private static uint CalculateChecksum(BinaryReader reader, long startOffset, uint length)
{
uint checksum = 0;
var restorePosition = reader.BaseStream.Position;
reader.BaseStream.Position = startOffset;
var checkCount = (length + 3) / 4;
for (var i = 0; i < checkCount; i++)
{
checksum += DataTypeConverter.ReadULong(reader);
}
reader.BaseStream.Position = restorePosition;
return(checksum);
}
public OpenTypeFont Deserialize(BinaryReader reader)
{
var font = new OpenTypeFont {
SfntVersion = DataTypeConverter.ReadFixed(reader)
};
if (!_supportedSfntVersions.Contains(font.SfntVersion))
{
throw new NotSupportedException("Bad sfnt version.");
}
// Table directory
var numberOfTables = DataTypeConverter.ReadUShort(reader);
reader.BaseStream.Position += 3 * DataTypeLength.UShort; // searchRange, entrySelector, rangeShift
var entryList = Enumerable.Range(0, numberOfTables).Select(i =>
{
var entry = new TableDirectoryEntry {
Tag = DataTypeConverter.ReadTag(reader)
};
reader.BaseStream.Position += DataTypeLength.ULong; // checksum
entry.Offset = DataTypeConverter.ReadULong(reader);
entry.Length = DataTypeConverter.ReadULong(reader);
return(entry);
}).ToList();
// Tables
font.Tables.AddRange(
entryList.OrderBy(entry => entry.Priority).Select <TableDirectoryEntry, IOpenTypeFontTable>(entry =>
{
switch (entry.Tag)
{
case "cmap":
return(CmapTable.Deserialize(reader, entry.Offset));
case "head":
return(HeadTable.Deserialize(reader, entry.Offset));
case "maxp":
return(MaxpTable.Deserialize(reader, entry.Offset));
case "loca":
return(LocaTable.Deserialize(reader, entry.Offset,
font.Get <MaxpTable>().NumberOfGlyphs,
font.Get <HeadTable>().LocaTableVersion));
case "glyf":
return(GlyfTable.Deserialize(reader, entry.Offset, entry.Length,
font.Get <LocaTable>()));
case "hhea":
return(HheaTable.Deserialize(reader, entry.Offset));
case "hmtx":
return(HmtxTable.Deserialize(reader, entry.Offset, font.Get <HheaTable>().NumberOfHMetrics,
font.Get <MaxpTable>().NumberOfGlyphs));
case "post":
return(PostTable.Deserialize(reader, entry.Offset));
default:
return(BinaryDataTable.Deserialize(reader, entry.Offset, entry.Length, entry.Tag));
}
}));
return(font);
}
/// <summary>
/// Convert sfnt file to woff file.
/// </summary>
/// <param name="reader">BinaryReader to read the sfnt data stream.</param>
/// <param name="writer">BinaryWriter to write the woff data.</param>
/// <param name="compression">Set to true to compress data.</param>
public static void SfntToWoff(BinaryReader reader, BinaryWriter writer, bool compression = false)
{
reader.BaseStream.Position = 0;
writer.BaseStream.Position = 0;
// Header
DataTypeConverter.WriteULong(writer, 0x774F4646); // signature
writer.Write(reader.ReadBytes(DataTypeLength.Fixed)); // flavor
writer.BaseStream.Position += DataTypeLength.ULong; // length
var numberOfTables = DataTypeConverter.ReadUShort(reader);
DataTypeConverter.WriteUShort(writer, numberOfTables); // numTables
DataTypeConverter.WriteUShort(writer, 0); // reserved
DataTypeConverter.WriteULong(writer, (uint)reader.BaseStream.Length); // totalSfntSize
DataTypeConverter.WriteUShort(writer, 1); // majorVision
DataTypeConverter.WriteUShort(writer, 0); // minorVision
DataTypeConverter.WriteULong(writer, 0); // metaOffset
DataTypeConverter.WriteULong(writer, 0); // metaLength
DataTypeConverter.WriteULong(writer, 0); // metaOriLength
DataTypeConverter.WriteULong(writer, 0); // privOffset
DataTypeConverter.WriteULong(writer, 0); // privLength
// Read original table directory
reader.BaseStream.Position += 3 * DataTypeLength.UShort;
var tags = new uint[numberOfTables];
var offsets = new uint[numberOfTables];
var compLengths = new uint[numberOfTables];
var origLengths = new uint[numberOfTables];
var origChecksum = new uint[numberOfTables];
var origOffsets = new uint[numberOfTables];
var startOffsetOfTableDirectory = writer.BaseStream.Position;
for (var i = 0; i < numberOfTables; i++)
{
tags[i] = DataTypeConverter.ReadULong(reader);
origChecksum[i] = DataTypeConverter.ReadULong(reader);
origOffsets[i] = DataTypeConverter.ReadULong(reader);
origLengths[i] = DataTypeConverter.ReadULong(reader);
}
// Table data
writer.BaseStream.Position += numberOfTables * 5 * DataTypeLength.ULong;
for (var i = 0; i < numberOfTables; i++)
{
offsets[i] = (uint)writer.BaseStream.Position;
reader.BaseStream.Position = origOffsets[i];
var tableData = reader.ReadBytes((int)origLengths[i]);
if (compression)
{
using (var compressedStream = new MemoryStream())
{
var zOutputStream = new ZOutputStream(compressedStream, zlibConst.Z_DEFAULT_COMPRESSION);
zOutputStream.Write(tableData, 0, (int)origLengths[i]);
zOutputStream.finish();
if (compressedStream.Length >= origLengths[i])
{
writer.Write(tableData);
}
else
{
compressedStream.WriteTo(writer.BaseStream);
}
}
}
else
{
writer.Write(tableData);
}
compLengths[i] = (uint)(writer.BaseStream.Position - offsets[i]);
// 4byte padding
if (writer.BaseStream.Position % 4 != 0)
{
var zeroCount = 4 - writer.BaseStream.Position % 4;
for (var j = 0; j < zeroCount; j++)
{
writer.Write((byte)0);
}
}
}
// Write table directory
writer.BaseStream.Position = startOffsetOfTableDirectory;
for (var i = 0; i < numberOfTables; i++)
{
DataTypeConverter.WriteULong(writer, tags[i]);
DataTypeConverter.WriteULong(writer, offsets[i]);
DataTypeConverter.WriteULong(writer, compLengths[i]);
DataTypeConverter.WriteULong(writer, origLengths[i]);
DataTypeConverter.WriteULong(writer, origChecksum[i]);
}
// Write length in header
writer.BaseStream.Position = 2 * DataTypeLength.ULong;
DataTypeConverter.WriteULong(writer, (uint)writer.BaseStream.Length);
}