diff --git a/include/nczarrcommon.h b/include/nczarrcommon.h
new file mode 100644
index 0000000..a1a6807
--- /dev/null
+++ b/include/nczarrcommon.h
@@ -0,0 +1,822 @@
+#pragma once
+#include "merrors.h"
+#include <utility>
+#include <variant>
+
+using michlib::Error;
+using michlib::int1;
+using michlib::int2;
+using michlib::int4;
+using michlib::int8;
+using michlib::int_cast;
+using michlib::MString;
+using michlib::RetVal;
+using michlib::uint1;
+using michlib::uint8;
+
+class NcZarrTypes
+{
+ protected:
+ using AttVT = std::variant<std::monostate, int8, uint8, double, MString, bool>;
+
+ class ArrCounter
+ {
+  using VT = std::vector<size_t>;
+  const VT count;
+  VT       ind;
+  bool     end;
+
+  public:
+  static size_t Index(const VT& i, const VT& c)
+  {
+   size_t out = 0;
+   size_t mul = 1;
+   for(size_t ii = i.size(); ii != 0; ii--)
+   {
+    out += mul * i[ii - 1];
+    mul *= c[ii - 1];
+   }
+   return out;
+  }
+
+  static VT Index(size_t lind, const VT& c)
+  {
+   VT out(c.size());
+
+   size_t j = lind;
+
+   for(auto i = c.size(); i > 0; i--)
+   {
+    out[i - 1] = j % c[i - 1];
+    j          = j / c[i - 1];
+   }
+
+   return out;
+  }
+
+  ArrCounter() = delete;
+  ArrCounter(const VT& cnt): count(cnt), ind(cnt.size(), 0), end(false) {}
+
+  size_t operator[](size_t i) const { return ind[i]; }
+
+  ArrCounter& operator++()
+  {
+   size_t curind = count.size();
+   while(curind != 0)
+   {
+    ind[curind - 1]++;
+    if(ind[curind - 1] >= count[curind - 1])
+    {
+     ind[curind - 1] = 0;
+     curind--;
+    }
+    else
+     return *this;
+   }
+   ind = count;
+   end = true;
+   return *this;
+  }
+
+  explicit operator bool() const { return !end; }
+
+  size_t Index() const { return Index(ind, count); }
+  size_t Index(const VT& i) const { return Index(i, count); }
+  VT     Index(size_t lind) const { return Index(lind, count); }
+
+  size_t Count(size_t i) const { return count[i]; }
+
+  const VT& VIndex() const { return ind; }
+  VT        VIndex(const VT& start) const
+  {
+   VT out(ind.size());
+   for(size_t i = 0; i < ind.size(); i++) out[i] = ind[i] + start[i];
+   return out;
+  }
+
+  const auto& Count() const { return count; }
+
+  size_t N() const
+  {
+   size_t out = 1;
+   for(size_t i = 0; i < count.size(); i++) out *= count[i];
+   return out;
+  }
+ };
+
+ public:
+ enum class AttType
+ {
+  UNDEF,
+  INT,
+  UINT,
+  REAL,
+  STRING,
+  BOOL
+ };
+ enum class VarType
+ {
+  UNDEF,
+  FLOAT,
+  DOUBLE,
+  INT1,
+  INT2,
+  INT4,
+  INT8,
+  UINT1
+ };
+
+ protected:
+ template<VarType VT, class Dummy = void> struct VarType2Type;
+
+ template<class Dummy> struct VarType2Type<VarType::FLOAT, Dummy>
+ {
+  using type = float;
+ };
+ template<class Dummy> struct VarType2Type<VarType::DOUBLE, Dummy>
+ {
+  using type = double;
+ };
+ template<class Dummy> struct VarType2Type<VarType::INT1, Dummy>
+ {
+  using type = int1;
+ };
+ template<class Dummy> struct VarType2Type<VarType::INT2, Dummy>
+ {
+  using type = int2;
+ };
+ template<class Dummy> struct VarType2Type<VarType::INT4, Dummy>
+ {
+  using type = int4;
+ };
+ template<class Dummy> struct VarType2Type<VarType::INT8, Dummy>
+ {
+  using type = int8;
+ };
+ template<class Dummy> struct VarType2Type<VarType::UINT1, Dummy>
+ {
+  using type = uint1;
+ };
+
+ template<VarType VT> using Type = VarType2Type<VT>::type;
+
+ static constexpr size_t SizeOf(VarType vt)
+ {
+  switch(vt)
+  {
+  case(VarType::UNDEF): return 0;
+  case(VarType::FLOAT): return sizeof(Type<VarType::FLOAT>);
+  case(VarType::DOUBLE): return sizeof(Type<VarType::DOUBLE>);
+  case(VarType::INT1): return sizeof(Type<VarType::INT1>);
+  case(VarType::INT2): return sizeof(Type<VarType::INT2>);
+  case(VarType::INT4): return sizeof(Type<VarType::INT4>);
+  case(VarType::INT8): return sizeof(Type<VarType::INT8>);
+  case(VarType::UINT1): return sizeof(Type<VarType::UINT1>);
+  }
+  return 0;
+ }
+
+ template<class T> static size_t FindInd(const MString& name, const std::vector<T>& arr)
+ {
+  for(size_t i = 0; i < arr.size(); i++)
+   if(arr[i].Name() == name) return i;
+  return arr.size();
+ }
+
+ class Attribute: public AttVT
+ {
+  MString name;
+
+  public:
+  Attribute(const MString& n, AttVT&& v): AttVT(std::move(v)), name(n) {}
+  Attribute(const std::string& n, AttVT&& v): AttVT(std::move(v)), name(n.c_str(), n.size()) {}
+
+  const MString& Name() const { return name; }
+
+  AttType Type() const
+  {
+   if(std::holds_alternative<int8>(*this))
+    return AttType::INT;
+   else if(std::holds_alternative<uint8>(*this))
+    return AttType::UINT;
+   else if(std::holds_alternative<double>(*this))
+    return AttType::REAL;
+   else if(std::holds_alternative<MString>(*this))
+    return AttType::STRING;
+   else if(std::holds_alternative<bool>(*this))
+    return AttType::BOOL;
+
+   return AttType::UNDEF;
+  }
+
+  int8 I() const
+  {
+   if(std::holds_alternative<int8>(*this))
+    return std::get<int8>(*this);
+   else if(std::holds_alternative<uint8>(*this))
+    return int_cast<int8>(std::get<uint8>(*this));
+   else if(std::holds_alternative<double>(*this))
+    return static_cast<int8>(std::get<double>(*this));
+   else if(std::holds_alternative<MString>(*this))
+    return std::get<MString>(*this).ToInteger<int8>();
+   else if(std::holds_alternative<bool>(*this))
+    return std::get<bool>(*this) ? 1 : 0;
+   return 0;
+  }
+
+  uint8 U() const
+  {
+   if(std::holds_alternative<int8>(*this))
+    return int_cast<uint8>(std::get<int8>(*this));
+   else if(std::holds_alternative<uint8>(*this))
+    return std::get<uint8>(*this);
+   else if(std::holds_alternative<double>(*this))
+    return static_cast<uint8>(std::get<double>(*this));
+   else if(std::holds_alternative<MString>(*this))
+    return std::get<MString>(*this).ToInteger<uint8>();
+   else if(std::holds_alternative<bool>(*this))
+    return std::get<bool>(*this) ? 1 : 0;
+   return 0;
+  }
+
+  double D() const
+  {
+   if(std::holds_alternative<int8>(*this))
+    return std::get<int8>(*this);
+   else if(std::holds_alternative<uint8>(*this))
+    return std::get<uint8>(*this);
+   else if(std::holds_alternative<double>(*this))
+    return std::get<double>(*this);
+   else if(std::holds_alternative<MString>(*this))
+    return michlib_internal::RealType<sizeof(double)>::String2Real(std::get<MString>(*this).Buf());
+   else if(std::holds_alternative<bool>(*this))
+    return std::get<bool>(*this) ? 1 : 0;
+   return 0;
+  }
+
+  MString S() const
+  {
+   if(std::holds_alternative<int8>(*this))
+    return MString().FromInt(std::get<int8>(*this));
+   else if(std::holds_alternative<uint8>(*this))
+    return MString().FromUInt(std::get<uint8>(*this));
+   else if(std::holds_alternative<double>(*this))
+    return MString().FromReal(std::get<double>(*this));
+   else if(std::holds_alternative<MString>(*this))
+    return std::get<MString>(*this);
+   else if(std::holds_alternative<bool>(*this))
+    return MString().FromBool(std::get<bool>(*this));
+   return "";
+  }
+
+  bool B() const
+  {
+   if(std::holds_alternative<int8>(*this))
+    return std::get<int8>(*this) != 0;
+   else if(std::holds_alternative<uint8>(*this))
+    return std::get<uint8>(*this) != 0;
+   else if(std::holds_alternative<double>(*this))
+    return std::get<double>(*this) != 0.0;
+   else if(std::holds_alternative<MString>(*this))
+    return std::get<MString>(*this).ToBool();
+   else if(std::holds_alternative<bool>(*this))
+    return std::get<bool>(*this);
+   return false;
+  }
+ };
+
+ class Dimension
+ {
+  MString name;
+  size_t  size;
+
+  public:
+  Dimension(const MString& str, size_t num): name(str), size(num) {}
+  const MString& Name() const { return name; }
+
+  size_t Size() const { return size; }
+ };
+
+ class Variable
+ {
+  public:
+  using FillType = std::variant<std::monostate, int8, uint8, double>;
+
+  private:
+  MString                name;
+  VarType                type = VarType::UNDEF;
+  std::vector<size_t>    dims;
+  std::vector<Attribute> atts;
+  FillType               fill;
+
+  public:
+  Variable(const MString& name_, VarType type_, std::vector<size_t>&& dims_, std::vector<Attribute>&& atts_, FillType fill_ = 0):
+      name(name_), type(type_), dims(std::move(dims_)), atts(std::move(atts_)), fill(fill_)
+  {
+  }
+
+  explicit operator bool() const { return type != VarType::UNDEF; }
+
+  const auto& Dims() const { return dims; }
+
+  size_t NDim() const { return dims.size(); }
+
+  size_t NAtt() const { return atts.size(); }
+
+  auto AttNames() const
+  {
+   std::vector<MString> out;
+   std::transform(atts.cbegin(), atts.cend(), std::back_inserter(out), [](const Attribute& a) { return a.Name(); });
+   return out;
+  }
+
+  AttType AttT(const MString& name) const
+  {
+   size_t ind = FindInd(name, atts);
+   return ind < atts.size() ? atts[ind].Type() : AttType::UNDEF;
+  }
+
+  int8 AttInt(const MString& name) const
+  {
+   size_t ind = FindInd(name, atts);
+   return ind < atts.size() ? atts[ind].I() : 0;
+  }
+
+  uint8 AttUInt(const MString& name) const
+  {
+   size_t ind = FindInd(name, atts);
+   return ind < atts.size() ? atts[ind].U() : 0;
+  }
+
+  double AttReal(const MString& name) const
+  {
+   size_t ind = FindInd(name, atts);
+   return ind < atts.size() ? atts[ind].D() : 0.0;
+  }
+
+  MString AttString(const MString& name) const
+  {
+   size_t ind = FindInd(name, atts);
+   return ind < atts.size() ? atts[ind].S() : MString();
+  }
+
+  bool AttBool(const MString& name) const
+  {
+   size_t ind = FindInd(name, atts);
+   return ind < atts.size() ? atts[ind].B() : false;
+  }
+
+  const MString& Name() const { return name; }
+
+  auto Type() const { return type; }
+
+  const auto& Fill() const { return fill; }
+ };
+
+ protected:
+ std::vector<Attribute> gats;
+ std::vector<Dimension> dims;
+ std::vector<Variable>  vars;
+
+ public:
+ operator bool() const { return !vars.empty(); }
+
+ size_t NDim() const { return dims.size(); }
+
+ size_t NDim(const MString& var) const
+ {
+  size_t ind = FindInd(var, vars);
+  return ind < vars.size() ? vars[ind].NDim() : 0;
+ }
+
+ size_t NAtt() const { return gats.size(); }
+
+ auto AttNames() const
+ {
+  std::vector<MString> out;
+  std::transform(gats.cbegin(), gats.cend(), std::back_inserter(out), [](const Attribute& a) { return a.Name(); });
+  return out;
+ }
+
+ size_t NAtt(const MString& var) const
+ {
+  if(!var.Exist()) return NAtt();
+  size_t ind = FindInd(var, vars);
+  return ind < vars.size() ? vars[ind].NAtt() : 0;
+ }
+
+ auto AttNames(const MString& var) const
+ {
+  if(!var.Exist()) return AttNames();
+  size_t ind = FindInd(var, vars);
+  return ind < vars.size() ? vars[ind].AttNames() : decltype(AttNames())();
+ }
+
+ auto VarNames() const
+ {
+  std::vector<MString> out;
+  std::transform(vars.cbegin(), vars.cend(), std::back_inserter(out), [](const Variable& v) { return v.Name(); });
+  return out;
+ }
+
+ VarType VarT(const MString& var) const
+ {
+  size_t ind = FindInd(var, vars);
+  return ind < vars.size() ? vars[ind].Type() : VarType::UNDEF;
+ }
+
+ auto VarFill(const MString& var) const
+ {
+  size_t ind = FindInd(var, vars);
+  return ind < vars.size() ? vars[ind].Fill() : Variable::FillType();
+ }
+
+ auto DimNames() const
+ {
+  std::vector<MString> out;
+  std::transform(dims.cbegin(), dims.cend(), std::back_inserter(out), [](const Dimension& d) { return d.Name(); });
+  return out;
+ }
+
+ auto DimNames(const MString& var) const
+ {
+  size_t ind = FindInd(var, vars);
+
+  std::vector<MString> out;
+  if(ind >= vars.size()) return out;
+
+  auto vdims = vars[ind].Dims();
+  std::transform(vdims.cbegin(), vdims.cend(), std::back_inserter(out), [&dims = std::as_const(dims)](const size_t& i) { return dims[i].Name(); });
+  return out;
+ }
+
+ size_t DimSize(const MString& dim) const
+ {
+  size_t ind = FindInd(dim, dims);
+  return ind < dims.size() ? dims[ind].Size() : 0;
+ }
+
+ AttType AttT(const MString& var, const MString& name) const
+ {
+  if(!var.Exist())
+  {
+   size_t ind = FindInd(name, gats);
+   return ind < gats.size() ? gats[ind].Type() : AttType::UNDEF;
+  }
+
+  size_t ind = FindInd(var, vars);
+  return ind < vars.size() ? vars[ind].AttT(name) : AttType::UNDEF;
+ }
+
+ int8 AttInt(const MString& var, const MString& name) const
+ {
+  if(!var.Exist())
+  {
+   size_t ind = FindInd(name, gats);
+   return ind < gats.size() ? gats[ind].I() : 0;
+  }
+
+  size_t ind = FindInd(var, vars);
+  return ind < vars.size() ? vars[ind].AttInt(name) : 0;
+ }
+
+ uint8 AttUInt(const MString& var, const MString& name) const
+ {
+  if(!var.Exist())
+  {
+   size_t ind = FindInd(name, gats);
+   return ind < gats.size() ? gats[ind].U() : 0;
+  }
+
+  size_t ind = FindInd(var, vars);
+  return ind < vars.size() ? vars[ind].AttUInt(name) : 0;
+ }
+
+ double AttReal(const MString& var, const MString& name) const
+ {
+  if(!var.Exist())
+  {
+   size_t ind = FindInd(name, gats);
+   return ind < gats.size() ? gats[ind].D() : 0.0;
+  }
+
+  size_t ind = FindInd(var, vars);
+  return ind < vars.size() ? vars[ind].AttReal(name) : 0.0;
+ }
+
+ MString AttString(const MString& var, const MString& name) const
+ {
+  if(!var.Exist())
+  {
+   size_t ind = FindInd(name, gats);
+   return ind < gats.size() ? gats[ind].S() : MString();
+  }
+
+  size_t ind = FindInd(var, vars);
+  return ind < vars.size() ? vars[ind].AttString(name) : MString();
+ }
+
+ bool AttBool(const MString& var, const MString& name) const
+ {
+  if(!var.Exist())
+  {
+   size_t ind = FindInd(name, gats);
+   return ind < gats.size() ? gats[ind].B() : false;
+  }
+
+  size_t ind = FindInd(var, vars);
+  return ind < vars.size() ? vars[ind].AttBool(name) : false;
+ }
+
+ auto AttT(const MString& name) const { return AttT("", name); }
+ auto AttInt(const MString& name) const { return AttInt("", name); }
+ auto AttUInt(const MString& name) const { return AttUInt("", name); }
+ auto AttReal(const MString& name) const { return AttReal("", name); }
+ auto AttString(const MString& name) const { return AttString("", name); }
+ auto AttBool(const MString& name) const { return AttBool("", name); }
+
+ bool HasDim(const MString& name) const { return FindInd(name, dims) < dims.size(); }
+ bool HasVar(const MString& name) const { return FindInd(name, vars) < vars.size(); }
+ bool HasAtt(const MString& vname, const MString& aname) const { return AttT(vname, aname) != AttType::UNDEF; }
+ bool HasAtt(const MString& aname) const { return AttT(aname) != AttType::UNDEF; }
+};
+
+class DimReqDef
+{
+ protected:
+ struct DimReq
+ {
+  static const auto fill = std::numeric_limits<size_t>::max();
+  MString           name;
+  size_t            beg, count;
+
+  DimReq(): name(MString()), beg(fill), count(fill) {}
+  DimReq(const char* n): name(n), beg(fill), count(fill) {}
+  DimReq(const MString& n): name(n), beg(fill), count(fill) {}
+  DimReq(MString&& n): name(std::move(n)), beg(fill), count(fill) {}
+  DimReq(const char* n, size_t s): name(n), beg(s), count(fill) {}
+  DimReq(const MString& n, size_t s): name(n), beg(s), count(fill) {}
+  DimReq(MString&& n, size_t s): name(std::move(n)), beg(s), count(fill) {}
+  DimReq(const char* n, size_t s, size_t c): name(n), beg(s), count(c) {}
+  DimReq(const MString& n, size_t s, size_t c): name(n), beg(s), count(c) {}
+  DimReq(MString&& n, size_t s, size_t c): name(std::move(n)), beg(s), count(c) {}
+
+  const MString& Name() const { return name; }
+ };
+};
+
+template<class C> class NcZarrRead: public C, public DimReqDef
+{
+ template<class Data> static constexpr size_t Dimensionity()
+ {
+  if constexpr(requires(Data& d) { d(0, 0, 0, 0); }) return 4;
+  if constexpr(requires(Data& d) { d(0, 0, 0); }) return 3;
+  if constexpr(requires(Data& d) { d(0, 0); }) return 2;
+  if constexpr(requires(Data& d) { d(0); }) return 1;
+  return 0;
+ }
+
+ template<class Data, size_t D, class Dummy = void> struct DataTypeExtractorS;
+
+ template<class Data, class Dummy> struct DataTypeExtractorS<Data, 1, Dummy>
+ {
+  using type = std::decay_t<decltype(std::declval<Data>()(0))>;
+ };
+ template<class Data, class Dummy> struct DataTypeExtractorS<Data, 2, Dummy>
+ {
+  using type = std::decay_t<decltype(std::declval<Data>()(0, 0))>;
+ };
+ template<class Data, class Dummy> struct DataTypeExtractorS<Data, 3, Dummy>
+ {
+  using type = std::decay_t<decltype(std::declval<Data>()(0, 0, 0))>;
+ };
+ template<class Data, class Dummy> struct DataTypeExtractorS<Data, 4, Dummy>
+ {
+  using type = std::decay_t<decltype(std::declval<Data>()(0, 0, 0, 0))>;
+ };
+
+ template<class Data> using DataTypeExtractor = DataTypeExtractorS<Data, Dimensionity<Data>()>::type;
+
+ template<class VType, class Data, class Transform>
+ Error Read(const MString& vname, const std::vector<size_t>& transindex, Data& data, Transform transform, std::vector<DimReq> reqs) const
+ {
+  size_t nval = 1;
+  for(const auto& r: reqs) nval *= r.count;
+  const size_t     indim  = reqs.size();
+  constexpr size_t outdim = Dimensionity<Data>();
+
+  std::vector<size_t> start;
+  std::vector<size_t> count;
+
+  start.resize(indim);
+  count.resize(indim);
+  for(size_t i = 0; i < indim; i++)
+  {
+   start[i] = reqs[i].beg;
+   count[i] = reqs[i].count;
+  }
+
+  using DataType = DataTypeExtractor<Data>;
+  DataType fillout;
+  bool     havefill = C::VarFill(vname).index() > 0;
+  VType    fillin   = std::visit(
+      [](auto v)
+      {
+       if constexpr(std::is_convertible_v<decltype(v), VType>)
+        return static_cast<VType>(v);
+       else
+        return std::numeric_limits<VType>::max();
+      },
+      C::VarFill(vname));
+
+  if constexpr(requires(Data& d) { // Data have own fillvalue
+                {
+                 d.Fillval()
+                } -> std::convertible_to<DataType>;
+               })
+
+   fillout = data.Fillval();
+  else // Data does'nt have own fillvalue, using variable fillvalue
+   fillout = static_cast<DataType>(fillin);
+
+  auto ret = C::template Read<VType>(vname, start.data(), count.data());
+  if(!ret) return ret;
+  const auto& rawdata = ret.Value();
+
+  std::vector<size_t> mul(indim, 1);
+  for(size_t i = indim - 1; i > 0; i--) mul[i - 1] = mul[i] * count[i];
+
+  size_t inind = 0;
+  for(typename C::ArrCounter i(count); i; ++i)
+  {
+   // TODO: Remove this testing block
+   size_t cind = 0;
+   for(size_t j = 0; j < indim; j++) cind += i[j] * mul[j];
+   if(cind != inind) return {"NcZarrRead::Read", "Internal error"};
+   if(i.Index() != inind) return {"NcZarrRead::Read", "Internal error"};
+   if(inind != i.Index(i.Index(inind, count), count)) return {"NcZarrRead::Read", "Internal error"};
+
+   DataType     out;
+   const VType& in = rawdata(inind);
+   if(havefill && in == fillin)
+    out = fillout;
+   else
+    out = transform(in);
+
+   if constexpr(outdim == 1)
+    data(i[transindex[0]]) = out;
+   else if constexpr(outdim == 2)
+    data(i[transindex[0]], i[transindex[1]]) = out;
+   else if constexpr(outdim == 3)
+    data(i[transindex[0]], i[transindex[1]], i[transindex[2]]) = out;
+   else if constexpr(outdim == 4)
+    data(i[transindex[0]], i[transindex[1]], i[transindex[2]], i[transindex[3]]) = out;
+
+   inind++;
+  }
+
+  michlib::message("Variable " + vname + ", request size " + nval);
+  for(const auto& r: reqs) michlib::message(r.name + " from " + r.beg + ", count " + r.count);
+  return Error();
+ }
+
+ public:
+ // Request is string
+ template<class Data, class Transform> Error Read(const MString& vname, Data& data, Transform transform, const char* request) const
+ {
+  return Read(vname, data, transform, MString(request));
+ }
+
+ // Request by one dimension
+ template<class Data, class Transform> Error Read(const MString& vname, Data& data, Transform transform, DimReq&& req1) const
+ {
+  return Read(vname, data, transform, std::vector<DimReq>{std::move(req1)});
+ }
+ // Request by two dimension
+ template<class Data, class Transform> Error Read(const MString& vname, Data& data, Transform transform, DimReq&& req1, DimReq&& req2) const
+ {
+  return Read(vname, data, transform, std::vector<DimReq>{std::move(req1), std::move(req2)});
+ }
+ // Request by three dimension
+ template<class Data, class Transform> Error Read(const MString& vname, Data& data, Transform transform, DimReq&& req1, DimReq&& req2, DimReq&& req3) const
+ {
+  return Read(vname, data, transform, std::vector<DimReq>{std::move(req1), std::move(req2), std::move(req3)});
+ }
+ // Request by four dimension
+ template<class Data, class Transform> Error Read(const MString& vname, Data& data, Transform transform, DimReq&& req1, DimReq&& req2, DimReq&& req3, DimReq&& req4) const
+ {
+  return Read(vname, data, transform, std::vector<DimReq>{std::move(req1), std::move(req2), std::move(req3), std::move(req4)});
+ }
+
+ // Request full variable
+ template<class Data, class Transform> Error Read(const MString& vname, Data& data, Transform transform) const
+ {
+  static const MString pref = "NcZarrRead::Read";
+  if(!C::HasVar(vname)) return {pref, "Variable " + vname + " not found"};
+
+  std::vector<struct DimReq> pdims;
+
+  const auto vdims = C::DimNames(vname);
+  std::transform(
+      vdims.cbegin(), vdims.cend(), std::back_inserter(pdims), [this](const MString& n) -> struct DimReq {
+       return {n, 0, C::DimSize(n)};
+      });
+
+  return Read(vname, data, transform, pdims);
+ }
+
+ // Base function for all Read's
+ template<class Data, class Transform> Error Read(const MString& vname, Data& data, Transform transform, std::vector<DimReq> reqs) const
+ {
+  static const MString pref = "NcZarrRead::Read";
+
+  if(!C::HasVar(vname)) return {pref, "Variable " + vname + " not found"};
+
+  std::vector<struct DimReq> pdims;
+  {
+   const auto vdims = C::DimNames(vname);
+   std::transform(
+       vdims.cbegin(), vdims.cend(), std::back_inserter(pdims), [](const MString& n) -> struct DimReq {
+        return {n, 0, 1};
+       });
+  }
+
+  std::vector<size_t> transindex;
+
+  // Parse request
+  if(reqs.size() == 0) return {pref, "Empty request"};
+  for(const auto& req: reqs)
+  {
+   size_t ind = C::FindInd(req.name, pdims);
+   if(ind >= pdims.size()) return {pref, "Variable " + vname + " has no dimension " + req.name};
+
+   for(size_t i = 0; i < transindex.size(); i++)
+    if(transindex[i] == ind) return {pref, "Parameters for dimension " + req.name + " already defined"};
+   transindex.push_back(ind);
+
+   size_t dlen = C::DimSize(pdims[ind].name);
+   if(req.beg == req.fill && req.count == req.fill) // Only name, so, we request full length
+   {
+    pdims[ind].beg   = 0;
+    pdims[ind].count = dlen;
+   }
+   else if(req.count == req.fill) // Name and first index
+   {
+    pdims[ind].beg   = req.beg;
+    pdims[ind].count = 1;
+   }
+   else // Name, first index, count
+   {
+    pdims[ind].beg   = req.beg;
+    pdims[ind].count = req.count;
+   }
+   // Sanity checks
+   if(pdims[ind].count <= 0) return {pref, "Error parsing request: count must be greter then zero"};
+   if(pdims[ind].beg >= dlen) return {pref, MString("Error parsing request: start index ") + pdims[ind].beg + " must be lesser then " + pdims[ind].name + " size " + dlen};
+   if(pdims[ind].beg + pdims[ind].count > dlen)
+    return {pref, MString("Error parsing request: start index ") + pdims[ind].beg + " with count " + pdims[ind].count + " exceeds " + pdims[ind].name + " size " + dlen};
+  }
+
+  if(transindex.size() != Dimensionity<Data>()) return {pref, "Output data dimensions not correspondind request dimensions"};
+  switch(C::VarT(vname))
+  {
+  case(C::VarType::UNDEF): return {pref, "No variable with name " + vname + " (impossible)"};
+  case(C::VarType::FLOAT): return Read<typename C::template Type<C::VarType::FLOAT>>(vname, transindex, data, transform, pdims);
+  case(C::VarType::DOUBLE): return Read<typename C::template Type<C::VarType::DOUBLE>>(vname, transindex, data, transform, pdims);
+  case(C::VarType::INT1): return Read<typename C::template Type<C::VarType::INT1>>(vname, transindex, data, transform, pdims);
+  case(C::VarType::INT2): return Read<typename C::template Type<C::VarType::INT2>>(vname, transindex, data, transform, pdims);
+  case(C::VarType::INT4): return Read<typename C::template Type<C::VarType::INT4>>(vname, transindex, data, transform, pdims);
+  case(C::VarType::INT8): return Read<typename C::template Type<C::VarType::INT8>>(vname, transindex, data, transform, pdims);
+  case(C::VarType::UINT1): return Read<typename C::template Type<C::VarType::UINT1>>(vname, transindex, data, transform, pdims);
+  }
+
+  return {pref, "Internal error (impossible)"};
+ }
+
+ // Request by string argument
+ template<class Data, class Transform> Error Read(const MString& vname, Data& data, Transform transform, const MString& request) const
+ {
+  static const MString pref = "NcZarrRead::Read";
+
+  std::vector<struct DimReq> pdims;
+
+  // Parse request
+  const auto dimdesc = request.Split(";, \t");
+  if(dimdesc.size() == 0) return {pref, "Empty request"};
+  for(const auto& dd: dimdesc)
+  {
+   const auto dimpar = dd.Split(":", true);
+
+   if(dimpar.size() == 1) // Only name, so, we request full length
+    pdims.emplace_back(dimpar[0]);
+   else if(dimpar.size() == 2) // Name and first index
+    pdims.emplace_back(dimpar[0], dimpar[1].ToInteger<size_t>());
+   else if(dimpar.size() == 3) // Name, first index, count
+    pdims.emplace_back(dimpar[0], dimpar[1].ToInteger<size_t>(), dimpar[2].ToInteger<size_t>());
+   else
+    return {pref, "Can't parse expression " + dd};
+  }
+
+  return Read(vname, data, transform, pdims);
+ }
+};
diff --git a/include/zarr.h b/include/zarr.h
new file mode 100644
index 0000000..0f692ec
--- /dev/null
+++ b/include/zarr.h
@@ -0,0 +1,174 @@
+#pragma once
+#include "GPL.h"
+#include "cache.h"
+#include "curlfuncs.h"
+#include "nczarrcommon.h"
+#include <json/json.h>
+#include <variant>
+
+class ZarrTypes: public NcZarrTypes
+{
+ protected:
+ template<class VType> class ReadedData
+ {
+  //public:
+  using Vec = std::vector<size_t>;
+
+  private:
+  Vec                                   start, chunkstart;
+  ArrCounter                            mainind, chunkind, inchunkind;
+  std::vector<std::unique_ptr<VType[]>> data;
+
+  public:
+  ReadedData():mainind(Vec()),chunkind(Vec()),inchunkind(Vec()){}
+
+  ReadedData(size_t N, const size_t* start, const size_t* count, const size_t* csize, std::vector<std::unique_ptr<VType[]>>&& d):
+      start(start, start + N),
+      chunkstart(
+          [](size_t N, const size_t* st, const size_t* cs)
+          {
+           Vec out(N);
+           for(size_t i = 0; i < N; i++) out[i] = st[i] / cs[i];
+           return out;
+          }(N, start, csize)),
+      mainind(Vec(count, count + N)),
+      chunkind(
+          [](size_t N, const size_t* st, const size_t* cn, const size_t* cs)
+          {
+           Vec out(N);
+           for(size_t i = 0; i < N; i++) out[i] = (st[i] + cn[i]) / cs[i] - st[i] / cs[i] + 1;
+           return out;
+          }(N, start, count, csize)),
+      inchunkind(Vec(csize, csize + N)),
+      data(std::move(d))
+  {
+  }
+
+  VType operator()(size_t lini) const
+  {
+   Vec ind = mainind.Index(lini, mainind.Count());
+   Vec cind(ind.size()), inind(ind.size());
+
+   for(size_t i = 0; i < ind.size(); i++)
+   {
+    cind[i]  = (ind[i] + start[i]) / inchunkind.Count(i) - chunkstart[i]; // indes of chunk
+    inind[i] = (ind[i] + start[i]) % inchunkind.Count(i);                 // index inside chunk
+   }
+   size_t chunk  = chunkind.Index(cind);
+   size_t inside = inchunkind.Index(inind);
+   return data[chunk][inside];
+  }
+ };
+
+ private:
+ // Create attribute from json value
+ static AttVT CreateAtt(const Json::Value& val)
+ {
+  if(val.type() == Json::intValue) return AttVT{std::in_place_type<int8>, val.asInt64()};
+  if(val.type() == Json::uintValue) return AttVT(std::in_place_type<uint8>, val.asUInt64());
+  if(val.type() == Json::realValue) return AttVT(std::in_place_type<double>, val.asDouble());
+  if(val.type() == Json::stringValue)
+  {
+   auto str = val.asString();
+   return AttVT(std::in_place_type<MString>, MString(str.c_str(), str.size()));
+  }
+  if(val.type() == Json::booleanValue) return AttVT(std::in_place_type<bool>, val.asBool());
+  return AttVT();
+ }
+
+ public:
+ // Read attributes from .zattrs
+ static auto ReadAtts(const Json::Value& obj)
+ {
+  std::vector<Attribute> out;
+  if(obj.type() != Json::objectValue) return out;
+  const auto keys = obj.getMemberNames();
+  for(const auto& key: keys)
+   if(key != "_ARRAY_DIMENSIONS") out.emplace_back(key, CreateAtt(obj[key]));
+  return out;
+ }
+};
+
+class ZarrFunctions: public ZarrTypes
+{
+ std::unique_ptr<GenericCache> cache;
+ CURLRAII                      chandle;
+ MString                       url;
+
+ std::vector<std::vector<size_t>> chunks;
+
+ // Find variable names in metadata
+ static std::vector<MString> ReadVarNames(const Json::Value& meta);
+
+ Error AddVar(const MString& name, const Json::Value& zattrs, const Json::Value& zarray);
+
+ protected:
+ ZarrFunctions()
+ {
+  auto oldprefix = michlib::GPL.UsePrefix("ZARR");
+  cache.reset(CreateCache(michlib::GPL.ParameterSValue("Cache", "")));
+  michlib::GPL.UsePrefix(oldprefix);
+  if(!cache)
+  {
+   michlib::errmessage("Can't init data cache");
+   cache.reset(new FakeCache);
+  }
+ }
+
+ template<class VType> RetVal<ReadedData<VType>> Read(const MString& var, const size_t* start, const size_t* count) const
+ {
+  using Vec = std::vector<size_t>;
+
+  size_t       ind   = FindInd(var, vars);
+  const size_t N     = vars[ind].NDim();
+  const auto&  csize = chunks[ind];
+  Vec          chunkstart(
+      [](size_t N, const size_t* st, const size_t* cs)
+      {
+       Vec out(N);
+       for(size_t i = 0; i < N; i++) out[i] = st[i] / cs[i];
+       return out;
+      }(N, start, csize.data()));
+  ArrCounter chunkind(
+      [](size_t N, const size_t* st, const size_t* cn, const size_t* cs)
+      {
+       Vec out(N);
+       for(size_t i = 0; i < N; i++) out[i] = (st[i] + cn[i]) / cs[i] - st[i] / cs[i] + 1;
+       return out;
+      }(N, start, count, csize.data()));
+
+  bool  havefill = vars[ind].Fill().index() > 0;
+  VType fill     = std::visit(
+      [](auto v)
+      {
+       if constexpr(std::is_convertible_v<decltype(v), VType>)
+        return static_cast<VType>(v);
+       else
+        return std::numeric_limits<VType>::max();
+      },
+      vars[ind].Fill());
+
+  std::vector<std::unique_ptr<VType[]>> cdata;
+
+  size_t chunksize = 1;
+  for(const auto c: csize) chunksize *= c;
+
+  cdata.resize(chunkind.N());
+
+  for(; chunkind; ++chunkind)
+  {
+   cdata[chunkind.Index()].reset(new VType[chunksize]);
+   auto res = GetChunk(var, chunkind.VIndex(chunkstart), chunksize, sizeof(VType), cdata[chunkind.Index()].get(),havefill?&fill:nullptr);
+   if(!res) return res;
+  }
+
+  return ReadedData<VType>(N, start, count, csize.data(), std::move(cdata));
+ }
+
+ Error GetChunk(const MString& var, const std::vector<size_t>& chunkind, size_t chunksize, size_t elsize, void* data, const void* fill) const;
+
+ public:
+ Error Open(const MString& product, const MString& dataset, bool time = true);
+};
+
+using Zarr = NcZarrRead<ZarrFunctions>;
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index c631727..a866fb7 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -9,16 +9,17 @@ find_package(CURL REQUIRED)
 find_package(LibXml2 REQUIRED)
 find_package(SQLite3 REQUIRED)
 pkg_check_modules(JSONCPP REQUIRED jsoncpp)
+pkg_check_modules(BLOSC REQUIRED blosc)
 
 set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
 
-include_directories(${JSONCPP_INCLUDE_DIRS} ${LIBXML2_INCLUDE_DIRS} ${SQLite3_INCLUDE_DIRS})
+include_directories(${JSONCPP_INCLUDE_DIRS} ${BLOSC_INCLUDE_DIRS} ${LIBXML2_INCLUDE_DIRS} ${SQLite3_INCLUDE_DIRS})
 
 file(GLOB srcs CONFIGURE_DEPENDS *.cpp)
 add_executable(${EXENAME} ${srcs} ${ACTIONLISTINC} ${SOURCELISTINC})
 target_include_directories(${EXENAME} PRIVATE ../michlib/michlib ${CMAKE_CURRENT_BINARY_DIR}/../include)
 
-target_link_libraries(${EXENAME} ${linker_options} ${netcdf} OpenMP::OpenMP_CXX CURL::libcurl ${JSONCPP_LINK_LIBRARIES} LibXml2::LibXml2 SQLite::SQLite3 teos)
+target_link_libraries(${EXENAME} ${linker_options} ${netcdf} OpenMP::OpenMP_CXX CURL::libcurl ${JSONCPP_LINK_LIBRARIES} ${BLOSC_LINK_LIBRARIES} LibXml2::LibXml2 SQLite::SQLite3 teos)
 set_target_properties(${EXENAME} PROPERTIES POSITION_INDEPENDENT_CODE ON)
 install(TARGETS ${EXENAME})
 
diff --git a/src/zarr.cpp b/src/zarr.cpp
new file mode 100644
index 0000000..0ae4d06
--- /dev/null
+++ b/src/zarr.cpp
@@ -0,0 +1,236 @@
+#define MICHLIB_NOSOURCE
+#include "zarr.h"
+#include "copcat.h"
+#include <blosc.h>
+
+std::vector<MString> ZarrFunctions::ReadVarNames(const Json::Value& meta)
+{
+ std::vector<MString> out;
+ if(meta.type() != Json::objectValue) return out;
+ const auto keys = meta.getMemberNames();
+ for(const auto& key: keys)
+ {
+  if(!key.ends_with("/.zarray")) continue;
+  const auto  vname = key.substr(0, key.size() - 8);
+  const auto& zattr = meta[vname + "/.zattrs"];
+  if(!(zattr && zattr.type() == Json::objectValue)) continue;
+
+  MString name(vname.c_str(), vname.size());
+  bool    found = false;
+  for(size_t id = 0; id < out.size(); id++)
+   if(out[id] == name)
+   {
+    found = true;
+    break;
+   }
+  if(!found) out.emplace_back(std::move(name));
+ }
+ return out;
+}
+
+Error ZarrFunctions::AddVar(const MString& name, const Json::Value& zattrs, const Json::Value& zarray)
+{
+ static const MString pref = "Zarr::AddVar";
+
+ VarType newtype;
+
+ Variable::FillType fill;
+
+ // Checks for parameters in zarray
+ {
+  const auto& cid = zarray["compressor"]["id"];
+  if(!cid || cid.type() != Json::stringValue || cid.asString() != "blosc") return {pref, "Unsupported compressor: " + MString(cid.asString().c_str())};
+ }
+ {
+  const auto& zf = zarray["zarr_format"];
+  if(!zf || (zf.type() != Json::uintValue && zf.type() != Json::intValue) || zf.asUInt() != 2) return {pref, "Unsupported format version: " + MString(zf.asUInt())};
+ }
+ {
+  const auto& ord = zarray["order"];
+  if(!ord || ord.type() != Json::stringValue || ord.asString() != "C") return {pref, "Order in not C"};
+ }
+ {
+  const auto& f = zarray["filters"];
+  if(f.type() != Json::nullValue) return {pref, "Filters is not null"};
+ }
+
+ // Read dtype
+ {
+  const auto& dtype = zarray["dtype"];
+  if(!dtype || dtype.type() != Json::stringValue) return {pref, "No datatype"};
+  const auto str = dtype.asString();
+  if(str == "<f4")
+   newtype = VarType::FLOAT;
+  else if(str == "<f8")
+   newtype = VarType::DOUBLE;
+  else if(str == "|i1")
+   newtype = VarType::INT1;
+  else if(str == "|u1")
+   newtype = VarType::UINT1;
+  else if(str == "<i2")
+   newtype = VarType::INT2;
+  else if(str == "<i4")
+   newtype = VarType::INT4;
+  else if(str == "<i8")
+   newtype = VarType::INT8;
+  else
+   return {pref, "Unsupported datatype: " + MString(str.c_str())};
+ }
+
+ // Read fill_value
+ {
+  const auto& fillval = zarray["fill_value"];
+  if(!fillval) return {pref, "No fillval"};
+  if(fillval.type() == Json::uintValue)
+   fill = fillval.asUInt64();
+  else if(fillval.type() == Json::intValue)
+   fill = fillval.asInt64();
+  else if(fillval.type() == Json::realValue)
+   fill = fillval.asDouble();
+  else if(fillval.type() == Json::stringValue && fillval.asString() == "NaN")
+   fill = NAN;
+ }
+
+ // Read attributes
+ auto atts = ReadAtts(zattrs);
+
+ std::vector<MString> dnames;
+ std::vector<size_t>  dsizes;
+ std::vector<size_t>  csizes;
+ std::vector<size_t>  dids;
+
+ // Read dimensions names
+ {
+  const auto& arrdim = zattrs["_ARRAY_DIMENSIONS"];
+  if(!(arrdim && arrdim.type() == Json::arrayValue)) return {pref, "_ARRAY_DIMENSIONS not found"};
+  for(Json::ArrayIndex i = 0; i < arrdim.size(); i++)
+   if(const auto& dim = arrdim[i]; dim.type() == Json::stringValue)
+   {
+    const auto val = dim.asString();
+    dnames.emplace_back(val.c_str(), val.size());
+   }
+ }
+
+ // Read dimensions sizes
+ {
+  const auto& shape = zarray["shape"];
+  if(!(shape && shape.type() == Json::arrayValue)) return {pref, "shape not found"};
+  for(Json::ArrayIndex i = 0; i < shape.size(); i++)
+   if(const auto& s = shape[i]; s.type() == Json::uintValue || s.type() == Json::intValue) dsizes.push_back(s.asUInt());
+ }
+
+ // Read chunk sizes
+ {
+  const auto& chunk = zarray["chunks"];
+  if(!(chunk && chunk.type() == Json::arrayValue)) return {pref, "chunks not found"};
+  for(Json::ArrayIndex i = 0; i < chunk.size(); i++)
+   if(const auto& c = chunk[i]; c.type() == Json::uintValue || c.type() == Json::intValue) csizes.push_back(c.asUInt());
+ }
+
+ if(dnames.size() != dsizes.size() || dnames.size() != csizes.size()) return {pref, "shape and chunks are in contradiction"};
+
+ dids.resize(dnames.size());
+
+ // Check dimensions names and sizes
+ for(size_t i = 0; i < dnames.size(); i++)
+ {
+  bool found = false;
+  for(size_t id = 0; id < dims.size(); id++)
+   if(dims[id].Name() == dnames[i])
+   {
+    found = true;
+    if(dims[id].Size() != dsizes[i])
+     return {pref, "According to previous data, the dimension " + dnames[i] + " has a size of " + dims[id].Size() + ", but here it is defined as " + dsizes[i]};
+    dids[i] = id;
+    break;
+   }
+  if(!found)
+  {
+   dids[i] = dims.size();
+   dims.emplace_back(dnames[i], dsizes[i]);
+  }
+ }
+
+ vars.emplace_back(name, newtype, std::move(dids), std::move(atts), fill);
+ chunks.push_back(std::move(csizes));
+
+ return Error();
+}
+
+Error ZarrFunctions::GetChunk(const MString& var, const std::vector<size_t>& chunkind, size_t chunksize, size_t elsize, void* data, const void* fill) const
+{
+ static const MString pref = "Zarr::GetChunk";
+
+ MString str = url + "/" + var + "/";
+ for(size_t i = 0; i < chunkind.size(); i++) str += (i == 0 ? "" : ".") + MString(chunkind[i]);
+
+ auto [content, suc] = cache->Get(str);
+
+ if(!suc)
+ {
+  michlib::message(str + " not found in cache, downloading");
+  auto [out, res] = GetUrl(chandle, str);
+  if(res != CURLE_OK) return Error(pref, MString("can't download chunk: ") + chandle.Err());
+  long respcode;
+  curl_easy_getinfo(chandle, CURLINFO_RESPONSE_CODE, &respcode);
+  michlib::message("Response: ", respcode);
+  if(respcode == 403) out = ""; // Failed chunk download mean that this chunk contains only fill
+  cache->Put(str, out, 3600);
+  content = std::move(out);
+ }
+
+ if(content.Exist())
+ {
+  size_t nb, cb, bs;
+  blosc_cbuffer_sizes(content.Buf(), &nb, &cb, &bs);
+  if(cb != content.Len()) return Error(pref, MString("bytes download: ") + content.Len() + ", but compressed bytes " + cb);
+  if(nb != chunksize * elsize) return Error(pref, MString("decompressed bytes: ") + nb + ", but buffer size " + chunksize * elsize);
+  auto res = blosc_decompress_ctx(content.Buf(), data, chunksize * elsize, 1);
+  if(int_cast<size_t>(res) != chunksize * elsize) return Error(pref, MString("decompress only ") + res + " bytes of " + chunksize * elsize);
+ }
+ else
+ {
+  if(fill == nullptr) return Error(pref, MString("can't download chunk: ") + chandle.Err());
+  for(size_t i = 0; i < chunksize; i++) memcpy(michlib::P1(data) + i * elsize, fill, elsize);
+ }
+
+ return Error();
+}
+
+Error ZarrFunctions::Open(const MString& product, const MString& dataset, bool time)
+{
+ static const MString pref = "Zarr::Open";
+
+ gats.clear();
+ dims.clear();
+ vars.clear();
+
+ CopernicusCatalog cat;
+ Json::Value       json;
+
+ {
+  auto urlret = time ? cat.DatasetTimeURL(product, dataset) : cat.DatasetGeoURL(product, dataset);
+  if(!urlret) return urlret.Add(pref, "Can't get url for the dataset " + dataset + " of product " + product);
+  url = urlret.Value();
+
+  auto ret = cat.GetJSON(url + "/.zmetadata");
+  if(ret)
+   json = ret.Value();
+  else
+   return ret.Add(pref, "can't download .zmetadata");
+ }
+
+ const auto& meta = json["metadata"];
+ if(!meta) return {pref, "No \"metadata\" key in JSON data"};
+
+ if(meta[".zattrs"]) gats = ReadAtts(meta[".zattrs"]);
+ auto vnames = ReadVarNames(meta);
+
+ for(size_t i = 0; i < vnames.size(); i++)
+ {
+  auto err = AddVar(vnames[i], meta[(vnames[i] + "/.zattrs").Buf()], meta[(vnames[i] + "/.zarray").Buf()]);
+  if(!err) return err.Add(pref, "Can't init variable " + vnames[i]);
+ }
+
+ return Error();
+}