Trip padding byte from last element in multiple value arrays if it is…

… odd length
dcmjs-org · Sep 4, 2024 · 2b57f10 · 2b57f10
1 parent b803667
commit 2b57f10
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Showing 3 changed files with 41 additions and 9 deletions.
diff --git a/src/ValueRepresentation.js b/src/ValueRepresentation.js
@@ -161,10 +161,9 @@ class ValueRepresentation {
             const lastIdx = values.length - 1;
             const lastValue = values[lastIdx];
 
-            // If the last element exceeds the max length by exactly one character and ends with the padding byte,
-            // trim the padding byte to avoid a max length violation during write.
-            if (lastValue.length === maxLength + 1 && lastValue.endsWith(padChar)) {
-                values[lastIdx] = lastValue.substring(0, maxLength); // Trim the padding byte
+            // If the last element is odd and ends with the padding byte trim to avoid potential max length violations during write
+            if (lastValue.length % 2 !== 0 && lastValue.endsWith(padChar)) {
+                values[lastIdx] = lastValue.substring(0, lastValue.length - 1); // Trim the padding byte
             }
         }
 

diff --git a/test/data.test.js b/test/data.test.js
@@ -1158,7 +1158,7 @@ describe("test_un_vr", () => {
                 '00041130',
                 'CS',
                 new Uint8Array([0x4F, 0x52, 0x49, 0x47, 0x49, 0x4E, 0x41, 0x4C, 0x20, 0x20, 0x5C, 0x20, 0x50, 0x52, 0x49, 0x4D, 0x41, 0x52, 0x59, 0x20]).buffer,
-                ["ORIGINAL  ", " PRIMARY "],
+                ["ORIGINAL  ", " PRIMARY"],
                 ["ORIGINAL", "PRIMARY"]
             ],
             [

diff --git a/test/lossless-read-write.test.js b/test/lossless-read-write.test.js
@@ -160,6 +160,39 @@ describe('lossless-read-write', () => {
         expect(deepEqual(expectedDataset, outputDicomDictPass2.dict)).toBeTruthy();
     });
 
+    test('test DS with multiplicity > 1 with padding byte on last element within VR max length is losslessly read', () => {
+        const dataset = {
+            '00200037': {
+                vr: 'DS',
+                Value: [0.99924236548978, -0.0322633220972, -0.0217663285287, 0],
+                _rawValue: ["0.99924236548978", "-0.0322633220972", "-0.0217663285287", " +0.00 "]
+            }
+        };
+
+        const dicomDict = new DicomDict({});
+        dicomDict.dict = dataset;
+
+        // write and re-read
+        const outputDicomDict = DicomMessage.readFile(dicomDict.write());
+
+        // ensure _rawValue strings have no added trailing spaces and retain original encoding details for + and spaces
+        const expectedDataset = {
+            '00200037': {
+                vr: 'DS',
+                Value: [0.99924236548978, -0.0322633220972, -0.0217663285287, 0],
+                _rawValue: ["0.99924236548978", "-0.0322633220972", "-0.0217663285287", " +0.00"]
+            }
+        };
+
+        expect(outputDicomDict.dict).toEqual(expectedDataset);
+
+        // re-write should succeeed
+        const outputDicomDictPass2 = DicomMessage.readFile(outputDicomDict.write());
+
+        // dataset should still be equal
+        expect(outputDicomDictPass2.dict).toEqual(expectedDataset);
+    });
+
     test('test IS with multiplicity > 1 and added space for even padding is read and written correctly', () => {
         const dataset = {
             '00081160': {
@@ -179,17 +212,17 @@ describe('lossless-read-write', () => {
             '00081160': {
                 vr: 'IS',
                 Value: [1234, 5678],
-                _rawValue: ["1234", "5678 "]
+                _rawValue: ["1234", "5678"]
             }
         };
 
-        expect(deepEqual(expectedDataset, outputDicomDict.dict)).toBeTruthy();
+        expect(outputDicomDict.dict).toEqual(expectedDataset);
 
         // re-write should succeeed
         const outputDicomDictPass2 = DicomMessage.readFile(outputDicomDict.write());
 
         // dataset should still be equal
-        expect(deepEqual(expectedDataset, outputDicomDictPass2.dict)).toBeTruthy();
+        expect(outputDicomDictPass2.dict).toEqual(expectedDataset);
     });
 
     describe('Multiplicity for non-binary String VRs', () => {
@@ -311,7 +344,7 @@ describe('lossless-read-write', () => {
             },
             {
                 vr: "CS",
-                _rawValue: ["ORIGINAL  ", " PRIMARY "], // spaces non-significant for interpretation but allowed
+                _rawValue: ["ORIGINAL  ", " PRIMARY"], // spaces non-significant for interpretation but allowed
                 Value: ["ORIGINAL", "PRIMARY"],
             },
             {