KMime::Decoder Class Reference
Stateful decoder class, modelled after Stateful CTE decoder class. More...
#include <kmime_codecs.h>
Inherited by KMime::Base64Decoder, KMime::IdentityEnDecoder, KMime::QuotedPrintableDecoder, and KMime::UUDecoder.
Public Member Functions
- virtual bool decode (const char *&scursor, const char *const send, char *&dcursor, const char *const dend)=0
- virtual bool finish (char *&dcursor, const char *const dend)=0
Protected Member Functions
- Decoder (bool withCRLF=false)
Protected Attributes
Friends
Detailed Description
Stateful decoder class, modelled after Stateful CTE decoder class.
- See also:
- QTextDecoder.
Overview
KMime decoders are designed to be able to process encoded data in chunks of arbitrary size and to work with output buffers of also arbitrary size. They maintain any state necessary to go on where the previous call left off.The class consists of only two methods of interest:
- See also:
- decode, which decodes an input block and
finalize, which flushes any remaining data to the output stream.
- See also:
- decode as often as necessary, then call
finalize (most often a single call suffices, but it might be that during that call the output buffer is filled, so you should be prepared to call
finalize as often as necessary, ie. until it returns
true
).
Values
Both methods returntrue
to indicate that they've finished their job. For- See also:
- decode, a return value of
true
means that the current input block has been finished (false
most often means that the output buffer is full, but that isn't required behavior. Thedecode call is free to return at arbitrary times during processing).
- See also:
- finalize, a return value of
true
means that all data implicitly or explicitly stored in the decoder instance has been flushed to the output buffer. Afalse
return value should be interpreted as "check if the output buffer is full and call me again", just as with
Pattern
Since the decoder maintains state, you can only use it once. After a sequence of input blocks has been processed, you- See also:
- finalize the output and then delete the decoder instance. If you want to process another input block sequence, you create a new instance.
in
contains the (base64-encoded) input data), taking into account all the conventions detailed above:
KMime::Codec * codec = KMime::Codec::codecForName( "base64" ); kdFatal( !codec ) << "No codec found for base64!" << endl; KMime::Decoder * dec = codec->makeDecoder(); assert( dec ); // should not happen QByteArray out( 256 ); // small buffer is enough ;-) QByteArray::Iterator iit = in.begin(); QByteArray::Iterator oit = out.begin(); // decode the chunk while ( !dec->decode( iit, in.end(), oit, out.end() ) ) if ( oit == out.end() ) { // output buffer full, process contents do_something_with( out ); oit = out.begin(); } // repeat while loop for each input block // ... // finish (flush remaining data from decoder): while ( !dec->finish( oit, out.end() ) ) if ( oit == out.end() ) { // output buffer full, process contents do_something_with( out ); oit = out.begin(); } // now process last chunk: out.resize( oit - out.begin() ); do_something_with( out ); // _delete_ the decoder, but not the codec: delete dec;
- Author:
- Marc Mutz <mutz@kde.org>
Constructor & Destructor Documentation
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Protected constructor. Use
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Member Function Documentation
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Decode a chunk of data, maintaining state information between calls. See class decumentation for calling conventions. |
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Call this method to finalize the output stream. Writes all remaining data and resets the decoder. See
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The documentation for this class was generated from the following file:
- kmime_codecs.h