DragonX/dragonx
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases 2 Wiki Activity

Speed up FullStepRow index comparison by leveraging big-endian byte layout

Browse Source
This commit is contained in:
Jack Grigg
2016-06-09 18:02:29 +12:00
parent 1dd8ce9ba5
commit d07cf62991
2 changed files with 5 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
src/crypto/equihash.cpp
View File

@@ -37,6 +37,7 @@ int Equihash<N,K>::InitialiseState(eh_HashState& base_state)
personalization); personalization);
} }
// Big-endian so that array comparison is equivalent to integer comparison
void EhIndexToArray(const eh_index i, unsigned char* array) void EhIndexToArray(const eh_index i, unsigned char* array)
{ {
assert(sizeof(eh_index) == 4); assert(sizeof(eh_index) == 4);
@@ -46,6 +47,7 @@ void EhIndexToArray(const eh_index i, unsigned char* array)
array[3] = i & 0xFF; array[3] = i & 0xFF;
} }
// Big-endian so that array comparison is equivalent to integer comparison
eh_index ArrayToEhIndex(const unsigned char* array) eh_index ArrayToEhIndex(const unsigned char* array)
{ {
assert(sizeof(eh_index) == 4); assert(sizeof(eh_index) == 4);
@@ -103,7 +105,7 @@ FullStepRow<WIDTH>::FullStepRow(const FullStepRow<W>& a, const FullStepRow<W>& b
assert(len-trim+(2*lenIndices) <= WIDTH); assert(len-trim+(2*lenIndices) <= WIDTH);
for (int i = trim; i < len; i++) for (int i = trim; i < len; i++)
hash[i-trim] = a.hash[i] ^ b.hash[i]; hash[i-trim] = a.hash[i] ^ b.hash[i];
if (a.IndicesBefore(b, len)) { if (a.IndicesBefore(b, len, lenIndices)) {
std::copy(a.hash+len, a.hash+len+lenIndices, hash+len-trim); std::copy(a.hash+len, a.hash+len+lenIndices, hash+len-trim);
std::copy(b.hash+len, b.hash+len+lenIndices, hash+len-trim+lenIndices); std::copy(b.hash+len, b.hash+len+lenIndices, hash+len-trim+lenIndices);
} else { } else {
@@ -532,7 +534,7 @@ bool Equihash<N,K>::IsValidSolution(const eh_HashState& base_state, std::vector<
LogPrint("pow", "X[i+1] = %s\n", X[i+1].GetHex(hashLen)); LogPrint("pow", "X[i+1] = %s\n", X[i+1].GetHex(hashLen));
return false; return false;
} }
if (X[i+1].IndicesBefore(X[i], hashLen)) { if (X[i+1].IndicesBefore(X[i], hashLen, lenIndices)) {
return false; return false;
LogPrint("pow", "Invalid solution: Index tree incorrectly ordered\n"); LogPrint("pow", "Invalid solution: Index tree incorrectly ordered\n");
} }

2
src/crypto/equihash.h
View File

@@ -80,7 +80,7 @@ public:
FullStepRow(const FullStepRow<W>& a, const FullStepRow<W>& b, size_t len, size_t lenIndices, int trim); FullStepRow(const FullStepRow<W>& a, const FullStepRow<W>& b, size_t len, size_t lenIndices, int trim);
FullStepRow& operator=(const FullStepRow<WIDTH>& a); FullStepRow& operator=(const FullStepRow<WIDTH>& a);
inline bool IndicesBefore(const FullStepRow<WIDTH>& a, size_t len) const { return ArrayToEhIndex(hash+len) < ArrayToEhIndex(a.hash+len); } inline bool IndicesBefore(const FullStepRow<WIDTH>& a, size_t len, size_t lenIndices) const { return memcmp(hash+len, a.hash+len, lenIndices) < 0; }
std::vector<eh_index> GetIndices(size_t len, size_t lenIndices) const; std::vector<eh_index> GetIndices(size_t len, size_t lenIndices) const;
template<size_t W> template<size_t W>