tryParseAsciiFloat64 function

double? tryParseAsciiFloat64(Uint8List data)

Parses UTF-8 float text without allocating a String on the ASCII path.

Falls back to utf8.decode + double.tryParse for non-ASCII or formats the fast path does not cover. Returns null when parsing fails.

Implementation

double? tryParseAsciiFloat64(Uint8List data) {
  if (data.isEmpty) {
    return null;
  }
  if (!isAsciiBytes(data)) {
    final text = utf8.decode(data, allowMalformed: true);
    return double.tryParse(text);
  }
  // Trim ASCII whitespace.
  var start = 0;
  var end = data.length;
  while (start < end && _isAsciiSpace(data[start])) {
    start++;
  }
  while (end > start && _isAsciiSpace(data[end - 1])) {
    end--;
  }
  if (start >= end) {
    return null;
  }
  final special = _tryParseAsciiFloatSpecial(data, start, end);
  if (special != null) {
    return special;
  }
  // Delegate to double.tryParse on a temporary Latin-1/ASCII string without
  // UTF-8 scanning — fromCharCodes is cheaper than utf8.decode for ASCII.
  return double.tryParse(
    String.fromCharCodes(data, start, end),
  );
}