[GitHub] [incubator-doris] ZhangYu0123 commented on a change in pull request #4366: Optimise coding bit operation in BE

[GitBox <gi...@apache.org>]

ZhangYu0123 commented on a change in pull request #4366:
URL: https://github.com/apache/incubator-doris/pull/4366#discussion_r471195742



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File path: be/src/util/coding.h
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@@ -143,7 +143,7 @@ extern uint8_t* encode_varint64(uint8_t* dst, uint64_t value);
 inline uint8_t* encode_varint64(uint8_t* dst, uint64_t v) {
     static const unsigned int B = 128;
     while (v >= B) {
-        *(dst++) = (v & (B - 1)) | B;
+        *(dst++) = v | B;

Review comment:
       (v & (B-1)) | B = (v | B) & ((B-1) | B ) = (v | B) & (11111111) = v | B
    
   eg: 
   129 & （128 - 1）  ｜ 128 = 1
   129 ｜ 128 =  1




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