44 lines
1.0 KiB
C++
44 lines
1.0 KiB
C++
#pragma once
|
|
|
|
// system includes
|
|
#include <limits>
|
|
#include <random>
|
|
#include <iterator>
|
|
|
|
// esp-idf includes
|
|
#include <esp_system.h>
|
|
|
|
namespace espcpputils {
|
|
namespace {
|
|
|
|
class esp_random_device
|
|
{
|
|
public:
|
|
using result_type = decltype(esp_random()); // should be uint32_t
|
|
|
|
result_type operator()() const { return esp_random(); }
|
|
|
|
double entropy() const { return 1.; }
|
|
static result_type min() { return std::numeric_limits<result_type>::min(); }
|
|
static result_type max() { return std::numeric_limits<result_type>::max(); }
|
|
};
|
|
|
|
std::string randomString(std::size_t length)
|
|
{
|
|
static constexpr const char chars[] =
|
|
"0123456789"
|
|
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
|
|
"abcdefghijklmnopqrstuvwxyz";
|
|
|
|
auto rng = esp_random_device{};
|
|
|
|
auto dist = std::uniform_int_distribution{{}, std::size(chars) - 1};
|
|
|
|
auto result = std::string(length, '\0');
|
|
std::generate_n(std::begin(result), length, [&]() { return chars[dist(rng)]; });
|
|
return result;
|
|
}
|
|
|
|
} // namespace
|
|
} // namespace espcpputils
|