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Implemented parametrized random number retrieval

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This commit is contained in:
Srdjan Obucina 2020-05-18 15:49:45 +02:00
parent be4869a64d
commit 56676b5a58
2 changed files with 51 additions and 2 deletions
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42
libraries/app/database_api.cpp
View file

@ -185,6 +185,7 @@ class database_api_impl : public std::enable_shared_from_this<database_api_impl>
gpos_info get_gpos_info(const account_id_type account) const;
// rng
vector<uint64_t> get_random_number_ex(uint64_t minimum, uint64_t maximum, uint64_t selections, bool duplicates) const;
int64_t get_random_number(uint64_t bound) const;
//private:
@ -2312,14 +2313,51 @@ graphene::app::gpos_info database_api_impl::get_gpos_info(const account_id_type
// //
//////////////////////////////////////////////////////////////////////
vector<uint64_t> database_api::get_random_number_ex(uint64_t minimum, uint64_t maximum, uint64_t selections, bool duplicates) const
{
return my->get_random_number_ex(minimum, maximum, selections, duplicates);
}
vector<uint64_t> database_api_impl::get_random_number_ex(uint64_t minimum, uint64_t maximum, uint64_t selections, bool duplicates) const
{
FC_ASSERT( selections <= 100000 );
if (duplicates == false) {
FC_ASSERT( maximum - minimum >= selections );
}
vector<uint64_t> v;
v.reserve(selections);
if (duplicates) {
for (uint64_t i = 0; i < selections; i++) {
int64_t rnd = _db.get_random_bits(maximum - minimum) + minimum;
v.push_back(rnd);
}
} else {
vector<uint64_t> tmpv;
tmpv.reserve(selections);
for (uint64_t i = minimum; i < maximum; i++) {
tmpv.push_back(i);
}
while (tmpv.size() > 0) {
uint64_t idx = _db.get_random_bits(tmpv.size());
v.push_back(tmpv.at(idx));
tmpv.erase(tmpv.begin() + idx);
}
}
return v;
}
int64_t database_api::get_random_number(uint64_t bound) const
{
return my->get_random_number(bound);
}
int64_t database_api_impl::get_random_number(uint64_t bound) const {
int64_t result = _db.get_random_bits(bound);
return result;
vector<uint64_t> v = get_random_number_ex(0, bound, 1, false);
return v.at(0);
}
//////////////////////////////////////////////////////////////////////

11
libraries/app/include/graphene/app/database_api.hpp
View file

@ -712,6 +712,16 @@ class database_api
/////////////////////////////
// Random number generator //
/////////////////////////////
/**
* @brief Returns the random number
* @param minimum Lower bound of segment containing random number
* @param maximum Upper bound of segment containing random number
* @param selections Number of random numbers to return
* @param duplicates Allow duplicated numbers
* @return Vector containing random numbers from segment [minimum, maximum)
*/
vector<uint64_t> get_random_number_ex(uint64_t minimum, uint64_t maximum, uint64_t selections, bool duplicates) const;
/**
* @brief Returns the random number
* @param bound Upper bound of segment containing random number
@ -858,5 +868,6 @@ FC_API(graphene::app::database_api,
(get_gpos_info)
// rngs
(get_random_number_ex)
(get_random_number)
)