lix/src/libutil/hash.hh
Eelco Dolstra a3e6415ba8 * New primop builtins.filterSource, which can be used to filter files
from a source directory.  All files for which a predicate function
  returns true are copied to the store.  Typical example is to leave
  out the .svn directory:

    stdenv.mkDerivation {
      ...
      src = builtins.filterSource
        (path: baseNameOf (toString path) != ".svn")
        ./source-dir;
      # as opposed to
      #   src = ./source-dir;
    }

  This is important because the .svn directory influences the hash in
  a rather unpredictable and variable way.
2006-12-12 23:05:01 +00:00

89 lines
2.1 KiB
C++

#ifndef __HASH_H
#define __HASH_H
#include "types.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);
}
#endif /* !__HASH_H */