/// <summary>
/// Estimates the file size of the output file.
/// Note: Not accurate, but will return equal or slightly more than actual file.
/// </summary>
public int EstimateFileSize(TextureArchiveWriterSettings options)
{
var estimateFileSize = 0;
estimateFileSize += sizeof(int); // Header
estimateFileSize += (sizeof(int) + 1 * Files.Count); // Offsets + Flags
estimateFileSize += Files.Sum(x => x.Data.Length + x.Name.Length + 1); // Names and Data
estimateFileSize += (options.Alignment * Files.Count); // Alignment
return(estimateFileSize);
}
/// <summary>
/// Writes the contents of the archive to be generated to the stream.
/// </summary>
public void Write(Stream writeStream, TextureArchiveWriterSettings options)
{
if (options.BigEndian)
{
Write(options, new BigEndianStreamWriter(writeStream));
}
else
{
Write(options, new LittleEndianStreamWriter(writeStream));
}
}
/// <summary>
/// Writes the contents of the archive to be generated to a byte array.
/// </summary>
public byte[] Write(TextureArchiveWriterSettings options)
{
using var stream = new MemoryStream(EstimateFileSize(options));
if (options.BigEndian)
{
Write(options, new BigEndianStreamWriter(stream));
}
else
{
Write(options, new LittleEndianStreamWriter(stream));
}
return(stream.ToArray());
}
private void PrecomputeFileOffsets(Span <int> offsets, int stringDataSize, TextureArchiveWriterSettings options)
{
const int headerSize = sizeof(int);
int fileOffsetArraySize = Files.Count * sizeof(int);
int unknownFlagArraySize = options.WriteFlagsSection ? Files.Count * sizeof(byte) : 0;
// Get offset for first file, aligned.
int currentFileDataOffset = Utilities.RoundUp(headerSize + fileOffsetArraySize + unknownFlagArraySize + stringDataSize, options.Alignment);
// Populate offsets for every file.
for (int x = 0; x < Files.Count; x++)
{
offsets[x] = currentFileDataOffset;
currentFileDataOffset += Utilities.RoundUp(Files[x].Data.Length, options.Alignment);
}
}
/// <summary>
/// Writes the contents of the archive to be generated to a byte array.
/// </summary>
public void Write <T>(TextureArchiveWriterSettings options, T target) where T : IEndianStreamWriter
{
// Precompute Offsets
var fileNameSize = Files.Sum(x => x.Name.Length) + (Files.Count);
Span <int> offsets = stackalloc int[Files.Count];
PrecomputeFileOffsets(offsets, fileNameSize, options);
// Texture Count
target.Write <short>((short)Files.Count);
target.Write((byte)0);
target.Write(options.WriteFlagsSection ? (byte)1 : (byte)0);
// Texture Offsets
for (int x = 0; x < offsets.Length; x++)
{
target.Write(offsets[x]);
}
// Texture Flags
if (options.WriteFlagsSection)
{
for (int x = 0; x < Files.Count; x++)
{
target.Write((byte)0x11);
}
}
// Texture Names
Span <byte> currentString = stackalloc byte[1024];
foreach (var file in Files)
{
int numEncoded = Encoding.ASCII.GetBytes(file.Name, currentString);
currentString[numEncoded] = 0x00;
target.Write(currentString.Slice(0, numEncoded + 1));
}
// Texture Data
target.Stream.AddPadding(options.Alignment);
for (int x = 0; x < Files.Count; x++)
{
target.Write(Files[x].Data.AsSpan());
target.Stream.AddPadding(options.Alignment);
}
}
