Fixes decoding (#23)

Author: JBosecker

Sources/ExtrasBase64/Chromium.swift

@@ -341,7 +341,7 @@ extension Base64 {
             }
 
             // inIndex is the first index in the last chunk
-            let inIndex = fullchunks > 1 ? fullchunks * 4 : 0
+            let inIndex = fullchunks * 4
             let a0 = inBuffer[inIndex]
             let a1 = inBuffer[inIndex + 1]
             var a2: UInt8?

Tests/ExtrasBase64Tests/ChromiumTests.swift

@@ -86,6 +86,30 @@ class ChromiumTests: XCTestCase {
         }
     }
 
+    func testBase64DecodingOneTwoThreeFour() {
+        let base64 = "AQIDBA=="
+        let bytes: [UInt8] = [1, 2, 3, 4]
+
+        XCTAssertEqual(Base64.encodeString(bytes: bytes), base64)
+        XCTAssertEqual(try Base64.decode(string: base64), bytes)
+    }
+
+    func testBase64DecodingOneTwoThreeFourFive() {
+        let base64 = "AQIDBAU="
+        let bytes: [UInt8] = [1, 2, 3, 4, 5]
+
+        XCTAssertEqual(Base64.encodeString(bytes: bytes), base64)
+        XCTAssertEqual(try Base64.decode(string: base64), bytes)
+    }
+
+    func testBase64DecodingOneTwoThreeFourFiveSix() {
+        let base64 = "AQIDBAUG"
+        let bytes: [UInt8] = [1, 2, 3, 4, 5, 6]
+
+        XCTAssertEqual(Base64.encodeString(bytes: bytes), base64)
+        XCTAssertEqual(try Base64.decode(string: base64), bytes)
+    }
+
     func testBase64DecodingWithInvalidLength() {
         XCTAssertThrowsError(_ = try Base64.decode(bytes: "AAAAA".utf8)) { error in
             XCTAssertEqual(error as? DecodingError, .invalidLength)