зеркало из https://github.com/mozilla/gecko-dev.git
213 строки
7.0 KiB
C++
213 строки
7.0 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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*
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is mozilla.org code.
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*
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* The Initial Developer of the Original Code is
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* Boris Zbarsky <bzbarsky@mit.edu>.
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* Portions created by the Initial Developer are Copyright (C) 2001
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Christian Biesinger <cbiesinger@web.de>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#ifndef nsReadLine_h__
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#define nsReadLine_h__
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#include "prmem.h"
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#include "nsIInputStream.h"
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/**
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* @file
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* Functions to read complete lines from an input stream.
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*
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* To properly use the helper function in here (NS_ReadLine) the caller
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* needs to declare a pointer to an nsLineBuffer, call
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* NS_InitLineBuffer on it, and pass it to NS_ReadLine every time it
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* wants a line out.
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*
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* When done, the pointer should be freed using PR_Free.
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*/
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/**
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* @internal
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* Buffer size. This many bytes will be buffered. If a line is longer than this,
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* the partial line will be appended to the out parameter of NS_ReadLine and the
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* buffer will be emptied.
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*/
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#define kLineBufferSize 1024
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/**
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* @internal
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* Line buffer structure, buffers data from an input stream.
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*/
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template<typename CharT>
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class nsLineBuffer {
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public:
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CharT buf[kLineBufferSize+1];
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CharT* start;
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CharT* current;
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CharT* end;
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PRBool empty;
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};
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/**
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* Initialize a line buffer for use with NS_ReadLine.
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*
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* @param aBufferPtr
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* Pointer to pointer to a line buffer. Upon successful return,
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* *aBufferPtr will contain a valid pointer to a line buffer, for use
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* with NS_ReadLine. Use PR_Free when the buffer is no longer needed.
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*
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* @retval NS_OK Success.
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* @retval NS_ERROR_OUT_OF_MEMORY Not enough memory to allocate the line buffer.
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*
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* @par Example:
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* @code
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* nsLineBuffer* lb;
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* rv = NS_InitLineBuffer(&lb);
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* if (NS_SUCCEEDED(rv)) {
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* // do stuff...
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* PR_Free(lb);
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* }
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* @endcode
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*/
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template<typename CharT>
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nsresult
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NS_InitLineBuffer (nsLineBuffer<CharT> ** aBufferPtr) {
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*aBufferPtr = PR_NEW(nsLineBuffer<CharT>);
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if (!(*aBufferPtr))
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return NS_ERROR_OUT_OF_MEMORY;
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(*aBufferPtr)->start = (*aBufferPtr)->current = (*aBufferPtr)->end = (*aBufferPtr)->buf;
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(*aBufferPtr)->empty = PR_TRUE;
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return NS_OK;
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}
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/**
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* Read a line from an input stream. Lines are separated by '\r' (0x0D) or '\n'
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* (0x0A), or "\r\n" or "\n\r".
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*
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* @param aStream
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* The stream to read from
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* @param aBuffer
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* The line buffer to use. Must have been inited with
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* NS_InitLineBuffer before. A single line buffer must not be used with
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* different input streams.
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* @param aLine [out]
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* The string where the line will be stored.
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* @param more [out]
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* Whether more data is available in the buffer. If true, NS_ReadLine may
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* be called again to read further lines. Otherwise, further calls to
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* NS_ReadLine will return an error.
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*
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* @retval NS_OK
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* Read successful
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* @retval error
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* Input stream returned an error upon read. See
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* nsIInputStream::read.
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*/
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template<typename CharT, class StreamType, class StringType>
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nsresult
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NS_ReadLine (StreamType* aStream, nsLineBuffer<CharT> * aBuffer,
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StringType & aLine, PRBool *more) {
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nsresult rv = NS_OK;
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PRUint32 bytesRead;
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*more = PR_TRUE;
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PRBool eolStarted = PR_FALSE;
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CharT eolchar = '\0';
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aLine.Truncate();
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while (1) { // will be returning out of this loop on eol or eof
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if (aBuffer->empty) { // buffer is empty. Read into it.
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rv = aStream->Read(aBuffer->buf, kLineBufferSize, &bytesRead);
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if (NS_FAILED(rv)) // read failed
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return rv;
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if (bytesRead == 0) { // end of file
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*more = PR_FALSE;
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return NS_OK;
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}
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aBuffer->end = aBuffer->buf + bytesRead;
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aBuffer->empty = PR_FALSE;
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*(aBuffer->end) = '\0'; // null-terminate this thing
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}
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// walk the buffer looking for an end-of-line
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while (aBuffer->current < aBuffer->end) {
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if (eolStarted) {
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if ((eolchar == '\n' && *(aBuffer->current) == '\r') ||
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(eolchar == '\r' && *(aBuffer->current) == '\n')) { // line end
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(aBuffer->current)++;
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aBuffer->start = aBuffer->current;
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}
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eolStarted = PR_FALSE;
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return NS_OK;
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} else if (*(aBuffer->current) == '\n' ||
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*(aBuffer->current) == '\r') { // line end
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eolStarted = PR_TRUE;
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eolchar = *(aBuffer->current);
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*(aBuffer->current) = '\0';
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aLine.Append(aBuffer->start);
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(aBuffer->current)++;
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aBuffer->start = aBuffer->current;
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} else {
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eolStarted = PR_FALSE;
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(aBuffer->current)++;
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}
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}
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// append whatever we currently have to the string
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aLine.Append(aBuffer->start);
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// we've run out of buffer. Begin anew
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aBuffer->current = aBuffer->start = aBuffer->buf;
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aBuffer->empty = PR_TRUE;
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if (eolStarted) { // have to read another char and possibly skip over it
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rv = aStream->Read(aBuffer->buf, 1, &bytesRead);
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if (NS_FAILED(rv)) // read failed
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return rv;
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if (bytesRead == 0) { // end of file
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*more = PR_FALSE;
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return NS_OK;
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}
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if ((eolchar == '\n' && *(aBuffer->buf) == '\r') ||
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(eolchar == '\r' && *(aBuffer->buf) == '\n')) {
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// Just return and all is good -- we've skipped the extra newline char
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return NS_OK;
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} else {
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// we have a byte that we should look at later
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aBuffer->empty = PR_FALSE;
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aBuffer->end = aBuffer->buf + 1;
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*(aBuffer->end) = '\0';
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}
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}
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}
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}
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#endif // nsReadLine_h__
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