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59 lines
1.4 KiB
Markdown
59 lines
1.4 KiB
Markdown
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# basic_json::merge_patch
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```cpp
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void merge_patch(const basic_json& apply_patch);
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```
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The merge patch format is primarily intended for use with the HTTP PATCH method as a means of describing a set of
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modifications to a target resource's content. This function applies a merge patch to the current JSON value.
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The function implements the following algorithm from Section 2 of
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[RFC 7396 (JSON Merge Patch)](https://tools.ietf.org/html/rfc7396):
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```python
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define MergePatch(Target, Patch):
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if Patch is an Object:
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if Target is not an Object:
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Target = {} // Ignore the contents and set it to an empty Object
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for each Name/Value pair in Patch:
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if Value is null:
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if Name exists in Target:
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remove the Name/Value pair from Target
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else:
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Target[Name] = MergePatch(Target[Name], Value)
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return Target
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else:
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return Patch
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```
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Thereby, `Target` is the current object; that is, the patch is applied to the current value.
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## Parameters
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`apply_patch` (in)
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: the patch to apply
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## Complexity
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Linear in the lengths of `apply_patch`.
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## Example
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??? example
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The following code shows how a JSON Merge Patch is applied to a JSON document.
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```cpp
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--8<-- "examples/merge_patch.cpp"
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```
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Output:
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```json
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--8<-- "examples/merge_patch.output"
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```
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## Version history
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- Added in version 3.0.0.
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