Merge pull request #46 from fugro-oss/EVLROffsetBug

Fix EVLR offset bug

Author: BenCurran98

Project.toml

@@ -1,7 +1,7 @@
 name = "LASDatasets"
 uuid = "cc498e2a-d443-4943-8f26-2a8a0f3c7cdb"
 authors = ["BenCurran98 <b.curran@fugro.com>"]
-version = "0.3.1"
+version = "0.3.2"
 
 [deps]
 BufferedStreams = "e1450e63-4bb3-523b-b2a4-4ffa8c0fd77d"
@@ -27,13 +27,15 @@ FileIO = "1"
 FixedPointNumbers = "0.8"
 PackedReadWrite = "0.1"
 Proj = "1"
+Random = "1.11.0"
 StaticArrays = "1"
 StructArrays = "0.6"
 TypedTables = "1"
 julia = "1.8"
 
 [extras]
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 
 [targets]
-test = ["Test"]
+test = ["Test", "Random"]

src/dataset.jl

@@ -174,6 +174,17 @@ Get the unit factor conversion that was applied to this dataset when ingested
 """
 get_unit_conversion(las::LASDataset) = las.unit_conversion
 
+"""
+    $(TYPEDSIGNATURES)
+
+Update the offset (in Bytes) to the first EVLR in a `LASDataset` `las`
+"""
+function update_evlr_offset!(header::LasHeader)
+    header.evlr_start = point_data_offset(header) + (number_of_points(header) * point_record_length(header))
+end
+
+update_evlr_offset!(las::LASDataset) = update_evlr_offset!(get_header(las))
+
 function Base.show(io::IO, las::LASDataset)
     println(io, "LAS Dataset")
     println(io, "\tNum Points: $(length(get_pointcloud(las)))")
@@ -239,13 +250,14 @@ function add_vlr!(las::LASDataset, vlr::LasVariableLengthRecord)
         push!(get_evlrs(las), vlr)
         if number_of_evlrs(header) == 1
             # if this is our first EVLR, need to set the EVLR offset to point to the correct location
-            header.evlr_start = point_data_offset(header) + (number_of_points(header) * point_record_length(header))
+            update_evlr_offset!(header)
         end
     else
         set_num_vlr!(header, number_of_vlrs(header) + 1)
         push!(get_vlrs(las), vlr)
         # make sure to increase the point offset since we're cramming another VLR before the points
         header.data_offset += sizeof(vlr)
+        update_evlr_offset!(header)
     end
 end
 
@@ -326,6 +338,8 @@ function add_column!(las::LASDataset, column::Symbol, values::AbstractVector{T})
     else
         add_extra_bytes!(las, column, T, extra_bytes_vlr)
     end
+    # make sure we keep our offset to our first EVLR consistent now we've crammed more data in
+    update_evlr_offset!(las)
     nothing
 end
 

test/dataset.jl

@@ -149,7 +149,8 @@
     @test length(evlrs) == 1
     @test number_of_evlrs(header) == 1
     @test evlrs[1] == long_comment
-    @test evlr_start(header) > 0
+    # make sure the offset makes sense
+    @test evlr_start(header) == point_data_offset(header) + (number_of_points(header) * point_record_length(header))
     # we can add a new comment on top of this one
     new_commment = LasVariableLengthRecord("Comment", 100, "This is a new comment", Comment(String(rand(UInt8, 2^8))), true)
     add_vlr!(las, new_commment)
@@ -165,6 +166,13 @@
     @test get_description(superseded_comment) == get_description(long_comment)
     @test get_data(superseded_comment) == get_data(long_comment)
     @test is_extended(superseded_comment) == is_extended(long_comment)
+    # if we add a regular VLR, we should update the offset to the first EVLR correctly
+    short_comment = LasVariableLengthRecord("Comment", 100, "This is a long comment", Comment(String(rand(UInt8, 10))))
+    add_vlr!(las, short_comment)
+    @test evlr_start(header) == point_data_offset(header) + (number_of_points(header) * point_record_length(header))
+    # and similarly if we add column data it should update properly
+    add_column!(las, :another_column, rand(UInt8, num_points))
+    @test evlr_start(header) == point_data_offset(header) + (number_of_points(header) * point_record_length(header))
     # and finally we can remove it
     remove_vlr!(las, superseded_comment)
     @test number_of_evlrs(get_header(las)) == 1

test/runtests.jl

@@ -2,10 +2,14 @@ using LASDatasets
 
 using ColorTypes
 using FixedPointNumbers
+using Random
 using StaticArrays
 using Test
 using TypedTables
 
+# fix random seed to avoid random errors
+Random.seed!(0)
+
 include("util.jl")
 include("spatial_info.jl")
 include("vlrs.jl")