/// <summary>
/// Attempt to parse the string into a data kind and (optionally) a keyCount. This method does not check whether
/// the returned <see cref="DataKind"/> can really be made into a key with the specified <paramref name="keyCount"/>.
/// </summary>
/// <param name="str">The string to parse.</param>
/// <param name="dataKind">The parsed data kind.</param>
/// <param name="keyCount">The parsed key count, or null if there's no key specification.</param>
/// <returns>Whether the parsing succeeded or not.</returns>
public static bool TryParseDataKind(string str, out DataKind dataKind, out KeyCount keyCount)
{
Contracts.CheckValue(str, nameof(str));
keyCount = null;
dataKind = default;
int ich = str.IndexOf('[');
if (0 <= ich)
{
if (str[str.Length - 1] != ']')
{
return(false);
}
keyCount = KeyCount.Parse(str.Substring(ich + 1, str.Length - ich - 2));
if (keyCount == null)
{
return(false);
}
if (ich == 0)
{
return(true);
}
str = str.Substring(0, ich);
}
if (!Enum.TryParse(str, true, out dataKind))
{
return(false);
}
return(true);
}
/// <summary>
/// Initializes a new instance of the <see cref="Column"/> class.
/// </summary>
/// <param name="name">Name of the column.</param>
/// <param name="dbType"><see cref="DbType"/> of the items in the column.</param>
/// <param name="source">Source index range(s) of the column.</param>
/// <param name="keyCount">For a key column, this defines the range of values.</param>
public Column(string name, DbType dbType, Range[] source, KeyCount keyCount = null)
{
Contracts.CheckValue(name, nameof(name));
Contracts.CheckValue(source, nameof(source));
Name = name;
Type = dbType;
Source = source;
KeyCount = keyCount;
}
/// <summary>
/// Parses the string format for a KeyCount, also supports the old KeyRange format for backwards compatibility.
/// </summary>
public static KeyCount Parse(string str)
{
Contracts.AssertValue(str);
var res = new KeyCount();
if (res.TryParse(str))
{
return(res);
}
return(null);
}
/// <summary>
/// Construct a <see cref="KeyType"/> out of the data kind and the keyCount.
/// </summary>
public static KeyType ConstructKeyType(DataKind?type, KeyCount keyCount)
{
Contracts.CheckValue(keyCount, nameof(keyCount));
KeyType keyType;
Type rawType = type.HasValue ? type.Value.ToType() : DataKind.U8.ToType();
Contracts.CheckUserArg(KeyType.IsValidDataType(rawType), nameof(TextLoader.Column.Type), "Bad item type for Key");
if (keyCount.Count == null)
{
keyType = new KeyType(rawType, rawType.ToMaxInt());
}
else
{
keyType = new KeyType(rawType, keyCount.Count.GetValueOrDefault());
}
return(keyType);
}
