The Tor Browser: intl/uconv/ucvcn/nsGBKToUnicode.cpp@97036ab72558 (annotated)

intl/uconv/ucvcn/nsGBKToUnicode.cpp@97036ab72558 (annotated)

intl/uconv/ucvcn/nsGBKToUnicode.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /**
  * A character set converter from GBK to Unicode.
  *
  *
  * @created         07/Sept/1999
  * @author  Yueheng Xu, Yueheng.Xu@intel.com
  */
 #include "nsGBKToUnicode.h"
 #include "gbku.h"
 //------------------------------------------------------------
 // nsGBKUnique2BytesToUnicode
 //------------------------------------------------------------
 class nsGBKUnique2BytesToUnicode : public nsTableDecoderSupport
 {
 public:
   nsGBKUnique2BytesToUnicode();
   virtual ~nsGBKUnique2BytesToUnicode()
     { }
 protected:
 };
 static const uint16_t g_utGBKUnique2Bytes[] = {
 #include "gbkuniq2b.ut"
 };
 nsGBKUnique2BytesToUnicode::nsGBKUnique2BytesToUnicode()
   : nsTableDecoderSupport(u2BytesCharset, nullptr,
         (uMappingTable*) &g_utGBKUnique2Bytes, 1)
 {
 }
 //------------------------------------------------------------
 // nsGB18030Unique2BytesToUnicode
 //------------------------------------------------------------
 class nsGB18030Unique2BytesToUnicode : public nsTableDecoderSupport
 {
 public:
   nsGB18030Unique2BytesToUnicode();
   virtual ~nsGB18030Unique2BytesToUnicode()
     { }
 protected:
 };
 static const uint16_t g_utGB18030Unique2Bytes[] = {
 #include "gb18030uniq2b.ut"
 };
 nsGB18030Unique2BytesToUnicode::nsGB18030Unique2BytesToUnicode()
   : nsTableDecoderSupport(u2BytesCharset, nullptr,
         (uMappingTable*) &g_utGB18030Unique2Bytes, 1)
 {
 }
 //------------------------------------------------------------
 // nsGB18030Unique4BytesToUnicode
 //------------------------------------------------------------
 class nsGB18030Unique4BytesToUnicode : public nsTableDecoderSupport
 {
 public:
   nsGB18030Unique4BytesToUnicode();
   virtual ~nsGB18030Unique4BytesToUnicode()
     { }
 protected:
 };
 static const uint16_t g_utGB18030Unique4Bytes[] = {
 #include "gb180304bytes.ut"
 };
 nsGB18030Unique4BytesToUnicode::nsGB18030Unique4BytesToUnicode()
   : nsTableDecoderSupport(u4BytesGB18030Charset, nullptr,
         (uMappingTable*) &g_utGB18030Unique4Bytes, 1)
 {
 }
 //----------------------------------------------------------------------
 // Class nsGBKToUnicode [implementation]
 //----------------------------------------------------------------------
 // Subclassing of nsTablesDecoderSupport class [implementation]
 #define LEGAL_GBK_MULTIBYTE_FIRST_BYTE(c)  \
       (UINT8_IN_RANGE(0x81, (c), 0xFE))
 #define FIRST_BYTE_IS_SURROGATE(c)  \
       (UINT8_IN_RANGE(0x90, (c), 0xFE))
 #define LEGAL_GBK_2BYTE_SECOND_BYTE(c) \
       (UINT8_IN_RANGE(0x40, (c), 0x7E)|| UINT8_IN_RANGE(0x80, (c), 0xFE))
 #define LEGAL_GBK_4BYTE_SECOND_BYTE(c) \
       (UINT8_IN_RANGE(0x30, (c), 0x39))
 #define LEGAL_GBK_4BYTE_THIRD_BYTE(c)  \
       (UINT8_IN_RANGE(0x81, (c), 0xFE))
 #define LEGAL_GBK_4BYTE_FORTH_BYTE(c) \
       (UINT8_IN_RANGE(0x30, (c), 0x39))
 NS_IMETHODIMP nsGBKToUnicode::ConvertNoBuff(const char* aSrc,
                                             int32_t * aSrcLength,
                                             char16_t *aDest,
                                             int32_t * aDestLength)
 {
   int32_t i=0;
   int32_t iSrcLength = (*aSrcLength);
   int32_t iDestlen = 0;
   nsresult rv=NS_OK;
   *aSrcLength = 0;
   for (i=0;i<iSrcLength;i++)
   {
     if ( iDestlen >= (*aDestLength) )
     {
       rv = NS_OK_UDEC_MOREOUTPUT;
       break;
     }
     // The valid range for the 1st byte is [0x81,0xFE]
     if(LEGAL_GBK_MULTIBYTE_FIRST_BYTE(*aSrc))
     {
       if(i+1 >= iSrcLength)
       {
         rv = NS_OK_UDEC_MOREINPUT;
         break;
       }
       // To make sure, the second byte has to be checked as well.
       // In GBK, the second byte range is [0x40,0x7E] and [0x80,0XFE]
       if(LEGAL_GBK_2BYTE_SECOND_BYTE(aSrc[1]))
       {
         // Valid GBK code
         *aDest = mUtil.GBKCharToUnicode(aSrc[0], aSrc[1]);
         if(UCS2_NO_MAPPING == *aDest)
         {
           // We cannot map in the common mapping, let's call the
           // delegate 2 byte decoder to decode the gbk or gb18030 unique
           // 2 byte mapping
           if(! TryExtensionDecoder(aSrc, aDest))
           {
             *aDest = UCS2_NO_MAPPING;
           }
         }
         aSrc += 2;
         i++;
       }
       else if (LEGAL_GBK_4BYTE_SECOND_BYTE(aSrc[1]))
       {
         // from the first 2 bytes, it looks like a 4 byte GB18030
         if(i+3 >= iSrcLength)  // make sure we got 4 bytes
         {
           rv = NS_OK_UDEC_MOREINPUT;
           break;
         }
         // 4 bytes patten
         // [0x81-0xfe][0x30-0x39][0x81-0xfe][0x30-0x39]
         // preset the
         if (LEGAL_GBK_4BYTE_THIRD_BYTE(aSrc[2]) &&
             LEGAL_GBK_4BYTE_FORTH_BYTE(aSrc[3]))
         {
            if ( ! FIRST_BYTE_IS_SURROGATE(aSrc[0]))
            {
              // let's call the delegated 4 byte gb18030 converter to convert it
              if(! Try4BytesDecoder(aSrc, aDest))
                *aDest = UCS2_NO_MAPPING;
            } else {
               // let's try supplement mapping
              if ( (iDestlen+1) < (*aDestLength) )
              {
                if(DecodeToSurrogate(aSrc, aDest))
                {
                  // surrogte two char16_t
                  iDestlen++;
                  aDest++;
                }  else {
                  *aDest = UCS2_NO_MAPPING;
               }
              } else {
                if (*aDestLength < 2) {
                  NS_ERROR("insufficient space in output buffer");
                  *aDest = UCS2_NO_MAPPING;
                } else {
                  rv = NS_OK_UDEC_MOREOUTPUT;
                  break;
                }
              }
            }
            aSrc += 4;
            i += 3;
         } else {
           *aDest = UCS2_NO_MAPPING;
           // If the third and fourth bytes are not in the legal ranges for
           // a four-byte sequnce, resynchronize on the second byte
           // (which we know is in the range of LEGAL_GBK_4BYTE_SECOND_BYTE,
           //  0x30-0x39)
           aSrc++;
         }
       }
       else if ((uint8_t) aSrc[0] == (uint8_t)0xA0 )
       {
         // stand-alone (not followed by a valid second byte) 0xA0 !
         // treat it as valid a la Netscape 4.x
         *aDest = CAST_CHAR_TO_UNICHAR(*aSrc);
         aSrc++;
       } else {
         // Invalid GBK code point (second byte should be 0x40 or higher)
         *aDest = UCS2_NO_MAPPING;
         aSrc++;
       }
     } else {
       if(IS_ASCII(*aSrc))
       {
         // The source is an ASCII
         *aDest = CAST_CHAR_TO_UNICHAR(*aSrc);
         aSrc++;
       } else {
         if(IS_GBK_EURO(*aSrc)) {
           *aDest = UCS2_EURO;
         } else {
           *aDest = UCS2_NO_MAPPING;
         }
         aSrc++;
       }
     }
     iDestlen++;
     aDest++;
     *aSrcLength = i+1;
   }
   *aDestLength = iDestlen;
   return rv;
 }
 void nsGBKToUnicode::CreateExtensionDecoder()
 {
   mExtensionDecoder = new nsGBKUnique2BytesToUnicode();
 }
 void nsGBKToUnicode::Create4BytesDecoder()
 {
   m4BytesDecoder =  nullptr;
 }
 void nsGB18030ToUnicode::CreateExtensionDecoder()
 {
   mExtensionDecoder = new nsGB18030Unique2BytesToUnicode();
 }
 void nsGB18030ToUnicode::Create4BytesDecoder()
 {
   m4BytesDecoder = new nsGB18030Unique4BytesToUnicode();
 }
 bool nsGB18030ToUnicode::DecodeToSurrogate(const char* aSrc, char16_t* aOut)
 {
   NS_ASSERTION(FIRST_BYTE_IS_SURROGATE(aSrc[0]),       "illegal first byte");
   NS_ASSERTION(LEGAL_GBK_4BYTE_SECOND_BYTE(aSrc[1]),   "illegal second byte");
   NS_ASSERTION(LEGAL_GBK_4BYTE_THIRD_BYTE(aSrc[2]),    "illegal third byte");
   NS_ASSERTION(LEGAL_GBK_4BYTE_FORTH_BYTE(aSrc[3]),    "illegal forth byte");
   if(! FIRST_BYTE_IS_SURROGATE(aSrc[0]))
     return false;
   if(! LEGAL_GBK_4BYTE_SECOND_BYTE(aSrc[1]))
     return false;
   if(! LEGAL_GBK_4BYTE_THIRD_BYTE(aSrc[2]))
     return false;
   if(! LEGAL_GBK_4BYTE_FORTH_BYTE(aSrc[3]))
     return false;
   uint8_t a1 = (uint8_t) aSrc[0];
   uint8_t a2 = (uint8_t) aSrc[1];
   uint8_t a3 = (uint8_t) aSrc[2];
   uint8_t a4 = (uint8_t) aSrc[3];
   a1 -= (uint8_t)0x90;
   a2 -= (uint8_t)0x30;
   a3 -= (uint8_t)0x81;
   a4 -= (uint8_t)0x30;
   uint32_t idx = (((a1 * 10 + a2 ) * 126 + a3) * 10) + a4;
   // idx == ucs4Codepoint - 0x10000
   if (idx > 0x000FFFFF)
     return false;
   *aOut++ = 0xD800 | (idx >> 10);
   *aOut = 0xDC00 | (0x000003FF & idx);
   return true;
 }
 bool nsGBKToUnicode::TryExtensionDecoder(const char* aSrc, char16_t* aOut)
 {
   if(!mExtensionDecoder)
     CreateExtensionDecoder();
   NS_ASSERTION(mExtensionDecoder, "cannot creqte 2 bytes unique converter");
   if(mExtensionDecoder)
   {
     nsresult res = mExtensionDecoder->Reset();
     NS_ASSERTION(NS_SUCCEEDED(res), "2 bytes unique conversoin reset failed");
     int32_t len = 2;
     int32_t dstlen = 1;
     res = mExtensionDecoder->Convert(aSrc,&len, aOut, &dstlen);
     NS_ASSERTION(NS_FAILED(res) || ((len==2) && (dstlen == 1)),
        "some strange conversion result");
      // if we failed, we then just use the 0xfffd
      // therefore, we ignore the res here.
     if(NS_SUCCEEDED(res))
       return true;
   }
   return  false;
 }
 bool nsGBKToUnicode::DecodeToSurrogate(const char* aSrc, char16_t* aOut)
 {
   return false;
 }
 bool nsGBKToUnicode::Try4BytesDecoder(const char* aSrc, char16_t* aOut)
 {
   if(!m4BytesDecoder)
     Create4BytesDecoder();
   if(m4BytesDecoder)
   {
     nsresult res = m4BytesDecoder->Reset();
     NS_ASSERTION(NS_SUCCEEDED(res), "4 bytes unique conversoin reset failed");
     int32_t len = 4;
     int32_t dstlen = 1;
     res = m4BytesDecoder->Convert(aSrc,&len, aOut, &dstlen);
     NS_ASSERTION(NS_FAILED(res) || ((len==4) && (dstlen == 1)),
        "some strange conversion result");
      // if we failed, we then just use the 0xfffd
      // therefore, we ignore the res here.
     if(NS_SUCCEEDED(res))
       return true;
   }
   return  false;
 }

The Tor Browser / annotate

intl/uconv/ucvcn/nsGBKToUnicode.cpp@97036ab72558 (annotated)

intl/uconv/ucvcn/nsGBKToUnicode.cpp