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Diffstat (limited to 'nix/libutil/hash.cc')
-rw-r--r--nix/libutil/hash.cc101
1 files changed, 28 insertions, 73 deletions
diff --git a/nix/libutil/hash.cc b/nix/libutil/hash.cc
index 050446610f..2da00a53de 100644
--- a/nix/libutil/hash.cc
+++ b/nix/libutil/hash.cc
@@ -84,7 +84,7 @@ string printHash(const Hash & hash)
return string(buf, hash.hashSize * 2);
}
-
+
Hash parseHash(HashType ht, const string & s)
{
Hash hash(ht);
@@ -92,7 +92,7 @@ Hash parseHash(HashType ht, const string & s)
throw Error(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]))
+ if (!isxdigit(s2[0]) || !isxdigit(s2[1]))
throw Error(format("invalid hash `%1%'") % s);
std::istringstream str(s2);
int n;
@@ -103,24 +103,6 @@ Hash parseHash(HashType ht, const string & s)
}
-static unsigned char divMod(unsigned char * bytes, unsigned char y)
-{
- unsigned int borrow = 0;
-
- int pos = Hash::maxHashSize - 1;
- while (pos >= 0 && !bytes[pos]) --pos;
-
- for ( ; pos >= 0; --pos) {
- unsigned int s = bytes[pos] + (borrow << 8);
- unsigned int d = s / y;
- borrow = s % y;
- bytes[pos] = d;
- }
-
- return borrow;
-}
-
-
unsigned int hashLength32(const Hash & hash)
{
return (hash.hashSize * 8 - 1) / 5 + 1;
@@ -136,19 +118,19 @@ string printHash32(const Hash & hash)
Hash hash2(hash);
unsigned int len = hashLength32(hash);
- const char * chars = base32Chars.data();
-
- string s(len, '0');
-
- int pos = len - 1;
- while (pos >= 0) {
- unsigned char digit = divMod(hash2.hash, 32);
- s[pos--] = chars[digit];
+ string s;
+ s.reserve(len);
+
+ for (int n = len - 1; n >= 0; n--) {
+ unsigned int b = n * 5;
+ unsigned int i = b / 8;
+ unsigned int j = b % 8;
+ unsigned char c =
+ (hash.hash[i] >> j)
+ | (i >= hash.hashSize - 1 ? 0 : hash.hash[i + 1] << (8 - j));
+ s.push_back(base32Chars[c & 0x1f]);
}
- for (unsigned int i = 0; i < hash2.maxHashSize; ++i)
- assert(hash2.hash[i] == 0);
-
return s;
}
@@ -159,51 +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;
@@ -299,7 +254,7 @@ Hash hashFile(HashType ht, const Path & path)
if (n == -1) throw SysError(format("reading file `%1%'") % path);
update(ht, ctx, buf, n);
}
-
+
finish(ht, ctx, hash.hash);
return hash;
}
@@ -311,7 +266,7 @@ HashSink::HashSink(HashType ht) : ht(ht)
bytes = 0;
start(ht, *ctx);
}
-
+
HashSink::~HashSink()
{
bufPos = 0;
@@ -369,7 +324,7 @@ HashType parseHashType(const string & s)
else return htUnknown;
}
-
+
string printHashType(HashType ht)
{
if (ht == htMD5) return "md5";
@@ -378,5 +333,5 @@ string printHashType(HashType ht)
else throw Error("cannot print unknown hash type");
}
-
+
}