The Tor Browser: intl/uconv/ucvlatin/nsUTF16ToUnicode.cpp@6474c204b198 (annotated)

intl/uconv/ucvlatin/nsUTF16ToUnicode.cpp@6474c204b198 (annotated)

intl/uconv/ucvlatin/nsUTF16ToUnicode.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 2; 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/. */
 #include "nsUTF16ToUnicode.h"
 #include "nsCharTraits.h"
 #include "mozilla/Endian.h"
 enum {
   STATE_NORMAL = 0,
   STATE_HALF_CODE_POINT = 1,
   STATE_FIRST_CALL = 2,
   STATE_SECOND_BYTE = STATE_FIRST_CALL | STATE_HALF_CODE_POINT,
   STATE_ODD_SURROGATE_PAIR = 4
 };
 nsresult
 nsUTF16ToUnicodeBase::UTF16ConvertToUnicode(const char * aSrc,
                                             int32_t * aSrcLength,
                                             char16_t * aDest,
                                             int32_t * aDestLength,
                                             bool aSwapBytes)
 {
   const char* src = aSrc;
   const char* srcEnd = aSrc + *aSrcLength;
   char16_t* dest = aDest;
   char16_t* destEnd = aDest + *aDestLength;
   char16_t oddHighSurrogate;
   switch(mState) {
     case STATE_FIRST_CALL:
       NS_ASSERTION(*aSrcLength > 1, "buffer too short");
       src+=2;
       mState = STATE_NORMAL;
       break;
     case STATE_SECOND_BYTE:
       NS_ASSERTION(*aSrcLength > 0, "buffer too short");
       src++;
       mState = STATE_NORMAL;
       break;
     case STATE_ODD_SURROGATE_PAIR:
       if (*aDestLength < 2)
         goto error;
       else {
         *dest++ = mOddHighSurrogate;
         *dest++ = mOddLowSurrogate;
         mOddHighSurrogate = mOddLowSurrogate = 0;
         mState = STATE_NORMAL;
       }
       break;
     case STATE_NORMAL:
     case STATE_HALF_CODE_POINT:
     default:
       break;
   }
   oddHighSurrogate = mOddHighSurrogate;
   if (src == srcEnd) {
     *aDestLength = dest - aDest;
     return (mState != STATE_NORMAL || oddHighSurrogate) ?
            NS_OK_UDEC_MOREINPUT : NS_OK;
   }
   const char* srcEvenEnd;
   char16_t u;
   if (mState == STATE_HALF_CODE_POINT) {
     if (dest == destEnd)
       goto error;
     // the 1st byte of a 16-bit code unit was stored in |mOddByte| in the
     // previous run while the 2nd byte has to come from |*src|.
     mState = STATE_NORMAL;
 #if MOZ_BIG_ENDIAN
     u = (mOddByte << 8) | uint8_t(*src++); // safe, we know we have at least one byte.
 #else
     u = (*src++ << 8) | mOddByte; // safe, we know we have at least one byte.
 #endif
     srcEvenEnd = src + ((srcEnd - src) & ~1); // handle even number of bytes in main loop
     goto have_codepoint;
   } else {
     srcEvenEnd = src + ((srcEnd - src) & ~1); // handle even number of bytes in main loop
   }
   while (src != srcEvenEnd) {
     if (dest == destEnd)
       goto error;
 #if !defined(__sparc__) && !defined(__arm__)
     u = *(const char16_t*)src;
 #else
     memcpy(&u, src, 2);
 #endif
     src += 2;
 have_codepoint:
     if (aSwapBytes)
       u = u << 8 | u >> 8;
     if (!IS_SURROGATE(u)) {
       if (oddHighSurrogate) {
         if (mErrBehavior == kOnError_Signal) {
           goto error2;
         }
         *dest++ = UCS2_REPLACEMENT_CHAR;
         if (dest == destEnd)
           goto error;
         oddHighSurrogate = 0;
       }
       *dest++ = u;
     } else if (NS_IS_HIGH_SURROGATE(u)) {
       if (oddHighSurrogate) {
         if (mErrBehavior == kOnError_Signal) {
           goto error2;
         }
         *dest++ = UCS2_REPLACEMENT_CHAR;
         if (dest == destEnd)
           goto error;
       }
       oddHighSurrogate = u;
     }
     else /* if (NS_IS_LOW_SURROGATE(u)) */ {
       if (oddHighSurrogate && *aDestLength > 1) {
         if (dest + 1 >= destEnd) {
           mOddLowSurrogate = u;
           mOddHighSurrogate = oddHighSurrogate;
           mState = STATE_ODD_SURROGATE_PAIR;
           goto error;
         }
         *dest++ = oddHighSurrogate;
         *dest++ = u;
       } else {
         if (mErrBehavior == kOnError_Signal) {
           goto error2;
         }
         *dest++ = UCS2_REPLACEMENT_CHAR;
       }
       oddHighSurrogate = 0;
     }
   }
   if (src != srcEnd) {
     // store the lead byte of a 16-bit unit for the next run.
     mOddByte = *src++;
     mState = STATE_HALF_CODE_POINT;
   }
   mOddHighSurrogate = oddHighSurrogate;
   *aDestLength = dest - aDest;
   *aSrcLength =  src  - aSrc;
   return (mState != STATE_NORMAL || oddHighSurrogate) ?
          NS_OK_UDEC_MOREINPUT : NS_OK;
 error:
   *aDestLength = dest - aDest;
   *aSrcLength =  src  - aSrc;
   return  NS_OK_UDEC_MOREOUTPUT;
 error2:
   *aDestLength = dest - aDest;
   *aSrcLength = --src - aSrc;
   return  NS_ERROR_ILLEGAL_INPUT;
 }
 NS_IMETHODIMP
 nsUTF16ToUnicodeBase::Reset()
 {
   mState = STATE_FIRST_CALL;
   mOddByte = 0;
   mOddHighSurrogate = 0;
   mOddLowSurrogate = 0;
   return NS_OK;
 }
 NS_IMETHODIMP
 nsUTF16ToUnicodeBase::GetMaxLength(const char * aSrc, int32_t aSrcLength,
                                    int32_t * aDestLength)
 {
   // the left-over data of the previous run have to be taken into account.
   *aDestLength = (aSrcLength + ((STATE_HALF_CODE_POINT & mState) ? 1 : 0)) / 2;
   if (mOddHighSurrogate)
     (*aDestLength)++;
   if (mOddLowSurrogate)
     (*aDestLength)++;
   return NS_OK;
 }
 NS_IMETHODIMP
 nsUTF16BEToUnicode::Convert(const char * aSrc, int32_t * aSrcLength,
                             char16_t * aDest, int32_t * aDestLength)
 {
   switch (mState) {
     case STATE_FIRST_CALL:
       if (*aSrcLength < 2) {
         if (*aSrcLength < 1) {
           *aDestLength = 0;
           return NS_OK;
         }
         if (uint8_t(*aSrc) != 0xFE) {
           mState = STATE_NORMAL;
           break;
         }
         *aDestLength = 0;
         mState = STATE_SECOND_BYTE;
         return NS_OK_UDEC_MOREINPUT;
       }
 #if MOZ_LITTLE_ENDIAN
       // on LE machines, BE BOM is 0xFFFE
       if (0xFFFE != *((char16_t*)aSrc)) {
         mState = STATE_NORMAL;
       }
 #else
       if (0xFEFF != *((char16_t*)aSrc)) {
         mState = STATE_NORMAL;
       }
 #endif
       break;
     case STATE_SECOND_BYTE:
       if (*aSrcLength < 1) {
         *aDestLength = 0;
         return NS_OK_UDEC_MOREINPUT;
       }
       if (uint8_t(*aSrc) != 0xFF) {
         mOddByte = 0xFE;
         mState = STATE_HALF_CODE_POINT;
       }
       break;
   }
   return UTF16ConvertToUnicode(aSrc, aSrcLength, aDest, aDestLength,
                                bool(MOZ_LITTLE_ENDIAN));
 }
 NS_IMETHODIMP
 nsUTF16LEToUnicode::Convert(const char * aSrc, int32_t * aSrcLength,
                             char16_t * aDest, int32_t * aDestLength)
 {
   switch (mState) {
     case STATE_FIRST_CALL:
       if (*aSrcLength < 2) {
         if (*aSrcLength < 1) {
           *aDestLength = 0;
           return NS_OK;
         }
         if (uint8_t(*aSrc) != 0xFF) {
           mState = STATE_NORMAL;
           break;
         }
         *aDestLength = 0;
         mState = STATE_SECOND_BYTE;
         return NS_OK_UDEC_MOREINPUT;
       }
 #if MOZ_BIG_ENDIAN
       // on BE machines, LE BOM is 0xFFFE
       if (0xFFFE != *((char16_t*)aSrc)) {
         mState = STATE_NORMAL;
       }
 #else
       if (0xFEFF != *((char16_t*)aSrc)) {
         mState = STATE_NORMAL;
       }
 #endif
       break;
     case STATE_SECOND_BYTE:
       if (*aSrcLength < 1) {
         *aDestLength = 0;
         return NS_OK_UDEC_MOREINPUT;
       }
       if (uint8_t(*aSrc) != 0xFE) {
         mOddByte = 0xFF;
         mState = STATE_HALF_CODE_POINT;
       }
       break;
   }
   return UTF16ConvertToUnicode(aSrc, aSrcLength, aDest, aDestLength,
                                bool(MOZ_BIG_ENDIAN));
 }
 NS_IMETHODIMP
 nsUTF16ToUnicode::Reset()
 {
   mEndian = kUnknown;
   mFoundBOM = false;
   return nsUTF16ToUnicodeBase::Reset();
 }
 NS_IMETHODIMP
 nsUTF16ToUnicode::Convert(const char * aSrc, int32_t * aSrcLength,
                           char16_t * aDest, int32_t * aDestLength)
 {
     if(STATE_FIRST_CALL == mState && *aSrcLength < 2)
     {
       nsresult res = (*aSrcLength == 0) ? NS_OK : NS_ERROR_ILLEGAL_INPUT;
       *aSrcLength=0;
       *aDestLength=0;
       return res;
     }
     if(STATE_FIRST_CALL == mState) // first time called
     {
       // check if BOM (0xFEFF) is at the beginning, remove it if found, and
       // set mEndian accordingly.
       if(0xFF == uint8_t(aSrc[0]) && 0xFE == uint8_t(aSrc[1])) {
         mEndian = kLittleEndian;
         mFoundBOM = true;
       }
       else if(0xFE == uint8_t(aSrc[0]) && 0xFF == uint8_t(aSrc[1])) {
         mEndian = kBigEndian;
         mFoundBOM = true;
       }
       // BOM is not found, but we can use a simple heuristic to determine
       // the endianness. Assume the first character is [U+0001, U+00FF].
       // Not always valid, but it's very likely to hold for html/xml/css.
       else if(!aSrc[0] && aSrc[1]) {  // 0x00 0xhh (hh != 00)
         mState = STATE_NORMAL;
         mEndian = kBigEndian;
       }
       else if(aSrc[0] && !aSrc[1]) {  // 0xhh 0x00 (hh != 00)
         mState = STATE_NORMAL;
         mEndian = kLittleEndian;
       }
       else { // Neither BOM nor 'plausible' byte patterns at the beginning.
              // Just assume it's BE (following Unicode standard)
              // and let the garbage show up in the browser. (security concern?)
              // (bug 246194)
         mState = STATE_NORMAL;
         mEndian = kBigEndian;
       }
     }
     nsresult rv = UTF16ConvertToUnicode(aSrc, aSrcLength, aDest, aDestLength,
 #if MOZ_BIG_ENDIAN
                                         (mEndian == kLittleEndian)
 #else
                                         (mEndian == kBigEndian)
 #endif
                                         );
     // If BOM is not found and we're to return NS_OK, signal that BOM
     // is not found. Otherwise, return |rv| from |UTF16ConvertToUnicode|
     return (rv == NS_OK && !mFoundBOM) ? NS_OK_UDEC_NOBOMFOUND : rv;
 }

The Tor Browser / annotate

intl/uconv/ucvlatin/nsUTF16ToUnicode.cpp@6474c204b198 (annotated)

intl/uconv/ucvlatin/nsUTF16ToUnicode.cpp