Soenneker.Utils.PooledStringBuilders

Tiny, fast ref struct string builder. Backed by ArrayPool<char>. Low allocations. Short-lived use.

Install

dotnet add package Soenneker.Utils.PooledStringBuilders

Example

using Soenneker.Utils.PooledStringBuilders;

using var sb = new PooledStringBuilder(128);

sb.Append("Hello, ");
sb.Append(name);
sb.Append(' ');
sb.Append(id);        // ISpanFormattable path, no boxing
sb.AppendLine();

string s = sb.ToString(); // returns string + returns buffer

Cheatsheet

• new PooledStringBuilder(int capacity = 128)
• Append(char), Append(string?), Append(ReadOnlySpan<char>)
• Append<T>(T value, ReadOnlySpan<char> fmt = default, IFormatProvider? prov = null) where T : ISpanFormattable
• AppendSpan(int length) → write directly into the buffer
• AppendLine(), AppendSeparatorIfNotEmpty(char)
• Length, Capacity, Clear()
• ToString() (keep using; you must Dispose() later)
• ToStringAndDispose(bool clear = false) (one-shot finish)
• Dispose() / Dispose(bool clear)

Notes

• ref struct → stack-only. Don’t capture, box, store in fields, or cross await.
• Dispose when done. using should be used, or there is ToStringAndDispose(). Don't use both.
• Handling secrets? Use ToStringAndDispose(clear: true) to zero the array before returning to the pool.
• Not thread-safe. Keep it short-lived and single-scope.