diff options
| -rw-r--r-- | nix/libutil/hash.cc | 49 |
1 files changed, 11 insertions, 38 deletions
diff --git a/nix/libutil/hash.cc b/nix/libutil/hash.cc index 0036e73cdd..2da00a53de 100644 --- a/nix/libutil/hash.cc +++ b/nix/libutil/hash.cc @@ -141,51 +141,24 @@ string printHash16or32(const Hash & hash) } -static bool mul(unsigned char * bytes, unsigned char y, int maxSize) -{ - unsigned char carry = 0; - - for (int pos = 0; pos < maxSize; ++pos) { - unsigned int m = bytes[pos] * y + carry; - bytes[pos] = m & 0xff; - carry = m >> 8; - } - - return carry; -} - - -static bool add(unsigned char * bytes, unsigned char y, int maxSize) -{ - unsigned char carry = y; - - for (int pos = 0; pos < maxSize; ++pos) { - unsigned int m = bytes[pos] + carry; - bytes[pos] = m & 0xff; - carry = m >> 8; - if (carry == 0) break; - } - - return carry; -} - - Hash parseHash32(HashType ht, const string & s) { Hash hash(ht); + unsigned int len = hashLength32(ht); + assert(s.size() == len); - const char * chars = base32Chars.data(); - - for (unsigned int i = 0; i < s.length(); ++i) { - char c = s[i]; + 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 (chars[digit] == c) break; + if (base32Chars[digit] == c) break; if (digit >= 32) - throw Error(format("invalid base-32 hash `%1%'") % s); - if (mul(hash.hash, 32, hash.hashSize) || - add(hash.hash, digit, hash.hashSize)) - throw Error(format("base-32 hash `%1%' is too large") % s); + throw Error(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); } return hash; |