Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

fix memory corruption when reading palette #69

Merged
merged 2 commits into from
Oct 18, 2023
Merged

fix memory corruption when reading palette #69

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
4823b1a
fix memory corruption when reading palette
vtjnash Oct 17, 2023
a4c4545
Update io.jl
vtjnash Oct 17, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
31 changes: 13 additions & 18 deletions src/io.jl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -191,30 +191,25 @@ function _load(png_ptr, info_ptr; gamma::Union{Nothing,Float64}=nothing, expand_

# Gamma correction is applied to a palette after `png_read_update_info` is called
if read_as_paletted
# TODO: Figure out the length of palette before calling png_get_PLTEs
# `png_get_palette_max(png_ptr, info_ptr)` seems like a good option
# I can't make it work (I only ever get it to return zero). Note that it
# has to be called after png_read_image / png_read_png.
palette_length = Ref{Cint}()
palette_buffer = Vector{RGB{N0f8}}(undef, PNG_MAX_PALETTE_LENGTH)
GC.@preserve palette_buffer begin
png_get_PLTE(png_ptr, info_ptr, pointer_from_objref(palette_buffer), palette_length)
palette = palette_buffer[1:palette_length[]]
end
palette_length = Ref{Cint}(0)
palette_buffer = Ref{Ptr{PNGFiles.png_color_struct}}(C_NULL)
png_get_PLTE(png_ptr, info_ptr, palette_buffer, palette_length)
palette = Vector{RGB{N0f8}}(undef, palette_length[])
GC.@preserve palette unsafe_copyto!(pointer(palette), Ptr{RGB{N0f8}}(palette_buffer[]), length(palette))
if valid_tRNS
alpha_buffer = Vector{N0f8}(undef, palette_length[])
alphas_cnt = Ref{Cint}()
GC.@preserve alpha_buffer begin
png_get_tRNS(png_ptr, info_ptr, pointer_from_objref(alpha_buffer), alphas_cnt, C_NULL)
end
alpha_buffer[alphas_cnt[]+1:palette_length[]] .= one(N0f8) # palette entries are opaque by default
palette = map(RGBA, palette, alpha_buffer)
alpha_buffer = Ref{Ptr{UInt8}}(C_NULL)
alphas_cnt = Ref{Cint}(0)
png_get_tRNS(png_ptr, info_ptr, alpha_buffer, alphas_cnt, C_NULL)
alpha = fill(one(N0f8), palette_length[]) # palette entries are opaque by default
@assert palette_length[] >= alphas_cnt[]
GC.@preserve alpha unsafe_copyto!(pointer(alpha), Ptr{N0f8}(alpha_buffer[]), min(palette_length[], alphas_cnt[]))
palette = map(RGBA, palette, alpha)
end
buffer_eltype = UInt8
end

# We transpose to work around libpng expecting row-major arrays
buffer = Array{buffer_eltype}(undef, width, height)
buffer = Matrix{buffer_eltype}(undef, width, height)

@debug(
"Read PNG info:",
Expand Down