StringBuilderExtensions.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Text;

namespace Gapotchenko.FX.Text
{
    /// <summary>
    /// <see cref="StringBuilder"/> extensions and polyfills.
    /// </summary>
    public static class StringBuilderExtensions
    {
        /// <summary>
        /// Appends the elements of an object array, using the specified separator between each element.
        /// </summary>
        /// <param name="sb">The string builder.</param>
        /// <param name="separator">The string to use as a separator.</param>
        /// <param name="values">An array that contains the elements to append.</param>
        /// <returns>A reference to string builder after the append operation has completed.</returns>
#if TFF_STRING_BUILDER_APPEND_JOIN
        [EditorBrowsable(EditorBrowsableState.Never)]
#endif
        public static StringBuilder AppendJoin(this StringBuilder sb, string? separator, params object?[] values)
        {
            if (sb == null)
                throw new ArgumentNullException(nameof(sb));

#if TFF_STRING_BUILDER_APPEND_JOIN
            return sb.AppendJoin(separator, values);
#else
            if (values == null)
                throw new ArgumentNullException(nameof(values));

            if (values.Length == 0)
                return sb;

            // Append the first value.
            sb.Append(values[0]);

            // Append remaining values.
            for (int i = 1; i < values.Length; ++i)
                sb.Append(separator).Append(values[i]);

            return sb;
#endif
        }

        /// <summary>
        /// Appends the members of a collection, using the specified separator between each element.
        /// </summary>
        /// <param name="sb">The string builder.</param>
        /// <param name="separator">The string to use as a separator.</param>
        /// <param name="values">A collection that contains the objects to append.</param>
        /// <returns>A reference to string builder after the append operation has completed.</returns>
#if TFF_STRING_BUILDER_APPEND_JOIN
        [EditorBrowsable(EditorBrowsableState.Never)]
#endif
        public static StringBuilder AppendJoin<T>(this StringBuilder sb, string? separator, IEnumerable<T> values)
        {
            if (sb == null)
                throw new ArgumentNullException(nameof(sb));

#if TFF_STRING_BUILDER_APPEND_JOIN
            return sb.AppendJoin(separator, values);
#else
            if (values == null)
                throw new ArgumentNullException(nameof(values));

            using (var enumerator = values.GetEnumerator())
            {
                if (!enumerator.MoveNext())
                    return sb;

                // Append the first value.
                sb.Append(enumerator.Current);

                // Append remaining values.
                while (enumerator.MoveNext())
                    sb.Append(separator).Append(enumerator.Current);
            }

            return sb;
#endif
        }

        /// <summary>
        /// Appends all the elements of a string array, using the specified separator between each element.
        /// </summary>
        /// <param name="sb">The string builder.</param>
        /// <param name="separator">The string to use as a separator.</param>
        /// <param name="values">An array that contains the elements to append.</param>
        /// <returns>A reference to string builder after the append operation has completed.</returns>
#if TFF_STRING_BUILDER_APPEND_JOIN
        [EditorBrowsable(EditorBrowsableState.Never)]
#endif
        public static StringBuilder AppendJoin(this StringBuilder sb, string? separator, params string?[] values)
        {
            if (sb == null)
                throw new ArgumentNullException(nameof(sb));

#if TFF_STRING_BUILDER_APPEND_JOIN
            return sb.AppendJoin(separator, values);
#else
            if (values == null)
                throw new ArgumentNullException(nameof(values));

            if (values.Length == 0)
                return sb;

            // Append the first value.
            sb.Append(values[0]);

            // Append remaining values.
            for (int i = 1; i < values.Length; ++i)
                sb.Append(separator).Append(values[i]);

            return sb;
#endif
        }

        /// <summary>
        /// Appends the elements of an object array, using the specified separator between each element.
        /// </summary>
        /// <param name="sb">The string builder.</param>
        /// <param name="separator">The character to use as a separator.</param>
        /// <param name="values">An array that contains the elements to append.</param>
        /// <returns>A reference to string builder after the append operation has completed.</returns>
#if TFF_STRING_BUILDER_APPEND_JOIN
        [EditorBrowsable(EditorBrowsableState.Never)]
#endif
        public static StringBuilder AppendJoin(this StringBuilder sb, char separator, params object?[] values)
        {
            if (sb == null)
                throw new ArgumentNullException(nameof(sb));

#if TFF_STRING_BUILDER_APPEND_JOIN
            return sb.AppendJoin(separator, values);
#else
            if (values == null)
                throw new ArgumentNullException(nameof(values));

            if (values.Length == 0)
                return sb;

            // Append the first value.
            sb.Append(values[0]);

            // Append remaining values.
            for (int i = 1; i < values.Length; ++i)
                sb.Append(separator).Append(values[i]);

            return sb;
#endif
        }

        /// <summary>
        /// Appends the members of a collection, using the specified separator between each element.
        /// </summary>
        /// <param name="sb">The string builder.</param>
        /// <param name="separator">The character to use as a separator.</param>
        /// <param name="values">A collection that contains the objects to append.</param>
        /// <returns>A reference to string builder after the append operation has completed.</returns>
#if TFF_STRING_BUILDER_APPEND_JOIN
        [EditorBrowsable(EditorBrowsableState.Never)]
#endif
        public static StringBuilder AppendJoin<T>(this StringBuilder sb, char separator, IEnumerable<T> values)
        {
            if (sb == null)
                throw new ArgumentNullException(nameof(sb));

#if TFF_STRING_BUILDER_APPEND_JOIN
            return sb.AppendJoin(separator, values);
#else
            if (values == null)
                throw new ArgumentNullException(nameof(values));

            using (var enumerator = values.GetEnumerator())
            {
                if (!enumerator.MoveNext())
                    return sb;

                // Append the first value.
                sb.Append(enumerator.Current);

                // Append remaining values.
                while (enumerator.MoveNext())
                    sb.Append(separator).Append(enumerator.Current);
            }

            return sb;
#endif
        }

        /// <summary>
        /// Appends all the elements of a string array, using the specified separator between each element.
        /// </summary>
        /// <param name="sb">The string builder.</param>
        /// <param name="separator">The character to use as a separator.</param>
        /// <param name="values">An array that contains the elements to append.</param>
        /// <returns>A reference to string builder after the append operation has completed.</returns>
#if TFF_STRING_BUILDER_APPEND_JOIN
        [EditorBrowsable(EditorBrowsableState.Never)]
#endif
        public static StringBuilder AppendJoin(this StringBuilder sb, char separator, params string?[] values)
        {
            if (sb == null)
                throw new ArgumentNullException(nameof(sb));

#if TFF_STRING_BUILDER_APPEND_JOIN
            return sb.AppendJoin(separator, values);
#else
            if (values == null)
                throw new ArgumentNullException(nameof(values));

            if (values.Length == 0)
                return sb;

            // Append the first value.
            sb.Append(values[0]);

            // Append remaining values.
            for (int i = 1; i < values.Length; ++i)
                sb.Append(separator).Append(values[i]);

            return sb;
#endif
        }

        /// <summary>
        /// Reverses the sequence of the elements in this instance of the entire <see cref="StringBuilder"/>.
        /// </summary>
        /// <param name="sb">The string builder.</param>
        /// <returns>A reference to string builder after the reverse operation has completed.</returns>
        public static StringBuilder Reverse(this StringBuilder sb)
        {
            if (sb == null)
                throw new ArgumentNullException(nameof(sb));

            ReverseCore(sb, 0, sb.Length);

            return sb;
        }

        /// <summary>
        /// Reverses the sequence of the elements in a range of elements in this instance of the <see cref="StringBuilder"/>.
        /// </summary>
        /// <param name="sb">The string builder.</param>
        /// <param name="index">The starting index of the section to reverse.</param>
        /// <param name="length">The number of elements in the section to reverse.</param>
        /// <returns>A reference to string builder after the reverse operation has completed.</returns>
        public static StringBuilder Reverse(this StringBuilder sb, int index, int length)
        {
            if (sb == null)
                throw new ArgumentNullException(nameof(sb));
            if (index < 0)
                throw new ArgumentOutOfRangeException(nameof(index), "Non-negative number required.");
            if (length < 0)
                throw new ArgumentOutOfRangeException(nameof(length), "Non-negative number required.");
            if (sb.Length - index < length)
                throw new ArgumentException("Index and length represent an out of range section of a collection.");

            ReverseCore(sb, index, length);

            return sb;
        }

        static void ReverseCore(StringBuilder sb, int index, int length)
        {
            int i = index;
            int j = index + length - 1;

            while (i < j)
            {
                var t = sb[i];
                sb[i] = sb[j];
                sb[j] = t;

                i++;
                j--;
            }
        }
    }
}