ArrayNDScanner.cc

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#include "JetMETCorrections/InterpolationTables/interface/NpstatException.h"
#include <cassert>

#include "JetMETCorrections/InterpolationTables/interface/ArrayNDScanner.h"

namespace npstat {
  void ArrayNDScanner::initialize(const unsigned* shape, const unsigned lenShape) {
    // Check argument validity
    if (lenShape == 0U || lenShape >= CHAR_BIT * sizeof(unsigned long))
      throw npstat::NpstatInvalidArgument("In npstat::ArrayNDScanner::initialize: invalid scan shape");
    assert(shape);
    for (unsigned j = 0; j < lenShape; ++j)
      if (!shape[j])
        throw npstat::NpstatInvalidArgument(
            "In npstat::ArrayNDScanner::initialize: "
            "number of scans must be positive in each dimension");

    // Initialize the scanner data
    state_ = 0UL;
    dim_ = lenShape;
    strides_[dim_ - 1] = 1UL;
    for (unsigned j = dim_ - 1; j > 0; --j)
      strides_[j - 1] = strides_[j] * shape[j];
    maxState_ = strides_[0] * shape[0];
  }

  void ArrayNDScanner::getIndex(unsigned* ix, const unsigned indexBufferLen) const {
    if (indexBufferLen < dim_)
      throw npstat::NpstatInvalidArgument(
          "In npstat::ArrayNDScanner::getIndex: "
          "insufficient length of the output buffer");
    if (state_ >= maxState_)
      throw npstat::NpstatRuntimeError("In npstat::ArrayNDScanner::getIndex: invalid scanner state");
    assert(ix);

    unsigned long l = state_;
    for (unsigned i = 0; i < dim_; ++i) {
      unsigned long idx = l / strides_[i];
      ix[i] = static_cast<unsigned>(idx);
      l -= (idx * strides_[i]);
    }
  }
}  // namespace npstat