NodeCopterHack/node_modules/nearest-neighbor/lib/nearest-neighbor.js

// Generated by CoffeeScript 1.6.2
(function() {
  var calculateSum, exactSimilarity, intersect, ipArraySimilarity, ipSimilarity, numberSimilarity, recordSimilarity, tokenize, wordArraySimilarity, wordSimilarity;

  recordSimilarity = function(a, b, fields) {
    var i, measure, name, similarity, sum, unmatchedFields;

    sum = 0;
    i = 0;
    unmatchedFields = {};
    while (i < fields.length) {
      name = fields[i].name;
      measure = fields[i].measure;
      if ('' + measure === '' + exports.comparisonMethods.number) {
        if (typeof fields[i].max !== 'undefined' && fields[i].max !== null) {
          similarity = measure(a[name], b[name], fields[i].max);
        } else {
          console.warn("max number missing, falling back to max: 9007199254740992");
          similarity = measure(a[name], b[name], 9007199254740992);
        }
      } else {
        similarity = measure(a[name], b[name]);
      }
      if (similarity < 1.0) {
        unmatchedFields[name] = similarity;
      }
      sum += similarity;
      i++;
    }
    return [sum / fields.length, unmatchedFields];
  };

  exactSimilarity = function(a, b) {
    var _ref;

    return (_ref = a === b) != null ? _ref : {
      1: 0
    };
  };

  wordSimilarity = function(a, b) {
    var left, middle, right;

    left = tokenize(a);
    right = tokenize(b);
    middle = intersect(left, right);
    return (2 * middle.length) / (left.length + right.length);
  };

  wordArraySimilarity = function(a, b) {
    var i, similarity;

    if (a.length === b.length) {
      i = 0;
      similarity = 0;
      while (i < a.length) {
        similarity += wordSimilarity(a[i], b[i]);
        i++;
      }
      return similarity / a.length;
    }
    return 0;
  };

  ipSimilarity = function(a, b) {
    var diff, diff1, diff2, diffs, distance, i, left, right;

    left = a.split(".");
    right = b.split(".");
    diffs = [];
    i = 0;
    while (i < 4) {
      diff1 = 255 - left[i];
      diff2 = 255 - right[i];
      diff = Math.abs(diff2 - diff1);
      diffs[i] = diff;
      i++;
    }
    distance = calculateSum(diffs) / (255 * 4);
    return 1 - distance;
  };

  ipArraySimilarity = function(a, b) {
    var i, num, similarity;

    if (a.length === b.length) {
      i = 0;
      similarity = 0;
      num = 0;
      while (i < a.length) {
        if (a[i].match(/\b(?:\d{1,3}\.){3}\d{1,3}\b/) !== null && b[i].match(/\b(?:\d{1,3}\.){3}\d{1,3}\b/) !== null) {
          similarity += ipSimilarity(a[i], b[i]);
          num++;
        }
        i++;
      }
      return similarity / num;
    }
    return 0;
  };

  numberSimilarity = function(a, b, max) {
    var diff, diff1, diff2, distance;

    diff1 = max - a;
    diff2 = max - b;
    diff = Math.abs(diff2 - diff1);
    distance = diff / max;
    return 1 - distance;
  };

  tokenize = function(string) {
    var i, tokens;

    tokens = [];
    if (typeof string !== 'undefined' && string !== null) {
      i = 0;
      while (i < string.length - 1) {
        tokens.push(string.substr(i, 2).toLowerCase());
        i++;
      }
    }
    return tokens.sort();
  };

  intersect = function(a, b) {
    var ai, bi, result;

    ai = 0;
    bi = 0;
    result = new Array();
    while (ai < a.length && bi < b.length) {
      if (a[ai] < b[bi]) {
        ai++;
      } else if (a[ai] > b[bi]) {
        bi++;
      } else {
        result.push(a[ai]);
        ai++;
        bi++;
      }
    }
    return result;
  };

  calculateSum = function(items) {
    var i, sum;

    sum = 0;
    i = 0;
    while (i < items.length) {
      sum += items[i];
      i++;
    }
    return sum;
  };

  exports.comparisonMethods = {
    exact: exactSimilarity,
    word: wordSimilarity,
    wordArray: wordArraySimilarity,
    ip: ipSimilarity,
    ipArray: ipArraySimilarity,
    number: numberSimilarity
  };

  exports.findMostSimilar = function(query, items, fields, callback) {
    var i, item, maxSimilarity, result, similarity, unmatchedFields, _ref;

    maxSimilarity = 0;
    result = null;
    i = 0;
    while (i < items.length) {
      item = items[i];
      _ref = recordSimilarity(item, query, fields), similarity = _ref[0], unmatchedFields = _ref[1];
      if (similarity > maxSimilarity) {
        maxSimilarity = similarity;
        result = item;
      }
      i++;
    }
    return callback(result, maxSimilarity, unmatchedFields);
  };

}).call(this);