diff options
Diffstat (limited to 'src/libutil/hash.cc')
| -rw-r--r-- | src/libutil/hash.cc | 185 |
1 files changed, 88 insertions, 97 deletions
diff --git a/src/libutil/hash.cc b/src/libutil/hash.cc index e6f8aa85c6d8..817ddc0b8bc9 100644 --- a/src/libutil/hash.cc +++ b/src/libutil/hash.cc @@ -16,17 +16,8 @@ namespace nix { -Hash::Hash() +void Hash::init() { - type = htUnknown; - hashSize = 0; - memset(hash, 0, maxHashSize); -} - - -Hash::Hash(HashType type) -{ - this->type = type; if (type == htMD5) hashSize = md5HashSize; else if (type == htSHA1) hashSize = sha1HashSize; else if (type == htSHA256) hashSize = sha256HashSize; @@ -64,16 +55,10 @@ bool Hash::operator < (const Hash & h) const } -std::string Hash::to_string(bool base32) const -{ - return printHashType(type) + ":" + (base32 ? printHash32(*this) : printHash(*this)); -} - - const string base16Chars = "0123456789abcdef"; -string printHash(const Hash & hash) +static string printHash16(const Hash & hash) { char buf[hash.hashSize * 2]; for (unsigned int i = 0; i < hash.hashSize; i++) { @@ -84,42 +69,11 @@ string printHash(const Hash & hash) } -Hash parseHash(const string & s) -{ - string::size_type colon = s.find(':'); - if (colon == string::npos) - throw BadHash(format("invalid hash ‘%s’") % s); - string hts = string(s, 0, colon); - HashType ht = parseHashType(hts); - if (ht == htUnknown) - throw BadHash(format("unknown hash type ‘%s’") % hts); - return parseHash16or32(ht, string(s, colon + 1)); -} - - -Hash parseHash(HashType ht, const string & s) -{ - Hash hash(ht); - if (s.length() != hash.hashSize * 2) - throw BadHash(format("invalid hash ‘%1%’") % s); - for (unsigned int i = 0; i < hash.hashSize; i++) { - string s2(s, i * 2, 2); - if (!isxdigit(s2[0]) || !isxdigit(s2[1])) - throw BadHash(format("invalid hash ‘%1%’") % s); - istringstream_nocopy str(s2); - int n; - str >> std::hex >> n; - hash.hash[i] = n; - } - return hash; -} - - // omitted: E O U T const string base32Chars = "0123456789abcdfghijklmnpqrsvwxyz"; -string printHash32(const Hash & hash) +static string printHash32(const Hash & hash) { assert(hash.hashSize); size_t len = hash.base32Len(); @@ -144,66 +98,103 @@ string printHash32(const Hash & hash) string printHash16or32(const Hash & hash) { - return hash.type == htMD5 ? printHash(hash) : printHash32(hash); + return hash.to_string(hash.type == htMD5 ? Base16 : Base32); } -Hash parseHash32(HashType ht, const string & s) +std::string Hash::to_string(Base base, bool includeType) const { - Hash hash(ht); - size_t len = hash.base32Len(); - assert(s.size() == len); - - for (unsigned int n = 0; n < len; ++n) { - char c = s[len - n - 1]; - unsigned char digit; - for (digit = 0; digit < base32Chars.size(); ++digit) /* !!! slow */ - if (base32Chars[digit] == c) break; - if (digit >= 32) - throw BadHash(format("invalid base-32 hash ‘%1%’") % s); - unsigned int b = n * 5; - unsigned int i = b / 8; - unsigned int j = b % 8; - hash.hash[i] |= digit << j; - - if (i < hash.hashSize - 1) { - hash.hash[i + 1] |= digit >> (8 - j); - } else { - if (digit >> (8 - j)) - throw BadHash(format("invalid base-32 hash ‘%1%’") % s); - } + std::string s; + if (includeType) { + s += printHashType(type); + s += ':'; } - - return hash; + switch (base) { + case Base16: + s += printHash16(*this); + break; + case Base32: + s += printHash32(*this); + break; + case Base64: + s += base64Encode(std::string((const char *) hash, hashSize)); + break; + } + return s; } -Hash parseHash16or32(HashType ht, const string & s) +Hash::Hash(const std::string & s, HashType type) + : type(type) { - Hash hash(ht); - if (s.size() == hash.hashSize * 2) - /* hexadecimal representation */ - hash = parseHash(ht, s); - else if (s.size() == hash.base32Len()) - /* base-32 representation */ - hash = parseHash32(ht, s); - else - throw BadHash(format("hash ‘%1%’ has wrong length for hash type ‘%2%’") - % s % printHashType(ht)); - return hash; -} + auto colon = s.find(':'); + + size_t pos = 0; + + if (colon == string::npos) { + if (type == htUnknown) + throw BadHash("hash ‘%s’ does not include a type", s); + } else { + string hts = string(s, 0, colon); + this->type = parseHashType(hts); + if (this->type == htUnknown) + throw BadHash("unknown hash type ‘%s’", hts); + if (type != htUnknown && type != this->type) + throw BadHash("hash ‘%s’ should have type ‘%s’", s, printHashType(type)); + pos = colon + 1; + } + init(); -bool isHash(const string & s) -{ - if (s.length() != 32) return false; - for (int i = 0; i < 32; i++) { - char c = s[i]; - if (!((c >= '0' && c <= '9') || - (c >= 'a' && c <= 'f'))) - return false; + size_t size = s.size() - pos; + + if (size == base16Len()) { + + auto parseHexDigit = [&](char c) { + if (c >= '0' && c <= '9') return c - '0'; + if (c >= 'A' && c <= 'F') return c - 'A' + 10; + if (c >= 'a' && c <= 'f') return c - 'a' + 10; + throw BadHash("invalid base-16 hash ‘%s’", s); + }; + + for (unsigned int i = 0; i < hashSize; i++) { + hash[i] = + parseHexDigit(s[pos + i * 2]) << 4 + | parseHexDigit(s[pos + i * 2 + 1]); + } } - return true; + + else if (size == base32Len()) { + + for (unsigned int n = 0; n < size; ++n) { + char c = s[pos + size - n - 1]; + unsigned char digit; + for (digit = 0; digit < base32Chars.size(); ++digit) /* !!! slow */ + if (base32Chars[digit] == c) break; + if (digit >= 32) + throw BadHash("invalid base-32 hash ‘%s’", s); + unsigned int b = n * 5; + unsigned int i = b / 8; + unsigned int j = b % 8; + hash[i] |= digit << j; + + if (i < hashSize - 1) { + hash[i + 1] |= digit >> (8 - j); + } else { + if (digit >> (8 - j)) + throw BadHash("invalid base-32 hash ‘%s’", s); + } + } + } + + else if (size == base64Len()) { + auto d = base64Decode(std::string(s, pos)); + assert(d.size() == hashSize); + memcpy(hash, d.data(), hashSize); + } + + else + throw BadHash("hash ‘%s’ has wrong length for hash type ‘%s’", s, printHashType(type)); } |