Add Base64 support for FileStorage #6697
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[GSoC] FileStorage: Add base64 support for reading and writting XML\YML file. The two new functions: ``` void cvWriteRawData_Base64(cv::FileStorage & fs, const void* _data, int len, const char* dt); void cvWriteMat_Base64(cv::FileStorage & fs, cv::String const & name, cv::Mat const & mat); ```
1. Add Base64 support for reading and writing XML\YML file. The two new functions for writing: ```cpp void cvWriteRawData_Base64(cv::FileStorage & fs, const void* _data, int len, const char* dt); void cvWriteMat_Base64(cv::FileStorage & fs, cv::String const & name, cv::Mat const & mat); ``` 2. Change YML file header form `YAML:1.0` to `YAML 1.0`. (standard format) 3. Add test for Base64 part.
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thanks! I will check it. Quick question - you've changed the header in YAML files written by OpenCV. Does the decoder support both the new and the old format? We want to be able to read all the previously stored .yml files. |
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Yes, it supports both the new and the old format. |
Two other test are still needed. 1. Verify the Base64 data. 2. Read an old YML file for compatibility test.
Two test are still needed: 1. Verify the Base64 data. 2. Read an old YML file for compatibility test.
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| CV_EXPORTS void cvWriteRawData_Base64(::cv::FileStorage & fs, const void* _data, int len, const char* dt); | |||
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please, change the API the first parameter to "CvFileStorage* fs"
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Hello! About changing this API, there is one problem to be discussed.
cvWriteRawData_Base64 cannot be continually called, like:
// in `icvWriteMat`
for( y = 0; y < size.height; y++ )
cvWriteRawData( fs, mat->data.ptr + (size_t)y*mat->step, size.width, dt );
When doing something like this, the output data cannot be merged into a single one. To solve this, I might need to add a private variable to CvFileStorage for recording status. Meanwhile, users must call cvStartWriteStruct(fs, name, CV_NODE_SEQ, "binary") themselves. It doesn't look good.
Another way, I can change the parameters to (CvFileStorage * fs, const char* name, const void* _data, int len, const char* dt) and treat it as a complete data type. But then this function must output all the data at once. Is this ok?
```cpp cvWriteMat_Base64(::cv::FileStorage & fs, ::cv::String const & name, ::cv::Mat const & mat) ``` becomes: ```cpp CV_EXPORTS void cvWriteMat_Base64(::CvFileStorage* fs, const char* name, const ::CvMat* mat); CV_EXPORTS void cvWriteMatND_Base64(::CvFileStorage* fs, const char* name, const ::CvMatND* mat); ```
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@wiryls, probably, we should have 3 functions then: cvStartWriteRawData_Base64(), cvWriteRawData_Base64() and cvEndWriteRawData_Base64() |
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@vpisarev Ok, and can I add a member variable to Because I need something to hold the length of binary data and data whose length is not a multiple of 3 (the part that temporarily should not be encoded). Or is there any better way to achieve it? |
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@wiryls, yes, sure, add all the necessary data to CvFileStorage |
The three new functions: ```cpp void cvStartWriteRawData_Base64(::CvFileStorage * fs, const char* name, int len, const char* dt); void cvWriteRawData_Base64(::CvFileStorage * fs, const void* _data, int len); void cvEndWriteRawData_Base64(::CvFileStorage * fs); ``` Test is also updated. (And it's remarkable that there is a bug in `cvWriteReadData`.)
I could not find the cause of the error: ``` C:\builds_ocv\precommit_opencl\opencv\modules\ts\src\ts_perf.cpp(361): error: The difference between expect_max and actual_max is 8445966.0000002384, which exceeds eps, where expect_max evaluates to 0.9999997615814209, actual_max evaluates to 8445967, and eps evaluates to 1.0000000000000001e-005. Argument "dst0" has unexpected maximal value ``` Hope this is a false alarm.
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@vpisarev . I've done that.
void cvStartWriteRawData_Base64(::CvFileStorage * fs, const char* name, int len, const char* dt);
void cvWriteRawData_Base64(::CvFileStorage * fs, const void* _data, int len);
void cvEndWriteRawData_Base64(::CvFileStorage * fs);By the way, I've also encountered a strange error when building on OpenCL (maybe it's a bug). See commit 677d4d20ce9de6b548887a05bbdd0ffb207281b0. And build success after I retry. |
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[GSoC 2016] FileStorage.
What does this PR change?
YAML:1.0toYAML 1.0. (standard format)