/// <summary>
/// Reads an uncompressed data block into the model.
/// </summary>
/// <param name="data">the data store to read from.</param>
private void ReadUncompressedBlock(byte[] data)
{
// the uncompressed block contains a list of filesystem entires
// as long we have data we will try to read more entries
// the first sector (0x1000 bytes) is empty (filled with 0xFF)
// so the first sector starts at 0x1000
// (we already skipped the 4 byte header so we don't have to take care of this)
var sectorSize = 0x1000;
var offset = sectorSize;
// we always need 4 bytes (+3 including offset) to read the type
while ((offset + 3) < data.Length)
{
var entryType = GetInteger(data, offset);
if (entryType == 2) // is a file?
{
// file structure:
// offset | type | size | what
// --------+----------+----------+------
// 0x04 | string | 127byte | FileName (zero terminated)
// 0x83 | ? | 9byte | Unknown
// 0x8c | int | 4byte | FileSize
// 0x90 | ? | 4byte | Unknown
// 0x94 | int[] | n*4byte | Indices of the sector containing the data (end is marked with 0)
// The sectors marked at 0x94 are absolutely positioned ( 1*0x1000 is sector 1, 2*0x1000 is sector 2,...)
var file = new GpxFile();
file.FileName = GetString(data, offset + 0x04, 127);
file.FileSize = GetInteger(data, offset + 0x8C);
// store file if needed
var storeFile = FileFilter == null || FileFilter(file.FileName);
if (storeFile)
{
Files.Add(file);
}
// we need to iterate the blocks because we need to move after the last datasector
var dataPointerOffset = offset + 0x94;
var sector = 0; // this var is storing the sector index
var sectorCount = 0; // we're keeping count so we can calculate the offset of the array item
// as long we have data blocks we need to iterate them,
var fileData = storeFile ? ByteBuffer.WithCapactiy(file.FileSize) : null;
while ((sector = GetInteger(data, (dataPointerOffset + (4 * (sectorCount++))))) != 0)
{
// the next file entry starts after the last data sector so we
// move the offset along
offset = sector * sectorSize;
// write data only if needed
if (storeFile)
{
fileData.Write(data, offset, sectorSize);
}
}
if (storeFile)
{
// trim data to filesize if needed
file.Data = new byte[(int)Math.Min(file.FileSize, fileData.Length)];
// we can use the getBuffer here because we are intelligent and know not to read the empty data.
byte[] raw = fileData.ToArray();
Platform.Platform.BlockCopy(raw, 0, file.Data, 0, file.Data.Length);
}
}
// let's move to the next sector
offset += sectorSize;
}
}
/// <summary>
/// Reads an uncompressed data block into the model.
/// </summary>
/// <param name="data">the data store to read from.</param>
private void ReadUncompressedBlock(byte[] data)
{
// the uncompressed block contains a list of filesystem entires
// as long we have data we will try to read more entries
// the first sector (0x1000 bytes) is empty (filled with 0xFF)
// so the first sector starts at 0x1000
// (we already skipped the 4 byte header so we don't have to take care of this)
var sectorSize = 0x1000;
var offset = sectorSize;
// we always need 4 bytes (+3 including offset) to read the type
while ((offset + 3) < data.Length)
{
var entryType = GetInteger(data, offset);
if (entryType == 2) // is a file?
{
// file structure:
// offset | type | size | what
// --------+----------+----------+------
// 0x04 | string | 127byte | FileName (zero terminated)
// 0x83 | ? | 9byte | Unknown
// 0x8c | int | 4byte | FileSize
// 0x90 | ? | 4byte | Unknown
// 0x94 | int[] | n*4byte | Indices of the sector containing the data (end is marked with 0)
// The sectors marked at 0x94 are absolutely positioned ( 1*0x1000 is sector 1, 2*0x1000 is sector 2,...)
var file = new GpxFile();
file.FileName = GetString(data, offset + 0x04, 127);
file.FileSize = GetInteger(data, offset + 0x8C);
// store file if needed
var storeFile = FileFilter == null || FileFilter(file.FileName);
if (storeFile)
{
Files.Add(file);
}
// we need to iterate the blocks because we need to move after the last datasector
var dataPointerOffset = offset + 0x94;
var sector = 0; // this var is storing the sector index
var sectorCount = 0; // we're keeping count so we can calculate the offset of the array item
// as long we have data blocks we need to iterate them,
var fileData = storeFile ? ByteBuffer.WithCapactiy(file.FileSize) : null;
while ((sector = GetInteger(data, (dataPointerOffset + (4 * (sectorCount++))))) != 0)
{
// the next file entry starts after the last data sector so we
// move the offset along
offset = sector * sectorSize;
// write data only if needed
if (storeFile)
{
fileData.Write(data, offset, sectorSize);
}
}
if (storeFile)
{
// trim data to filesize if needed
file.Data = new byte[(int)Math.Min(file.FileSize, fileData.Length)];
// we can use the getBuffer here because we are intelligent and know not to read the empty data.
byte[] raw = fileData.ToArray();
Std.BlockCopy(raw, 0, file.Data, 0, file.Data.Length);
}
}
// let's move to the next sector
offset += sectorSize;
}
}
