Hi,
I have a library in C for compression. I made Python script
for testing it, called using ctypes.
Now, I am working on a .NET library for something very
similar and would like to test it in the same way. However, I am
getting lost in how to do some of the things with your library.
The function I need to call looks like:
public static long Compress(Memory input, Memory output)
The Memory class is a wrapper around either managed byte
arrays, void* (for efficiency), or memory mapped files. This
allows a unified system for accessing general chunks of memory
regardless if they are managed, native, or on the filesystem.
They are created through static functions:
public static Memory From(MemoryStream s, bool all = true)
public static Memory From(byte[] b, bool readOnly = false)
public static Memory From(byte[] b, long offset, long size, bool readOnly = false)
public unsafe static Memory From(UnmanagedMemoryStream s, bool all = true)
public unsafe static Memory From(void* b, long size, bool readOnly = false)
public unsafe static Memory From(IntPtr b, long size, bool readOnly = false)
public static Memory FromFile(string file, bool readOnly = false)
public static Memory OfSize(long size)
The only ones I can easily use are the last two (OfSize and
FromFile). I have not yet figured out how to call the other ones
properly. I don't seem to be able to allocate byte arrays
with Array[Byte](10), it complains that 10 cannot be converted
to System.Byte[] so it seems that it believes I am casting
instead of creating a new array. No overloads seem to exist.
So now here are my questions and the ctypes answer:
- How do I construct a byte array?
(ctypes.create_string_buffer)
- How do I take a Python list/array and pass it as a
pointer? (ctypes has this conversion happen automatically)
- How do I turn a byte array into a useful Python
list/array? As-is I can't use the Python-style indexers
(except negative numbers). (The ctypes buffer works directly
as a list, but also supports ".raw" and ".value")
- How do I convert a pointer into a useful Python
list/array? (ctypes casting allows this to work)
Last point, although this is probably a limitation of .NET,
but just to make sure. The default argument values can't be
used, but it is possible that this isn't even in the assembly
information and only works for source in the same module.
Thanks,
Jeff
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