Convert compression filters to in-place transforms and refactor

to minimize the amount of logic needed in the files specific to each
library.

1 files changed, 90 insertions, 0 deletions

diff --git a/src/lib/compression/comp_util.h b/src/lib/compression/comp_util.h
new file mode 100644
index 000000000..15fc23418
--- /dev/null
+++ b/src/lib/compression/comp_util.h
@@ -0,0 +1,90 @@
+/*
+* Shared code for compression libraries
+* (C) 2014 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_COMPRESSION_UTILS_H__
+#define BOTAN_COMPRESSION_UTILS_H__
+
+#include <botan/compression.h>
+#include <cstring>
+#include <memory>
+#include <unordered_map>
+
+namespace Botan {
+
+/*
+* Allocation Size Tracking Helper for Zlib/Bzlib/LZMA
+*/
+class Compression_Alloc_Info
+   {
+   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>
+class Zlib_Style_Stream : public Compression_Stream
+   {
+   public:
+      void next_in(byte* b, size_t len) override
+         {
+         m_stream.next_in = reinterpret_cast<ByteType*>(b);
+         m_stream.avail_in = len;
+         }
+
+      void next_out(byte* b, size_t len) override
+         {
+         m_stream.next_out = reinterpret_cast<ByteType*>(b);
+         m_stream.avail_out = 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()
+         {
+         std::memset(&m_stream, 0, sizeof(stream_t));
+         m_allocs.reset(new Compression_Alloc_Info);
+         }
+
+      ~Zlib_Style_Stream()
+         {
+         std::memset(&m_stream, 0, sizeof(stream_t));
+         m_allocs.reset();
+         }
+
+   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