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 /**
 * A character set converter from Unicode to GBK.
 * 
 *
 * @created         08/Sept/1999
 * @author  Yueheng Xu, Yueheng.Xu@intel.com
 * Revision History
 * 04/Oct/1999. Yueheng Xu: used table gUnicodeToGBKTable[0x5200] to make 
 *              Unicode to GB mapping fast 
 */

#include "nsUnicodeToGBK.h"
#include "nsICharRepresentable.h"
#include "nsUCvCnDll.h"
#include "gbku.h"
#include "uconvutil.h"

//-------------------------------------------------------------
// Global table initialization function defined in gbku.h
//-------------------------------------------------------------

static PRInt16 g_2BytesShiftTable[] = {
 0, u2BytesCharset,
 ShiftCell(0,0,0,0,0,0,0,0)
};
static PRInt16 g_4BytesGB18030ShiftTable[] = {
 0, u4BytesGB18030Charset,
 ShiftCell(0,0,0,0,0,0,0,0)
};

//-----------------------------------------------------------------------
//  Private class used by nsUnicodeToGB18030 and nsUnicodeToGB18030Font0
//    nsUnicodeToGB18030Uniq2Bytes
//-----------------------------------------------------------------------
static PRUint16 g_uf_gb18030_2bytes[] = {
#include "gb18030uniq2b.uf"
};
class nsUnicodeToGB18030Uniq2Bytes : public nsTableEncoderSupport
{
public: 
  nsUnicodeToGB18030Uniq2Bytes() 
    : nsTableEncoderSupport((uShiftTable*) &g_2BytesShiftTable,
                            (uMappingTable*) &g_uf_gb18030_2bytes) {};
protected: 
  NS_IMETHOD GetMaxLength(const PRUnichar * aSrc, 
                                PRInt32 aSrcLength,
                                PRInt32 * aDestLength)
  {
    *aDestLength = 2 * aSrcLength;
    return NS_OK;
  };
};
//-----------------------------------------------------------------------
//  Private class used by nsUnicodeToGB18030
//    nsUnicodeTo4BytesGB18030
//-----------------------------------------------------------------------
static PRUint16 g_uf_gb18030_4bytes[] = {
#include "gb180304bytes.uf"
};
class nsUnicodeTo4BytesGB18030 : public nsTableEncoderSupport
{
public: 
  nsUnicodeTo4BytesGB18030()
    : nsTableEncoderSupport( (uShiftTable*) &g_4BytesGB18030ShiftTable,
                             (uMappingTable*) &g_uf_gb18030_4bytes) {};
protected: 
  NS_IMETHOD GetMaxLength(const PRUnichar * aSrc, 
                                PRInt32 aSrcLength,
                                PRInt32 * aDestLength)
  {
    *aDestLength = 4 * aSrcLength;
    return NS_OK_UDEC_EXACTLENGTH;
  };
};
//-----------------------------------------------------------------------
//  Private class used by nsUnicodeToGBK
//    nsUnicodeToGBKUniq2Bytes
//-----------------------------------------------------------------------
static PRUint16 g_uf_gbk_2bytes[] = {
#include "gbkuniq2b.uf"
};
class nsUnicodeToGBKUniq2Bytes : public nsTableEncoderSupport
{
public: 
  nsUnicodeToGBKUniq2Bytes()
    : nsTableEncoderSupport( (uShiftTable*) &g_2BytesShiftTable,
                             (uMappingTable*) &g_uf_gbk_2bytes) {};
protected: 
  NS_IMETHOD GetMaxLength(const PRUnichar * aSrc, 
                                PRInt32 aSrcLength,
                                PRInt32 * aDestLength)
  {
    *aDestLength = 2 * aSrcLength;
    return NS_OK_UDEC_EXACTLENGTH;
  };
};
//-----------------------------------------------------------------------
//  nsUnicodeToGB18030
//-----------------------------------------------------------------------
void nsUnicodeToGB18030::CreateExtensionEncoder()
{
  mExtensionEncoder = new nsUnicodeToGB18030Uniq2Bytes();
}
void nsUnicodeToGB18030::Create4BytesEncoder()
{
  m4BytesEncoder = new nsUnicodeTo4BytesGB18030();
}
NS_IMETHODIMP nsUnicodeToGB18030::GetMaxLength(const PRUnichar * aSrc, 
                                              PRInt32 aSrcLength,
                                              PRInt32 * aDestLength)
{
  *aDestLength = 4 * aSrcLength;
  return NS_OK;
}
//-----------------------------------------------------------------------
//  nsUnicodeToGB18030Font0
//-----------------------------------------------------------------------
NS_IMETHODIMP nsUnicodeToGB18030Font0::GetMaxLength(const PRUnichar * aSrc, 
                                              PRInt32 aSrcLength,
                                              PRInt32 * aDestLength)
{
  *aDestLength = 2 * aSrcLength;
  return NS_OK_UDEC_EXACTLENGTH; // font encoding is only 2 bytes
}
void nsUnicodeToGB18030Font0::Create4BytesEncoder()
{
  m4BytesEncoder = nsnull;
}

NS_IMETHODIMP nsUnicodeToGB18030Font0::FillInfo(PRUint32 *aInfo)
{
  nsresult rv = nsUnicodeToGB18030::FillInfo(aInfo); // call the super class
  if(NS_SUCCEEDED(rv))
  {
    // mark the first 128 bits as 0. 4 x 32 bits = 128 bits
    aInfo[0] = aInfo[1] = aInfo[2] = aInfo[3] = 0;
  }
  return rv;
}

//-----------------------------------------------------------------------
//  nsUnicodeToGB18030Font1
//-----------------------------------------------------------------------
nsUnicodeToGB18030Font1::nsUnicodeToGB18030Font1()
    : nsTableEncoderSupport( (uShiftTable*) &g_2BytesShiftTable,
                             (uMappingTable*) &g_uf_gb18030_4bytes)
{

}

NS_IMETHODIMP nsUnicodeToGB18030Font1::GetMaxLength(const PRUnichar * aSrc, 
                                              PRInt32 aSrcLength,
                                              PRInt32 * aDestLength)
{
  *aDestLength = 4 * aSrcLength;
  return NS_OK_UDEC_EXACTLENGTH; // font encoding is exactly 4 bytes
}

NS_IMETHODIMP nsUnicodeToGB18030Font1::FillInfo(PRUint32 *aInfo)
{
  nsresult res = nsTableEncoderSupport::FillInfo(aInfo);
  // remove below U+3400
  PRUint32 i;
  for(i = 0; i<(0x3400 >> 5); i++)
    aInfo[i] = 0;

  // remove above U+4db5
  //   remove U+4db6 to U+4dbf one by one
  for(i = 0x4db6;i <0x4dc0;i++)
    CLEAR_REPRESENTABLE(aInfo, i);

  //   remove above U+4dc0
  for(i = (0x4dc0 >> 5);i < (0x10000>>5) ; i++)
    aInfo[i] = 0;
  return res;
}
//----------------------------------------------------------------------
// Class nsUnicodeToGBK [implementation]

nsUnicodeToGBK::nsUnicodeToGBK()
{
  mExtensionEncoder = nsnull;
  m4BytesEncoder = nsnull;
  mUtil.InitToGBKTable();
}
void nsUnicodeToGBK::CreateExtensionEncoder()
{
  mExtensionEncoder = new nsUnicodeToGBKUniq2Bytes();
}
void nsUnicodeToGBK::Create4BytesEncoder()
{
  m4BytesEncoder = nsnull;
}
PRBool nsUnicodeToGBK::TryExtensionEncoder(
  PRUnichar aChar,
  char* aOut,
  PRInt32 *aOutLen
)
{
  if(! mExtensionEncoder )
    CreateExtensionEncoder();
  if(mExtensionEncoder) 
  {
    PRInt32 len = 1;
    nsresult res = NS_OK;
    res = mExtensionEncoder->Convert(&aChar, &len, aOut, aOutLen);
    if(NS_SUCCEEDED(res) && (*aOutLen > 0))
      return PR_TRUE;
  }
  return PR_FALSE;
}

PRBool nsUnicodeToGBK::Try4BytesEncoder(
  PRUnichar aChar,
  char* aOut,
  PRInt32 *aOutLen
)
{
  if(! m4BytesEncoder )
    Create4BytesEncoder();
  if(m4BytesEncoder) 
  {
    PRInt32 len = 1;
    nsresult res = NS_OK;
    res = m4BytesEncoder->Convert(&aChar, &len, aOut, aOutLen);
    NS_ASSERTION(NS_FAILED(res) || ((1 == len) && (4 == *aOutLen)),
      "unexpect conversion length");
    if(NS_SUCCEEDED(res) && (*aOutLen > 0))
      return PR_TRUE;
  }
  return PR_FALSE;
}

NS_IMETHODIMP nsUnicodeToGBK::ConvertNoBuff(
  const PRUnichar * aSrc, 
  PRInt32 * aSrcLength, 
  char * aDest, 
  PRInt32 * aDestLength)
{
  PRInt32 iSrcLength = 0;
  PRInt32 iDestLength = 0;
  PRUnichar unicode;
  nsresult res = NS_OK;
  while (iSrcLength < *aSrcLength )
  {
    unicode = *aSrc;
    //if unicode's hi byte has something, it is not ASCII, must be a GB
    if(IS_ASCII(unicode))
    {
      // this is an ASCII
      *aDest = CAST_UNICHAR_TO_CHAR(*aSrc);
      aDest++; // increment 1 byte
      iDestLength +=1;
    } else {
      char byte1, byte2;
      if(mUtil.UnicodeToGBKChar( unicode, PR_FALSE, &byte1, &byte2))
      {
        // make sure we still have 2 bytes for output first
        if(iDestLength+2 > *aDestLength)
        {
          res = NS_OK_UENC_MOREOUTPUT;
          break;
        }
        aDest[0] = byte1;
        aDest[1] = byte2;
        aDest += 2;	// increment 2 bytes
        iDestLength +=2;
      } else {
        PRInt32 aOutLen = 2;
        // make sure we still have 2 bytes for output first
        if(iDestLength+2 > *aDestLength)
        {
          res = NS_OK_UENC_MOREOUTPUT;
          break;
        }
        // we cannot map in the common mapping. Let's try to
        // call the delegated 2 byte converter for the gbk or gb18030
        // unique 2 byte mapping
        if(TryExtensionEncoder(unicode, aDest, &aOutLen))
        {
          iDestLength += aOutLen;
          aDest += aOutLen;
        } else {
          // make sure we still have 4 bytes for output first
          if(iDestLength+4 > *aDestLength)
          {
            res = NS_OK_UENC_MOREOUTPUT;
            break;
          }
          // we still cannot map. Let's try to
          // call the delegated GB18030 4 byte converter 
          aOutLen = 4;
          if(Try4BytesEncoder(unicode, aDest, &aOutLen))
          {
            NS_ASSERTION((aOutLen == 4), "we should always generate 4 bytes here");
            iDestLength += aOutLen;
            aDest += aOutLen;
          } else {
            res = NS_ERROR_UENC_NOMAPPING;
            iSrcLength++;   // include length of the unmapped character
            break;
          }
        }
      } 
    }
    iSrcLength++ ; // Each unicode char just count as one in PRUnichar string;  	  
    aSrc++;
    if ( iDestLength >= (*aDestLength) && (iSrcLength < *aSrcLength) )
    {
      res = NS_OK_UENC_MOREOUTPUT;
      break;
    }
  }
  *aDestLength = iDestLength;
  *aSrcLength = iSrcLength;
  return res;
}

//----------------------------------------------------------------------
// Subclassing of nsTableEncoderSupport class [implementation]

NS_IMETHODIMP nsUnicodeToGBK::GetMaxLength(const PRUnichar * aSrc, 
                                              PRInt32 aSrcLength,
                                              PRInt32 * aDestLength)
{
  *aDestLength = 2 * aSrcLength;
  return NS_OK;
}


NS_IMETHODIMP nsUnicodeToGBK::FillInfo(PRUint32 *aInfo)
{
  mUtil.FillInfo(aInfo, 0x81, 0xFE, 0x40, 0xFE);
  if(! mExtensionEncoder )
    CreateExtensionEncoder();
  if(mExtensionEncoder) 
  {
    nsCOMPtr<nsICharRepresentable> aRep = do_QueryInterface(mExtensionEncoder);
    aRep->FillInfo(aInfo);
  }
  
  if(! m4BytesEncoder )
    Create4BytesEncoder();
  if(m4BytesEncoder) 
  {
    nsCOMPtr<nsICharRepresentable> aRep = do_QueryInterface(m4BytesEncoder);
    aRep->FillInfo(aInfo);
  }

  //GBK font lib also have single byte ASCII characters, set them here
  for (PRUint16 SrcUnicode = 0x0000; SrcUnicode <= 0x007F; SrcUnicode++)
    SET_REPRESENTABLE(aInfo, SrcUnicode);
  SET_REPRESENTABLE(aInfo, 0x20ac); // euro
  return NS_OK;
}