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#ifndef _DIGEST_H
#define _DIGEST_H

#include <sys/types.h>
#include <stdint.h>
#include <CommonCrypto/CommonDigest.h>

#include "Utils.h"

////
//  Digest
//
//  Digest is the abstract root class for all message digest algorithms
//  supported by darwinup. Subclasses must implement the constructors 
//  and digest() APIs.
//
//  SHA1Digest is the only concrete subclass.  There are two
//  subclasses of SHA1Digest which add convenience functions
//  for digesting a canonicalized Mach-O binary, and the
//  target of a symlink obtained by readlink(2).
//
////

struct Digest {
	
	////
	//  Accessor functions
	////
	
	// Returns the raw digest.
	virtual	uint8_t*	data();

	// Returns the size of the raw digest.
	virtual uint32_t	size();
	
	// Returns the digest as an ASCII string, represented in hexidecimal.
	virtual char*		string();
    
    virtual ~Digest();
	
	////
	//  Class functions
	////
	
	// Compares two digest objects for equality.
	// Returns 1 if equal, 0 if not.
	static	int		equal(Digest* a, Digest* b);


	protected:

	virtual	void	digest(unsigned char* md, int fd) = 0;
	virtual	void	digest(unsigned char* md, uint8_t* data, uint32_t size) = 0;

	unsigned char m_data[CC_SHA512_DIGEST_LENGTH]; // support up to 64 bytes
	uint32_t	  m_size;
	
	friend struct Depot;
	friend struct DarwinupDatabase;
};

////
//  SHA1Digest
////
struct SHA1Digest : Digest {
	// Creates an empty digest.
	SHA1Digest();
    	
	// Computes the SHA-1 digest of data read from the stream.
	SHA1Digest(int fd);
	
	// Computes the SHA-1 digest of data in the file.
	SHA1Digest(const char* filename);
	
	// Computes the SHA-1 digest of the block of memory.
	SHA1Digest(uint8_t* data, uint32_t size);
	
    ~SHA1Digest();

	void	digest(unsigned char* md, int fd);
	void	digest(unsigned char* md, uint8_t* data, uint32_t size);

};

////
//  SHA1DigestSymlink
//  Digests of the target of a symlink.
////
struct SHA1DigestSymlink : SHA1Digest {
	// Computes the SHA-1 digest of the target of the symlink.
	// The target is obtained via readlink(2).
	SHA1DigestSymlink(const char* filename);
    ~SHA1DigestSymlink();
};

#endif