7zip Assembly

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Initial setup ​

To create plugins for 7-Zip, you have two options:

  1. (Easy) Download the plugin_headers_vXX.XX folder from the releases section on GitHub under Plugin API vXX.X. Extract this folder into your project and implement the required declarations in the 7z-assembly.h files. Refer to the API section for documentation on the declarations implementation.

  2. (Hard) Build the initial infrastructure yourself by following these steps:

    • Download the 7-Zip source code from SourceForge. Go to Files -> 7-Zip -> Version -> ***-src.7z and extract the archive.
    • Look for the definition files CPP/7zip/Archive/Archive.def and CPP/7zip/Archive/Archive2.def in the extracted source code. We recommend using Archive2.def as it is specifically designed for new plugins.
    • Continue step by step with this documentation to build understanding of the plugins.

Here is the content of Archive2.def:

txt
EXPORTS
  CreateObject PRIVATE
  GetHandlerProperty PRIVATE
  GetNumberOfFormats PRIVATE
  GetHandlerProperty2 PRIVATE
  GetIsArc PRIVATE
  GetNumberOfMethods PRIVATE
  GetMethodProperty PRIVATE
  CreateDecoder PRIVATE
  CreateEncoder PRIVATE
  GetHashers PRIVATE
  SetCodecs PRIVATE
  SetLargePageMode PRIVATE
  SetCaseSensitive PRIVATE
  GetModuleProp PRIVATE
EXPORTS
  CreateObject PRIVATE
  GetHandlerProperty PRIVATE
  GetNumberOfFormats PRIVATE
  GetHandlerProperty2 PRIVATE
  GetIsArc PRIVATE
  GetNumberOfMethods PRIVATE
  GetMethodProperty PRIVATE
  CreateDecoder PRIVATE
  CreateEncoder PRIVATE
  GetHashers PRIVATE
  SetCodecs PRIVATE
  SetLargePageMode PRIVATE
  SetCaseSensitive PRIVATE
  GetModuleProp PRIVATE

We will search for all of the methods defined in the definition file and will copy function signatures to the 7z-assembly.h file. After copying the definitions, we must add the missing includes. I will place these files in the ./src/plugins/ directory to organize everything in one place. In addition to that, I will create Export.h inside the plugins directory to have just one #include in the 7z-assembly.h file. When I copy files from the 7-zip source code archive, I update the #includes to reference local files neglecting the source code directory structure. Here is the list of the definitions I have assembled from the 7-zip source code archive:

cpp
STDAPI_LIB CreateObject(const GUID *clsid, const GUID *iid, void **outObject);
STDAPI_LIB GetHandlerProperty(PROPID propID, PROPVARIANT *value);
STDAPI_LIB GetNumberOfFormats(UINT32 *numFormats);
STDAPI_LIB GetHandlerProperty2(UInt32 formatIndex, PROPID propID, PROPVARIANT *value);
STDAPI_LIB GetIsArc(UInt32 formatIndex, Func_IsArc *isArc);
STDAPI_LIB GetNumberOfMethods(UInt32 *numCodecs);
STDAPI_LIB GetMethodProperty(UInt32 codecIndex, PROPID propID, PROPVARIANT *value);
STDAPI_LIB CreateDecoder(UInt32 index, const GUID *iid, void **outObject);
STDAPI_LIB CreateEncoder(UInt32 index, const GUID *iid, void **outObject);
STDAPI_LIB GetHashers(IHashers **hashers);
STDAPI_LIB SetCodecs(ICompressCodecsInfo *compressCodecsInfo)
STDAPI_LIB SetLargePageMode();
STDAPI_LIB SetCaseSensitive(Int32 caseSensitive)
STDAPI_LIB GetModuleProp(PROPID propID, PROPVARIANT *value);
STDAPI_LIB CreateObject(const GUID *clsid, const GUID *iid, void **outObject);
STDAPI_LIB GetHandlerProperty(PROPID propID, PROPVARIANT *value);
STDAPI_LIB GetNumberOfFormats(UINT32 *numFormats);
STDAPI_LIB GetHandlerProperty2(UInt32 formatIndex, PROPID propID, PROPVARIANT *value);
STDAPI_LIB GetIsArc(UInt32 formatIndex, Func_IsArc *isArc);
STDAPI_LIB GetNumberOfMethods(UInt32 *numCodecs);
STDAPI_LIB GetMethodProperty(UInt32 codecIndex, PROPID propID, PROPVARIANT *value);
STDAPI_LIB CreateDecoder(UInt32 index, const GUID *iid, void **outObject);
STDAPI_LIB CreateEncoder(UInt32 index, const GUID *iid, void **outObject);
STDAPI_LIB GetHashers(IHashers **hashers);
STDAPI_LIB SetCodecs(ICompressCodecsInfo *compressCodecsInfo)
STDAPI_LIB SetLargePageMode();
STDAPI_LIB SetCaseSensitive(Int32 caseSensitive)
STDAPI_LIB GetModuleProp(PROPID propID, PROPVARIANT *value);

I have defined the STDAPI_LIB as is to make them exported from the library. I am using the cmake GENERATE_EXPORT_HEADER function to define the LIB_EXPORT macro.