add simpler jagged array root

README.md

@@ -25,8 +25,8 @@ documentation](https://github.com/scikit-hep/uproot/issues/401)
 The project is in early alpha prototyping phase and contributions are very
 welcome.
 
-Reading of raw basket data is already working for uncompressed and
-Zlib-compressed files. The raw data consists of two vectors: the bytes
+Reading of raw basket data is already working for files of all different compression algorithms.
+The raw data consists of two vectors: the bytes
 and the offsets and are available using the
 `UnROOT.array(f::ROOTFile, path; raw=true)` method. This data can
 be reinterpreted using a custom type with the method

src/io.jl

@@ -135,7 +135,7 @@ function endcheck(io, preamble::T) where {T<:Preamble}
             error("Object '$(preamble.type)' has $(observed) bytes; expected $(preamble.cnt)")
         end
     end
-    return true
+    nothing
 end
 
 

src/root.jl

@@ -231,9 +231,7 @@ function readbasketsraw(io, branch)
     idx = 1
     for (basket_seek, n_bytes) in zip(seeks, bytes)
         @debug "Reading raw basket data" basket_seek n_bytes
-        if basket_seek == 0
-            break
-        end
+        basket_seek == 0 && break
         seek(io, basket_seek)
         idx += readbasketbytes!(data, offsets, io, idx)
     end
@@ -284,5 +282,5 @@ Efficient read of bytes into an existing array at a given offset
 function readbytes!(io, b, offset, nr)
     resize!(b, offset + nr - 1)
     nb = UInt(nr)
-    GC.@preserve b unsafe_read(io, pointer(b, offset), nr)
+    GC.@preserve b unsafe_read(io, pointer(b, offset), nb)
 end

src/streamers.jl

@@ -301,7 +301,12 @@ function unpack(io, tkey::TKey, refs::Dict{Int32, Any}, T::Type{TObjArray})
     name = readtype(io, String)
     size = readtype(io, Int32)
     low = readtype(io, Int32)
-    elements = [readobjany!(io, tkey, refs) for i in 1:size]
+    elements = Vector{Any}(undef, size)
+    for i in 1:size
+        ele = readobjany!(io, tkey, refs)
+        !ismissing(ele) && @show ele.fName
+        elements[i] = ele
+     end
     endcheck(io, preamble)
     return TObjArray(name, low, elements)
 end

src/types.jl

@@ -103,7 +103,7 @@ function datastream(io, tkey::T) where T<:Union{TKey, TBasketKey}
     seekstart(io, tkey)
     fufilled = 0
     uncomp_data = Vector{UInt8}(undef, tkey.fObjlen)
-    while fufilled < tkey.fObjlen # careful with 0/1-based index when thinking about offsets
+    while fufilled < length(uncomp_data) # careful with 0/1-based index when thinking about offsets
         compression_header = unpack(io, CompressionHeader)
         cname, _, compbytes, uncompbytes = unpack(compression_header)
         io_buf = IOBuffer(read(io, compbytes))
@@ -122,7 +122,7 @@ function datastream(io, tkey::T) where T<:Union{TKey, TBasketKey}
 
         fufilled += uncompbytes
     end
-
+    @assert fufilled == length(uncomp_data) # fail means something bad happens we over shoot
     return IOBuffer(uncomp_data)
 end
 

test/samples/tree_with_jagged_array.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python
+# Example taken from https://root.cern.ch/how/how-write-ttree-python
+# and modified to run...
+import ROOT
+from ROOT import TFile, TTree
+from array import array
+
+f = TFile('tree_with_jagged_array.root', 'recreate')
+t = TTree('t1', 'tree with jagged array')
+
+n = ROOT.vector('int')()
+t.Branch('int32_array', n)
+
+for i in range(100):
+    if i % 10 == 0:
+        n.clear()
+    t.Fill()
+    n.push_back(i)
+
+f.Write()
+f.Close()