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NIX DataFrame Proof of Concept
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//NIX DataFrame test | |
#include <nix.hpp> | |
#include <cstdlib> | |
#include <cstring> | |
#include <iostream> | |
#include "backend/hdf5/h5x/H5DataType.hpp" | |
#include "backend/hdf5/h5x/H5Group.hpp" | |
#include "backend/hdf5/h5x/H5DataSet.hpp" | |
namespace h5x = nix::hdf5::h5x; | |
namespace h5 = nix::hdf5; | |
//API | |
class DataFrame { | |
public: | |
struct Header { | |
std::string name; | |
std::string unit; | |
nix::DataType dtype; | |
}; | |
static void create(const std::vector<Header> &cols); | |
static std::vector<nix::Variant> readRow(nix::ndsize_t row); | |
static void writeRow(h5::DataSet &ds, const std::vector<nix::Variant> &vals, nix::ndssize_t row = -1); | |
}; | |
void DataFrame::writeRow(h5::DataSet &ds, const std::vector<nix::Variant> &vals, nix::ndssize_t row) { | |
std::vector<size_t> offset(vals.size()); | |
std::vector<h5x::DataType> dtypes(vals.size()); | |
size_t s = sizeof(nix::Variant) * vals.size(); | |
std::cout << s << std::endl; | |
char *base = (char *) std::malloc(s); | |
s = 0; | |
for (size_t i = 0; i < vals.size(); i++) { | |
h5x::DataType ft = h5::data_type_to_h5_memtype(vals[i].type()); | |
char *ptr = base + s; | |
dtypes[i] = ft; | |
offset[i] = s; | |
s += ft.size(); | |
switch(vals[i].type()) { | |
case nix::DataType::Int32: { | |
int32_t v; | |
vals[i].get(v); | |
std::memcpy(ptr, &v, sizeof(v)); | |
} | |
break; | |
case nix::DataType::String: { | |
const char *str = vals[i].get<const char *>(); | |
std::memcpy(ptr, &str, sizeof(char **)); | |
} | |
break; | |
case nix::DataType::Double: { | |
double v; | |
vals[i].get(v); | |
std::memcpy(ptr, &v, sizeof(v)); | |
} | |
break; | |
default: | |
std::cerr << "Unsupported DataType" << std::endl; | |
} | |
} | |
h5x::DataType ct = h5x::DataType::makeCompound(s); | |
h5x::DataType dfile = ds.dataType(); | |
for (size_t i = 0; i < vals.size(); i++) { | |
std::string name = dfile.member_name(i); | |
ct.insert(name, offset[i], dtypes[i]); | |
} | |
std::cout << ct.isVariableString() << std::endl; | |
ds.write(base, ct, nix::NDSize({1, 1})); | |
} | |
static h5::DataSet createDataFrame(h5::H5Group &group, const std::string &name, const std::vector<DataFrame::Header> &cols) { | |
size_t s = 0; | |
std::vector<size_t> offset(cols.size()); | |
std::vector<h5x::DataType> dtypes(cols.size()); | |
for (size_t i = 0; i < cols.size(); i++) { | |
h5x::DataType ft = h5::data_type_to_h5_filetype(cols[i].dtype); | |
dtypes[i] = ft; | |
offset[i] = s; | |
s += ft.size(); | |
} | |
h5x::DataType ct = h5x::DataType::makeCompound(s); | |
for (size_t i = 0; i < cols.size(); i++) { | |
ct.insert(cols[i].name, offset[i], dtypes[i]); | |
} | |
h5::DataSet ds = group.createData(name, ct, nix::NDSize({1, 1})); | |
return ds; | |
} | |
int main(int argc, char **argv) { | |
std::vector<nix::Variant> vals = {nix::Variant(10), | |
nix::Variant("test"), | |
nix::Variant(42.0)}; | |
h5::H5Group fd = H5Fcreate("test_dataframe.h5", H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); | |
std::vector<DataFrame::Header> hdr = { | |
{"int32", "V", nix::DataType::Int32}, | |
{"string", "", nix::DataType::String}, | |
{"double", "mV", nix::DataType::Double}}; | |
h5::DataSet ds = createDataFrame(fd, "dataframe", hdr); | |
DataFrame::writeRow(ds, vals); | |
ds.close(); | |
fd.close(); | |
return 0; | |
} |
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