XOY-Leveldb

作者： 谢瑞阳 10225101483 徐翔宇 10225101535

作者：谢瑞阳 10225101483 徐翔宇 10225101535

costan 09217fd067 Replace NULL with nullptr in C++ files. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=192365747		pirms 7 gadiem
..
memenv.cc	Replace NULL with nullptr in C++ files.	pirms 7 gadiem
memenv.h	Add CMake build support.	pirms 7 gadiem
memenv_test.cc	LevelDB now attempts to reuse the preceding MANIFEST and log file when re-opened.	pirms 9 gadiem