mmg/bonus/mmg_csv.js

Simple markers for Modest Maps

function mmg_csv(url, callback) {
    // Extracted from d3
    function csv_parse(text) {
      var header;
      return csv_parseRows(text, function(row, i) {
        if (i) {
          var o = {}, j = -1, m = header.length;
          while (++j < m) o[header[j]] = row[j];
          return o;
        } else {
          header = row;
          return null;
        }
      });
    }

    function csv_parseRows (text, f) {
      var EOL = {}, // sentinel value for end-of-line
          EOF = {}, // sentinel value for end-of-file
          rows = [], // output rows
          re = /\r\n|[,\r\n]/g, // field separator regex
          n = 0, // the current line number
          t, // the current token
          eol; // is the current token followed by EOL?

      re.lastIndex = 0; // work-around bug in FF 3.6

      /** @private Returns the next token. */
      function token() {
        if (re.lastIndex >= text.length) return EOF; // special case: end of file
        if (eol) { eol = false; return EOL; } // special case: end of line

        // special case: quotes
        var j = re.lastIndex;
        if (text.charCodeAt(j) === 34) {
          var i = j;
          while (i++ < text.length) {
            if (text.charCodeAt(i) === 34) {
              if (text.charCodeAt(i + 1) !== 34) break;
              i++;
            }
          }
          re.lastIndex = i + 2;
          var c = text.charCodeAt(i + 1);
          if (c === 13) {
            eol = true;
            if (text.charCodeAt(i + 2) === 10) re.lastIndex++;
          } else if (c === 10) {
            eol = true;
          }
          return text.substring(j + 1, i).replace(/""/g, "\"");
        }

        // common case
        var m = re.exec(text);
        if (m) {
          eol = m[0].charCodeAt(0) !== 44;
          return text.substring(j, m.index);
        }
        re.lastIndex = text.length;
        return text.substring(j);
      }

      while ((t = token()) !== EOF) {
        var a = [];
        while ((t !== EOL) && (t !== EOF)) {
          a.push(t);
          t = token();
        }
        if (f && !(a = f(a, n++))) continue;
        rows.push(a);
      }

      return rows;
    }

    if (!arguments.length) return urls;
    if (typeof reqwest === 'undefined') throw 'reqwest is required for url loading';

    var log = (typeof console !== 'undefined') ? function(x) { console.log(x); } : function() {};

    function add_features(x) {
        var features = [];

        if (x.status >= 400) {
            if (typeof console != 'undefined') throw 'URL returned 404';
            return callback(features);
        }

        var parsed = csv_parse(x.responseText);
        if (!parsed.length) return callback(features);

        var latfield = '',
            lonfield = '';

        for (var f in parsed[0]) {
            if (f.match(/^Lat/i)) latfield = f;
            if (f.match(/^Lon/i)) lonfield = f;
        }

        for (var i = 0; i < parsed.length; i++) {
            if (parsed[i][lonfield] !== undefined &&
                parsed[i][lonfield] !== undefined) {
                features.push({
                    type: 'Feature',
                    properties: parsed[i],
                    geometry: {
                        type: 'Point',
                        coordinates: [
                            parsed[i][lonfield],
                            parsed[i][latfield]]
                    }
                });
            } else {
                log('Some points did not contain lat/lon data');
                log(parsed[i]);
            }
        }

        if (callback) callback(features);
    }

    reqwest({
        url: url,
        type: 'string',
        success: add_features,
        error: add_features
    });
}