Introduction

Welcome to Wolfgang.Etl.FixedWidth!

Overview

Wolfgang.Etl.FixedWidth provides an extractor and loader for reading and writing fixed-width text files, built on Wolfgang.Etl.Abstractions. It maps fixed-width columns to strongly typed POCO properties using declarative attributes, handles alignment, padding, parsing, and formatting, and streams records asynchronously with IAsyncEnumerable<T>.

Key Features

  • Attribute-based field mapping — [FixedWidthField] and [FixedWidthSkip] attributes define column index, length, alignment, padding, and header text
  • Left/right alignment with configurable padding — control how values are positioned within their column and which pad character is used
  • Custom ValueParser and ValueConverter delegates — plug in custom parsing (extraction) and conversion (loading) logic per field or globally
  • Header rows, separator lines, field delimiters — optional header output, configurable separator characters, and inter-field delimiters
  • BlankLineHandling and MalformedLineHandling modes — choose to skip, error, or pass through blank and malformed lines during extraction
  • SkipItemCount / MaximumItemCount pagination — skip the first N records and cap the total extracted or loaded
  • LineFilter for custom line control — supply a delegate to include or exclude lines before parsing
  • Timer-based progress reporting — periodic FixedWidthReport snapshots via the Abstractions progress-timer infrastructure
  • Zero-copy parsing with ReadOnlyMemory<char> — slices line data without allocating intermediate strings where possible
  • Span-based numeric parsing on net8.0+ — uses ISpanParsable<T> for allocation-free numeric conversion on modern runtimes
  • Compiled delegates for reflection-free field access — property getters and setters are compiled once and cached for fast field access
  • Multi-TFM support — targets netstandard2.0, netstandard2.1, net8.0, net9.0, and net10.0

Getting Help

If you need help with Wolfgang.Etl.FixedWidth, please:

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