Files
BinaryObjectScanner/BurnOutSharp/External/libmspack/CAB/Decompressor.cs
Matt Nadareski c54181e9ac "as" not "cast"
2022-05-19 11:56:38 -07:00

269 lines
12 KiB
C#

/* libmspack -- a library for working with Microsoft compression formats.
* (C) 2003-2019 Stuart Caie <kyzer@cabextract.org.uk>
*
* libmspack is free software; you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License (LGPL) version 2.1
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
using System;
namespace LibMSPackSharp.CAB
{
/// <summary>
/// A decompressor for .CAB (Microsoft Cabinet) files
///
/// All fields are READ ONLY.
/// </summary>
/// <see cref="Library.CreateCABDecompressor(SystemImpl)"/>
/// <see cref="Library.DestroyCABDecompressor(Decompressor)"/>
public class Decompressor
{
/// <summary>
/// Opens a cabinet file and reads its contents.
///
/// If the file opened is a valid cabinet file, all headers will be read
/// and a Cabinet structure will be returned, with a full list of
/// folders and files.
///
/// In the case of an error occuring, NULL is returned and the error code
/// is available from last_error().
///
/// The filename pointer should be considered "in use" until close() is
/// called on the cabinet.
/// </summary>
/// <param name="decompressor">A self-referential pointer to the Decompressor instance being called</param>
/// <param name="filename">The filename of the cabinet file. This is passed directly to SystemImpl::open().</param>
/// <returns>A pointer to a Cabinet structure, or NULL on failure</returns>
/// <see cref="Close"/>
/// <see cref="Search"/>
/// <see cref="LastError"/>
public Func<Decompressor, string, CabinetImpl> Open;
/// <summary>
/// Closes a previously opened cabinet or cabinet set.
///
/// This closes a cabinet, all cabinets associated with it via the
/// Cabinet::next, Cabinet::prevcab and
/// Cabinet::nextcab pointers, and all folders and files. All
/// memory used by these entities is freed.
///
/// The cabinet pointer is now invalid and cannot be used again. All
/// Folder and InternalFile pointers from that cabinet or cabinet
/// set are also now invalid, and cannot be used again.
///
/// If the cabinet pointer given was created using search(), it MUST be
/// the cabinet pointer returned by search() and not one of the later
/// cabinet pointers further along the Cabinet::next chain.
///
/// If extra cabinets have been added using append() or prepend(), these
/// will all be freed, even if the cabinet pointer given is not the first
/// cabinet in the set. Do NOT close() more than one cabinet in the set.
///
/// The Cabinet::filename is not freed by the library, as it is
/// not allocated by the library. The caller should free this itself if
/// necessary, before it is lost forever.
/// </summary>
/// <param name="decompressor">A self-referential pointer to the Decompressor instance being called</param>
/// <param name="cab">The cabinet to close</param>
/// <see cref="Open"/>
/// <see cref="Search"/>
/// <see cref="Append"/>
/// <see cref="Prepend"/>
public Action<Decompressor, Cabinet> Close;
/// <summary>
/// Searches a regular file for embedded cabinets.
///
/// This opens a normal file with the given filename and will search the
/// entire file for embedded cabinet files
///
/// If any cabinets are found, the equivalent of open() is called on each
/// potential cabinet file at the offset it was found. All successfully
/// open()ed cabinets are kept in a list.
///
/// The first cabinet found will be returned directly as the result of
/// this method. Any further cabinets found will be chained in a list
/// using the Cabinet::next field.
///
/// In the case of an error occuring anywhere other than the simulated
/// open(), NULL is returned and the error code is available from
/// last_error().
///
/// If no error occurs, but no cabinets can be found in the file, NULL is
/// returned and last_error() returns MSPACK_ERR_OK.
///
/// The filename pointer should be considered in use until close() is
/// called on the cabinet.
///
/// close() should only be called on the result of search(), not on any
/// subsequent cabinets in the Cabinet::next chain.
/// </summary>
/// <param name="self">
/// a self-referential pointer to the Decompressor
/// instance being called
/// </param>
/// <param name="filename">
/// the filename of the file to search for cabinets. This
/// is passed directly to SystemImpl::open().
/// </param>
/// <returns>a pointer to a Cabinet structure, or NULL</returns>
/// <see cref="Close"/>
/// <see cref="Open"/>
/// <see cref="LastError"/>
public Func<Decompressor, string, Cabinet> Search;
/// <summary>
/// Appends one Cabinet to another, forming or extending a cabinet
/// set.
///
/// This will attempt to append one cabinet to another such that
/// <tt>(cab->nextcab == nextcab) && (nextcab->prevcab == cab)</tt> and
/// any folders split between the two cabinets are merged.
///
/// The cabinets MUST be part of a cabinet set -- a cabinet set is a
/// cabinet that spans more than one physical cabinet file on disk -- and
/// must be appropriately matched.
///
/// It can be determined if a cabinet has further parts to load by
/// examining the Cabinet::flags field:
///
/// - if <tt>(flags & MSCAB_HDR_PREVCAB)</tt> is non-zero, there is a
/// predecessor cabinet to open() and prepend(). Its MS-DOS
/// case-insensitive filename is Cabinet::prevname
/// - if <tt>(flags & MSCAB_HDR_NEXTCAB)</tt> is non-zero, there is a
/// successor cabinet to open() and append(). Its MS-DOS case-insensitive
/// filename is Cabinet::nextname
///
/// If the cabinets do not match, an error code will be returned. Neither
/// cabinet has been altered, and both should be closed seperately.
///
/// Files and folders in a cabinet set are a single entity. All cabinets
/// in a set use the same file list, which is updated as cabinets in the
/// set are added. All pointers to Folder and InternalFile
/// structures in either cabinet must be discarded and re-obtained after
/// merging.
/// </summary>
/// <param name="self">
/// a self-referential pointer to the Decompressor
/// instance being called
/// </param>
/// <param name="cab">
/// the cabinet which will be appended to,
/// predecessor of nextcab
/// </param>
/// <param name="nextcab">
/// the cabinet which will be appended,
/// successor of cab
/// </param>
/// <returns>an error code, or MSPACK_ERR_OK if successful</returns>
/// <see cref="Prepend"/>
/// <see cref="Open"/>
/// <see cref="Close"/>
public Func<Decompressor, Cabinet, Cabinet, Error> Append;
/// <summary>
/// Prepends one Cabinet to another, forming or extending a
/// cabinet set.
///
/// This will attempt to prepend one cabinet to another, such that
/// <tt>(cab->prevcab == prevcab) && (prevcab->nextcab == cab)</tt>. In
/// all other respects, it is identical to append(). See append() for the
/// full documentation.
/// </summary>
/// <param name="self">
/// a self-referential pointer to the Decompressor
/// instance being called
/// </param>
/// <param name="cab">
/// the cabinet which will be prepended to,
/// successor of nextcab
/// </param>
/// <param name="nextcab">
/// the cabinet which will be prepended,
/// predecessor of cab
/// </param>
/// <returns>an error code, or MSPACK_ERR_OK if successful</returns>
/// <see cref="Append"/>
/// <see cref="Open"/>
/// <see cref="Close"/>
public Func<Decompressor, Cabinet, Cabinet, Error> Prepend;
/// <summary>
/// Extracts a file from a cabinet or cabinet set.
///
/// This extracts a compressed file in a cabinet and writes it to the given
/// filename.
///
/// The MS-DOS filename of the file, InternalFile::filename, is NOT USED
/// by extract(). The caller must examine this MS-DOS filename, copy and
/// change it as necessary, create directories as necessary, and provide
/// the correct filename as a parameter, which will be passed unchanged
/// to the decompressor's SystemImpl::open()
///
/// If the file belongs to a split folder in a multi-part cabinet set,
/// and not enough parts of the cabinet set have been loaded and appended
/// or prepended, an error will be returned immediately.
/// </summary>
/// <param name="self">
/// a self-referential pointer to the Decompressor
/// instance being called
/// </param>
/// <param name="file">the file to be decompressed</param>
/// <param name="filename">the filename of the file being written to</param>
/// <returns>an error code, or MSPACK_ERR_OK if successful</returns>
public Func<Decompressor, InternalFile, string, Error> Extract;
/// <summary>
/// Sets a CAB decompression engine parameter.
///
/// The following parameters are defined:
/// - #MSCABD_PARAM_SEARCHBUF: How many bytes should be allocated as a
/// buffer when using search()? The minimum value is 4. The default
/// value is 32768.
/// - #MSCABD_PARAM_FIXMSZIP: If non-zero, extract() will ignore bad
/// checksums and recover from decompression errors in MS-ZIP
/// compressed folders. The default value is 0 (don't recover).
/// - #MSCABD_PARAM_DECOMPBUF: How many bytes should be used as an input
/// bit buffer by decompressors? The minimum value is 4. The default
/// value is 4096.
/// </summary>
/// <param name="self">
/// a self-referential pointer to the Decompressor
/// instance being called
/// </param>
/// <param name="param">the parameter to set</param>
/// <param name="value">the value to set the parameter to</param>
/// <returns>
/// MSPACK_ERR_OK if all is OK, or MSPACK_ERR_ARGS if there
/// is a problem with either parameter or value.
/// </returns>
/// <see cref="Search"/>
/// <see cref="Extract"/>
public Func<Decompressor, Parameters, int, Error> SetParam;
/// <summary>
/// Returns the error code set by the most recently called method.
///
/// This is useful for open() and search(), which do not return an error
/// code directly.
/// </summary>
/// <param name="self">
/// a self-referential pointer to the Decompressor
/// instance being called
/// </param>
/// <returns>the most recent error code</returns>
/// <see cref="Open"/>
/// <see cref="Search"/>
public Func<Decompressor, Error> LastError;
}
}