covutils/lib/subset.js

Utilities for creating, transforming, and handling Coverage Data objects.

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});

var _slicedToArray = function () { function sliceIterator(arr, i) { var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"]) _i["return"](); } finally { if (_d) throw _e; } } return _arr; } return function (arr, i) { if (Array.isArray(arr)) { return arr; } else if (Symbol.iterator in Object(arr)) { return sliceIterator(arr, i); } else { throw new TypeError("Invalid attempt to destructure non-iterable instance"); } }; }();

exports.normalizeIndexSubsetConstraints = normalizeIndexSubsetConstraints;
exports.subsetDomainByIndex = subsetDomainByIndex;
exports.subsetCoverageByIndex = subsetCoverageByIndex;
exports.subsetCoverageByValue = subsetCoverageByValue;

var _referencing = require('./referencing.js');

var _array = require('./array.js');

var _constants = require('./constants.js');

function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }

/**
 * After normalization, all constraints are start,stop,step objects.
 * It holds that stop > start, step > 0, start >= 0, stop >= 1.
 * For each axis, a constraint exists.
 */
function normalizeIndexSubsetConstraints(domain, constraints) {
  // check and normalize constraints to simplify code
  var normalizedConstraints = {};
  for (var axisName in constraints) {
    if (!domain.axes.has(axisName)) {
      // TODO clarify cov behaviour in the JS API spec
      continue;
    }
    if (constraints[axisName] === undefined || constraints[axisName] === null) {
      continue;
    }
    if (typeof constraints[axisName] === 'number') {
      var constraint = constraints[axisName];
      normalizedConstraints[axisName] = { start: constraint, stop: constraint + 1 };
    } else {
      normalizedConstraints[axisName] = constraints[axisName];
    }

    var _normalizedConstraint = normalizedConstraints[axisName];
    var _normalizedConstraint2 = _normalizedConstraint.start;
    var start = _normalizedConstraint2 === undefined ? 0 : _normalizedConstraint2;
    var _normalizedConstraint3 = _normalizedConstraint.stop;
    var stop = _normalizedConstraint3 === undefined ? domain.axes.get(axisName).values.length : _normalizedConstraint3;
    var _normalizedConstraint4 = _normalizedConstraint.step;
    var step = _normalizedConstraint4 === undefined ? 1 : _normalizedConstraint4;

    if (step <= 0) {
      throw new Error('Invalid constraint for ' + axisName + ': step=' + step + ' must be > 0');
    }
    if (start >= stop || start < 0) {
      throw new Error('Invalid constraint for ' + axisName + ': stop=' + stop + ' must be > start=' + start + ' and both >= 0');
    }
    normalizedConstraints[axisName] = { start: start, stop: stop, step: step };
  }
  var _iteratorNormalCompletion = true;
  var _didIteratorError = false;
  var _iteratorError = undefined;

  try {
    for (var _iterator = domain.axes.keys()[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
      var _axisName = _step.value;

      if (!(_axisName in normalizedConstraints)) {
        var len = domain.axes.get(_axisName).values.length;
        normalizedConstraints[_axisName] = { start: 0, stop: len, step: 1 };
      }
    }
  } catch (err) {
    _didIteratorError = true;
    _iteratorError = err;
  } finally {
    try {
      if (!_iteratorNormalCompletion && _iterator.return) {
        _iterator.return();
      }
    } finally {
      if (_didIteratorError) {
        throw _iteratorError;
      }
    }
  }

  return normalizedConstraints;
}

function subsetDomainByIndex(domain, constraints) {
  constraints = normalizeIndexSubsetConstraints(domain, constraints);

  // subset the axis arrays of the domain (immediately + cached)
  var newdomain = {
    type: _constants.DOMAIN,
    // TODO remove profiles in favour of domainType at some point
    // TODO are the profiles still valid?
    profiles: domain.profiles,
    domainType: domain.domainType,
    axes: new Map(domain.axes),
    referencing: domain.referencing
  };

  var _iteratorNormalCompletion2 = true;
  var _didIteratorError2 = false;
  var _iteratorError2 = undefined;

  try {
    var _loop = function _loop() {
      var axisName = _step2.value;

      var axis = domain.axes.get(axisName);
      var coords = axis.values;
      var bounds = axis.bounds;
      var constraint = constraints[axisName];
      var newcoords = void 0;
      var newbounds = void 0;

      var start = constraint.start;
      var stop = constraint.stop;
      var step = constraint.step;

      if (start === 0 && stop === coords.length && step === 1) {
        newcoords = coords;
        newbounds = bounds;
      } else if (step === 1) {
        // TypedArray has subarray which creates a view, while Array has slice which makes a copy
        if (coords.subarray) {
          newcoords = coords.subarray(start, stop);
        } else {
          newcoords = coords.slice(start, stop);
        }
        if (bounds) {
          newbounds = {
            get: function get(i) {
              return bounds.get(start + i);
            }
          };
        }
      } else {
        var q = Math.trunc((stop - start) / step);
        var r = (stop - start) % step;
        var len = q + r;
        newcoords = new coords.constructor(len); // array or typed array
        for (var i = start, j = 0; i < stop; i += step, j++) {
          newcoords[j] = coords[i];
        }
        if (bounds) {
          newbounds = {
            get: function get(i) {
              return bounds.get(start + i * step);
            }
          };
        }
      }

      var newaxis = {
        dataType: axis.dataType,
        components: axis.components,
        values: newcoords,
        bounds: newbounds
      };
      newdomain.axes.set(axisName, newaxis);
    };

    for (var _iterator2 = Object.keys(constraints)[Symbol.iterator](), _step2; !(_iteratorNormalCompletion2 = (_step2 = _iterator2.next()).done); _iteratorNormalCompletion2 = true) {
      _loop();
    }
  } catch (err) {
    _didIteratorError2 = true;
    _iteratorError2 = err;
  } finally {
    try {
      if (!_iteratorNormalCompletion2 && _iterator2.return) {
        _iterator2.return();
      }
    } finally {
      if (_didIteratorError2) {
        throw _iteratorError2;
      }
    }
  }

  return newdomain;
}

/**
 * Generic subsetByIndex function that can be used when building new Coverage objects.
 * 
 * @example
 * var cov = {
 *   type: 'Coverage',
 *   ...
 *   subsetByIndex: constraints => subsetCoverageByIndex(cov, constraints)
 * }
 */
function subsetCoverageByIndex(cov, constraints) {
  return cov.loadDomain().then(function (domain) {
    constraints = normalizeIndexSubsetConstraints(domain, constraints);
    var newdomain = subsetDomainByIndex(domain, constraints);

    // subset ranges (on request)
    var rangeWrapper = function rangeWrapper(range) {
      var newrange = {
        dataType: range.dataType,
        get: function get(obj) {
          // translate subsetted to original indices
          var newobj = {};
          var _iteratorNormalCompletion3 = true;
          var _didIteratorError3 = false;
          var _iteratorError3 = undefined;

          try {
            for (var _iterator3 = Object.keys(obj)[Symbol.iterator](), _step3; !(_iteratorNormalCompletion3 = (_step3 = _iterator3.next()).done); _iteratorNormalCompletion3 = true) {
              var axisName = _step3.value;
              var _constraints$axisName = constraints[axisName];
              var _start = _constraints$axisName.start;
              var _step4 = _constraints$axisName.step;

              newobj[axisName] = _start + obj[axisName] * _step4;
            }
          } catch (err) {
            _didIteratorError3 = true;
            _iteratorError3 = err;
          } finally {
            try {
              if (!_iteratorNormalCompletion3 && _iterator3.return) {
                _iterator3.return();
              }
            } finally {
              if (_didIteratorError3) {
                throw _iteratorError3;
              }
            }
          }

          return range.get(newobj);
        }
      };
      newrange.shape = new Map();
      var _iteratorNormalCompletion4 = true;
      var _didIteratorError4 = false;
      var _iteratorError4 = undefined;

      try {
        for (var _iterator4 = domain.axes.keys()[Symbol.iterator](), _step5; !(_iteratorNormalCompletion4 = (_step5 = _iterator4.next()).done); _iteratorNormalCompletion4 = true) {
          var axisName = _step5.value;

          var size = newdomain.axes.get(axisName).values.length;
          newrange.shape.set(axisName, size);
        }
      } catch (err) {
        _didIteratorError4 = true;
        _iteratorError4 = err;
      } finally {
        try {
          if (!_iteratorNormalCompletion4 && _iterator4.return) {
            _iterator4.return();
          }
        } finally {
          if (_didIteratorError4) {
            throw _iteratorError4;
          }
        }
      }

      return newrange;
    };

    var loadRange = function loadRange(key) {
      return cov.loadRange(key).then(rangeWrapper);
    };

    var loadRanges = function loadRanges(keys) {
      return cov.loadRanges(keys).then(function (ranges) {
        return new Map([].concat(_toConsumableArray(ranges)).map(function (_ref) {
          var _ref2 = _slicedToArray(_ref, 2);

          var key = _ref2[0];
          var range = _ref2[1];
          return [key, rangeWrapper(range)];
        }));
      });
    };

    // assemble everything to a new coverage
    var newcov = {
      type: _constants.COVERAGE,
      // TODO are the profiles still valid?
      domainProfiles: cov.domainProfiles,
      domainType: cov.domainType,
      parameters: cov.parameters,
      loadDomain: function loadDomain() {
        return Promise.resolve(newdomain);
      },
      loadRange: loadRange,
      loadRanges: loadRanges
    };
    newcov.subsetByIndex = subsetCoverageByIndex.bind(null, newcov);
    newcov.subsetByValue = subsetCoverageByValue.bind(null, newcov);
    return newcov;
  });
}

/**
 * Generic subsetByValue function that can be used when building new Coverage objects.
 * Requires cov.subsetByIndex function.
 * 
 * @example
 * var cov = {
 *   type: 'Coverage',
 *   ...
 *   subsetByValue: constraints => subsetCoverageByValue(cov, constraints)
 * }
 */
function subsetCoverageByValue(cov, constraints) {
  return cov.loadDomain().then(function (domain) {
    // calculate indices and use subsetByIndex
    var indexConstraints = {};

    var _iteratorNormalCompletion5 = true;
    var _didIteratorError5 = false;
    var _iteratorError5 = undefined;

    try {
      for (var _iterator5 = Object.keys(constraints)[Symbol.iterator](), _step6; !(_iteratorNormalCompletion5 = (_step6 = _iterator5.next()).done); _iteratorNormalCompletion5 = true) {
        var axisName = _step6.value;

        var spec = constraints[axisName];
        if (spec === undefined || spec === null || !domain.axes.has(axisName)) {
          continue;
        }
        var axis = domain.axes.get(axisName);
        var vals = axis.values;

        // special-case handling
        var isISODate = (0, _referencing.isISODateAxis)(domain, axisName);
        var isLongitude = (0, _referencing.isLongitudeAxis)(domain, axisName);

        // wrap input longitudes into longitude range of domain axis
        var lonWrapper = isLongitude ? (0, _referencing.getLongitudeWrapper)(domain, axisName) : undefined;

        if (typeof spec === 'number' || typeof spec === 'string' || spec instanceof Date) {
          var match = spec;
          if (isISODate) {
            // convert times to numbers before searching
            match = (0, _referencing.asTime)(match);
            vals = vals.map(function (v) {
              return new Date(v).getTime();
            });
          } else if (isLongitude) {
            match = lonWrapper(match);
          }
          var i = void 0;
          // older browsers don't have TypedArray.prototype.indexOf
          if (vals.indexOf) {
            i = vals.indexOf(match);
          } else {
            i = Array.prototype.indexOf.call(vals, match);
          }
          if (i === -1) {
            throw new Error('Domain value not found: ' + spec);
          }
          indexConstraints[axisName] = i;
        } else if ('target' in spec) {
          // find index of value closest to target
          var target = spec.target;
          if (isISODate) {
            // convert times to numbers before searching
            target = (0, _referencing.asTime)(target);
            vals = vals.map(function (v) {
              return new Date(v).getTime();
            });
          } else if (isLongitude) {
            target = lonWrapper(target);
          } else if (typeof vals[0] !== 'number' || typeof target !== 'number') {
            throw new Error('Invalid axis or constraint value type');
          }
          var _i = (0, _array.indexOfNearest)(vals, target);
          indexConstraints[axisName] = _i;
        } else if ('start' in spec && 'stop' in spec) {
          // TODO what about bounds?

          var _start2 = spec.start;
          var _stop = spec.stop;

          if (isISODate) {
            var _ref3 = [(0, _referencing.asTime)(_start2), (0, _referencing.asTime)(_stop)];
            // convert times to numbers before searching

            _start2 = _ref3[0];
            _stop = _ref3[1];

            vals = vals.map(function (v) {
              return new Date(v).getTime();
            });
          } else if (isLongitude) {
            var _ref4 = [lonWrapper(_start2), lonWrapper(_stop)];
            _start2 = _ref4[0];
            _stop = _ref4[1];
          } else if (typeof vals[0] !== 'number' || typeof _start2 !== 'number') {
            throw new Error('Invalid axis or constraint value type');
          }

          var _indicesOfNearest = (0, _array.indicesOfNearest)(vals, _start2);

          var _indicesOfNearest2 = _slicedToArray(_indicesOfNearest, 2);

          var lo1 = _indicesOfNearest2[0];
          var hi1 = _indicesOfNearest2[1];

          var _indicesOfNearest3 = (0, _array.indicesOfNearest)(vals, _stop);

          var _indicesOfNearest4 = _slicedToArray(_indicesOfNearest3, 2);

          var lo2 = _indicesOfNearest4[0];
          var hi2 = _indicesOfNearest4[1];

          // cov is a bit arbitrary and may include one or two indices too much
          // (but since we don't handle bounds it doesn't matter that much)

          var imin = Math.min(lo1, hi1, lo2, hi2);
          var imax = Math.max(lo1, hi1, lo2, hi2) + 1; // subsetByIndex is exclusive

          indexConstraints[axisName] = { start: imin, stop: imax };
        } else {
          throw new Error('Invalid subset constraints');
        }
      }
    } catch (err) {
      _didIteratorError5 = true;
      _iteratorError5 = err;
    } finally {
      try {
        if (!_iteratorNormalCompletion5 && _iterator5.return) {
          _iterator5.return();
        }
      } finally {
        if (_didIteratorError5) {
          throw _iteratorError5;
        }
      }
    }

    return cov.subsetByIndex(indexConstraints);
  });
}