/* 18.3 Worksheets */
function parse_ws_xml(data, opts) {
	if(!data) return data;
	/* 18.3.1.99 worksheet CT_Worksheet */
	var s = {};

	/* 18.3.1.35 dimension CT_SheetDimension ? */
	var ref = data.match(/<dimension ref="([^"]*)"\s*\/>/);
	if(ref && ref.length == 2 && ref[1].indexOf(":") !== -1) s["!ref"] = ref[1];

	/* 18.3.1.55 mergeCells CT_MergeCells */
	var mergecells = [];
	if(data.match(/<\/mergeCells>/)) {
		var merges = data.match(/<mergeCell ref="([A-Z0-9:]+)"\s*\/>/g);
		mergecells = merges.map(function(range) { 
			return decode_range(/<mergeCell ref="([A-Z0-9:]+)"\s*\/>/.exec(range)[1]);
		});
	}

	var refguess = {s: {r:1000000, c:1000000}, e: {r:0, c:0} };
	var q = ["v","f"];
	var sidx = 0;

	/* 18.3.1.80 sheetData CT_SheetData ? */
	if(!data.match(/<sheetData *\/>/))
	data.match(/<sheetData>([^\u2603]*)<\/sheetData>/m)[1].split("</row>").forEach(function(x) {
		if(x === "" || x.trim() === "") return;

		/* 18.3.1.73 row CT_Row */
		var row = parsexmltag(x.match(/<row[^>]*>/)[0]);
		if(opts.sheetRows && opts.sheetRows < +row.r) return;
		if(refguess.s.r > row.r - 1) refguess.s.r = row.r - 1;
		if(refguess.e.r < row.r - 1) refguess.e.r = row.r - 1;
		/* 18.3.1.4 c CT_Cell */
		var cells = x.substr(x.indexOf('>')+1).split(/<c /);
		cells.forEach(function(c, idx) { if(c === "" || c.trim() === "") return;
			var cref = c.match(/r=["']([^"']*)["']/);
			c = "<c " + c;
			if(cref && cref.length == 2) idx = decode_cell(cref[1]).c;
			var cell = parsexmltag((c.match(/<c[^>]*>/)||[c])[0]); delete cell[0];
			var d = c.substr(c.indexOf('>')+1);
			var p = {};
			q.forEach(function(f){var x=d.match(matchtag(f));if(x)p[f]=unescapexml(x[1]);});

			/* SCHEMA IS ACTUALLY INCORRECT HERE.  IF A CELL HAS NO T, EMIT "" */
			if(cell.t === undefined && p.v === undefined) {
				if(!opts.sheetStubs) return;
				p.t = "str"; p.v = undefined;
			}
			else p.t = (cell.t ? cell.t : "n"); // default is "n" in schema
			if(refguess.s.c > idx) refguess.s.c = idx;
			if(refguess.e.c < idx) refguess.e.c = idx;
			/* 18.18.11 t ST_CellType */
			switch(p.t) {
				case 'n': p.v = parseFloat(p.v); break;
				case 's': {
					sidx = parseInt(p.v, 10);
					p.v = strs[sidx].t;
					p.r = strs[sidx].r;
					if(opts.cellHTML) p.h = strs[sidx].h;
				} break;
				case 'str': if(p.v) p.v = utf8read(p.v); break;
				case 'inlineStr':
					var is = d.match(/<is>(.*)<\/is>/);
					is = is ? parse_si(is[1]) : {t:"",r:""};
					p.t = 'str'; p.v = is.t;
					break; // inline string
				case 'b': if(typeof p.v !== 'boolean') p.v = parsexmlbool(p.v); break;
				case 'd': /* TODO: date1904 logic */
					var epoch = Date.parse(p.v);
					p.v = (epoch - new Date(Date.UTC(1899, 11, 30))) / (24 * 60 * 60 * 1000);
					p.t = 'n';
					break;
				/* in case of error, stick value in .raw */
				case 'e': p.raw = RBErr[p.v]; break;
			}

			/* formatting */
			var fmtid = 0;
			if(cell.s && styles.CellXf) {
				var cf = styles.CellXf[cell.s];
				if(cf && cf.numFmtId) fmtid = cf.numFmtId;
			}
			try {
				p.w = SSF.format(fmtid,p.v,_ssfopts);
				if(opts.cellNF) p.z = SSF._table[fmtid];
			} catch(e) { if(opts.WTF) throw e; }
			s[cell.r] = p;
		});
	});
	if(!s["!ref"]) s["!ref"] = encode_range(refguess);
	if(opts.sheetRows) {
		var tmpref = decode_range(s["!ref"]);
		if(opts.sheetRows < +tmpref.e.r) {
			tmpref.e.r = opts.sheetRows - 1;
			if(tmpref.e.r > refguess.e.r) tmpref.e.r = refguess.e.r;
			if(tmpref.e.r < tmpref.s.r) tmpref.s.r = tmpref.e.r;
			if(tmpref.e.c > refguess.e.c) tmpref.e.c = refguess.e.c;
			if(tmpref.e.c < tmpref.s.c) tmpref.s.c = tmpref.e.c;
			s["!fullref"] = s["!ref"];
			s["!ref"] = encode_range(tmpref);
		}
	}
	if(mergecells.length > 0) s["!merges"] = mergecells;
	return s;
}