From a256df47de7f8da7fd4773b13745c450537cafb2 Mon Sep 17 00:00:00 2001
From: Jason Hostetter MD <jhostetter@gmail.com>
Date: Tue, 7 Jun 2022 22:33:31 -0400
Subject: [PATCH] Fix parsing of truncated byte arrays Return all parsed data
 in thrown exception

---
 src/parseDicom.js       | 15 ++++++++++++---
 test/parseDicom_test.js | 17 +++++++++++++++++
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/src/parseDicom.js b/src/parseDicom.js
index df0ebfee..f44c6769 100644
--- a/src/parseDicom.js
+++ b/src/parseDicom.js
@@ -158,11 +158,20 @@ export default function parseDicom(byteArray, options = {}) {
   // main function here
   function parseTheByteStream() {
     const metaHeaderDataSet = readPart10Header(byteArray, options);
-    const dataSet = readDataSet(metaHeaderDataSet);
 
-    return mergeDataSets(metaHeaderDataSet, dataSet);
+    try {
+      const dataSet = readDataSet(metaHeaderDataSet);
+      return mergeDataSets(metaHeaderDataSet, dataSet);
+    } catch (e) {
+      // If an exception is thrown when parsing main dataset (i.e. truncated
+      // byte array), go ahead and include everything parsed so far in the exception.
+      if (e.dataSet) {
+        e.dataSet = mergeDataSets(metaHeaderDataSet, e.dataSet);
+      }
+      throw e;
+    }
   }
-
+  
   // This is where we actually start parsing
   return parseTheByteStream();
 }
diff --git a/test/parseDicom_test.js b/test/parseDicom_test.js
index 751f45b4..b2f18759 100644
--- a/test/parseDicom_test.js
+++ b/test/parseDicom_test.js
@@ -220,4 +220,21 @@ describe('parseDicom', () => {
     expect(dataSet.string('x00201041')).to.equal('-43');
   });
 
+  it('should parse a truncated byte array and return all parsed elements in the exception (explicitLittleEndian)', () => {
+    // Arrange
+    const byteArray = makeExplicitLittleEndianTestData();
+    // Truncate between x00201041 and x00280010
+    const partialByteArray = byteArray.slice(0, 320)
+
+    // Act
+    try {
+      const dataSet = parseDicom(partialByteArray);
+    } catch (err) {
+      // Assert
+      assertMetaHeaderElements(err.dataSet, '1.2.840.10008.1.2.1', 159);
+      expect(err.dataSet.string('x00020010')).to.equal('1.2.840.10008.1.2.1')
+      expect(err.dataSet.string('x00201041')).to.equal('-43');
+      // expect(err.dataSet.uint16('x00280010')).to.equal(512);
+    }
+  });
 });