TakeV
/
guix
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Simplify printHash32

This commit is contained in:
Eelco Dolstra 2015-02-03 18:35:11 +01:00 committed by Ludovic Courtès
parent 7a7a15877f
commit 70c3d2f176
1 changed files with 16 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
nix/libutil/hash.cc
View File

@ -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;
s.reserve(len);
string s(len, '0');
int pos = len - 1;
while (pos >= 0) {
unsigned char digit = divMod(hash2.hash, 32);
s[pos--] = chars[digit];
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;
}