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, 152 insertions, 0 deletions

diff --git a/src/lib/compression/compression.cpp b/src/lib/compression/compression.cpp
new file mode 100644
index 000000000..3eb26e81b
--- /dev/null
+++ b/src/lib/compression/compression.cpp
@@ -0,0 +1,152 @@
+/*
+* Compression Transform
+* (C) 2014 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/compression.h>
+
+namespace Botan {
+
+void Stream_Compression::clear()
+   {
+   m_stream.reset();
+   }
+
+secure_vector<byte> Stream_Compression::start_raw(const byte[], size_t nonce_len)
+   {
+   if(!valid_nonce_length(nonce_len))
+      throw Invalid_IV_Length(name(), nonce_len);
+
+   clear();
+   m_stream.reset(make_stream());
+   return secure_vector<byte>();
+   }
+
+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);
+
+   m_stream->next_in(&buf[offset], buf.size() - offset);
+   m_stream->next_out(&m_buffer[offset], m_buffer.size() - offset);
+
+   while(true)
+      {
+      const bool end = 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[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[0], &buf[0], offset);
+   buf.swap(m_buffer);
+   }
+
+void Stream_Compression::update(secure_vector<byte>& buf, size_t offset)
+   {
+   process(buf, offset, m_stream->run_flag());
+   }
+
+void Stream_Compression::flush(secure_vector<byte>& buf, size_t offset)
+   {
+   process(buf, offset, m_stream->flush_flag());
+   }
+
+void Stream_Compression::finish(secure_vector<byte>& buf, size_t offset)
+   {
+   process(buf, offset, m_stream->finish_flag());
+   clear();
+   }
+
+void Stream_Decompression::clear()
+   {
+   m_stream.reset();
+   }
+
+secure_vector<byte> Stream_Decompression::start_raw(const byte[], size_t nonce_len)
+   {
+   if(!valid_nonce_length(nonce_len))
+      throw Invalid_IV_Length(name(), nonce_len);
+
+   clear();
+   m_stream.reset(make_stream());
+
+   return secure_vector<byte>();
+   }
+
+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[offset], buf.size() - offset);
+   m_stream->next_out(&m_buffer[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[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[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[0], &buf[0], 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 std::runtime_error(name() + " finished but not at stream end");
+   }
+
+}