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#pragma once
#include "libutil/serialise.hh"
#include "libutil/types.hh"
namespace nix {
MakeError(BadHash, Error);
enum HashType : char { htUnknown, htMD5, htSHA1, htSHA256, htSHA512 };
const int md5HashSize = 16;
const int sha1HashSize = 20;
const int sha256HashSize = 32;
const int sha512HashSize = 64;
enum Base : int { Base64, Base32, Base16, SRI };
struct Hash {
static const unsigned int maxHashSize = 64;
unsigned int hashSize = 0;
unsigned char hash[maxHashSize] = {};
HashType type = htUnknown;
/* Create an unset hash object. */
Hash(){};
/* Create a zero-filled hash object. */
Hash(HashType type) : type(type) { init(); };
/* Initialize the hash from a string representation, in the format
"[<type>:]<base16|base32|base64>" or "<type>-<base64>" (a
Subresource Integrity hash expression). If the 'type' argument
is htUnknown, then the hash type must be specified in the
string. */
Hash(const std::string& s, HashType type = htUnknown);
void init();
/* Check whether a hash is set. */
operator bool() const { return type != htUnknown; }
/* 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;
/* Returns the length of a base-16 representation of this hash. */
size_t base16Len() const { return hashSize * 2; }
/* Returns the length of a base-32 representation of this hash. */
size_t base32Len() const { return (hashSize * 8 - 1) / 5 + 1; }
/* Returns the length of a base-64 representation of this hash. */
size_t base64Len() const { return ((4 * hashSize / 3) + 3) & ~3; }
/* Return a string representation of the hash, in base-16, base-32
or base-64. By default, this is prefixed by the hash type
(e.g. "sha256:"). */
std::string to_string(Base base = Base32, bool includeType = true) const;
/* Returns whether the passed string contains entirely valid base32
characters. */
static bool IsValidBase32(absl::string_view s);
};
/* Print a hash in base-16 if it's MD5, or base-32 otherwise. */
std::string printHash16or32(const Hash& hash);
/* Compute the hash of the given string. */
Hash hashString(HashType ht, const std::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)). */
typedef std::pair<Hash, unsigned long long> HashResult;
HashResult 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 std::string& s);
/* And the reverse. */
std::string printHashType(HashType ht);
union Ctx;
class HashSink : public BufferedSink {
private:
HashType ht;
Ctx* ctx;
unsigned long long bytes;
public:
HashSink(HashType ht);
HashSink(const HashSink& h);
~HashSink();
void write(const unsigned char* data, size_t len);
HashResult finish();
HashResult currentHash();
};
} // namespace nix
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