#365 Improve file header equals check to include offset of local file header

Author: srikanth-lingala

src/main/java/net/lingala/zip4j/model/FileHeader.java

@@ -18,6 +18,8 @@
 
 import net.lingala.zip4j.headers.HeaderSignature;
 
+import java.util.Objects;
+
 public class FileHeader extends AbstractFileHeader {
 
   private int versionMadeBy;
@@ -92,4 +94,26 @@ public void setFileComment(String fileComment) {
   public String toString() {
     return getFileName();
   }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) return true;
+    if (o == null || getClass() != o.getClass()) return false;
+    if (!super.equals(o)) return false;
+    FileHeader that = (FileHeader) o;
+    return determineOffsetOfLocalFileHeader(this) == determineOffsetOfLocalFileHeader(that);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(getFileName(), determineOffsetOfLocalFileHeader(this));
+  }
+
+  private long determineOffsetOfLocalFileHeader(FileHeader fileHeader) {
+    if (fileHeader.getZip64ExtendedInfo() != null) {
+      return fileHeader.getZip64ExtendedInfo().getOffsetLocalHeader();
+    }
+
+    return fileHeader.getOffsetLocalHeader();
+  }
 }

src/test/java/net/lingala/zip4j/RemoveFilesFromZipIT.java

@@ -234,6 +234,18 @@ public void testRemoveEntryWithAnotherSimilarNameFromZipRemovesOnlyTheEntryToBeR
     assertZipFileDoesNotContainsFileByName(new ZipFile(zipFileUnderTest), fileNameToRemove);
   }
 
+  @Test
+  public void testRemoveEntryFromAZipFileWithDuplicateEntriesRemovesSuccessfully() throws IOException {
+    TestUtils.copyFile(TestUtils.getTestArchiveFromResources("zip_with_duplicate_entries.zip"), generatedZipFile);
+    ZipFile zipFile = new ZipFile(generatedZipFile);
+    int actualNumberOfEntries = zipFile.getFileHeaders().size();
+    zipFile.removeFile("sample.pdf");
+
+    zipFile = new ZipFile(generatedZipFile);
+    assertThat(zipFile.getFileHeaders().size()).isEqualTo(actualNumberOfEntries - 1);
+    assertZipFileDoesNotContainsFileByName(zipFile, "sample.pdf");
+  }
+
   private void testRemoveEntryFromZipWhichHasCentralDirEntriesInDifferentOrderThanLocalEntries(
       String fileNameToRemove) throws IOException {
     TestUtils.copyFile(TestUtils.getTestArchiveFromResources("cen_dir_entries_diff_order_as_local_entries.zip"),