gecko-dev/netwerk/streamconv/converters/nsBinHexDecoder.h
2012-05-21 12:12:37 +01:00

121 lines
4.3 KiB
C++

/* -*- 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/. */
// A decoder for Mac Bin Hex 4.0.
// This decoder is currently only intended to be used on NON-Mac platforms. It isn't hooked up to
// code which would actually save the file to disk. As a result, we can't leverage the resource fork.
// This makes this decoder most unhelpful for the Mac. Our assumption is that if you save a bin hex file
// on the mac and try to open it, stuffit or some other tool is already going to be on the Mac which knows how
// to handle bin hex. On windows and unix, that's not the case. We need client code to strip out the data fork.
// So this decoder currently just strips out the data fork.
// Note: it's possible that we can eventually turn this decoder into both a decoder and into a file stream (much
// like the apple double decoder) so on the Mac, if we are saving to disk, we can invoke the decoder as a file stream
// and it will process the resource fork and do the right magic.
#ifndef nsBinHexDecoder_h__
#define nsBinHexDecoder_h__
#include "nsIStreamConverter.h"
#include "nsIChannel.h"
#include "nsIOutputStream.h"
#include "nsIInputStream.h"
#include "nsCOMPtr.h"
#include "nsString.h"
#define NS_BINHEXDECODER_CID \
{ /* 301DEA42-6850-4cda-8945-81F7DBC2186B */ \
0x301dea42, 0x6850, 0x4cda, \
{ 0x89, 0x45, 0x81, 0xf7, 0xdb, 0xc2, 0x18, 0x6b } \
}
typedef struct _binhex_header
{
PRUint32 type, creator;
PRUint16 flags;
PRInt32 dlen, rlen;
} binhex_header;
typedef union
{
unsigned char c[4];
PRUint32 val;
} longbuf;
#define BINHEX_STATE_START 0
#define BINHEX_STATE_FNAME 1
#define BINHEX_STATE_HEADER 2
#define BINHEX_STATE_HCRC 3
#define BINHEX_STATE_DFORK 4
#define BINHEX_STATE_DCRC 5
#define BINHEX_STATE_RFORK 6
#define BINHEX_STATE_RCRC 7
#define BINHEX_STATE_FINISH 8
#define BINHEX_STATE_DONE 9
/* #define BINHEX_STATE_ERROR 10 */
class nsBinHexDecoder : public nsIStreamConverter
{
public:
// nsISupports methods
NS_DECL_ISUPPORTS
// nsIStreamConverter methods
NS_DECL_NSISTREAMCONVERTER
// nsIStreamListener methods
NS_DECL_NSISTREAMLISTENER
// nsIRequestObserver methods
NS_DECL_NSIREQUESTOBSERVER
nsBinHexDecoder();
protected:
virtual ~nsBinHexDecoder();
PRInt16 GetNextChar(PRUint32 numBytesInBuffer);
nsresult ProcessNextChunk(nsIRequest * aRequest, nsISupports * aContext, PRUint32 numBytesInBuffer);
nsresult ProcessNextState(nsIRequest * aRequest, nsISupports * aContext);
nsresult DetectContentType(nsIRequest * aRequest, const nsAFlatCString &aFilename);
protected:
nsCOMPtr<nsIStreamListener> mNextListener;
// the input and output streams form a pipe...they need to be passed around together..
nsCOMPtr<nsIOutputStream> mOutputStream; // output stream
nsCOMPtr<nsIInputStream> mInputStream;
PRInt16 mState; /* current state */
PRUint16 mCRC; /* cumulative CRC */
PRUint16 mFileCRC; /* CRC value from file */
longbuf mOctetBuf; /* buffer for decoded 6-bit values */
PRInt16 mOctetin; /* current input position in octetbuf */
PRInt16 mDonePos; /* ending position in octetbuf */
PRInt16 mInCRC; /* flag set when reading a CRC */
// Bin Hex Header Information
binhex_header mHeader;
nsCString mName; /* fsspec for the output file */
// unfortunately we are going to need 2 8K buffers here. One for the data we are currently digesting. Another
// for the outgoing decoded data. I tried getting them to share a buffer but things didn't work out so nicely.
char * mDataBuffer; // temporary holding pen for the incoming data.
char * mOutgoingBuffer; // temporary holding pen for the incoming data.
PRUint32 mPosInDataBuffer;
unsigned char mRlebuf; /* buffer for last run length encoding value */
PRUint32 mCount; /* generic counter */
PRInt16 mMarker; /* flag indicating maker */
PRInt32 mPosInbuff; /* the index of the inbuff. */
PRInt32 mPosOutputBuff; /* the position of the out buff. */
};
#endif /* nsBinHexDecoder_h__ */