Botan::Stream_Compression Class Reference

#include <compression.h>

Inheritance diagram for Botan::Stream_Compression:

Public Member Functions
void	clear () final
void	finish (secure_vector< uint8_t > &buf, size_t offset) final
virtual std::string	name () const =0
void	update (secure_vector< uint8_t > &buf, size_t offset, bool flush) final

Static Public Member Functions
static std::unique_ptr< Compression_Algorithm >	create (std::string_view algo_spec)
static std::unique_ptr< Compression_Algorithm >	create_or_throw (std::string_view algo_spec)

Detailed Description

Used to implement compression using Compression_Stream

Definition at line 211 of file compression.h.

Member Function Documentation

clear()

void Botan::Stream_Compression::clear ( )

finalvirtual

Reset the state and abort the current message; start can be called again to process a new message.

Implements Botan::Compression_Algorithm.

Definition at line 59 of file compress_utils.cpp.

                               {
   m_stream.reset();
}

Referenced by finish().

create()

std::unique_ptr< Compression_Algorithm > Botan::Compression_Algorithm::create ( std::string_view algo_spec )

staticinherited

Create an instance based on a name, or return null if the algo combination cannot be found.

Definition at line 29 of file compression.cpp.

                                                                                      {
#if defined(BOTAN_HAS_ZLIB)
   if(name == "Zlib" || name == "zlib") {
      return std::make_unique<Zlib_Compression>();
   }
   if(name == "Gzip" || name == "gzip" || name == "gz") {
      return std::make_unique<Gzip_Compression>();
   }
   if(name == "Deflate" || name == "deflate") {
      return std::make_unique<Deflate_Compression>();
   }
#endif
 
#if defined(BOTAN_HAS_BZIP2)
   if(name == "bzip2" || name == "bz2" || name == "Bzip2") {
      return std::make_unique<Bzip2_Compression>();
   }
#endif
 
#if defined(BOTAN_HAS_LZMA)
   if(name == "lzma" || name == "xz" || name == "LZMA") {
      return std::make_unique<LZMA_Compression>();
   }
#endif
 
   BOTAN_UNUSED(name);
   return nullptr;
}

References BOTAN_UNUSED, and Botan::Compression_Algorithm::name().

Referenced by Botan::Compression_Algorithm::create_or_throw(), and Botan::make_compressor().

create_or_throw()

std::unique_ptr< Compression_Algorithm > Botan::Compression_Algorithm::create_or_throw ( std::string_view algo_spec )

staticinherited

Create an instance based on a name

Parameters

algo_spec

algorithm name Throws Lookup_Error if not found.

Definition at line 59 of file compression.cpp.

                                                                                               {
   if(auto compressor = Compression_Algorithm::create(algo)) {
      return compressor;
   }
   throw Lookup_Error("Compression", algo, "");
}

References Botan::Compression_Algorithm::create().

finish()

void Botan::Stream_Compression::finish ( secure_vector< uint8_t > & final_block, size_t offset )

finalvirtual

Finish compressing

The buf and offset parameters are treated as in update(). It is acceptable to call start() followed by finish() with the entire message, without any intervening call to update().

Parameters

final_block	in/out parameter
offset	an offset into final_block to begin processing

Implements Botan::Compression_Algorithm.

Definition at line 118 of file compress_utils.cpp.

                                                                          {
   BOTAN_ASSERT(m_stream, "Initialized");
   process(buf, offset, m_stream->finish_flag());
   clear();
}

References BOTAN_ASSERT, and clear().

name()

virtual std::string Botan::Compression_Algorithm::name ( ) const

pure virtualinherited

Returns

name of the compression algorithm

Implemented in Botan::Bzip2_Compression, Botan::Deflate_Compression, Botan::Gzip_Compression, Botan::LZMA_Compression, and Botan::Zlib_Compression.

Referenced by Botan::Compression_Algorithm::create().

update()

void Botan::Stream_Compression::update ( secure_vector< uint8_t > & buf, size_t offset, bool flush )

finalvirtual

Process some data.

The leading offset bytes of buf are ignored and remain untouched; this can be useful for ignoring packet headers. If flush is true, the compression state is flushed, allowing the decompressor to recover the entire message up to this point without having to see the rest of the compressed stream.

Parameters

buf	in/out parameter which will possibly be resized or swapped
offset	an offset into blocks to begin processing
flush	if true the compressor will be told to flush state

Implements Botan::Compression_Algorithm.

Definition at line 113 of file compress_utils.cpp.

                                                                                      {
   BOTAN_ASSERT(m_stream, "Initialized");
   process(buf, offset, flush ? m_stream->flush_flag() : m_stream->run_flag());
}

References BOTAN_ASSERT.

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The documentation for this class was generated from the following files:

• src/lib/compression/compression.h
• src/lib/compression/compress_utils.cpp