Added ability to tune offset of ByteChunkProvider (Fixes #22)

.gitlab-ci.yml

@@ -0,0 +1,33 @@
+image: java:8-jdk
+
+stages:
+  - build
+  - test
+  - deploy
+
+before_script:
+#  - echo `pwd` # debug
+#  - echo "$CI_BUILD_NAME, $CI_BUILD_REF_NAME $CI_BUILD_STAGE" # debug
+  - export GRADLE_USER_HOME=`pwd`/.gradle
+
+cache:
+  paths:
+    - .gradle/wrapper
+    - .gradle/caches
+
+build:
+  stage: build
+  script:
+    - ./gradlew assemble
+  artifacts:
+    paths:
+      - build/libs/*.jar
+    expire_in: 1 week
+  only:
+    - master
+
+test:
+  stage: test
+  script:
+    - ./gradlew check
+

src/main/java/com/hierynomus/smbj/io/ByteChunkProvider.java

@@ -22,14 +22,15 @@
 import java.io.OutputStream;
 
 public abstract class ByteChunkProvider {
-    static final int CHUNK_SIZE = 64 * 1024;
+    protected static final int CHUNK_SIZE = 64 * 1024;
 
-    private long offset;
+    protected long offset;
+    protected int chunkSize = CHUNK_SIZE;
 
     public abstract boolean isAvailable();
 
     public void writeChunk(OutputStream os) {
-        byte[] chunk = new byte[CHUNK_SIZE];
+        byte[] chunk = new byte[chunkSize];
         try {
             int size = getChunk(chunk);
             os.write(chunk, 0, size);
@@ -40,7 +41,7 @@ public void writeChunk(OutputStream os) {
     }
 
     public void writeChunks(Buffer<?> buffer, int nrChunks) {
-        byte[] chunk = new byte[CHUNK_SIZE];
+        byte[] chunk = new byte[chunkSize];
         for (int i = 0; i < nrChunks; i++) {
             try {
                 int size = getChunk(chunk);
@@ -53,7 +54,7 @@ public void writeChunks(Buffer<?> buffer, int nrChunks) {
     }
 
     public void writeChunk(Buffer<?> buffer) {
-        byte[] chunk = new byte[CHUNK_SIZE];
+        byte[] chunk = new byte[chunkSize];
         try {
             int size = getChunk(chunk);
             buffer.putRawBytes(chunk, 0, size);

src/main/java/com/hierynomus/smbj/io/FileByteChunkProvider.java

@@ -29,6 +29,24 @@ public FileByteChunkProvider(File file) throws FileNotFoundException {
         fis = new BufferedInputStream(new FileInputStream(file), CHUNK_SIZE);
     }
 
+    public FileByteChunkProvider(File file, long offset) throws IOException {
+        this.file = file;
+        fis = new BufferedInputStream(new FileInputStream(file), CHUNK_SIZE);
+        ensureSkipped(fis, offset);
+        this.offset = offset;
+    }
+
+    private void ensureSkipped(final BufferedInputStream fis, final long offset) throws IOException {
+        long skipped = 0;
+        while (skipped < offset && fis.available() > 0) {
+            skipped += fis.skip(offset);
+        }
+
+        if (skipped < offset) {
+            throw new IOException("Was unable to go to the requested offset of " + offset + " of file " + file);
+        }
+    }
+
     @Override
     protected int getChunk(byte[] chunk) throws IOException {
         int count = 0;

src/test/groovy/com/hierynomus/smbj/io/FileByteChunkProviderTest.groovy

@@ -67,6 +67,24 @@ class FileByteChunkProviderTest extends Specification {
     provider.isAvailable()
   }
 
+  def "should start at provided offset"() {
+    given:
+    def file = getFileWithRandomData(ByteChunkProvider.CHUNK_SIZE)
+    def provider = new FileByteChunkProvider(file, 100)
+    def baos = new ByteArrayOutputStream()
+
+    when:
+    provider.writeChunk(baos)
+
+    then:
+    def tmpBytes = new byte[ByteChunkProvider.CHUNK_SIZE - 100]
+    System.arraycopy(file.bytes, 100, tmpBytes, 0, tmpBytes.length)
+    baos.toByteArray() == tmpBytes
+    provider.offset == ByteChunkProvider.CHUNK_SIZE
+    !provider.isAvailable()
+
+  }
+
   private def getFileWithRandomData(int size) {
     def bytes = new byte[size]
     new Random().nextBytes(bytes)