d58a11e019
bits, then encode them in a radix-32 representation (using digits and letters except e, o, u, and t). This produces store paths like /nix/store/4i0zb0z7f88mwghjirkz702a71dcfivn-aterm-2.3.1. The nice thing about this is that the hash part of the file name is still 32 characters, as before with MD5. (Of course, shortening SHA-256 to 160 bits makes it no better than SHA-160 in theory, but hopefully it's a bit more resistant to attacks; it's certainly a lot slower.)
76 lines
1.7 KiB
C++
76 lines
1.7 KiB
C++
#ifndef __HASH_H
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#define __HASH_H
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#include <string>
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#include "util.hh"
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using namespace std;
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typedef enum { htUnknown, htMD5, htSHA1, htSHA256 } HashType;
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const int md5HashSize = 16;
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const int sha1HashSize = 20;
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const int sha256HashSize = 32;
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struct Hash
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{
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static const unsigned int maxHashSize = 32;
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unsigned int hashSize;
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unsigned char hash[maxHashSize];
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HashType type;
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/* Create an unusable hash object. */
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Hash();
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/* Create a zero-filled hash object. */
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Hash(HashType type);
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/* Check whether two hash are equal. */
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bool operator == (const Hash & h2) const;
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/* Check whether two hash are not equal. */
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bool operator != (const Hash & h2) const;
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/* For sorting. */
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bool operator < (const Hash & h) const;
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};
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/* Convert a hash to a hexadecimal representation. */
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string printHash(const Hash & hash);
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/* Parse a hexadecimal representation of a hash code. */
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Hash parseHash(HashType ht, const string & s);
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/* Convert a hash to a base-32 representation. */
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string printHash32(const Hash & hash);
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/* Parse a base-32 representation of a hash code. */
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Hash parseHash32(HashType ht, const string & s);
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/* Verify that the given string is a valid hash code. */
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bool isHash(const string & s);
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/* Compute the hash of the given string. */
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Hash hashString(const string & s, HashType ht);
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/* Compute the hash of the given file. */
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Hash hashFile(const Path & path, HashType ht);
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/* Compute the hash of the given path. The hash is defined as
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md5(dump(path)). */
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Hash hashPath(const Path & path, HashType ht);
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/* Compress a hash to the specified number of bytes by cyclically
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XORing bytes together. */
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Hash compressHash(const Hash & hash, unsigned int newSize);
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#endif /* !__HASH_H */
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