compress_utils.h

Go to the documentation of this file.

/*
* Compression utility header
* (C) 2014 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
 
#ifndef BOTAN_COMPRESSION_UTILS_H_
#define BOTAN_COMPRESSION_UTILS_H_
 
#include <botan/compression.h>
#include <memory>
#include <unordered_map>
 
namespace Botan {
 
/*
* Allocation Size Tracking Helper for Zlib/Bzlib/LZMA
*/
class Compression_Alloc_Info final
   {
   public:
      template<typename T>
      static void* malloc(void* self, T n, T size)
         {
         return static_cast<Compression_Alloc_Info*>(self)->do_malloc(n, size);
         }
 
      static void free(void* self, void* ptr)
         {
         static_cast<Compression_Alloc_Info*>(self)->do_free(ptr);
         }
 
   private:
      void* do_malloc(size_t n, size_t size);
      void do_free(void* ptr);
 
      std::unordered_map<void*, size_t> m_current_allocs;
   };
 
/**
* Wrapper for Zlib/Bzlib/LZMA stream types
*/
template<typename Stream, typename ByteType, typename StreamLenType = size_t>
class Zlib_Style_Stream : public Compression_Stream
   {
   public:
      void next_in(uint8_t* b, size_t len) override
         {
         m_stream.next_in = reinterpret_cast<ByteType*>(b);
         m_stream.avail_in = static_cast<StreamLenType>(len);
         }
 
      void next_out(uint8_t* b, size_t len) override
         {
         m_stream.next_out = reinterpret_cast<ByteType*>(b);
         m_stream.avail_out = static_cast<StreamLenType>(len);
         }
 
      size_t avail_in() const override { return m_stream.avail_in; }
 
      size_t avail_out() const override { return m_stream.avail_out; }
 
      Zlib_Style_Stream() :
         m_allocs(std::make_unique<Compression_Alloc_Info>())
         {
         clear_mem(&m_stream, 1);
         }
 
      ~Zlib_Style_Stream()
         {
         clear_mem(&m_stream, 1);
         }
 
   protected:
      typedef Stream stream_t;
 
      stream_t* streamp() { return &m_stream; }
 
      Compression_Alloc_Info* alloc() { return m_allocs.get(); }
   private:
      stream_t m_stream;
      std::unique_ptr<Compression_Alloc_Info> m_allocs;
   };
 
}
 
#endif