First commit of file entropy analyzer.

- Code comments need cleaned up still.

src/file_analysis/analyzer/entropy/Entropy.h

@@ -0,0 +1,84 @@
+// See the file "COPYING" in the main distribution directory for copyright.
+
+#ifndef FILE_ANALYSIS_ENTROPY_H
+#define FILE_ANALYSIS_ENTROPY_H
+
+#include <string>
+
+#include "Val.h"
+#include "OpaqueVal.h"
+#include "File.h"
+#include "Analyzer.h"
+
+#include "events.bif.h"
+
+namespace file_analysis {
+
+/**
+ * An analyzer to produce a hash of file contents.
+ */
+class Entropy : public file_analysis::Analyzer {
+public:
+
+	/**
+	 * Destructor.
+	 */
+	virtual ~Entropy();
+
+	/**
+	 * Create a new instance of an Extract analyzer.
+	 * @param args the \c AnalyzerArgs value which represents the analyzer.
+	 * @param file the file to which the analyzer will be attached.
+	 * @return the new Extract analyzer instance or a null pointer if the
+	 *         the "extraction_file" field of \a args wasn't set.
+	 */
+	static file_analysis::Analyzer* Instantiate(RecordVal* args, File* file);
+
+	/**
+	 * Incrementally hash next chunk of file contents.
+	 * @param data pointer to start of a chunk of a file data.
+	 * @param len number of bytes in the data chunk.
+	 * @return false if the digest is in an invalid state, else true.
+	 */
+	virtual bool DeliverStream(const u_char* data, uint64 len);
+
+	/**
+	 * Finalizes the hash and raises a "file_entropy_test" event.
+	 * @return always false so analyze will be deteched from file.
+	 */
+	virtual bool EndOfFile();
+
+	/**
+	 * Missing data can't be handled, so just indicate the this analyzer should
+	 * be removed from receiving further data.  The hash will not be finalized.
+	 * @param offset byte offset in file at which missing chunk starts.
+	 * @param len number of missing bytes.
+	 * @return always false so analyzer will detach from file.
+	 */
+	virtual bool Undelivered(uint64 offset, uint64 len);
+
+protected:
+
+	/**
+	 * Constructor.
+	 * @param args the \c AnalyzerArgs value which represents the analyzer.
+	 * @param file the file to which the analyzer will be attached.
+	 * @param hv specific hash calculator object.
+	 * @param kind human readable name of the hash algorithm to use.
+	 */
+	Entropy(RecordVal* args, File* file);
+
+	/**
+	 * If some file contents have been seen, finalizes the hash of them and
+	 * raises the "file_hash" event with the results.
+	 */
+	void Finalize();
+
+private:
+	EntropyVal* entropy;
+	bool fed;
+};
+
+} // namespace file_analysis
+
+#endif