1 files changed, 120 insertions, 0 deletions
diff --git a/src/utils/buf_op/buf_op.cpp b/src/utils/buf_op/buf_op.cpp
new file mode 100644
index 000000000..2b5b943cd
--- /dev/null
+++ b/src/utils/buf_op/buf_op.cpp
@@ -0,0 +1,120 @@
+/**
+* Buffering Central
+* (C) 2009 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/buf_op.h>
+#include <botan/mem_ops.h>
+#include <botan/internal/rounding.h>
+#include <stdexcept>
+
+#include <stdio.h>
+#include <assert.h>
+
+namespace Botan {
+
+namespace {
+
+const size_t BUFFER_MULTIPLE = 2;
+
+//static_assert(BUFFER_MULTIPLE >= 2, "BUFFER_MULTIPLE must be >= 2");
+
+}
+
+Buffered_Operation::Buffered_Operation(callback_fn m_fn,
+                                       callback_fn f_fn,
+                                       size_t buf_mod,
+                                       size_t final_minimum) :
+   main_fn(m_fn), final_fn(f_fn),
+   final_minimum(final_minimum), main_block_mod(buf_mod),
+   buffer(BUFFER_MULTIPLE * buf_mod), buffer_pos(0)
+   {
+   if(buf_mod == 0)
+      throw std::invalid_argument("buf_mod == 0");
+
+   if(final_minimum > buf_mod)
+      throw std::invalid_argument("final_minimum > buf_mod");
+   }
+
+void Buffered_Operation::reset()
+   {
+   clear_mem(&buffer[0], buffer.size());
+   buffer_pos = 0;
+   }
+
+void Buffered_Operation::write(const byte input[],
+                               size_t input_size)
+   {
+   if(!input_size)
+      return;
+
+   if(buffer_pos + input_size >= main_block_mod + final_minimum)
+      {
+      size_t to_copy = std::min(buffer.size() - buffer_pos, input_size);
+
+      copy_mem(&buffer[buffer_pos], input, to_copy);
+      buffer_pos += to_copy;
+
+      input += to_copy;
+      input_size -= to_copy;
+
+      if(input_size >= final_minimum)
+         {
+         size_t to_proc = round_down(buffer_pos, main_block_mod);
+         main_fn(&buffer[0], to_proc);
+
+         buffer_pos -= to_proc;
+
+         copy_mem(&buffer[0], &buffer[to_proc], buffer_pos);
+         }
+      }
+
+   if(input_size >= final_minimum)
+      {
+      size_t full_blocks = (input_size - final_minimum) / buffer.size();
+      size_t to_copy = full_blocks * buffer.size();
+
+      if(to_copy)
+         {
+         main_fn(input, to_copy);
+
+         input += to_copy;
+         input_size -= to_copy;
+         }
+      }
+
+   assert(input_size + buffer_pos <= buffer.size());
+
+   copy_mem(&buffer[buffer_pos], input, input_size);
+   buffer_pos += input_size;
+   }
+
+void Buffered_Operation::final()
+   {
+   assert(buffer_pos >= final_minimum);
+
+   if(buffer_pos < final_minimum)
+      throw std::runtime_error("Buffered_Operation::final - not enough input");
+
+   size_t spare_blocks = (buffer_pos - final_minimum) / main_block_mod;
+
+   if(spare_blocks)
+      {
+      size_t spare_bytes = main_block_mod * spare_blocks;
+
+      assert(spare_bytes <= buffer_pos);
+
+      main_fn(&buffer[0], spare_bytes);
+
+      assert(buffer_pos - spare_bytes >= final_minimum);
+      final_fn(&buffer[spare_bytes], buffer_pos - spare_bytes);
+      }
+   else
+      {
+      final_fn(&buffer[0], buffer_pos);
+      }
+   }
+
+}