tree d8b8bd3ba1c3129cc8232abd92c139a7d2586c9d
parent 6fde5971ff53f43ece1aa3977b0689390934b06e
author Nan Zhou <nanzhoumails@gmail.com> 1660610660 +0000
committer Ed Tanous <edtanous@google.com> 1687367300 -0700

json utils: add getEstimatedJsonSize

Add a utility function which estimates the size of the JSON tree.

It is used in the children change to limit the reponse size of expand
query.

Tested:
1. unit test passed;
2. tested on hardware, the following are real sizes and estimation
```
Real payload size, Estimation, query
15.69 KB,  10.21 KB, redfish/v1?$expand=.($levels=1)
95.76 KB,  62.11 KB, redfish/v1?$expand=.($levels=2)
117.14 KB, 72.71 KB, redfish/v1?$expand=.($levels=3)
127.65 KB, 77.64 KB, redfish/v1?$expand=.($levels=4)
```

Signed-off-by: Nan Zhou <nanzhoumails@gmail.com>
Change-Id: Iae26d6732a6ec63ecc59eacf657b4bf33c07c046