Commit a16956dc authored by Simon Montagu's avatar Simon Montagu
Browse files

Don't split a surrogate pair over two output buffers. Bug 600974, r=emk, dbaron, a=blocking

parent 4535492f

intl/uconv/src/nsUTF8ToUnicode.cpp

+35 −4
Original line number Diff line number Diff line
@@ -44,6 +44,15 @@ 


#define UNICODE_BYTE_ORDER_MARK    0xFEFF



static PRUnichar* EmitSurrogatePair(PRUint32 ucs4, PRUnichar* aDest)

{

  NS_ASSERTION(ucs4 > 0xFFFF, "Should be a supplementary character");

  ucs4 -= 0x00010000;

  *aDest++ = 0xD800 | (0x000003FF & (ucs4 >> 10));

  *aDest++ = 0xDC00 | (0x000003FF & ucs4);

  return aDest;

}



//----------------------------------------------------------------------

// Class nsUTF8ToUnicode [implementation]
@@ -277,6 +286,22 @@ NS_IMETHODIMP nsUTF8ToUnicode::Convert(const char * aSrc, 


  nsresult res = NS_OK; // conversion result



  out = aDest;

  if (mState == 0xFF) {

    // Emit supplementary character left over from previous iteration. If the

    // buffer size is insufficient, treat it as an illegal character.

    if (aDestLen < 2) {

      NS_ERROR("Output buffer insufficient to hold supplementary character");

      mState = 0;

      return NS_ERROR_ILLEGAL_INPUT;

    }

    out = EmitSurrogatePair(mUcs4, out);

    mUcs4 = 0;

    mState = 0;

    mBytes = 1;

    mFirst = PR_FALSE;

  }



  // alias these locally for speed

  PRInt32 mUcs4 = this->mUcs4;

  PRUint8 mState = this->mState;
@@ -288,7 +313,7 @@ NS_IMETHODIMP nsUTF8ToUnicode::Convert(const char * aSrc, 
  if (mFirst && aSrcLen && (0 == (0x80 & (*aSrc))))

    mFirst = PR_FALSE;



  for (in = aSrc, out = aDest; ((in < inend) && (out < outend)); ++in) {

  for (in = aSrc; ((in < inend) && (out < outend)); ++in) {

    if (0 == mState) {

      // When mState is zero we expect either a US-ASCII character or a

      // multi-octet sequence.
@@ -375,9 +400,15 @@ NS_IMETHODIMP nsUTF8ToUnicode::Convert(const char * aSrc, 
          }

          if (mUcs4 > 0xFFFF) {

            // mUcs4 is in the range 0x10000 - 0x10FFFF. Output a UTF-16 pair

            mUcs4 -= 0x00010000;

            *out++ = 0xD800 | (0x000003FF & (mUcs4 >> 10));

            *out++ = 0xDC00 | (0x000003FF & mUcs4);

            if (out + 2 > outend) {

              // insufficient space left in the buffer. Keep mUcs4 for the

              // next iteration.

              mState = 0xFF;

              ++in;

              res = NS_OK_UDEC_MOREOUTPUT;

              break;

            }

            out = EmitSurrogatePair(mUcs4, out);

          } else if (UNICODE_BYTE_ORDER_MARK != mUcs4 || !mFirst) {

            // Don't output the BOM only if it is the first character

            *out++ = mUcs4;