https://github.com/sundarnagarajan/cffi_utils

Utility modules to build python wrappers around C code
https://github.com/sundarnagarajan/cffi_utils

cffi ffi python

Last synced: 23 days ago
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Utility modules to build python wrappers around C code

• Host: GitHub
• URL: https://github.com/sundarnagarajan/cffi_utils
• Owner: sundarnagarajan
• License: gpl-3.0
• Created: 2016-03-16T12:58:10.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2016-09-27T19:55:16.000Z (about 8 years ago)
• Last Synced: 2024-10-15T17:22:45.024Z (30 days ago)
• Topics: cffi, ffi, python
• Language: Python
• Size: 64.5 KB
• Stars: 0
• Watchers: 3
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE-GPLv3.txt

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README

        
# Module cffi_utils.sowrapper

Utility functions to locate and load shared libraries

### DESCRIPTION

Recommended usage:

	    

Should only need to use get_lib_ffi_shared() or get_lib_ffi_resource()

	    

Use get_lib_ffi_shared to load a system-wide shared library with a known library filename and / or path

	    

Use get_lib_ffi_resource to load a module-specific shared library where library filename _MAY_ be mangled as per PEP3149 and path _MAY_ need to be looked up using pkg_resources. Internally, get_lib_ffi_resource() calls get_lib_ffi_shared()

	    

Both return a tuple: (ffi, lib):

	ffi-->FFIExt - should behave like cffi.FFI with some additional

		utility methods

	lib-->SharedLibWrapper instance - use methods on this object to

		call methods in the shared library

### CLASSES

	    class SharedLibWrapper(__builtin__.object)

	     |  Methods defined here:

	     |  

	     |  __init__(self, libpath, c_hdr, module_name=None)

	     |      libpath-->str: library name; can also be full path

	     |      c_hdr-->str: C-style header definitions for functions to wrap

	     |      ffi-->FFIExt or cffi.FFI

### FUNCTIONS

	get_lib_ffi_resource(module_name, libpath, c_hdr)

		module_name-->str: module name to retrieve resource

		libpath-->str: shared library filename with optional path

		c_hdr-->str: C-style header definitions for functions to wrap

		Returns-->(ffi, lib)

		

		Use this method when you are loading a package-specific shared library

		If you want to load a system-wide shared library, use get_lib_ffi_shared

		instead

	    

	get_lib_ffi_shared(libpath, c_hdr)

		libpath-->str: shared library filename with optional path

		c_hdr-->str: C-style header definitions for functions to wrap

		Returns-->(ffi, lib)

# Module cffi_utils.ffi

Extension of cffi.FFI adding a few utility methods

### CLASSES

	    class FFIExt(cffi.api.FFI)

	     |  FFIExt is an extension of cffi.FFI, adding a few utility methods

	     |  

	     |  get_cdata(), get_buffer() and get_bytes() all operate on a variable

	     |  list of arguments as a convenience.

	     |  

	     |  Otherwise, get_cdata() and get_buffer() are equivalent to

	     |  FFI.from_buffer() and FFI.buffer() respectively

	     |  

	     |  get_bytes() is identical to get_buffer() except that outputs are

	     |  converted to bytes

	     |  

	     |  get_buffer(self, *args)

	     |      all args-->_cffi_backend.CDataOwn

	     |      Must be a pointer or an array

	     |      Returns-->buffer (if a SINGLE argument was provided)

	     |                LIST of buffer (if a args was a tuple or list)

	     |  

	     |  get_bytes(self, *args)

	     |      all args-->_cffi_backend.CDataOwn

	     |      Must be a pointer or an array

	     |      Returns-->bytes (if a SINGLE argument was provided)

	     |                LIST of bytes (if a args was a tuple or list)

	     |  

	     |  get_cdata(self, *args)

	     |      all args-->_cffi_backend.buffer

	     |      Returns-->cdata (if a SINGLE argument was provided)

	     |                LIST of cdata (if a args was a tuple or list)

	     |  

	     |  get_extension(self)

# Module cffi_utils.py2to3

Utility functions for Py2/Py3 compatibility

### FUNCTIONS

	chr(x)

		x-->int / byte

		Returns-->byte / str of length 1

		    Behaves like PY2 chr() in PY2 or PY3

	    

	decode(b, encoding='latin-1')

		b-->bytes

		encoding-->str: encoding to use. Recommended to use default

		Returns-->str: b decoded to str using encoding

		    Works in PY2, PY3

	    

	encode(s, encoding='latin-1')

		s-->str

		encoding-->str: encoding to use. Recommended to use default

		Returns-->bytes: s encoded to bytes using encoding

		    Works in PY2, PY3

	    

	fromBytes(b)

		s-->bytes (or str)

		Returns-->str (works in PY2, PY3)

	    

	inputFromBytes(func, *args, **kwargs)

		Descriptor that converts all arguments to str

	    

	inputToBytes(func, *args, **kwargs)

		Descriptor that converts all arguments to bytes

	    

	ord(x)

		x-->int / byte

		Returns-->int

		    Behaves like PY2 ord() in PY2 or PY3

	    

	outputFromBytes(func, *args, **kwargs)

		Descriptor that converts all return values to str

	    

	outputToBytes(func, *args, **kwargs)

		Descriptor that converts all return values to bytes

	    

	toBytes(s)

		s-->str (or bytes)

		Returns-->bytes (works in PY2, PY3)