tvl-depot/src/libutil/hash.hh
2008-12-03 16:10:17 +00:00

108 lines
2.4 KiB
C++

#ifndef __HASH_H
#define __HASH_H
#include "types.hh"
#include "serialise.hh"
namespace nix {
typedef enum { htUnknown, htMD5, htSHA1, htSHA256 } HashType;
const int md5HashSize = 16;
const int sha1HashSize = 20;
const int sha256HashSize = 32;
extern const string base32Chars;
struct Hash
{
static const unsigned int maxHashSize = 32;
unsigned int hashSize;
unsigned char hash[maxHashSize];
HashType type;
/* Create an unusable hash object. */
Hash();
/* Create a zero-filled hash object. */
Hash(HashType type);
/* Check whether two hash are equal. */
bool operator == (const Hash & h2) const;
/* Check whether two hash are not equal. */
bool operator != (const Hash & h2) const;
/* For sorting. */
bool operator < (const Hash & h) const;
};
/* Convert a hash to a hexadecimal representation. */
string printHash(const Hash & hash);
/* Parse a hexadecimal representation of a hash code. */
Hash parseHash(HashType ht, const string & s);
/* Returns the length of a base-32 hash representation. */
unsigned int hashLength32(const Hash & hash);
/* Convert a hash to a base-32 representation. */
string printHash32(const Hash & hash);
/* Parse a base-32 representation of a hash code. */
Hash parseHash32(HashType ht, const string & s);
/* Verify that the given string is a valid hash code. */
bool isHash(const string & s);
/* Compute the hash of the given string. */
Hash hashString(HashType ht, const string & s);
/* Compute the hash of the given file. */
Hash hashFile(HashType ht, const Path & path);
/* Compute the hash of the given path. The hash is defined as
(essentially) hashString(ht, dumpPath(path)). */
struct PathFilter;
extern PathFilter defaultPathFilter;
Hash hashPath(HashType ht, const Path & path,
PathFilter & filter = defaultPathFilter);
/* Compress a hash to the specified number of bytes by cyclically
XORing bytes together. */
Hash compressHash(const Hash & hash, unsigned int newSize);
/* Parse a string representing a hash type. */
HashType parseHashType(const string & s);
/* And the reverse. */
string printHashType(HashType ht);
union Ctx;
class HashSink : public Sink
{
private:
HashType ht;
Ctx * ctx;
public:
HashSink(HashType ht);
~HashSink();
virtual void operator () (const unsigned char * data, unsigned int len);
Hash finish();
};
}
#endif /* !__HASH_H */