markdig/src/Markdig/Syntax/SourceSpan.cs

// Copyright (c) Alexandre Mutel. All rights reserved.
// This file is licensed under the BSD-Clause 2 license. 
// See the license.txt file in the project root for more information.

using System;

namespace Markdig.Syntax
{
    /// <summary>
    /// A span of text.
    /// </summary>
    public struct SourceSpan : IEquatable<SourceSpan>
    {
        public static readonly SourceSpan Empty = new SourceSpan(0, -1);

        /// <summary>
        /// Initializes a new instance of the <see cref="SourceSpan"/> struct.
        /// </summary>
        /// <param name="start">The start.</param>
        /// <param name="end">The end.</param>
        public SourceSpan(int start, int end)
        {
            Start = start;
            End = end;
        }

        /// <summary>
        /// Gets or sets the starting character position from the original text source. 
        /// Note that for inline elements, this is only valid if <see cref="MarkdownExtensions.UsePreciseSourceLocation"/> is setup on the pipeline.
        /// </summary>
        public int Start { get; set; }

        /// <summary>
        /// Gets or sets the ending character position from the original text source.
        /// Note that for inline elements, this is only valid if <see cref="MarkdownExtensions.UsePreciseSourceLocation"/> is setup on the pipeline.
        /// </summary>
        public int End { get; set; }

        /// <summary>
        /// Gets the character length of this element within the original source code.
        /// </summary>
        public int Length => End - Start + 1;

        public bool IsEmpty => Start > End;

        public bool Equals(SourceSpan other)
        {
            return Start == other.Start && End == other.End;
        }

        public override bool Equals(object obj)
        {
            if (ReferenceEquals(null, obj)) return false;
            return obj is SourceSpan && Equals((SourceSpan) obj);
        }

        public override int GetHashCode()
        {
            unchecked
            {
                return (Start*397) ^ End;
            }
        }

        public static bool operator ==(SourceSpan left, SourceSpan right)
        {
            return left.Equals(right);
        }

        public static bool operator !=(SourceSpan left, SourceSpan right)
        {
            return !left.Equals(right);
        }

        public override string ToString()
        {
            return $"{Start}-{End}";
        }
    }
}