ParallelHash.h

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#ifndef __PARALLELHASH_H__
#define __PARALLELHASH_H__

#include "PKIFCMSDLL.h"
#include "PKIFCMSUtils.h"

class IPKIFHashContext;
class IPKIFCryptoMisc;

//CPKIFParallelHash is intended for use by CPKIFSignedData.  It could probably be used
//elsewhere if similar, parallel hashing functionality is needed (and Objective 
//structures are used).  It is up to the called to make sure that the IPKIFCryptoMisc
//interface used to create the hash contexts remains active until FreeHashVector has been
//called (which is called by the destructor if necessary).
//
//This class may thrown CPKIFMessageExceptions or CPKIFCryptoExceptions.

struct HashInfo
{
    HashInfo(){m_hashContext = NULL;m_hashAlg = PKIFCRYPTO::SHA1;}
    PKIFCRYPTO::HASH_ALG m_hashAlg;
    IPKIFHashContext* m_hashContext;
    unsigned char m_hashResult[MAXHASH];
};
class PKIFCMS_API CPKIFParallelHash
{
public:
    CPKIFParallelHash();
    virtual ~CPKIFParallelHash();

    //1) Always add ALL hash algorithms that are necessary.
    void SetDigestAlgs(IPKIFCryptoMisc* cMisc, CPKIFBufferPtr digestAlgsBuf);
    void SetDigestAlgs(IPKIFCryptoMisc* cMisc, CCACDigestAlgorithmIdentifiers& digestAlgs);  //added for TAP purposes 9/5/03

    //2) Next, add data iteratively or in a single shot.
    void UpdateMessage(IPKIFCryptoMisc* cMisc, unsigned char* buf, int bufLen); 
    
    //3) After all calls to UpdateMessage have been made call FinalizeHashes to finish the process.
    void FinalizeHashes(IPKIFCryptoMisc* cMisc);

    //4) Call GetHashInfo with a HASH_ALG identifier to retrieve result for that algorithm.
    HashInfo* GetHashInfo(PKIFCRYPTO::HASH_ALG alg);

    //5) Be sure to call FreeHashVector before reusing a CPKIFParallelHash object.
    void FreeHashVector();

    //This class silently ignores unsupported algorithms.  If usage in cases other than CPKIFSignedData
    //is desired this may not be a good thing.  This flag was added to facilitate alternate uses.
    //By default it is set to true.
    void SetIgnoreUnsupportedAlgs(bool b);

private:
    CPKIFParallelHash(const CPKIFParallelHash& copy);
    CPKIFParallelHash& operator=(const CPKIFParallelHash& rhs); //added 4/6/2004

    struct CPKIFParallelHashImpl *m_impl;
};
DECLARE_SMART_POINTERS(CPKIFParallelHash);

#endif //__PARALLELHASH_H__