// trans.h// new transformation interface; only considers one direction at a time//   (security.h is *protocol* primitives,//    trans.h is *cryptographic* primitives)// copyright SafeTP Development Group, Inc., 2000  Terms of use are as specified in license.txt#ifndef __TRANS_H#define __TRANS_H#include "typ.h"          // byte, boolclass DataBlock;          // datablok.h// object to transform dataclass Trans {public:  virtual ~Trans();  // size relationships  virtual int minInputSize() const;    // minimum bytes of input    // default: returns 0  virtual int maxInputSize() const;    // maximum bytes of input    // default: returns MAXINT  virtual int minOutputSize(int inputSize) const;    // minimum bytes of output for a given input size    // default: returns inputSize  virtual int maxOutputSize(int inputSize) const;    // maximum bytes of output for a given input size    // default: returns inputSize  // actual transform (in-place)  virtual void trans(DataBlock &data);    // changes 'data' to be the output    // should call data.ensureAllocated(outputsize), to make sure the buffer    //   will be big enough under any circumstances, but also take advantage    //   of times when it already is    // default: does nothing (identity transform)  void checkingTrans(DataBlock &data);    // same as 'trans', but min/maxOutputSize is verified    // (for debugging purposes)};// a transform and its inverseclass TransPair {public:  Trans &encoder, &decoder;public:  TransPair(Trans &enc, Trans &dec)    : encoder(enc), decoder(dec) {}  // test that the transform+inverse pair == identity; returns true  // if all tests succeed  bool test(int randIters, bool echo=false);  bool testBuffer(byte const *data, int length, bool echo=false);  // initialize a non-crypto-strength random generator, for  // calls to 'test'  static void initRandom();};#endif // __TRANS_H