netwerk/streamconv/converters/nsBinHexDecoder.h

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  38
  39 // A decoder for Mac Bin Hex 4.0.
  40
  41 // This decoder is currently only intended to be used on NON-Mac platforms. It isn't hooked up to
  42 // code which would actually save the file to disk. As a result, we can't leverage the resource fork.
  43 // This makes this decoder most unhelpful for the Mac. Our assumption is that if you save a bin hex file
  44 // on the mac and try to open it, stuffit or some other tool is already going to be on the Mac which knows how
  45 // to handle bin hex. On windows and unix, that's not the case. We need client code to strip out the data fork.
  46 // So this decoder currently just strips out the data fork.
  47
  48 // Note: it's possible that we can eventually turn this decoder into both a decoder and into a file stream (much
  49 // like the apple double decoder) so on the Mac, if we are saving to disk, we can invoke the decoder as a file stream
  50 // and it will process the resource fork and do the right magic.
  51
  52 #ifndef nsBinHexDecoder_h__
  53 #define nsBinHexDecoder_h__
  54
  55 #include "nsIStreamConverter.h"
  56 #include "nsIChannel.h"
  57 #include "nsIOutputStream.h"
  58 #include "nsIInputStream.h"
  59
  60 #include "nsCOMPtr.h"
  61 #include "nsString.h"
  62
  63 #define NS_BINHEXDECODER_CID                        \
  64 { /* 301DEA42-6850-4cda-8945-81F7DBC2186B */         \
  65     0x301dea42, 0x6850, 0x4cda,                      \
  66     { 0x89, 0x45, 0x81, 0xf7, 0xdb, 0xc2, 0x18, 0x6b } \
  67 }
  68
  69 typedef struct _binhex_header
  70 {
  71         PRUint32        type, creator;
  72         PRUint16  flags;
  73         PRInt32 dlen, rlen;
  74 } binhex_header;
  75
  76 typedef union
  77 {
  78         unsigned char c[4];
  79         PRUint32          val;
  80 } longbuf;
  81
  82 #define BINHEX_STATE_START      0
  83 #define BINHEX_STATE_FNAME      1
  84 #define BINHEX_STATE_HEADER     2
  85 #define BINHEX_STATE_HCRC       3
  86 #define BINHEX_STATE_DFORK      4
  87 #define BINHEX_STATE_DCRC       5
  88 #define BINHEX_STATE_RFORK      6
  89 #define BINHEX_STATE_RCRC       7
  90 #define BINHEX_STATE_FINISH     8
  91 #define BINHEX_STATE_DONE               9
  92 /* #define BINHEX_STATE_ERROR           10 */
  93
  94 class nsBinHexDecoder : public nsIStreamConverter
  95 {
  96 public:
  97   // nsISupports methods
  98   NS_DECL_ISUPPORTS
  99
 100   // nsIStreamConverter methods
 101   NS_DECL_NSISTREAMCONVERTER
 102
 103   // nsIStreamListener methods
 104   NS_DECL_NSISTREAMLISTENER
 105
 106   // nsIRequestObserver methods
 107   NS_DECL_NSIREQUESTOBSERVER
 108
 109   nsBinHexDecoder();
 110
 111 protected:
 112   virtual ~nsBinHexDecoder();
 113
 114   PRInt16  GetNextChar(PRUint32 numBytesInBuffer);
 115   nsresult ProcessNextChunk(nsIRequest * aRequest, nsISupports * aContext, PRUint32 numBytesInBuffer);
 116   nsresult ProcessNextState(nsIRequest * aRequest, nsISupports * aContext);
 117   nsresult SetContentType(nsIRequest * aRequest, const char * fileName);
 118
 119 protected:
 120   nsCOMPtr<nsIStreamListener> mNextListener;
 121
 122   // the input and output streams form a pipe...they need to be passed around together..
 123   nsCOMPtr<nsIOutputStream>     mOutputStream;     // output stream
 124   nsCOMPtr<nsIInputStream>          mInputStream;
 125
 126   PRInt16   mState;                     /* current state */
 127   PRUint16  mCRC; /* cumulative CRC */
 128         PRUint16  mFileCRC;             /* CRC value from file */
 129   longbuf   mOctetBuf;          /* buffer for decoded 6-bit values              */
 130         PRInt16         mOctetin;               /* current input position in octetbuf */
 131         PRInt16         mDonePos;               /* ending position in octetbuf */
 132         PRInt16         mInCRC;                 /* flag set when reading a CRC */
 133
 134   // Bin Hex Header Information
 135   binhex_header mHeader;
 136   char  mName[64];              /* fsspec for the output file */
 137
 138   // unfortunately we are going to need 2 8K buffers here. One for the data we are currently digesting. Another
 139   // for the outgoing decoded data. I tried getting them to share a buffer but things didn't work out so nicely.
 140   char * mDataBuffer; // temporary holding pen for the incoming data.
 141   char * mOutgoingBuffer; // temporary holding pen for the incoming data.
 142   PRUint32 mPosInDataBuffer;
 143
 144         unsigned char mRlebuf;  /* buffer for last run length encoding value */
 145
 146         PRInt32 mCount;                   /* generic counter */
 147   PRInt16 mMarker;                      /* flag indicating maker */
 148
 149         PRInt32 mPosInbuff;                /* the index of the inbuff.  */
 150         PRInt32 mPosOutputBuff; /* the position of the out buff.                */
 151 };
 152
 153 #endif /* nsBinHexDecoder_h__ */