From 8102e56cd9ebe064a1f4757b8d28c64661ab7cb3 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Fri, 29 May 2015 17:58:25 +0200
Subject: [server] Started work on the internal file server

---
 .../src/main/java/fileserv/FileChunk.java          | 50 ++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 dozentenmodulserver/src/main/java/fileserv/FileChunk.java

(limited to 'dozentenmodulserver/src/main/java/fileserv/FileChunk.java')

diff --git a/dozentenmodulserver/src/main/java/fileserv/FileChunk.java b/dozentenmodulserver/src/main/java/fileserv/FileChunk.java
new file mode 100644
index 00000000..2fee6378
--- /dev/null
+++ b/dozentenmodulserver/src/main/java/fileserv/FileChunk.java
@@ -0,0 +1,50 @@
+package fileserv;
+
+import java.util.Collection;
+import java.util.List;
+
+import org.openslx.filetransfer.FileRange;
+
+public class FileChunk {
+	public static final int CHUNK_SIZE = 16 * 1024 * 1024;
+
+	public final FileRange range;
+	public final byte[] sha1sum;
+
+	public FileChunk(long startOffset, long endOffset, byte[] sha1sum) {
+		this.range = new FileRange(startOffset, endOffset);
+		this.sha1sum = sha1sum;
+	}
+
+	public static int fileSizeToChunkCount(long fileSize) {
+		return (int) ((fileSize + CHUNK_SIZE - 1) / CHUNK_SIZE);
+	}
+
+	public static void createChunkList(Collection<FileChunk> list, long fileSize, List<byte[]> sha1sums) {
+		if (fileSize < 0)
+			throw new IllegalArgumentException("fileSize cannot be negative");
+		long chunkCount = fileSizeToChunkCount(fileSize);
+		if (sha1sums != null) {
+			if (sha1sums.size() != chunkCount)
+				throw new IllegalArgumentException(
+						"Passed a sha1sum list, but hash count in list doesn't match expected chunk count");
+			long offset = 0;
+			for (byte[] sha1sum : sha1sums) { // Do this as we don't know how efficient List.get(index) is...
+				long end = offset + CHUNK_SIZE;
+				if (end > fileSize)
+					end = fileSize;
+				list.add(new FileChunk(offset, end, sha1sum));
+				offset = end;
+			}
+			return;
+		}
+		long offset = 0;
+		while (offset < fileSize) { // ...otherwise we could share this code
+			long end = offset + CHUNK_SIZE;
+			if (end > fileSize)
+				end = fileSize;
+			list.add(new FileChunk(offset, end, null));
+			offset = end;
+		}
+	}
+}
-- 
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