pjs/netwerk/base/public/nsReadLine.h

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C

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Mozilla Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is Boris Zbarsky
* <bzbarsky@mit.edu> Portions created by Boris Zbarsky are Copyright
* (C) 2001. All Rights Reserved.
*
* Contributor(s):
*/
#ifndef nsReadLine_h__
#define nsReadLine_h__
#include "prmem.h"
#include "nsIInputStream.h"
/* To properly use the helper function in here (ReadLine) the caller
* needs to declare a pointer to an nsLineBuffer, call
* NS_InitLineBuffer on it, and pass it to ReadLine every time it
* wants a line out.
*
* When done, the pointer should be freed using PR_FREEIF.
*/
#define kLineBufferSize 1024
typedef struct {
char buf[kLineBufferSize+1];
char* start;
char* current;
char* end;
PRBool empty;
} nsLineBuffer;
static nsresult
NS_InitLineBuffer (nsLineBuffer ** aBufferPtr) {
*aBufferPtr = PR_NEW(nsLineBuffer);
if (!(*aBufferPtr)) return NS_ERROR_OUT_OF_MEMORY;
(*aBufferPtr)->start = (*aBufferPtr)->current = (*aBufferPtr)->end = (*aBufferPtr)->buf;
(*aBufferPtr)->empty = PR_TRUE;
return NS_OK;
}
static nsresult
NS_ReadLine (nsIInputStream* aStream, nsLineBuffer * aBuffer,
nsAString & aLine, PRBool *more) {
nsresult rv = NS_OK;
PRUint32 bytesRead;
nsAutoString temp;
*more = PR_TRUE;
PRBool eolStarted = PR_FALSE;
char eolchar = '\0';
aLine.Truncate();
while (1) { // will be returning out of this loop on eol or eof
if (aBuffer->empty) { // buffer is empty. Read into it.
rv = aStream->Read(aBuffer->buf, kLineBufferSize, &bytesRead);
if (NS_FAILED(rv)) // read failed
return rv;
if (bytesRead == 0) { // end of file
*more = PR_FALSE;
return NS_OK;
}
aBuffer->end = aBuffer->buf + bytesRead;
aBuffer->empty = PR_FALSE;
*(aBuffer->end) = '\0'; // null-terminate this thing
}
// walk the buffer looking for an end-of-line
while (aBuffer->current < aBuffer->end) {
if (eolStarted) {
if ((eolchar == '\n' && *(aBuffer->current) == '\r') ||
(eolchar == '\r' && *(aBuffer->current) == '\n')) { // line end
(aBuffer->current)++;
aBuffer->start = aBuffer->current;
}
eolStarted = PR_FALSE;
return NS_OK;
} else if (*(aBuffer->current) == '\n' ||
*(aBuffer->current) == '\r') { // line end
eolStarted = PR_TRUE;
eolchar = *(aBuffer->current);
*(aBuffer->current) = '\0';
temp.AssignWithConversion(aBuffer->start);
aLine.Append(temp);
(aBuffer->current)++;
aBuffer->start = aBuffer->current;
} else {
eolStarted = PR_FALSE;
(aBuffer->current)++;
}
}
// append whatever we currently have to the string
temp.AssignWithConversion(aBuffer->start);
aLine.Append(temp);
// we've run out of buffer. Begin anew
aBuffer->current = aBuffer->start = aBuffer->buf;
aBuffer->empty = PR_TRUE;
if (eolStarted) { // have to read another char and possibly skip over it
rv = aStream->Read(aBuffer->buf, 1, &bytesRead);
if (NS_FAILED(rv)) // read failed
return rv;
if (bytesRead == 0) { // end of file
*more = PR_FALSE;
return NS_OK;
}
if ((eolchar == '\n' && *(aBuffer->buf) == '\r') ||
(eolchar == '\r' && *(aBuffer->buf) == '\n')) {
// Just return and all is good -- we've skipped the extra newline char
return NS_OK;
} else {
// we have a byte that we should look at later
aBuffer->empty = PR_FALSE;
aBuffer->end = aBuffer->buf + 1;
*(aBuffer->end) = '\0';
}
}
}
}
#endif // nsReadLine_h__