Class: LibMsPack::MsCab::CabDecompressor
- Inherits:
-
Object
- Object
- LibMsPack::MsCab::CabDecompressor
- Defined in:
- lib/libmspack/mscab.rb
Overview
CAB decompressor
Instance Attribute Summary collapse
-
#Decompressor ⇒ Object
readonly
Returns the value of attribute Decompressor.
Instance Method Summary collapse
-
#append(cab, nextcab) ⇒ Object
Appends one MsCabdCabinet to another, forming or extending a cabinet set.
-
#close(cabinet) ⇒ Object
Closes a previously opened cabinet or cabinet set.
-
#destroy ⇒ Object
Destroys an existing CAB decompressor.
-
#extract(cabfile, filename) ⇒ Object
Extracts a file from a cabinet or cabinet set.
- #init(system = MsPack::RubyPackSystem) ⇒ Object
-
#initialize(system = nil) ⇒ CabDecompressor
constructor
Creates a new CAB decompressor.
-
#lastError ⇒ Fixnum
Returns the error code set by the most recently called method.
-
#open(filename) ⇒ MsCabdCabinet
Opens a cabinet file and reads its contents.
-
#prepend(cab, prevcab) ⇒ Object
Prepends one MsCabdCabinet to another, forming or extending a cabinet set.
-
#search(filename) ⇒ MsCabdCabinet
Searches a regular file for embedded cabinets.
-
#setParam(param, value) ⇒ Object
Sets a CAB decompression engine parameter.
Constructor Details
#initialize(system = nil) ⇒ CabDecompressor
Creates a new CAB decompressor.
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# File 'lib/libmspack/mscab.rb', line 557 def initialize(system = nil) @Decompressor = nil init(system) end |
Instance Attribute Details
#Decompressor ⇒ Object (readonly)
Returns the value of attribute Decompressor.
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# File 'lib/libmspack/mscab.rb', line 553 def Decompressor @Decompressor end |
Instance Method Details
#append(cab, nextcab) ⇒ Object
Appends one MsCabdCabinet to another, forming or extending a cabinet set.
This will attempt to append one cabinet to another such that (cab.nextcab == nextcab) && (nextcab.prevcab == cab) 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 MsCabdCabinet.flags field:
- if (flags & MSCAB_HDR_PREVCAB) is non-zero, there is a predecessor cabinet to #open and #prepend. Its MS-DOS case-insensitive filename is MsCabdCabinet.prevname
- if (flags & MSCAB_HDR_NEXTCAB) is non-zero, there is a successor cabinet to #open and #append. Its MS-DOS case-insensitive filename is MsCabdCabinet.nextname
If the cabinets do not match, an exception will be raised. 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.
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# File 'lib/libmspack/mscab.rb', line 655 def append(cab, nextcab) raise Exceptions::NotInitializedError unless @Decompressor error = @Decompressor.append(@Decompressor, cab, nextcab) raise Exceptions::LibMsPackError.new(error) unless error == LibMsPack::MSPACK_ERR_OK error end |
#close(cabinet) ⇒ Object
Closes a previously opened cabinet or cabinet set.
This closes a cabinet, all cabinets associated with it via the MsCabdCabinet#next, MsCabdCabinet#prevcab and MsCabdCabinet#nextcab, and all folders and files. All memory used by these entities is freed.
The cabinet is now invalid and cannot be used again. All MsCabdFolder and MsCabdFile from that cabinet or cabinet set are also now invalid, and cannot be used again.
If the cabinet given was created using #search, it MUST be the cabinet returned by #search and not one of the later cabinet pointers further along the MsCabdCabinet::next chain.
If extra cabinets have been added using #append or #prepend, these will all be freed, even if the cabinet given is not the first cabinet in the set. Do NOT #close more than one cabinet in the set.
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# File 'lib/libmspack/mscab.rb', line 602 def close(cabinet) raise Exceptions::NotInitializedError unless @Decompressor @Decompressor.close(@Decompressor, cabinet) end |
#destroy ⇒ Object
Destroys an existing CAB decompressor
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# File 'lib/libmspack/mscab.rb', line 727 def destroy raise Exceptions::NotInitializedError unless @Decompressor LibMsPack.DestroyCabDecompressor(@Decompressor) @Decompressor = nil end |
#extract(cabfile, filename) ⇒ Object
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, MsCabdCabinet.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 MsPackSystem#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 exception will be raised immediately.
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# File 'lib/libmspack/mscab.rb', line 692 def extract(cabfile, filename) raise Exceptions::NotInitializedError unless @Decompressor error = @Decompressor.extract(@Decompressor, cabfile, filename) raise Exceptions::LibMsPackError.new(error) unless error == LibMsPack::MSPACK_ERR_OK error end |
#init(system = MsPack::RubyPackSystem) ⇒ Object
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# File 'lib/libmspack/mscab.rb', line 563 def init(system = MsPack::RubyPackSystem) raise Exceptions::AlreadyInitializedError if @Decompressor @Decompressor = LibMsPack.CreateCabDecompressor(system) end |
#lastError ⇒ Fixnum
Returns the error code set by the most recently called method
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# File 'lib/libmspack/mscab.rb', line 721 def lastError raise Exceptions::NotInitializedError unless @Decompressor @Decompressor.last_error(@Decompressor) end |
#open(filename) ⇒ MsCabdCabinet
Opens a cabinet file and reads its contents.
If the file opened is a valid cabinet file, all headers will be read and a MsCabdCabinet structure will be returned, with a full list of folders and files.
In the case of an error occuring, exception will be raised.
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# File 'lib/libmspack/mscab.rb', line 579 def open(filename) raise Exceptions::NotInitializedError unless @Decompressor cabinet = @Decompressor.open(@Decompressor, filename) error = lastError raise Exceptions::LibMsPackError.new(error) unless error == LibMsPack::MSPACK_ERR_OK cabinet end |
#prepend(cab, prevcab) ⇒ Object
Prepends one MsCabdCabinet to another, forming or extending a cabinet set.
This will attempt to prepend one cabinet to another, such that (cab.prevcab == prevcab) && (prevcab.nextcab == cab). In all other respects, it is identical to #append.
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# File 'lib/libmspack/mscab.rb', line 674 def prepend(cab, prevcab) raise Exceptions::NotInitializedError unless @Decompressor error = @Decompressor.prepend(@Decompressor, cab, prevcab) raise Exceptions::LibMsPackError.new(error) unless error == LibMsPack::MSPACK_ERR_OK error end |
#search(filename) ⇒ MsCabdCabinet
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 MsCabdCabinet#next field.
In the case of an error occuring anywhere other than the simulated #open, exception will be raised.
If no error occurs, but no cabinets can be found in the file, nil is returned.
#close
should only be called on the result of #search, not on any subsequent cabinets in the MsCabdCabinet#next chain.
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# File 'lib/libmspack/mscab.rb', line 626 def search(filename) raise Exceptions::NotInitializedError unless @Decompressor cabinet = @Decompressor.search(@Decompressor, filename) error = lastError raise Exceptions::LibMsPackError.new(error) unless error == LibMsPack::MSPACK_ERR_OK cabinet end |
#setParam(param, value) ⇒ Object
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.
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# File 'lib/libmspack/mscab.rb', line 712 def setParam(param, value) raise Exceptions::NotInitializedError unless @Decompressor error = @Decompressor.set_param(@Decompressor, param, value) raise Exceptions::LibMsPackError.new(error) unless error == LibMsPack::MSPACK_ERR_OK error end |