diff -r 000000000000 -r 6474c204b198 xpcom/io/nsLinebreakConverter.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/io/nsLinebreakConverter.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,465 @@
+/* -*- 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 "nsLinebreakConverter.h"
+
+#include "nsMemory.h"
+#include "nsCRT.h"
+
+
+/*----------------------------------------------------------------------------
+	GetLinebreakString 
+	
+	Could make this inline
+----------------------------------------------------------------------------*/
+static const char* GetLinebreakString(nsLinebreakConverter::ELinebreakType aBreakType)
+{
+  static const char* const sLinebreaks[] = {
+    "",             // any
+    NS_LINEBREAK,   // platform
+    LFSTR,          // content
+    CRLF,           // net
+    CRSTR,          // Mac
+    LFSTR,          // Unix
+    CRLF,           // Windows
+    " ",            // space
+    nullptr  
+  };
+  
+  return sLinebreaks[aBreakType];
+}
+
+
+/*----------------------------------------------------------------------------
+	AppendLinebreak 
+	
+	Wee inline method to append a line break. Modifies ioDest.
+----------------------------------------------------------------------------*/
+template<class T>
+void AppendLinebreak(T*& ioDest, const char* lineBreakStr)
+{
+  *ioDest++ = *lineBreakStr;
+
+  if (lineBreakStr[1])
+    *ioDest++ = lineBreakStr[1];
+}
+
+/*----------------------------------------------------------------------------
+	CountChars 
+	
+	Counts occurrences of breakStr in aSrc
+----------------------------------------------------------------------------*/
+template<class T>
+int32_t CountLinebreaks(const T* aSrc, int32_t inLen, const char* breakStr)
+{
+  const T* src = aSrc;
+  const T* srcEnd = aSrc + inLen;
+  int32_t theCount = 0;
+
+  while (src < srcEnd)
+  {
+    if (*src == *breakStr)
+    {
+      src++;
+
+      if (breakStr[1])
+      {
+        if (src < srcEnd && *src == breakStr[1])
+        {
+          src++;
+          theCount++;
+        }
+      }
+      else
+      {
+        theCount++;
+      }
+    }
+    else
+    {
+      src++;
+    }
+  }
+  
+  return theCount;
+}
+
+
+/*----------------------------------------------------------------------------
+	ConvertBreaks 
+	
+	ioLen *includes* a terminating null, if any
+----------------------------------------------------------------------------*/
+template<class T>
+static T* ConvertBreaks(const T* inSrc, int32_t& ioLen, const char* srcBreak, const char* destBreak)
+{
+  NS_ASSERTION(inSrc && srcBreak && destBreak, "Got a null string");
+  
+  T* resultString = nullptr;
+   
+  // handle the no conversion case
+  if (nsCRT::strcmp(srcBreak, destBreak) == 0)
+  {
+    resultString = (T *)nsMemory::Alloc(sizeof(T) * ioLen);
+    if (!resultString) return nullptr;
+    memcpy(resultString, inSrc, sizeof(T) * ioLen); // includes the null, if any
+    return resultString;
+  }
+    
+  int32_t srcBreakLen = strlen(srcBreak);
+  int32_t destBreakLen = strlen(destBreak);
+
+  // handle the easy case, where the string length does not change, and the
+  // breaks are only 1 char long, i.e. CR <-> LF
+  if (srcBreakLen == destBreakLen && srcBreakLen == 1)
+  {
+    resultString = (T *)nsMemory::Alloc(sizeof(T) * ioLen);
+    if (!resultString) return nullptr;
+    
+    const T* src = inSrc;
+    const T* srcEnd = inSrc + ioLen;		// includes null, if any
+    T*       dst = resultString;
+    
+    char srcBreakChar = *srcBreak;        // we know it's one char long already
+    char dstBreakChar = *destBreak;
+    
+    while (src < srcEnd)
+    {
+      if (*src == srcBreakChar)
+      {
+        *dst++ = dstBreakChar;
+        src++;
+      }
+      else
+      {
+        *dst++ = *src++;
+      }
+    }
+
+    // ioLen does not change
+  }
+  else
+  {
+    // src and dest termination is different length. Do it a slower way.
+    
+    // count linebreaks in src. Assumes that chars in 2-char linebreaks are unique.
+    int32_t numLinebreaks = CountLinebreaks(inSrc, ioLen, srcBreak);
+    
+    int32_t newBufLen = ioLen - (numLinebreaks * srcBreakLen) + (numLinebreaks * destBreakLen);
+    resultString = (T *)nsMemory::Alloc(sizeof(T) * newBufLen);
+    if (!resultString) return nullptr;
+    
+    const T* src = inSrc;
+    const T* srcEnd = inSrc + ioLen;		// includes null, if any
+    T*       dst = resultString;
+    
+    while (src < srcEnd)
+    {
+      if (*src == *srcBreak)
+      {
+        *dst++ = *destBreak;
+        if (destBreak[1])
+          *dst++ = destBreak[1];
+      
+        src++;
+        if (src < srcEnd && srcBreak[1] && *src == srcBreak[1])
+          src++;
+      }
+      else
+      {
+        *dst++ = *src++;
+      }
+    }
+    
+    ioLen = newBufLen;
+  }
+  
+  return resultString;
+}
+
+
+/*----------------------------------------------------------------------------
+  ConvertBreaksInSitu 
+	
+  Convert breaks in situ. Can only do this if the linebreak length
+  does not change.
+----------------------------------------------------------------------------*/
+template<class T>
+static void ConvertBreaksInSitu(T* inSrc, int32_t inLen, char srcBreak, char destBreak)
+{
+  T* src = inSrc;
+  T* srcEnd = inSrc + inLen;
+
+  while (src < srcEnd)
+  {
+    if (*src == srcBreak)
+      *src = destBreak;
+    
+    src++;
+  }
+}
+
+
+/*----------------------------------------------------------------------------
+  ConvertUnknownBreaks 
+	
+  Convert unknown line breaks to the specified break.
+	
+  This will convert CRLF pairs to one break, and single CR or LF to a break.
+----------------------------------------------------------------------------*/
+template<class T>
+static T* ConvertUnknownBreaks(const T* inSrc, int32_t& ioLen, const char* destBreak)
+{
+  const T* src = inSrc;
+  const T* srcEnd = inSrc + ioLen;		// includes null, if any
+  
+  int32_t destBreakLen = strlen(destBreak);
+  int32_t finalLen = 0;
+
+  while (src < srcEnd)
+  {
+    if (*src == nsCRT::CR)
+    {
+      if (src < srcEnd && src[1] == nsCRT::LF)
+      {
+        // CRLF
+        finalLen += destBreakLen;
+        src++;
+      }
+      else
+      {
+        // Lone CR
+        finalLen += destBreakLen;
+      }
+    }
+    else if (*src == nsCRT::LF)
+    {
+      // Lone LF
+      finalLen += destBreakLen;
+    }
+    else
+    {
+      finalLen++;
+    }
+    src++;
+  }
+  
+  T* resultString = (T *)nsMemory::Alloc(sizeof(T) * finalLen);
+  if (!resultString) return nullptr;
+
+  src = inSrc;
+  srcEnd = inSrc + ioLen;		// includes null, if any
+
+  T* dst = resultString;
+  
+  while (src < srcEnd)
+  {
+    if (*src == nsCRT::CR)
+    {
+      if (src < srcEnd && src[1] == nsCRT::LF)
+      {
+        // CRLF
+        AppendLinebreak(dst, destBreak);
+        src++;
+      }
+      else
+      {
+        // Lone CR
+        AppendLinebreak(dst, destBreak);
+      }
+    }
+    else if (*src == nsCRT::LF)
+    {
+      // Lone LF
+      AppendLinebreak(dst, destBreak);
+    }
+    else
+    {
+      *dst++ = *src;
+    }
+    src++;
+  }
+
+  ioLen = finalLen;
+  return resultString;
+}
+
+
+/*----------------------------------------------------------------------------
+	ConvertLineBreaks 
+	
+----------------------------------------------------------------------------*/
+char* nsLinebreakConverter::ConvertLineBreaks(const char* aSrc,
+            ELinebreakType aSrcBreaks, ELinebreakType aDestBreaks, int32_t aSrcLen, int32_t* outLen)
+{
+  NS_ASSERTION(aDestBreaks != eLinebreakAny &&
+               aSrcBreaks != eLinebreakSpace, "Invalid parameter");
+  if (!aSrc) return nullptr;
+  
+  int32_t sourceLen = (aSrcLen == kIgnoreLen) ? strlen(aSrc) + 1 : aSrcLen;
+
+  char* resultString;
+  if (aSrcBreaks == eLinebreakAny)
+    resultString = ConvertUnknownBreaks(aSrc, sourceLen, GetLinebreakString(aDestBreaks));
+  else
+    resultString = ConvertBreaks(aSrc, sourceLen, GetLinebreakString(aSrcBreaks), GetLinebreakString(aDestBreaks));
+  
+  if (outLen)
+    *outLen = sourceLen;
+  return resultString;
+}
+
+
+/*----------------------------------------------------------------------------
+	ConvertLineBreaksInSitu 
+	
+----------------------------------------------------------------------------*/
+nsresult nsLinebreakConverter::ConvertLineBreaksInSitu(char **ioBuffer, ELinebreakType aSrcBreaks,
+            ELinebreakType aDestBreaks, int32_t aSrcLen, int32_t* outLen)
+{
+  NS_ASSERTION(ioBuffer && *ioBuffer, "Null pointer passed");
+  if (!ioBuffer || !*ioBuffer) return NS_ERROR_NULL_POINTER;
+  
+  NS_ASSERTION(aDestBreaks != eLinebreakAny &&
+               aSrcBreaks != eLinebreakSpace, "Invalid parameter");
+
+  int32_t sourceLen = (aSrcLen == kIgnoreLen) ? strlen(*ioBuffer) + 1 : aSrcLen;
+  
+  // can we convert in-place?
+  const char* srcBreaks = GetLinebreakString(aSrcBreaks);
+  const char* dstBreaks = GetLinebreakString(aDestBreaks);
+  
+  if ( (aSrcBreaks != eLinebreakAny) &&
+       (strlen(srcBreaks) == 1) &&
+       (strlen(dstBreaks) == 1) )
+  {
+    ConvertBreaksInSitu(*ioBuffer, sourceLen, *srcBreaks, *dstBreaks);
+    if (outLen)
+      *outLen = sourceLen;
+  }
+  else
+  {
+    char* destBuffer;
+    
+    if (aSrcBreaks == eLinebreakAny)
+      destBuffer = ConvertUnknownBreaks(*ioBuffer, sourceLen, dstBreaks);
+    else
+      destBuffer = ConvertBreaks(*ioBuffer, sourceLen, srcBreaks, dstBreaks);
+
+    if (!destBuffer) return NS_ERROR_OUT_OF_MEMORY;
+    *ioBuffer = destBuffer;
+    if (outLen)
+      *outLen = sourceLen;
+  }
+  
+  return NS_OK;
+}
+
+
+/*----------------------------------------------------------------------------
+	ConvertUnicharLineBreaks 
+	
+----------------------------------------------------------------------------*/
+char16_t* nsLinebreakConverter::ConvertUnicharLineBreaks(const char16_t* aSrc,
+            ELinebreakType aSrcBreaks, ELinebreakType aDestBreaks, int32_t aSrcLen, int32_t* outLen)
+{
+  NS_ASSERTION(aDestBreaks != eLinebreakAny &&
+               aSrcBreaks != eLinebreakSpace, "Invalid parameter");
+  if (!aSrc) return nullptr;
+  
+  int32_t bufLen = (aSrcLen == kIgnoreLen) ? NS_strlen(aSrc) + 1 : aSrcLen;
+
+  char16_t* resultString;
+  if (aSrcBreaks == eLinebreakAny)
+    resultString = ConvertUnknownBreaks(aSrc, bufLen, GetLinebreakString(aDestBreaks));
+  else
+    resultString = ConvertBreaks(aSrc, bufLen, GetLinebreakString(aSrcBreaks), GetLinebreakString(aDestBreaks));
+  
+  if (outLen)
+    *outLen = bufLen;
+  return resultString;
+}
+
+
+/*----------------------------------------------------------------------------
+	ConvertStringLineBreaks 
+	
+----------------------------------------------------------------------------*/
+nsresult nsLinebreakConverter::ConvertUnicharLineBreaksInSitu(char16_t **ioBuffer,
+            ELinebreakType aSrcBreaks, ELinebreakType aDestBreaks, int32_t aSrcLen, int32_t* outLen)
+{
+  NS_ASSERTION(ioBuffer && *ioBuffer, "Null pointer passed");
+  if (!ioBuffer || !*ioBuffer) return NS_ERROR_NULL_POINTER;
+  NS_ASSERTION(aDestBreaks != eLinebreakAny &&
+               aSrcBreaks != eLinebreakSpace, "Invalid parameter");
+
+  int32_t sourceLen = (aSrcLen == kIgnoreLen) ? NS_strlen(*ioBuffer) + 1 : aSrcLen;
+
+  // can we convert in-place?
+  const char* srcBreaks = GetLinebreakString(aSrcBreaks);
+  const char* dstBreaks = GetLinebreakString(aDestBreaks);
+  
+  if ( (aSrcBreaks != eLinebreakAny) &&
+       (strlen(srcBreaks) == 1) &&
+       (strlen(dstBreaks) == 1) )
+  {
+    ConvertBreaksInSitu(*ioBuffer, sourceLen, *srcBreaks, *dstBreaks);
+    if (outLen)
+      *outLen = sourceLen;
+  }
+  else
+  {
+    char16_t* destBuffer;
+    
+    if (aSrcBreaks == eLinebreakAny)
+      destBuffer = ConvertUnknownBreaks(*ioBuffer, sourceLen, dstBreaks);
+    else
+      destBuffer = ConvertBreaks(*ioBuffer, sourceLen, srcBreaks, dstBreaks);
+
+    if (!destBuffer) return NS_ERROR_OUT_OF_MEMORY;
+    *ioBuffer = destBuffer;
+    if (outLen)
+      *outLen = sourceLen;
+  }
+  
+  return NS_OK;
+}
+
+/*----------------------------------------------------------------------------
+	ConvertStringLineBreaks 
+	
+----------------------------------------------------------------------------*/
+nsresult nsLinebreakConverter::ConvertStringLineBreaks(nsString& ioString,
+          ELinebreakType aSrcBreaks, ELinebreakType aDestBreaks)
+{
+
+  NS_ASSERTION(aDestBreaks != eLinebreakAny &&
+               aSrcBreaks != eLinebreakSpace, "Invalid parameter");
+
+  // nothing to do
+  if (ioString.IsEmpty()) return NS_OK;
+  
+  nsresult rv;
+  
+  // remember the old buffer in case
+  // we blow it away later
+  nsString::char_iterator stringBuf;
+  ioString.BeginWriting(stringBuf);
+  
+  int32_t    newLen;
+    
+  rv = ConvertUnicharLineBreaksInSitu(&stringBuf,
+                                      aSrcBreaks, aDestBreaks,
+                                      ioString.Length() + 1, &newLen);
+  if (NS_FAILED(rv)) return rv;
+
+  if (stringBuf != ioString.get())
+    ioString.Adopt(stringBuf);
+  
+  return NS_OK;
+}
+
+
+