BiffSstReader Struct

Definition

Namespace

Bodu.IO.Biff

Assembly

Bodu.IO.Biff.dll

Package

Bodu.IO.Biff 1.0.0

Source

BiffSstReader.cs

Reads the strings of a BIFF8 shared string table (SST) one at a time, pulling the CONTINUE records that carry the table's overflow from the parent BiffReader as they are needed.

public ref struct BiffSstReader

Inherited Members

ValueType.Equals(object)

ValueType.GetHashCode()

ValueType.ToString()

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Remarks

The reader is created while the parent is positioned on the SST record; each call to Read(scoped ref BiffReader) is passed the parent by reference and advances it past every CONTINUE record it consumes, so the parent's BytesConsumed stays truthful and the next Read() resumes after the table. A ref struct cannot hold a reference to another, which is why the parent is supplied per call rather than captured. It follows the BIFF continuation rules for strings: a string's header never straddles a boundary, character data may, and a continued run restarts with its own option-flags byte selecting 8-bit or 16-bit characters.

A string whose characters lie within one record is exposed as a span-backed Current view. A string whose characters straddle a boundary (IsFragmented) has no single span; it is decoded into a reusable scratch buffer during Read(scoped ref BiffReader), and GetString() and CopyTo(Span<char>) serve both kinds uniformly. Formatting-run and extended-data trailers that straddle a boundary are skipped and reported as empty.

while (reader.Read())
{
    if (reader.RecordType != BiffRecordType.Sst)
        continue;

    var strings = new BiffSstReader(ref reader);
    while (strings.Read(ref reader))
        Console.WriteLine($"[{strings.Index}] {strings.GetString()}");
}

Constructors

BiffSstReader(scoped ref BiffReader)

Initializes a new instance of the BiffSstReader struct over the SST record the parent reader is positioned on.

public BiffSstReader(scoped ref BiffReader reader)

Parameters

reader BiffReader

The parent reader, positioned on an SST record.

Exceptions

InvalidOperationException

Thrown when reader is not positioned on an SST record.

BiffFormatException

Thrown when the record is too short to hold the table header.

Properties

Current

Gets the span-backed view of the current string.

public readonly BiffString Current { get; }

Property Value

BiffString

The view over the string's characters and trailers within their record.

Exceptions

InvalidOperationException

Thrown when no string is current, or the current string is fragmented.

HasCurrent

Gets a value indicating whether a string is current.

public readonly bool HasCurrent { get; }

Property Value

bool

true after a successful Read(scoped ref BiffReader) until the table is exhausted.

HasExtendedData

Gets a value indicating whether the current string carries extended (phonetic) data.

public readonly bool HasExtendedData { get; }

Property Value

bool

true when the string header declared extended data.

Exceptions

InvalidOperationException

Thrown when no string is current.

HasRichRuns

Gets a value indicating whether the current string carries rich-text formatting runs.

public readonly bool HasRichRuns { get; }

Property Value

bool

true when the string header declared runs.

Exceptions

InvalidOperationException

Thrown when no string is current.

Header

Gets the counts from the table header.

public readonly BiffSstHeader Header { get; }

Property Value

BiffSstHeader

The total reference count and the unique string count.

Index

Gets the zero-based index of the current string within the table.

public readonly int Index { get; }

Property Value

int

The index, or −1 before the first string has been read.

IsFragmented

Gets a value indicating whether the current string's characters straddled a continuation boundary and therefore have no contiguous view.

public readonly bool IsFragmented { get; }

Property Value

bool

true when Current is unavailable and GetString() must be used.

Exceptions

InvalidOperationException

Thrown when no string is current.

Length

Gets the declared character count of the current string.

public readonly int Length { get; }

Property Value

int

The UTF-16 code-unit count.

Exceptions

InvalidOperationException

Thrown when no string is current.

Methods

CopyTo(Span<char>)

Decodes the current string into the supplied destination, whether or not it is fragmented.

public readonly int CopyTo(Span<char> destination)

Parameters

destination Span<char>

The buffer that receives the decoded characters.

Returns

int

The number of characters written.

Exceptions

InvalidOperationException

Thrown when no string is current.

ArgumentException

Thrown when destination is shorter than Length.

GetString()

Decodes the current string into a new string, whether or not it is fragmented.

public readonly string GetString()

Returns

string

The decoded text.

Exceptions

InvalidOperationException

Thrown when no string is current.

Read(scoped ref BiffReader)

Advances to the next string in the table, consuming continuation records from the parent reader as needed.

public bool Read(scoped ref BiffReader reader)

Parameters

reader BiffReader

The parent reader the table was created from.

Returns

bool

true when a string was read; false once every declared string has been read.

Exceptions

BiffFormatException

Thrown when the table ends before the declared strings do, a string header or its characters are truncated, or a continuation record is empty where character data was expected.

Applies to

Product	Versions
.NET	8, 10