[SR-14496] - When Base64 encoding, only add line separators if there …

…are more lines available
readdle · May 1, 2021 · 7f8462a · 7f8462a
1 parent eec4b26
commit 7f8462a
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Showing 2 changed files with 35 additions and 2 deletions.
diff --git a/Sources/Foundation/NSData.swift b/Sources/Foundation/NSData.swift
@@ -900,12 +900,14 @@ open class NSData : NSObject, NSCopying, NSMutableCopying, NSSecureCoding {
             // anyway.
             buffer.baseAddress!.advanced(by: outputIndex).copyMemory(from: &outputBytes, byteCount: 4)
             outputIndex += 4
+            bytesLeft = dataBuffer.count - inputIndex
+
             if lineLength != 0 {
                 // Add required EOL markers.
                 currentLineCount += 4
                 assert(currentLineCount <= lineLength)
 
-                if currentLineCount == lineLength {
+                if currentLineCount == lineLength && bytesLeft > 0 {
                     buffer[outputIndex] = separatorByte1
                     outputIndex += 1
 
@@ -916,7 +918,6 @@ open class NSData : NSObject, NSCopying, NSMutableCopying, NSSecureCoding {
                     currentLineCount = 0
                 }
             }
-            bytesLeft = dataBuffer.count - inputIndex
         }
 
         // Return the number of ASCII bytes written to the buffer

diff --git a/Tests/Foundation/Tests/TestNSData.swift b/Tests/Foundation/Tests/TestNSData.swift
@@ -244,6 +244,8 @@ class TestNSData: LoopbackServerTest {
             ("test_base64EncodedDataWithOptionToInsertCarriageReturnContainsCarriageReturn", test_base64EncodedDataWithOptionToInsertCarriageReturnContainsCarriageReturn),
             ("test_base64EncodedDataWithOptionToInsertLineFeedsContainsLineFeed", test_base64EncodedDataWithOptionToInsertLineFeedsContainsLineFeed),
             ("test_base64EncodedDataWithOptionToInsertCarriageReturnAndLineFeedContainsBoth", test_base64EncodedDataWithOptionToInsertCarriageReturnAndLineFeedContainsBoth),
+            ("test_base64EncodeDoesNotAddLineSeparatorsWhenStringFitsInLine", test_base64EncodeDoesNotAddLineSeparatorsWhenStringFitsInLine),
+            ("test_base64EncodeAddsLineSeparatorsWhenStringDoesNotFitInLine", test_base64EncodeAddsLineSeparatorsWhenStringDoesNotFitInLine),
             ("test_base64EncodedStringGetsEncodedText", test_base64EncodedStringGetsEncodedText),
             ("test_initializeWithBase64EncodedStringGetsDecodedData", test_initializeWithBase64EncodedStringGetsDecodedData),
             ("test_base64DecodeWithPadding1", test_base64DecodeWithPadding1),
@@ -814,6 +816,36 @@ class TestNSData: LoopbackServerTest {
         XCTAssertEqual(encodedTextResult, encodedText)
     }
 
+    func test_base64EncodeDoesNotAddLineSeparatorsWhenStringFitsInLine() {
+
+        XCTAssertEqual(
+            Data(repeating: 0, count: 48).base64EncodedString(options: .lineLength64Characters),
+            "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
+            "each 3 byte is converted into 4 characterss. 48 / 3 * 4 <= 64, therefore result should not have line separator."
+        )
+
+        XCTAssertEqual(
+            Data(repeating: 0, count: 57).base64EncodedString(options: .lineLength76Characters),
+            "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA",
+            "each 3 byte is converted into 4 characterss. 57 / 3 * 4 <= 76, therefore result should not have line separator."
+        )
+    }
+
+    func test_base64EncodeAddsLineSeparatorsWhenStringDoesNotFitInLine() {
+
+        XCTAssertEqual(
+            Data(repeating: 0, count: 49).base64EncodedString(options: .lineLength64Characters),
+            "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\r\nAA==",
+            "each 3 byte is converted into 4 characterss. 49 / 3 * 4 > 64, therefore result should have lines with separator."
+        )
+
+        XCTAssertEqual(
+            Data(repeating: 0, count: 58).base64EncodedString(options: .lineLength76Characters),
+            "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\r\nAA==",
+            "each 3 byte is converted into 4 characterss. 58 / 3 * 4 > 76, therefore result should have lines with separator."
+        )
+    }
+
     func test_base64EncodedStringGetsEncodedText() {
         let plainText = "Revocate animos, maestumque timorem mittite: forsan et haec olim meminisse iuvabit."
         let encodedText = "UmV2b2NhdGUgYW5pbW9zLCBtYWVzdHVtcXVlIHRpbW9yZW0gbWl0dGl0ZTogZm9yc2FuIGV0IGhhZWMgb2xpbSBtZW1pbmlzc2UgaXV2YWJpdC4="