Add:
- two stream buffer classes (ZlibCompressorIStreambuf and
ZlibDecompressorIStreambuf), both based on the same abstract class:
ZlibAbstractIStreambuf;
- two std::istream subclasses (ZlibCompressorIStream and
ZlibDecompressorIStream), each creating and using the corresponding
stream buffer class from the previous item.
All these allow one to work with RFC 1950 and RFC 1952 compression
formats, respectively known as the zlib and gzip formats.
These classes are *input* streaming classes, which means they can
efficiently handle arbitrary amounts of data without using any disk
space nor increasing amounts of memory, and allow "client code" to pull
exactly as much data as it wants at any given time, resuming later when
it is ready to handle the next chunk.
See comments in simgear/io/iostreams/zlibstream.hxx for more details.
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