Python internals: support int8[] metadata and ICCProfile, refactor #3556
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This patch allows ParamValue, ParamValueList, and ImageSpec to support attribute/getattribute of metadata consisting of uint8[] arrays, which is how we store certain binary blobs or raw byte arrays. We translate this to Python as a numpy array of type uint8 (dtype='B'). This fixes a limitation where it was not possible to directly retrieve or set the "ICCProfile" metadata (which is stored as a uint8 array) from the Python APIs, as you could easily do from the C++ APIs. In the process, I found similar bits of code in several different places, in various states of incompleteness. I refactored to make a single make_pyobject() utility and then used that call in place of several other redundant pieces of functionality.
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@christopherdavies this is the fix necessary to allow get/set of ICCProfile metadata from python. |
src/python/py_oiio.cpp
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| // Have to make a copy of the data, because make_numpy_array will | ||
| // take possession of it. | ||
| uint8_t* ucdata(new uint8_t[type.arraylen * nvalues]); | ||
| memcpy(ucdata, data, type.arraylen * nvalues); |
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Maybe std::memcpy? Recent C++ standards are starting to diverge from C, e.g. functions from got constexpr specifiers.
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But these are dynamic memory and so can't possibly use a constexpr version here anyway.
I dunno, is it considered bad style to use the "non-std::" way to call a traditional C function that's also in C++? I've always just called the C function when they are identical.
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Yes, it is considered bad style. Prior to C++23 these headers were actually deprecated. C++23 clarifies the status of the headers as "For compatibility with the C standard library" and also says that "Source files that are not intended to also be valid ISO C should not use any of the C headers."
If interesting, this paper contains rationale.
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Interesting!
Ok, I will change this. I'm sure we have this kind of thing scattered all over the place. We'll clean up a bit here and there as we go.
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Updated, thanks for the suggestion and the education.
…cademySoftwareFoundation#3556) This patch allows ParamValue, ParamValueList, and ImageSpec to support attribute/getattribute of metadata consisting of uint8[] arrays, which is how we store certain binary blobs or raw byte arrays. We translate this to Python as a numpy array of type uint8 (dtype='B'). This fixes a limitation where it was not possible to directly retrieve or set the "ICCProfile" metadata (which is stored as a uint8 array) from the Python APIs, as you could easily do from the C++ APIs. In the process, I found similar bits of code in several different places, in various states of incompleteness. I refactored to make a single make_pyobject() utility and then used that call in place of several other redundant pieces of functionality.
…cademySoftwareFoundation#3556) This patch allows ParamValue, ParamValueList, and ImageSpec to support attribute/getattribute of metadata consisting of uint8[] arrays, which is how we store certain binary blobs or raw byte arrays. We translate this to Python as a numpy array of type uint8 (dtype='B'). This fixes a limitation where it was not possible to directly retrieve or set the "ICCProfile" metadata (which is stored as a uint8 array) from the Python APIs, as you could easily do from the C++ APIs. In the process, I found similar bits of code in several different places, in various states of incompleteness. I refactored to make a single make_pyobject() utility and then used that call in place of several other redundant pieces of functionality.
This patch allows ParamValue, ParamValueList, and ImageSpec to support attribute/getattribute of metadata consisting of uint8[] arrays, which is how we store certain binary blobs or raw byte arrays. We translate this to Python as a numpy array of type uint8 (dtype='B').
This fixes a limitation where it was not possible to directly retrieve or set the "ICCProfile" metadata (which is stored as a uint8 array) from the Python APIs, as you could easily do from the C++ APIs.
In the process, I found similar bits of code in several different places, in various states of incompleteness. I refactored to make a single make_pyobject() utility and then used that call in place of several other redundant pieces of functionality.