public static LookupTable Load(BigEndianBinaryReader reader, long offset)
{
// +----------+--------------------------------+-------------------------------------------------------------+
// | Type | Name | Description |
// +==========+================================+=============================================================+
// | uint16 | lookupType | Different enumerations for GSUB and GPOS. |
// +----------+--------------------------------+-------------------------------------------------------------+
// | uint16 | lookupFlag | Lookup qualifiers . |
// +----------+--------------------------------+-------------------------------------------------------------+
// | uint16 | subTableCount | Number of subtables for this lookup. |
// +----------+--------------------------------+-------------------------------------------------------------+
// | Offset16 | subtableOffsets[subTableCount] | Array of offsets to lookup subtables, from beginning of |
// | | | Lookup table. |
// +----------+--------------------------------+-------------------------------------------------------------+
// | uint16 | markFilteringSet | Index (base 0) into GDEF mark glyph sets structure. |
// | | | This field is only present if the USE_MARK_FILTERING_SET |
// | | | lookup flag is set. |
// +----------+--------------------------------+-------------------------------------------------------------+
reader.Seek(offset, SeekOrigin.Begin);
ushort lookupType = reader.ReadUInt16();
LookupFlags lookupFlags = reader.ReadUInt16 <LookupFlags>();
ushort subTableCount = reader.ReadUInt16();
using Buffer <ushort> subTableOffsetsBuffer = new(subTableCount);
Span <ushort> subTableOffsets = subTableOffsetsBuffer.GetSpan();
reader.ReadUInt16Array(subTableOffsets);
// The fifth bit indicates the presence of a MarkFilteringSet field in the Lookup table.
ushort markFilteringSet = ((lookupFlags & LookupFlags.UseMarkFilteringSet) != 0)
? reader.ReadUInt16()
: (ushort)0;
var lookupSubTables = new LookupSubTable[subTableCount];
for (int i = 0; i < lookupSubTables.Length; i++)
{
lookupSubTables[i] = LoadLookupSubTable(lookupType, lookupFlags, reader, offset + subTableOffsets[i]);
}
return(new LookupTable(lookupType, lookupFlags, markFilteringSet, lookupSubTables));
}
public LookupResult(LookupSubTable foundOnTable, int foundAtIndex)
{
this.foundAtIndex = foundAtIndex;
this.foundOnTable = foundOnTable;
}
