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Merged
jishnub merged 2 commits into from
Oct 10, 2020
Merged

Idempotent indexing in range[IdOffsetRange] #161

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ffd6bc9
Idempotent indexing range[IdOffsetRange]
jishnub Sep 27, 2020
1783826
Add methods to index a UnitRange{<:Integer}
jishnub Oct 10, 2020
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25 changes: 12 additions & 13 deletions src/OffsetArrays.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -307,21 +307,20 @@ end
@propagate_inbounds Base.getindex(a::OffsetRange, r::AbstractRange) = a.parent[r .- a.offsets[1]]
@propagate_inbounds Base.getindex(a::AbstractRange, r::OffsetRange) = OffsetArray(a[parent(r)], r.offsets)

@propagate_inbounds Base.getindex(r::UnitRange, s::IIUR) =
OffsetArray(r[s.indices], s)

@propagate_inbounds Base.getindex(r::StepRange, s::IIUR) =
OffsetArray(r[s.indices], s)

# this method is needed for ambiguity resolution
@propagate_inbounds Base.getindex(r::StepRangeLen{T,<:Base.TwicePrecision,<:Base.TwicePrecision}, s::IIUR) where T =
OffsetArray(r[s.indices], s)
for OR in [:IIUR, :IdOffsetRange]
for R in [:StepRange, :StepRangeLen, :LinRange, :UnitRange]
@eval @propagate_inbounds Base.getindex(r::$R, s::$OR) = OffsetArray(r[_unwrap(s)], axes(s))
end

@propagate_inbounds Base.getindex(r::StepRangeLen{T}, s::IIUR) where {T} =
OffsetArray(r[s.indices], s)
# this method is needed for ambiguity resolution
@eval @propagate_inbounds Base.getindex(r::StepRangeLen{T,<:Base.TwicePrecision,<:Base.TwicePrecision}, s::$OR) where T =
OffsetArray(r[_unwrap(s)], axes(s))
end

@propagate_inbounds Base.getindex(r::LinRange, s::IIUR) =
OffsetArray(r[s.indices], s)
#= Integer UnitRanges may return an appropriate AbstractUnitRange{<:Integer}, as the result may be used in indexing, and
indexing is faster with ranges =#
@propagate_inbounds Base.getindex(r::UnitRange{<:Integer}, s::IdOffsetRange) = IdOffsetRange(r[_unwrap(s)] .- s.offset, s.offset)
@propagate_inbounds Base.getindex(r::UnitRange{<:Integer}, s::IIUR) = IdentityUnitRange(r[_unwrap(s)])

function Base.show(io::IO, r::OffsetRange)
show(io, r.parent)
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5 changes: 4 additions & 1 deletion src/utils.jl
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Expand Up @@ -70,4 +70,7 @@ _checkindices(A::AbstractArray, indices, label) = _checkindices(ndims(A), indice
function _checkindices(N::Integer, indices, label)
throw_argumenterror(N, indices, label) = throw(ArgumentError(label*" $indices are not compatible with a $(N)D array"))
N == length(indices) || throw_argumenterror(N, indices, label)
end
end

_unwrap(r::IdOffsetRange) = r.parent .+ r.offset
_unwrap(r::IdentityUnitRange) = r.indices
53 changes: 35 additions & 18 deletions test/runtests.jl
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Expand Up @@ -110,27 +110,44 @@ end
check_indexed_by(r3, 0:2)

@testset "Idempotent indexing" begin
r = OffsetArrays.IdOffsetRange(3:5, -1)

# Indexing with IdentityUnitRange
s = IdentityUnitRange(0:2)
@test axes(r[s]) == axes(s)
for i in eachindex(s)
@test r[s[i]] == r[s][i]
end
@testset "Indexing into an IdOffsetRange" begin
r = OffsetArrays.IdOffsetRange(3:5, -1)
# Indexing with IdentityUnitRange
s = IdentityUnitRange(0:2)
@test axes(r[s]) == axes(s)
for i in eachindex(s)
@test r[s[i]] == r[s][i]
end

# Indexing with IdOffsetRange
s = OffsetArrays.IdOffsetRange(-4:-2, 4)
@test axes(r[s]) == axes(s)
for i in eachindex(s)
@test r[s[i]] == r[s][i]
# Indexing with IdOffsetRange
s = OffsetArrays.IdOffsetRange(-4:-2, 4)
@test axes(r[s]) == axes(s)
for i in eachindex(s)
@test r[s[i]] == r[s][i]
end

# Indexing with UnitRange
s = 0:2
@test axes(r[s]) == axes(s)
for i in eachindex(s)
@test r[s[i]] == r[s][i]
end
end
@testset "Indexing using an IdOffsetRange" begin
r = OffsetArrays.IdOffsetRange(3:5, -1)
# Indexing into an IdentityUnitRange
s = IdentityUnitRange(-1:5)
@test axes(s[r]) == axes(r)
for i in eachindex(r)
@test s[r[i]] == s[r][i]
end

# Indexing with UnitRange
s = 0:2
@test axes(r[s]) == axes(s)
for i in eachindex(s)
@test r[s[i]] == r[s][i]
# Indexing into an UnitRange
s = -3:6
@test axes(s[r]) == axes(r)
for i in eachindex(r)
@test s[r[i]] == s[r][i]
end
end
end

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