From db2ec599039ebe794eb56770a546c7b2ef87fc50 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Tue, 3 Feb 2015 18:35:11 +0100 Subject: [PATCH] Simplify printHash32 --- src/libutil/hash.cc | 50 +++++++++++++++------------------------------ 1 file changed, 16 insertions(+), 34 deletions(-) diff --git a/src/libutil/hash.cc b/src/libutil/hash.cc index 965f3ed47..00804c2a1 100644 --- a/src/libutil/hash.cc +++ b/src/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'); + string s; + s.reserve(len); - 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; } @@ -299,7 +281,7 @@ 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 +293,7 @@ HashSink::HashSink(HashType ht) : ht(ht) bytes = 0; start(ht, *ctx); } - + HashSink::~HashSink() { bufPos = 0; @@ -369,7 +351,7 @@ HashType parseHashType(const string & s) else return htUnknown; } - + string printHashType(HashType ht) { if (ht == htMD5) return "md5"; @@ -378,5 +360,5 @@ string printHashType(HashType ht) else throw Error("cannot print unknown hash type"); } - + }