1 files changed, 189 insertions, 0 deletions
diff --git a/src/lib/compression/compress_utils.cpp b/src/lib/compression/compress_utils.cpp
new file mode 100644
index 000000000..2af629b9c
--- /dev/null
+++ b/src/lib/compression/compress_utils.cpp
@@ -0,0 +1,189 @@
+/*
+* Compression Utils
+* (C) 2014,2016 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/internal/compress_utils.h>
+#include <botan/exceptn.h>
+
+namespace Botan {
+
+void* Compression_Alloc_Info::do_malloc(size_t n, size_t size)
+   {
+   const size_t total_size = n * size;
+
+   BOTAN_ASSERT_EQUAL(total_size / size, n, "Overflow check");
+
+   // TODO maximum length check here?
+
+   void* ptr = std::malloc(total_size);
+
+   /*
+   * Return null rather than throwing here as we are being called by a
+   * C library and it may not be possible for an exception to unwind
+   * the call stack from here. The compression library is expecting a
+   * function written in C and a null return on error, which it will
+   * send upwards to the compression wrappers.
+   */
+
+   if(ptr)
+      {
+      std::memset(ptr, 0, total_size);
+      m_current_allocs[ptr] = total_size;
+      }
+
+   return ptr;
+   }
+
+void Compression_Alloc_Info::do_free(void* ptr)
+   {
+   if(ptr)
+      {
+      auto i = m_current_allocs.find(ptr);
+
+      if(i == m_current_allocs.end())
+         throw Exception("Compression_Alloc_Info::free got pointer not allocated by us");
+
+      zero_mem(ptr, i->second);
+      std::free(ptr);
+      m_current_allocs.erase(i);
+      }
+   }
+
+void Stream_Compression::clear()
+   {
+   m_stream.reset();
+   }
+
+void Stream_Compression::start(size_t level)
+   {
+   m_stream.reset(make_stream(level));
+   }
+
+void Stream_Compression::process(secure_vector<byte>& buf, size_t offset, u32bit flags)
+   {
+   BOTAN_ASSERT(m_stream, "Initialized");
+   BOTAN_ASSERT(buf.size() >= offset, "Offset is sane");
+
+   if(m_buffer.size() < buf.size() + offset)
+      m_buffer.resize(buf.size() + offset);
+
+   // If the output buffer has zero length, .data() might return nullptr. This would
+   // make some compression algorithms (notably those provided by zlib) fail.
+   // Any small positive value works fine, but we choose 32 as it is the smallest power
+   // of two that is large enough to hold all the headers and trailers of the common
+   // formats, preventing further resizings to make room for output data.
+   if(m_buffer.size() == 0)
+      m_buffer.resize(32);
+
+   m_stream->next_in(buf.data() + offset, buf.size() - offset);
+   m_stream->next_out(m_buffer.data() + offset, m_buffer.size() - offset);
+
+   while(true)
+      {
+      m_stream->run(flags);
+
+      if(m_stream->avail_out() == 0)
+         {
+         const size_t added = 8 + m_buffer.size();
+         m_buffer.resize(m_buffer.size() + added);
+         m_stream->next_out(m_buffer.data() + m_buffer.size() - added, added);
+         }
+      else if(m_stream->avail_in() == 0)
+         {
+         m_buffer.resize(m_buffer.size() - m_stream->avail_out());
+         break;
+         }
+      }
+
+   copy_mem(m_buffer.data(), buf.data(), offset);
+   buf.swap(m_buffer);
+   }
+
+void Stream_Compression::update(secure_vector<byte>& buf, size_t offset, bool flush)
+   {
+   BOTAN_ASSERT(m_stream, "Initialized");
+   process(buf, offset, flush ? m_stream->flush_flag() : m_stream->run_flag());
+   }
+
+void Stream_Compression::finish(secure_vector<byte>& buf, size_t offset)
+   {
+   BOTAN_ASSERT(m_stream, "Initialized");
+   process(buf, offset, m_stream->finish_flag());
+   clear();
+   }
+
+void Stream_Decompression::clear()
+   {
+   m_stream.reset();
+   }
+
+void Stream_Decompression::start()
+   {
+   m_stream.reset(make_stream());
+   }
+
+void Stream_Decompression::process(secure_vector<byte>& buf, size_t offset, u32bit flags)
+   {
+   BOTAN_ASSERT(m_stream, "Initialized");
+   BOTAN_ASSERT(buf.size() >= offset, "Offset is sane");
+
+   if(m_buffer.size() < buf.size() + offset)
+      m_buffer.resize(buf.size() + offset);
+
+   m_stream->next_in(buf.data() + offset, buf.size() - offset);
+   m_stream->next_out(m_buffer.data() + offset, m_buffer.size() - offset);
+
+   while(true)
+      {
+      const bool stream_end = m_stream->run(flags);
+
+      if(stream_end)
+         {
+         if(m_stream->avail_in() == 0) // all data consumed?
+            {
+            m_buffer.resize(m_buffer.size() - m_stream->avail_out());
+            clear();
+            break;
+            }
+
+         // More data follows: try to process as a following stream
+         const size_t read = (buf.size() - offset) - m_stream->avail_in();
+         start();
+         m_stream->next_in(buf.data() + offset + read, buf.size() - offset - read);
+         }
+
+      if(m_stream->avail_out() == 0)
+         {
+         const size_t added = 8 + m_buffer.size();
+         m_buffer.resize(m_buffer.size() + added);
+         m_stream->next_out(m_buffer.data() + m_buffer.size() - added, added);
+         }
+      else if(m_stream->avail_in() == 0)
+         {
+         m_buffer.resize(m_buffer.size() - m_stream->avail_out());
+         break;
+         }
+      }
+
+   copy_mem(m_buffer.data(), buf.data(), offset);
+   buf.swap(m_buffer);
+   }
+
+void Stream_Decompression::update(secure_vector<byte>& buf, size_t offset)
+   {
+   process(buf, offset, m_stream->run_flag());
+   }
+
+void Stream_Decompression::finish(secure_vector<byte>& buf, size_t offset)
+   {
+   if(buf.size() != offset || m_stream.get())
+      process(buf, offset, m_stream->finish_flag());
+
+   if(m_stream.get())
+      throw Exception(name() + " finished but not at stream end");
+   }
+
+}