add piece size and file length

core/src/main/groovy/com/muwire/core/collections/FileCollectionBuilder.groovy

@@ -84,7 +84,7 @@ class FileCollectionBuilder {
             String comment = sf.getComment() // TODO: check comment encoding
             if (comment == null)
                 comment = ""
-            def item = new FileCollectionItem(new InfoHash(sf.root), comment, sfPathElements.get(sf))
+            def item = new FileCollectionItem(new InfoHash(sf.root), comment, sfPathElements.get(sf), (byte)sf.pieceSize, sf.getCachedLength())
             files.add(item)
         } 
         

core/src/main/groovy/com/muwire/core/collections/FileCollectionItem.groovy

@@ -3,19 +3,24 @@ package com.muwire.core.collections
 import com.muwire.core.Constants
 import com.muwire.core.InfoHash
 import com.muwire.core.Name
+import com.muwire.core.files.FileHasher
 
 class FileCollectionItem {
     
     private final InfoHash infoHash
     private final String comment
     private final File file
+    private final byte pieceSizePow2
+    private final long length
     private volatile byte[] payload
     private final List<String> pathElements = new ArrayList<>()
 
-    public FileCollectionItem(InfoHash infoHash, String comment, List<String> pathElements) {
+    public FileCollectionItem(InfoHash infoHash, String comment, List<String> pathElements, byte pieceSizePow2, long length) {
         this.infoHash = infoHash
         this.comment = comment
         this.pathElements = pathElements
+        this.pieceSizePow2 = pieceSizePow2
+        this.length = length
         
         File f = null
         pathElements.each { 
@@ -38,6 +43,14 @@ class FileCollectionItem {
         dis.readFully(hash)
         infoHash = new InfoHash(hash)
         
+        pieceSizePow2 = dis.readByte()
+        if (pieceSizePow2 < FileHasher.MIN_PIECE_SIZE_POW2 || pieceSizePow2 > FileHasher.MAX_PIECE_SIZE_POW2)
+            throw new InvalidCollectionException("invalid piece size $pieceSizePow2")
+        
+        length = dis.readLong()
+        if (length < 1 || length > FileHasher.MAX_SIZE)
+            throw new InvalidCollectionException("invalid length $length")
+        
         int nPathElements = dis.readUnsignedByte()
         File f = null
         nPathElements.times { 
@@ -62,6 +75,8 @@ class FileCollectionItem {
             
             daos.writeByte(Constants.COLLECTION_ENTRY_VERSION)
             daos.write(infoHash.getRoot())
+            daos.writeByte(pieceSizePow2)
+            daos.writeLong(length)
             daos.writeByte((byte) pathElements.size())
             pathElements.each { 
                 def name = new Name(it)

doc/collections.md

@@ -24,8 +24,10 @@ The header is followed by a file entry for each file in the collection.  The for
 ```
 byte 0: File entry version, currently fixed at "1".
 byte 1-33: hash of the file
-byte 34: Unsigned 8-bit number of path elements from root to where the file will ultimately be placed upon download.
+byte 34: piece size power of 2
-bytes 35-N : UTF-8 encoded length-prefixed path elements.  Each element can be at most 32kb long.  The last element is the name of the file.
+bytes 35-43: length of the file
+byte 44: Unsigned 8-bit number of path elements from root to where the file will ultimately be placed upon download.
+bytes 45-N : UTF-8 encoded length-prefixed path elements.  Each element can be at most 32kb long.  The last element is the name of the file.
 bytes N-M: length-prefixed free from description of the file (comment).  Format is UTF-8, maximum size is 32kb.
 ```