Shrink CRC checksums from longs to ints

Author: gmta

btrfs-io/src/main/java/nl/gmta/btrfs/io/BtrfsStreamReader.java

@@ -166,7 +166,7 @@ private BtrfsCommandHeader readCommandHeader() throws IOException {
 
         // The CRC32 checksum of the header + body (w/ zeroes for the checksum value itself)
         this.reader.setChecksumZeroBytes(true);
-        long crc = this.reader.readLE32() & 0xFFFFFFFFL;
+        int crc = this.reader.readLE32();
         this.reader.setChecksumZeroBytes(false);
 
         return new BtrfsCommandHeader(length, command, crc);

btrfs-io/src/main/java/nl/gmta/btrfs/io/VerifyingDataReader.java

@@ -17,7 +17,7 @@ class VerifyingDataReader extends DataReader {
     private final Checksum checksum = new CRC32C();
     private boolean checksumZeroBytes = false;
     private long commandEndPosition;
-    private long expectedChecksum;
+    private int expectedChecksum;
 
     VerifyingDataReader(InputStream is) {
         super(is);
@@ -57,7 +57,7 @@ protected byte[] readBytes(int length) throws IOException {
 
         // If we've reached the command's end position, verify the checksum
         if (verify && (this.position >= this.commandEndPosition)) {
-            long checksumValue = this.checksum.getValue();
+            int checksumValue = (int) this.checksum.getValue();
             if (checksumValue != this.expectedChecksum) {
                 throw new BtrfsStructureException(String.format(
                     "Command body checksum mismatch: expected %08x but got %08x",
@@ -89,7 +89,7 @@ void setChecksumZeroBytes(boolean checksumZeroBytes) {
      * @param size The size of the command's body in bytes
      * @param crc32c The CRC32C checksum value of the command's body
      */
-    void setCommandVerification(int size, long crc32c) {
+    void setCommandVerification(int size, int crc32c) {
         if (this.commandEndPosition > 0) {
             throw new IllegalStateException("Command verification cannot be set while a command is still in progress");
         }

btrfs-structures/src/main/java/nl/gmta/btrfs/structure/stream/BtrfsCommandHeader.java

@@ -3,9 +3,9 @@
 public class BtrfsCommandHeader {
     private final int length;
     private final BtrfsCommandType command;
-    private final long crc;
+    private final int crc;
 
-    public BtrfsCommandHeader(int length, BtrfsCommandType command, long crc) {
+    public BtrfsCommandHeader(int length, BtrfsCommandType command, int crc) {
         this.length = length;
         this.command = command;
         this.crc = crc;
@@ -19,7 +19,7 @@ public BtrfsCommandType getCommand() {
         return this.command;
     }
 
-    public long getCrc() {
+    public int getCrc() {
         return this.crc;
     }