fix: clearer signalling of "zip overflow"

Related to #5.

src/main/java/net/e175/klaus/zip/ZipOverflowException.java

@@ -0,0 +1,16 @@
+package net.e175.klaus.zip;
+
+import java.util.zip.ZipException;
+
+
+/**
+ * A ZipException that marks cases when the current ZIP file format cannot accommodate the new offsets.
+ */
+public final class ZipOverflowException extends ZipException {
+    public ZipOverflowException() {
+    }
+
+    public ZipOverflowException(String s) {
+        super(s);
+    }
+}

src/main/java/net/e175/klaus/zip/ZipPrefixer.java

@@ -92,7 +92,8 @@ private ZipPrefixer() {
      * @param targetPath Target ZIP file. Must be a writeable ZIP format file, in a writeable directory with enough space to hold a temporary copy.
      * @param prefixes   Binary prefixes that will be sequentially written before the original ZIP file's contents.
      * @return Total number of bytes written as prefixes.
-     * @throws IOException on errors related to I/O and ZIP integrity
+     * @throws IOException          on errors related to I/O and ZIP integrity
+     * @throws ZipOverflowException If the current ZIP format cannot accommodate the new offsets.
      */
     public static long applyPrefixesToZip(Path targetPath, byte[]... prefixes) throws IOException {
         validateZipOffsets(isUsableFile(targetPath));
@@ -106,7 +107,8 @@ public static long applyPrefixesToZip(Path targetPath, byte[]... prefixes) throw
      * @param targetPath  Target ZIP file. Must be a writeable ZIP format file, in a writeable directory with enough space to hold a temporary copy.
      * @param prefixFiles Prefix files that will be sequentially written before the original file's contents.
      * @return Total number of bytes written as prefixes.
-     * @throws IOException on errors related to I/O and ZIP integrity
+     * @throws IOException          on errors related to I/O and ZIP integrity
+     * @throws ZipOverflowException If the current ZIP format cannot accommodate the new offsets.
      */
     public static long applyPrefixesToZip(Path targetPath, Collection<Path> prefixFiles) throws IOException {
         validateZipOffsets(isUsableFile(targetPath));
@@ -182,8 +184,9 @@ public static void validateZipOffsets(Path targetPath) throws IOException {
      *
      * @param targetPath ZIP file to process.
      * @param adjustment Offset to add to the current offsets.
-     * @throws IOException  On I/O errors.
-     * @throws ZipException On errors in the ZIP's integrity.
+     * @throws IOException          On I/O errors.
+     * @throws ZipException         On errors in the ZIP's integrity.
+     * @throws ZipOverflowException If the current ZIP format cannot accommodate the new offsets.
      */
     public static void adjustZipOffsets(Path targetPath, long adjustment) throws IOException {
         final boolean mustAdjust = adjustment != 0;
@@ -329,9 +332,9 @@ private static Queue<Write> analyseOffsets(boolean mustAdjust, long adjustment,
         return writeQueue;
     }
 
-    private static int uintBoundsChecked(long unsignedIntOffset) throws ZipException {
+    private static int uintBoundsChecked(long unsignedIntOffset) throws ZipOverflowException {
         if (unsignedIntOffset > UINT_MAX_VALUE) {
-            throw new ZipException("This is a non-ZIP64 archive, but would have to be ZIP64 to accommodate the new offsets.");
+            throw new ZipOverflowException("This is a non-ZIP64 archive, but would have to be ZIP64 to accommodate the new offsets.");
         }
         return (int) unsignedIntOffset;
     }

src/test/java/net/e175/klaus/zip/CountingSeekableByteChannel.java

@@ -5,7 +5,9 @@
 import java.nio.channels.SeekableByteChannel;
 import java.util.concurrent.atomic.AtomicLong;
 
-/** An instrumented pass-through SeekableByteChannel. */
+/**
+ * An instrumented pass-through SeekableByteChannel.
+ */
 final class CountingSeekableByteChannel implements SeekableByteChannel {
     private final SeekableByteChannel basedOn;
 

src/test/java/net/e175/klaus/zip/ZipPrefixerTest.java

@@ -12,7 +12,6 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
-import java.util.zip.ZipException;
 
 import static net.e175.klaus.zip.TestUtil.prepareTestFile;
 import static net.e175.klaus.zip.ZipPrefixer.*;
@@ -117,7 +116,7 @@ void bailsOutOn4gBoundaryCrossing() throws IOException {
         validateZipOffsets(zip);
 
         assertThrows(
-                ZipException.class,
+                ZipOverflowException.class,
                 () -> applyPrefixesToZip(zip, Arrays.asList(filler, filler, filler, filler)));
     }