LiangliangSui commented on code in PR #1650:
URL: https://github.com/apache/incubator-fury/pull/1650#discussion_r1618808382


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java/fury-core/src/main/java/org/apache/fury/memory/MemoryBuffer.java:
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@@ -1774,7 +1774,7 @@ private long readVarUint36Slow() {
   /** Reads the 1-5 byte int part of a non-negative varint. */
   public int readVarUint32() {
     int readIdx = readerIndex;
-    if (size - readIdx < 5) {
+    if (size - readIdx < 4) {

Review Comment:
   > later result |= (UNSAFE.getByte(heapMemory, address + readIdx++) & 0x7F) 
<< 28; wqill read one more byte without check. If we lower threshold, we may 
get crash in such cases.
   
   The premise for executing `result |= (UNSAFE.getByte(heapMemory, address + 
readIdx++) & 0x7F) << 28` is that the fourth byte of `fourByteValue` is 
`0b1xxxxxxxx` (that is, there are more bytes to be parsed).
   
   In `readVarUint36Slow()`, it is also possible to read 5 bytes continuously 
(provided that `(b & 0x80) != 0`).
   
   Therefore, the premise of executing `result |= (UNSAFE.getByte(heapMemory, 
address + readIdx++) & 0x7F) << 28` is that we still have content that can be 
read in the Buffer. If there is no content to read, it means that an error 
occurred during writing.



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