lix/src/hash.hh
2003-06-16 15:59:23 +00:00

102 lines
2.1 KiB
C++

#ifndef __HASH_H
#define __HASH_H
#include <string>
#include "util.hh"
using namespace std;
struct Hash
{
static const unsigned int hashSize = 16;
unsigned char hash[hashSize];
/* Create a zeroed hash object. */
Hash();
/* Check whether two hash are equal. */
bool operator == (Hash & h2);
/* Check whether two hash are not equal. */
bool operator != (Hash & h2);
/* Convert a hash code into a hexadecimal representation. */
operator string() const;
};
class BadRefError : public Error
{
public:
BadRefError(string _err) : Error(_err) { };
};
/* Parse a hexadecimal representation of a hash code. */
Hash parseHash(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(const string & s);
/* Compute the hash of the given file. */
Hash hashFile(const string & fileName);
/* Compute the hash of the given path. The hash is defined as
follows:
hash(path) = md5(dump(path))
*/
Hash hashPath(const string & path);
/* Dump a path as follows:
IF path points to a REGULAR FILE:
dump(path) = attrs(
[ ("type", "regular")
, ("contents", contents(path))
])
IF path points to a DIRECTORY:
dump(path) = attrs(
[ ("type", "directory")
, ("entries", concat(map(f, sort(entries(path)))))
])
where f(fn) = attrs(
[ ("name", fn)
, ("file", dump(path + "/" + fn))
])
where:
attrs(as) = concat(map(attr, as)) + encN(0)
attrs((a, b)) = encS(a) + encS(b)
encS(s) = encN(len(s)) + s + (padding until next 64-bit boundary)
encN(n) = 64-bit little-endian encoding of n.
contents(path) = the contents of a regular file.
sort(strings) = lexicographic sort by 8-bit value (strcmp).
entries(path) = the entries of a directory, without `.' and
`..'.
`+' denotes string concatenation. */
struct DumpSink
{
virtual void operator () (const unsigned char * data, unsigned int len) = 0;
};
void dumpPath(const string & path, DumpSink & sink);
#endif /* !__HASH_H */