src/hotspot/share/oops/symbol.hpp

@@ -157,10 +157,13 @@
    unsigned identity_hash() const {
      unsigned addr_bits = (unsigned)((uintptr_t)this >> LogBytesPerWord);
      return ((unsigned)extract_hash(_hash_and_refcount) & 0xffff) |
             ((addr_bits ^ (length() << 8) ^ (( _body[0] << 8) | _body[1])) << 16);
    }
+   static unsigned identity_hash(const Symbol* symbol_or_null) {
+     return symbol_or_null == nullptr ? 0 : symbol_or_null->identity_hash();
+   }
  
    // Reference counting.  See comments above this class for when to use.
    int refcount() const { return extract_refcount(_hash_and_refcount); }
    bool try_increment_refcount();
    void increment_refcount();

@@ -246,10 +249,23 @@
  
    // Three-way compare for sorting; returns -1/0/1 if receiver is </==/> than arg
    // note that the ordering is not alfabetical
    inline int fast_compare(const Symbol* other) const;
  
+   // Perform a memcmp against the other block of bytes, up to the end
+   // of the shorter of the two.  If lengths differ but the bytes are
+   // the same, the shorter one compares lower.
+   int cmp(const Symbol* other) const {
+     return cmp((char*)other->base(), other->utf8_length());
+   }
+   int cmp(const char* str, int len) const {
+     int mylen = utf8_length();
+     int cmp = memcmp((char*)base(), str, mylen < len ? mylen : len);
+     // mylen - len cannot overflow because symbol length >= 0
+     return cmp != 0 ? cmp : mylen - len;
+   }
+ 
    // Returns receiver converted to null-terminated UTF-8 string; string is
    // allocated in resource area, or in the char buffer provided by caller.
    char* as_C_string() const;
    char* as_C_string(char* buf, int size) const;