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 /* -*- 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

 {

   uint32_t type, creator;

   uint16_t flags;

   int32_t dlen, rlen;

 } binhex_header;

 typedef union

 {

   unsigned char c[4];

   uint32_t      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();

   int16_t  GetNextChar(uint32_t numBytesInBuffer);

   nsresult ProcessNextChunk(nsIRequest * aRequest, nsISupports * aContext, uint32_t 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;

   int16_t   mState;      /* current state */

   uint16_t  mCRC;        /* cumulative CRC */

   uint16_t  mFileCRC;    /* CRC value from file */

   longbuf   mOctetBuf;   /* buffer for decoded 6-bit values     */

   int16_t   mOctetin;    /* current input position in octetbuf */

   int16_t   mDonePos;    /* ending position in octetbuf */

   int16_t   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.

   uint32_t mPosInDataBuffer;

   unsigned char mRlebuf;  /* buffer for last run length encoding value */

   uint32_t mCount;        /* generic counter */

   int16_t mMarker;        /* flag indicating maker */

   int32_t mPosInbuff;     /* the index of the inbuff.  */

   int32_t mPosOutputBuff; /* the position of the out buff.    */

 };

 #endif /* nsBinHexDecoder_h__ */