public static Woff2Header ReadHeader(Woff2VersionReader version, BigEndianReader reader)
{
uint flavour = reader.ReadUInt32();
uint length = reader.ReadUInt32();
ushort numTables = reader.ReadUInt16();
var reserved = reader.ReadUInt16();
var totalFontSize = reader.ReadUInt32();
var compressedSize = reader.ReadUInt32();
var major = reader.ReadUInt16();
var minor = reader.ReadUInt16();
Woff2Header header = new Woff2Header(version, numTables);
header.Flavour = flavour;
header.Length = length;
header.TotalFontSize = totalFontSize;
header.TotalCompressedSize = compressedSize;
header.WoffInnerVersion = new Version(major, minor);
header.MetaDataOffset = reader.ReadUInt32();
header.MetaDataLength = reader.ReadUInt32();
header.MetaDataOriginalLength = reader.ReadUInt32();
header.PrivateDataOffset = reader.ReadUInt32();
header.PrivateDataLength = reader.ReadUInt32();
return(header);
}
private Woff2CacheData ReadCachableDataAfterVersion(BigEndianReader reader, string source)
{
Woff2CacheData cache = null;
Woff2Header header = Woff2Header.ReadHeader(this, reader);
Woff2TableEntryList list = new Woff2TableEntryList();
uint startAt = (uint)reader.Position;
uint offset = 0;
bool hasOs2 = false;
bool hasFHead = false;
bool hasName = false;
for (var i = 0; i < header.NumberOfTables; i++)
{
Woff2TableEntry entry = new Woff2TableEntry(offset);
entry.Read(reader);
if (entry.Tag == TrueTypeTableNames.WindowsMetrics)
{
hasOs2 = true;
}
else if (entry.Tag == TrueTypeTableNames.FontHeader)
{
hasFHead = true;
}
else if (entry.Tag == TrueTypeTableNames.NamingTable)
{
hasName = true;
}
// If the table data has been transformed,
// then that will be the offset of the next table
if (entry.HasTransformation)
{
offset += entry.TransformedLength;
}
else
{
offset += entry.Length;
}
list.Add(entry);
}
if (!(hasOs2 || hasName))
{
return(null);// new Utility.UnknownTypefaceInfo(source, "Not all the required tables (head with OS/2 or name) were found in the font file");
}
if (!hasFHead)
{
return(null);// new Utility.UnknownTypefaceInfo(source, "Not all the required tables (head with OS/2 or name) were found in the font file");
}
//After the table entries, the entire table data is compressed using the Brotli alogorythm
offset = (uint)reader.Position;
var compressedData = reader.Read((int)header.TotalCompressedSize);
var decompressedData = Woff2Brotli.DecompressData(compressedData);
using (var uncompressed = new MemoryStream(decompressedData))
{
#if RANGE_CHECK
if (uncompressed.Length + offset != header.TotalFontSize)
{
throw new ArgumentOutOfRangeException("The header uncompressed size is not the same");
}
#endif
using (var newReader = new BigEndianReader(uncompressed))
{
var info = ReadInfoFromTables(list, newReader, source, hasOs2);
if (null != info && info.FontCount > 0)
{
cache = new Woff2CacheData()
{
Entries = list,
Header = header,
Info = info,
Source = source,
UncompressedData = decompressedData
};
}
}
}
return(cache);
}
