1 files changed, 147 insertions, 0 deletions
diff --git a/src/algo_base/buf_comp.h b/src/algo_base/buf_comp.h
new file mode 100644
index 000000000..ec9b89152
--- /dev/null
+++ b/src/algo_base/buf_comp.h
@@ -0,0 +1,147 @@
+/*
+* Buffered Computation
+* (C) 1999-2007 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_BUFFERED_COMPUTATION_H__
+#define BOTAN_BUFFERED_COMPUTATION_H__
+
+#include <botan/secmem.h>
+#include <botan/get_byte.h>
+
+namespace Botan {
+
+/**
+* This class represents any kind of computation which uses an internal
+* state, such as hash functions or MACs
+*/
+class BOTAN_DLL Buffered_Computation
+   {
+   public:
+      /**
+      * @return length of the output of this function in bytes
+      */
+      virtual size_t output_length() const = 0;
+
+      /**
+      * Add new input to process.
+      * @param in the input to process as a byte array
+      * @param length of param in in bytes
+      */
+      void update(const byte in[], size_t length) { add_data(in, length); }
+
+      /**
+      * Add new input to process.
+      * @param in the input to process as a MemoryRegion
+      */
+      void update(const MemoryRegion<byte>& in)
+         {
+         add_data(&in[0], in.size());
+         }
+
+      /**
+      * Add an integer in big-endian order
+      * @param in the value
+      */
+      template<typename T> void update_be(const T in)
+         {
+         for(size_t i = 0; i != sizeof(T); ++i)
+            {
+            byte b = get_byte(i, in);
+            add_data(&b, 1);
+            }
+         }
+
+      /**
+      * Add new input to process.
+      * @param str the input to process as a std::string. Will be interpreted
+      * as a byte array based on
+      * the strings encoding.
+      */
+      void update(const std::string& str)
+         {
+         add_data(reinterpret_cast<const byte*>(str.data()), str.size());
+         }
+
+      /**
+      * Process a single byte.
+      * @param in the byte to process
+      */
+      void update(byte in) { add_data(&in, 1); }
+
+      /**
+      * Complete the computation and retrieve the
+      * final result.
+      * @param out The byte array to be filled with the result.
+      * Must be of length output_length()
+      */
+      void final(byte out[]) { final_result(out); }
+
+      /**
+      * Complete the computation and retrieve the
+      * final result.
+      * @return SecureVector holding the result
+      */
+      SecureVector<byte> final()
+         {
+         SecureVector<byte> output(output_length());
+         final_result(&output[0]);
+         return output;
+         }
+
+      /**
+      * Update and finalize computation. Does the same as calling update()
+      * and final() consecutively.
+      * @param in the input to process as a byte array
+      * @param length the length of the byte array
+      * @result the result of the call to final()
+      */
+      SecureVector<byte> process(const byte in[], size_t length)
+         {
+         add_data(in, length);
+         return final();
+         }
+
+      /**
+      * Update and finalize computation. Does the same as calling update()
+      * and final() consecutively.
+      * @param in the input to process
+      * @result the result of the call to final()
+      */
+      SecureVector<byte> process(const MemoryRegion<byte>& in)
+         {
+         add_data(&in[0], in.size());
+         return final();
+         }
+
+      /**
+      * Update and finalize computation. Does the same as calling update()
+      * and final() consecutively.
+      * @param in the input to process as a string
+      * @result the result of the call to final()
+      */
+      SecureVector<byte> process(const std::string& in)
+         {
+         update(in);
+         return final();
+         }
+   private:
+      /**
+      * Add more data to the computation
+      * @param input is an input buffer
+      * @param length is the length of input in bytes
+      */
+      virtual void add_data(const byte input[], size_t length) = 0;
+
+      /**
+      * Write the final output to out
+      * @param out is an output buffer of output_length()
+      */
+      virtual void final_result(byte out[]) = 0;
+   };
+
+}
+
+#endif