From ccfbc5eb67d6e2e52d208532cb7bf18e9fe8157d Mon Sep 17 00:00:00 2001
From: msdsoftware <8718035+rschmunk@users.noreply.github.com>
Date: Fri, 1 Mar 2024 00:18:43 -0500
Subject: [PATCH] Handle empty zip itemName in NetcdfFiles.makeUncompressed

---
 .../src/main/java/ucar/nc2/NetcdfFiles.java   | 22 +++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/cdm/core/src/main/java/ucar/nc2/NetcdfFiles.java b/cdm/core/src/main/java/ucar/nc2/NetcdfFiles.java
index 9320903cf8..4220552a7c 100644
--- a/cdm/core/src/main/java/ucar/nc2/NetcdfFiles.java
+++ b/cdm/core/src/main/java/ucar/nc2/NetcdfFiles.java
@@ -498,6 +498,8 @@ private static String findCompressedSuffix(String filename) {
   private static String makeUncompressed(String filename) throws Exception {
     String suffix = findCompressedSuffix(filename);
     int pos = filename.lastIndexOf(suffix);
+    log.debug("suffix {}, pos {}", suffix, pos);
+
     String basepath = filename.substring(0, pos - 1);
     String itempath = filename.substring(pos + suffix.length());
     // rebuild filepath without suffix (same as base path if there is not item path)
@@ -505,6 +507,11 @@ private static String makeUncompressed(String filename) throws Exception {
     // name of parent file
     String baseFilename = basepath + "." + suffix;
 
+    log.debug("basepath '{}'", basepath);
+    log.debug("itempath '{}'", itempath);
+    log.debug("uncompressedFilename '{}'", uncompressedFilename);
+    log.debug("baseFilename '{}'", baseFilename);
+
     // coverity claims resource leak, but attempts to fix break. so beware
     // see if already decompressed, check in cache as needed
     File uncompressedFile = DiskCache.getFileStandardPolicy(uncompressedFilename);
@@ -571,18 +578,25 @@ private static String makeUncompressed(String filename) throws Exception {
           try (InputStream in = new UncompressInputStream(new FileInputStream(baseFilename))) {
             copy(in, fout, 100000);
           }
-          if (NetcdfFile.debugCompress)
+          if (NetcdfFile.debugCompress) {
             log.info("uncompressed {} to {}", filename, uncompressedFile);
+          }
+
         } else if (suffix.equalsIgnoreCase("zip")) {
           // find specified zip entry, if it exists
           try (ZipInputStream zin = new ZipInputStream(new FileInputStream(baseFilename))) {
+            // If a desired zipentry ID was appended to method's filename parameter, then itempath
+            // is of length > 1 and ID starts at itempath char offset 1.
+            String itemName = (itempath.length() > 1) ? itempath.substring(1) : "";
+            log.debug("seeking zip itemName '{}'", itempath, itemName);
             ZipEntry ze = zin.getNextEntry();
-            String itemName = itempath.substring(1); // remove initial /
+
             while (ze != null) {
               if (itempath.isEmpty() || ze.getName().equals(itemName)) {
                 copy(zin, fout, 100000);
-                if (NetcdfFile.debugCompress)
-                  log.info("unzipped {} entry {} to {}", filename, ze.getName(), uncompressedFile);
+                if (NetcdfFile.debugCompress) {
+                  log.debug("unzipped {} entry {} to {}", filename, ze.getName(), uncompressedFile);
+                }
                 break;
               }
               zin.closeEntry();