WpfHexEditor.Plugins.FileComparison

March 8, 2026 · View on GitHub

Project: WpfHexEditor.Plugins.FileComparison License: GNU Affero General Public License v3.0 Platform: net8.0-windows (WPF) Default dock: Bottom

Description

The File Comparison plugin provides a side-by-side structural diff of two binary files. Each file is parsed using the automatic format detection engine (400+ format definitions); the extracted named fields are then compared by name and value. Changed, added, and removed fields are color-coded. Summary statistics show the number of matching, added, modified, and removed fields.

Features

  • Structural diff — files are compared at the field level (not raw byte level); each named field is matched by name and its decoded string value is compared.
  • Format auto-detection — FormatDetectionService with JSON format definitions from FormatDefinitions/ is applied to each file independently.
  • Multi-candidate resolution — when more than one format matches a file, a selection dialog (up to 5 candidates) lets the user choose the correct format.
  • Side-by-side display — two synchronized ListView columns, one per file.
  • Diff status coloring — each field row is color-coded: Unchanged, Added, Removed, or Modified.
  • Summary statistics: matching field count, added, modified, and removed fields.
  • Supported primitive value types for field decoding: uint8, uint16, uint32, int16, int32, string/ASCII, UTF-8, and raw hex fallback.
  • ViewModel (FileComparisonPanelViewModel) tracks file names, diff counts, comparison status, and a loading flag.

Panel

PropertyValue
Panel IDWpfHexEditor.Plugins.FileComparison.Panel.FileComparisonPanel
Default dock sideBottom
View menu entryView > File Comparison

Internal components

ComponentResponsibility
FileComparisonPanel.xaml(.cs)File picker buttons, side-by-side ListViews, diff logic, statistics labels
FileComparisonPanelViewModel.csFile names, diff counts, comparison status flag
ParsedFieldLocal field model (name, value, type, offset, length)
DiffFieldObservable diff row model with DiffStatus (Unchanged / Added / Removed / Modified)
FormatSelectionDialogDialog shown when multiple format candidates are detected

Architecture notes

  • Pattern: MVVM + Strategy — field decoding is a switch expression over the valueType string; the format detection pipeline is injected via FormatDetectionService.
  • Diff algorithm: O(n) dictionary lookup (file 1 fields indexed by name), not an LCS diff — sufficient for named-field comparison where order may vary by format.
  • Metadata-typed blocks (no byte offset) are decoded from the variables dictionary rather than from the raw byte buffer.

Theme compliance

All brushes use DynamicResource tokens from the active global theme.