
  {
    iconv_close((iconv_t)icd);
    icd = 0;
  }
  return true;
}

string& CStyxCharConv::getError()
{
  return errmsg;
}

wchar_t* CStyxCharConv::ucs42intern(wchar_t* ws, size_t size /*bytes*/, wchar_t endian)
{
  // assertion: size % wchar_size = 0 !
  if( endian != 0 )
  { char*  s = (char*)ws;
    char   buf[80+1];
    size_t i, j, k;
    for( i=0; i < size; i+=sizeof(wchar_t) )
    {
      for( j=0, k=sizeof(wchar_t)-1; j < sizeof(wchar_t); ++j, --k )
      {
        buf[j] = s[i+((char*)&endian)[k]-1];
      }
      memcpy(&s[i],buf,sizeof(wchar_t));
    }
  }
  return ws;
}

wchar_t* CStyxCharConv::intern2ucs4(wchar_t* ws, size_t size /*bytes*/, wchar_t endian)
{
  // assertion: size % wchar_size = 0 !
  if( endian != 0 )
  { char*  s = (char*)ws;
    char   buf[80+1];
    size_t i, j, k;
    for( i=0; i < size; i+=sizeof(wchar_t) )
    {
      for( j=0, k=sizeof(wchar_t)-1; j < sizeof(wchar_t); ++j, --k )
      {
        buf[((char*)&endian)[k]-1] = s[i+j];
      }
      memcpy(&s[i],buf,sizeof(wchar_t));
    }
  }
  return ws;
}


int CStyxCharConv::convert(string& src, size_t size, string& dst)
{ int rc = -2; char buf[1024+1];
  errmsg = "";
  if( icd > 0 )
  { size_t isize = size,
           osize = isize*6,
           oleft = osize; 
    char   in[isize],
        *  iptr  = in,
           out[osize],
        *  optr  = out;
    memset(in,0,isize); memset(out,0,osize);
    //memcpy(in,src.data(),isize);
    memcpy(in,src.c_str(),isize);
    if( s_endian != 0 && (isize % sizeof(wchar_t)) != 0 )
    {
      dst    = src;
      errmsg = "illegal size";
      return -1;
    }
    else
    if( s_endian != 0 )
    {
      ucs42intern((wchar_t*)in,isize,s_endian);
    }
    rc = iconv((iconv_t)icd,&iptr,&isize,&optr,&oleft);
    if( rc >= 0 )
    { 
      osize -= oleft; // number of used bytes
      if( t_endian != 0 )
      {
        intern2ucs4((wchar_t*)out,osize,t_endian);
      }
      //dst = string(out,osize);
      dst = out;
//cout << "RC=" << rc << ",ISIZE=" << isize << ",IN=" << in << ",OUT=" << out << ",DST=" << dst.c_str() << "\n";
      return rc==0?size:rc;
    }
    else
    if( rc == -1 && errno == EINVAL )
    {
      errmsg = strerror_r(errno,buf,1024);
    }
    else
    {
      errmsg = strerror_r(errno,buf,1024);
      rc = -2;
    }
  }
  else errmsg = "iconv not initialized";
  dst = src;
  return rc;
}