toolkit/javascript/d3/src/core/format.js
changeset 47 c0b4a8b5a012
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/javascript/d3/src/core/format.js	Thu Apr 10 14:20:23 2014 +0200
@@ -0,0 +1,100 @@
+// TODO align
+d3.format = function(specifier) {
+  var match = d3_format_re.exec(specifier),
+      fill = match[1] || " ",
+      sign = match[3] || "",
+      zfill = match[5],
+      width = +match[6],
+      comma = match[7],
+      precision = match[8],
+      type = match[9],
+      scale = 1,
+      suffix = "",
+      integer = false;
+
+  if (precision) precision = +precision.substring(1);
+
+  if (zfill) {
+    fill = "0"; // TODO align = "=";
+    if (comma) width -= Math.floor((width - 1) / 4);
+  }
+
+  switch (type) {
+    case "n": comma = true; type = "g"; break;
+    case "%": scale = 100; suffix = "%"; type = "f"; break;
+    case "p": scale = 100; suffix = "%"; type = "r"; break;
+    case "d": integer = true; precision = 0; break;
+    case "s": scale = -1; type = "r"; break;
+  }
+
+  // If no precision is specified for r, fallback to general notation.
+  if (type == "r" && !precision) type = "g";
+
+  type = d3_format_types[type] || d3_format_typeDefault;
+
+  return function(value) {
+
+    // Return the empty string for floats formatted as ints.
+    if (integer && (value % 1)) return "";
+
+    // Convert negative to positive, and record the sign prefix.
+    var negative = (value < 0) && (value = -value) ? "\u2212" : sign;
+
+    // Apply the scale, computing it from the value's exponent for si format.
+    if (scale < 0) {
+      var prefix = d3.formatPrefix(value, precision);
+      value *= prefix.scale;
+      suffix = prefix.symbol;
+    } else {
+      value *= scale;
+    }
+
+    // Convert to the desired precision.
+    value = type(value, precision);
+
+    // If the fill character is 0, the sign and group is applied after the fill.
+    if (zfill) {
+      var length = value.length + negative.length;
+      if (length < width) value = new Array(width - length + 1).join(fill) + value;
+      if (comma) value = d3_format_group(value);
+      value = negative + value;
+    }
+
+    // Otherwise (e.g., space-filling), the sign and group is applied before.
+    else {
+      if (comma) value = d3_format_group(value);
+      value = negative + value;
+      var length = value.length;
+      if (length < width) value = new Array(width - length + 1).join(fill) + value;
+    }
+
+    return value + suffix;
+  };
+};
+
+// [[fill]align][sign][#][0][width][,][.precision][type]
+var d3_format_re = /(?:([^{])?([<>=^]))?([+\- ])?(#)?(0)?([0-9]+)?(,)?(\.[0-9]+)?([a-zA-Z%])?/;
+
+var d3_format_types = {
+  g: function(x, p) { return x.toPrecision(p); },
+  e: function(x, p) { return x.toExponential(p); },
+  f: function(x, p) { return x.toFixed(p); },
+  r: function(x, p) { return d3.round(x, p = d3_format_precision(x, p)).toFixed(Math.max(0, Math.min(20, p))); }
+};
+
+function d3_format_precision(x, p) {
+  return p - (x ? 1 + Math.floor(Math.log(x + Math.pow(10, 1 + Math.floor(Math.log(x) / Math.LN10) - p)) / Math.LN10) : 1);
+}
+
+function d3_format_typeDefault(x) {
+  return x + "";
+}
+
+// Apply comma grouping for thousands.
+function d3_format_group(value) {
+  var i = value.lastIndexOf("."),
+      f = i >= 0 ? value.substring(i) : (i = value.length, ""),
+      t = [];
+  while (i > 0) t.push(value.substring(i -= 3, i + 3));
+  return t.reverse().join(",") + f;
+}