Create utility function CRC32Equal()

bodgit · Apr 30, 2022 · 5766fbc · 5766fbc
1 parent e4d5ed4
commit 5766fbc
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Showing 2 changed files with 11 additions and 3 deletions.
diff --git a/internal/util/checksum.go b/internal/util/checksum.go
@@ -0,0 +1,8 @@
+package util
+
+import "bytes"
+
+// CRC32Equal compares CRC32 checksums.
+func CRC32Equal(b []byte, c uint32) bool {
+	return bytes.Equal(b, []byte{byte(0xff & (c >> 24)), byte(0xff & (c >> 16)), byte(0xff & (c >> 8)), byte(0xff & c)})
+}
diff --git a/reader.go b/reader.go
@@ -999,7 +999,7 @@ func (z *Reader) init(r io.ReaderAt, size int64) error {
 	}
 
 	// CRC of the start header should match
-	if crc32Compare(h.Sum(nil), sh.CRC) != 0 {
+	if !util.CRC32Equal(h.Sum(nil), sh.CRC) {
 		return errChecksum
 	}
 
@@ -1048,7 +1048,7 @@ func (z *Reader) init(r io.ReaderAt, size int64) error {
 	}
 
 	// CRC should match the one from the start header
-	if crc32Compare(h.Sum(nil), start.CRC) != 0 {
+	if !util.CRC32Equal(h.Sum(nil), start.CRC) {
 		return errChecksum
 	}
 
@@ -1080,7 +1080,7 @@ func (z *Reader) init(r io.ReaderAt, size int64) error {
 		}
 
 		if cr, ok := fr.(checksumReadCloser); ok && crc != 0 {
-			if crc32Compare(cr.Checksum(), crc) != 0 {
+			if !util.CRC32Equal(cr.Checksum(), crc) {
 				return errChecksum
 			}
 		}