Class ExternalTextFileResolver

Namespace

EncDotNet.S100.Datasets.Pipelines

Assembly

EncDotNet.S100.Datasets.Pipelines.dll

Resolves the textual content of an externally referenced text file (named by an S-100 fileReference attribute — S-101 Feature Catalogue, alias TXTDSC / NTXTDS) from the dataset's exchange-set IAssetSource. When the exchange-set catalogue's supportFileDiscoveryMetadata is supplied, the referenced file is located through it first (the canonical ECDIS mechanism); otherwise the file is looked up relative to the dataset's own directory, then at the exchange-set root, then under a sibling SUPPORT_FILES / support directory (the S100_ROOT exchange-set layout).

public sealed class ExternalTextFileResolver

Inheritance

object

ExternalTextFileResolver

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Remarks

Resolution is synchronous because the pick / object-info path that consumes it is synchronous; support text files are small and the underlying FileSystemAssetSource / ZipAssetSource reads are memory-backed (no network I/O), so the awaiter-result bridge is bounded.

Content is decoded as UTF-8 when valid, otherwise as ISO/IEC 8859-1 (Latin-1), which is the legacy character set most S-57/S-101 producers use for support text files. Missing, oversized, or unreadable files resolve to null so the pick report keeps showing the bare file name.

Constructors

ExternalTextFileResolver(IAssetSource, string?, IReadOnlyDictionary<string, string>?)

Initializes a new ExternalTextFileResolver.

public ExternalTextFileResolver(IAssetSource source, string? datasetRelativePath = null, IReadOnlyDictionary<string, string>? supportFiles = null)

Parameters

source IAssetSource

The asset source backing the dataset's exchange set (folder or ZIP).

datasetRelativePath string

The source-relative path of the dataset whose features carry the file references; its directory is used as the primary lookup location. May be null or a bare file name, in which case only the exchange-set root is searched.

supportFiles IReadOnlyDictionary<string, string>

Optional map of support-file name (case-insensitive) to its source-relative path, as declared by the exchange-set catalogue's supportFileDiscoveryMetadata (S-100 Edition 5.2.1 Part 17). When supplied, a referenced file is located via the catalogue first — the canonical ECDIS mechanism — before falling back to directory probing.

Fields

MaxFileSizeBytes

Upper bound on the size of a referenced text file that will be read into memory. Support text files are short; anything larger is treated as unresolvable to bound the cost of a pick gesture.

public const long MaxFileSizeBytes = 4194304

Field Value

long

Methods

AsDelegate()

Returns a Func<T, TResult> view of this resolver, suitable for passing to ResolveFileReferences(IReadOnlyList<PickAttribute>, Func<string, string?>).

public Func<string, string?> AsDelegate()

Returns

Func<string, string>

Resolve(string)

Resolves the textual content of the file named fileName, or null when it cannot be located or read within the size bound.

public string? Resolve(string fileName)

Parameters

fileName string

Returns

string