/// <summary>
/// Decode the raw on-disk representation of a DragonDos file to a file object.
/// </summary>
/// <param name="fileinfo">File information.</param>
/// <param name="raw">Raw on-disk file data.</param>
/// <returns>File object.</returns>
/// <exception cref="InvalidFileException">Thrown if the file is invalid and cannot be properly decoded.</exception>
internal static DragonDosFile DecodeFile(DragonDosFileInfo fileinfo, byte[] raw)
{
/* If the file does not contain a valid file header it must be a data file. */
if (raw.Length < FileHeaderSize || raw[0] != FileHeaderFirstByte || raw[8] != FileHeaderLastByte)
{
return(new DragonDosFile(fileinfo, DragonDosFileType.Data, raw));
}
/* Extract the file payload data. */
var data = new byte[raw.Length - FileHeaderSize];
Array.Copy(raw, FileHeaderSize, data, 0, data.Length);
/* Create the correct file object. */
switch ((DragonDosFileType)raw[1])
{
case DragonDosFileType.Basic:
return(new DragonDosFile(fileinfo, DragonDosFileType.Basic, data));
case DragonDosFileType.MachineCode:
int loadAddress = (raw[2] << 8) | raw[3];
int startAddress = (raw[6] << 8) | raw[7];
return(new DragonDosFile(fileinfo, DragonDosFileType.MachineCode, data, loadAddress, startAddress));
default:
throw new InvalidFileException(fileinfo.Name, String.Format("Unknown file type identifier {0}", raw[1]));
}
}
/// <summary>
/// Decode the raw on-disk representation of a DragonDos file to a file object.
/// </summary>
/// <param name="fileinfo">File information.</param>
/// <param name="raw">Raw on-disk file data.</param>
/// <returns>File object.</returns>
/// <exception cref="InvalidFileException">Thrown if the file is invalid and cannot be properly decoded.</exception>
internal static DragonDosFile DecodeFile(DragonDosFileInfo fileinfo, byte[] raw)
{
/* If the file does not contain a valid file header it must be a data file. */
if (raw.Length < FileHeaderSize || raw[0] != FileHeaderFirstByte || raw[8] != FileHeaderLastByte)
return new DragonDosFile(fileinfo, DragonDosFileType.Data, raw);
/* Extract the file payload data. */
var data = new byte[raw.Length - FileHeaderSize];
Array.Copy(raw, FileHeaderSize, data, 0, data.Length);
/* Create the correct file object. */
switch ((DragonDosFileType) raw[1])
{
case DragonDosFileType.Basic:
return new DragonDosFile(fileinfo, DragonDosFileType.Basic, data);
case DragonDosFileType.MachineCode:
int loadAddress = (raw[2] << 8) | raw[3];
int startAddress = (raw[6] << 8) | raw[7];
return new DragonDosFile(fileinfo, DragonDosFileType.MachineCode, data, loadAddress, startAddress);
default:
throw new InvalidFileException(fileinfo.Name, String.Format("Unknown file type identifier {0}", raw[1]));
}
}
/// <summary>
/// Create a DragonDos file object that is associated with a filesystem directory entry.
/// </summary>
/// <param name="info">File directory information.</param>
/// <param name="type">File type.</param>
/// <param name="data">File payload data.</param>
/// <param name="loadaddress">Load address for machine code programs.</param>
/// <param name="startaddress">Execution start address for machine code programs.</param>
/// <remarks>
/// This class assumes ownership of the data parameter and assumes that the caller will not make changes to the contents of this
/// array.
/// </remarks>
private DragonDosFile(DragonDosFileInfo info, DragonDosFileType type, byte[] data, int loadaddress = 0, int startaddress = 0)
: this(type, data, loadaddress, startaddress)
{
fileinfo = info;
}
/// <summary>
/// Create a DragonDos file object that is associated with a filesystem directory entry.
/// </summary>
/// <param name="info">File directory information.</param>
/// <param name="type">File type.</param>
/// <param name="data">File payload data.</param>
/// <param name="loadaddress">Load address for machine code programs.</param>
/// <param name="startaddress">Execution start address for machine code programs.</param>
/// <remarks>
/// This class assumes ownership of the data parameter and assumes that the caller will not make changes to the contents of this
/// array.
/// </remarks>
private DragonDosFile(DragonDosFileInfo info, DragonDosFileType type, byte[] data, int loadaddress = 0, int startaddress = 0)
: this(type, data, loadaddress, startaddress)
{
fileinfo = info;
}
