// Copyright (c) Six Labors.
// Licensed under the Six Labors Split License.

namespace SixLabors.Fonts.Tables.Cff {
  /// <summary>
  /// Defines the operand interpretation for a CFF DICT operator.
  /// Used to describe how operands on the DICT stack should be decoded.
  /// <see href="https://adobe-type-tools.github.io/font-tech-notes/pdfs/5176.CFF.pdf"/>
  /// </summary>
  internal enum OperatorOperandKind
  {
      /// <summary>
      /// A string identifier referencing the String INDEX.
      /// </summary>
      SID,

      /// <summary>
      /// A boolean value (0 or 1).
      /// </summary>
      Boolean,

      /// <summary>
      /// A single numeric value (integer or real).
      /// </summary>
      Number,

      /// <summary>
      /// An array of numeric values.
      /// </summary>
      Array,

      /// <summary>
      /// A delta-encoded array of numeric values.
      /// </summary>
      Delta,

      /// <summary>
      /// Two numeric values (e.g. Private DICT size and offset).
      /// </summary>
      NumberNumber,

      /// <summary>
      /// Two SIDs followed by a number (e.g. ROS: Registry, Ordering, Supplement).
      /// </summary>
      SID_SID_Number,
  }
}