src/java.base/share/classes/jdk/internal/jimage/BasicImageReader.java

rev 16767 : 8175561: Memory churn in jimage code affects startup after resource encapsulation changes
Reviewed-by: jlaskey
rev 16768 : imported patch imgstr_oneup

*** 247,261 ****
  
      public ImageStringsReader getStrings() {
          return stringsReader;
      }
  
!     public ImageLocation findLocation(String mn, String rn) {
!         Objects.requireNonNull(mn);
!         Objects.requireNonNull(rn);
  
!         return findLocation("/" + mn + "/" + rn);
      }
  
      public synchronized ImageLocation findLocation(String name) {
          Objects.requireNonNull(name);
          // Details of the algorithm used here can be found in
--- 247,281 ----
  
      public ImageStringsReader getStrings() {
          return stringsReader;
      }
  
!     public synchronized ImageLocation findLocation(String module, String name) {
!         Objects.requireNonNull(module);
!         Objects.requireNonNull(name);
!         // Details of the algorithm used here can be found in
!         // jdk.tools.jlink.internal.PerfectHashBuilder.
!         int count = header.getTableLength();
!         int index = redirect.get(ImageStringsReader.hashCode(module, name) % count);
! 
!         if (index < 0) {
!             // index is twos complement of location attributes index.
!             index = -index - 1;
!         } else if (index > 0) {
!             // index is hash seed needed to compute location attributes index.
!             index = ImageStringsReader.hashCode(module, name, index) % count;
!         } else {
!             // No entry.
!             return null;
!         }
! 
!         long[] attributes = getAttributes(offsets.get(index));
  
!         if (!ImageLocation.verify(module, name, attributes, stringsReader)) {
!             return null;
!         }
!         return new ImageLocation(attributes, stringsReader);
      }
  
      public synchronized ImageLocation findLocation(String name) {
          Objects.requireNonNull(name);
          // Details of the algorithm used here can be found in