221 lines
9.7 KiB
Julia
221 lines
9.7 KiB
Julia
# This file is a part of Julia. License is MIT: https://julialang.org/license
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module Mmap
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const PAGESIZE = Int(is_unix() ? ccall(:jl_getpagesize, Clong, ()) : ccall(:jl_getallocationgranularity, Clong, ()))
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# for mmaps not backed by files
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mutable struct Anonymous <: IO
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name::AbstractString
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readonly::Bool
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create::Bool
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end
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Anonymous() = Anonymous("",false,true)
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Base.isopen(::Anonymous) = true
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Base.isreadable(::Anonymous) = true
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Base.iswritable(a::Anonymous) = !a.readonly
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const INVALID_HANDLE_VALUE = -1
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# const used for zeroed, anonymous memory; same value on Windows & Unix; say what?!
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gethandle(io::Anonymous) = INVALID_HANDLE_VALUE
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# platform-specific mmap utilities
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if is_unix()
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const PROT_READ = Cint(1)
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const PROT_WRITE = Cint(2)
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const MAP_SHARED = Cint(1)
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const MAP_PRIVATE = Cint(2)
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const MAP_ANONYMOUS = Cint(is_bsd() ? 0x1000 : 0x20)
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const F_GETFL = Cint(3)
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gethandle(io::IO) = fd(io)
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# Determine a stream's read/write mode, and return prot & flags appropriate for mmap
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function settings(s::Int, shared::Bool)
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flags = shared ? MAP_SHARED : MAP_PRIVATE
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if s == INVALID_HANDLE_VALUE
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flags |= MAP_ANONYMOUS
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prot = PROT_READ | PROT_WRITE
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else
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mode = ccall(:fcntl,Cint,(Cint,Cint),s,F_GETFL)
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systemerror("fcntl F_GETFL", mode == -1)
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mode = mode & 3
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prot = mode == 0 ? PROT_READ : mode == 1 ? PROT_WRITE : PROT_READ | PROT_WRITE
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if prot & PROT_READ == 0
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throw(ArgumentError("mmap requires read permissions on the file (choose r+)"))
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end
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end
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return prot, flags, (prot & PROT_WRITE) > 0
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end
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# Before mapping, grow the file to sufficient size
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# Note: a few mappable streams do not support lseek. When Julia
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# supports structures in ccall, switch to fstat.
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grow!(::Anonymous,o::Integer,l::Integer) = return
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function grow!(io::IO, offset::Integer, len::Integer)
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pos = position(io)
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filelen = filesize(io)
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if filelen < offset + len
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failure = ccall(:jl_ftruncate, Cint, (Cint, Int64), fd(io), offset+len)
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Base.systemerror(:ftruncate, failure != 0)
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end
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seek(io, pos)
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return
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end
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elseif is_windows()
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const DWORD = Culong
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const PAGE_READONLY = DWORD(0x02)
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const PAGE_READWRITE = DWORD(0x04)
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const PAGE_WRITECOPY = DWORD(0x08)
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const PAGE_EXECUTE_READ = DWORD(0x20)
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const PAGE_EXECUTE_READWRITE = DWORD(0x40)
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const PAGE_EXECUTE_WRITECOPY = DWORD(0x80)
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const FILE_MAP_COPY = DWORD(0x01)
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const FILE_MAP_WRITE = DWORD(0x02)
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const FILE_MAP_READ = DWORD(0x04)
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const FILE_MAP_EXECUTE = DWORD(0x20)
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function gethandle(io::IO)
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handle = Libc._get_osfhandle(RawFD(fd(io))).handle
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systemerror("could not get handle for file to map: $(Libc.FormatMessage())", handle == -1)
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return Int(handle)
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end
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settings(sh::Anonymous) = sh.name, sh.readonly, sh.create
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settings(io::IO) = Ptr{Cwchar_t}(0), isreadonly(io), true
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else
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error("mmap not defined for this OS")
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end # os-test
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# core implementation of mmap
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function mmap(io::IO,
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::Type{Array{T,N}}=Vector{UInt8},
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dims::NTuple{N,Integer}=(div(filesize(io)-position(io),sizeof(T)),),
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offset::Integer=position(io); grow::Bool=true, shared::Bool=true) where {T,N}
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# check inputs
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isopen(io) || throw(ArgumentError("$io must be open to mmap"))
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isbits(T) || throw(ArgumentError("unable to mmap $T; must satisfy isbits(T) == true"))
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len = prod(dims) * sizeof(T)
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len >= 0 || throw(ArgumentError("requested size must be ≥ 0, got $len"))
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len == 0 && return Array{T}(ntuple(x->0,Val{N}))
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len < typemax(Int) - PAGESIZE || throw(ArgumentError("requested size must be < $(typemax(Int)-PAGESIZE), got $len"))
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offset >= 0 || throw(ArgumentError("requested offset must be ≥ 0, got $offset"))
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# shift `offset` to start of page boundary
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offset_page::Int64 = div(offset, PAGESIZE) * PAGESIZE
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# add (offset - offset_page) to `len` to get total length of memory-mapped region
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mmaplen = (offset - offset_page) + len
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file_desc = gethandle(io)
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# platform-specific mmapping
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@static if is_unix()
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prot, flags, iswrite = settings(file_desc, shared)
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iswrite && grow && grow!(io, offset, len)
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# mmap the file
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ptr = ccall(:jl_mmap, Ptr{Void}, (Ptr{Void}, Csize_t, Cint, Cint, Cint, Int64), C_NULL, mmaplen, prot, flags, file_desc, offset_page)
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systemerror("memory mapping failed", reinterpret(Int,ptr) == -1)
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else
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name, readonly, create = settings(io)
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szfile = convert(Csize_t, len + offset)
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readonly && szfile > filesize(io) && throw(ArgumentError("unable to increase file size to $szfile due to read-only permissions"))
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handle = create ? ccall(:CreateFileMappingW, stdcall, Ptr{Void}, (Cptrdiff_t, Ptr{Void}, DWORD, DWORD, DWORD, Cwstring),
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file_desc, C_NULL, readonly ? PAGE_READONLY : PAGE_READWRITE, szfile >> 32, szfile & typemax(UInt32), name) :
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ccall(:OpenFileMappingW, stdcall, Ptr{Void}, (DWORD, Cint, Cwstring),
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readonly ? FILE_MAP_READ : FILE_MAP_WRITE, true, name)
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handle == C_NULL && error("could not create file mapping: $(Libc.FormatMessage())")
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ptr = ccall(:MapViewOfFile, stdcall, Ptr{Void}, (Ptr{Void}, DWORD, DWORD, DWORD, Csize_t),
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handle, readonly ? FILE_MAP_READ : FILE_MAP_WRITE, offset_page >> 32, offset_page & typemax(UInt32), (offset - offset_page) + len)
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ptr == C_NULL && error("could not create mapping view: $(Libc.FormatMessage())")
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end # os-test
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# convert mmapped region to Julia Array at `ptr + (offset - offset_page)` since file was mapped at offset_page
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A = unsafe_wrap(Array, convert(Ptr{T}, UInt(ptr) + UInt(offset - offset_page)), dims)
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finalizer(A, function(x)
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@static if is_unix()
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systemerror("munmap", ccall(:munmap, Cint, (Ptr{Void}, Int), ptr, mmaplen) != 0)
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else
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status = ccall(:UnmapViewOfFile, stdcall, Cint, (Ptr{Void},), ptr)!=0
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status |= ccall(:CloseHandle, stdcall, Cint, (Ptr{Void},), handle)!=0
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status || error("could not unmap view: $(Libc.FormatMessage())")
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end
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end)
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return A
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end
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mmap(file::AbstractString,
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::Type{T}=Vector{UInt8},
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dims::NTuple{N,Integer}=(div(filesize(file),sizeof(eltype(T))),),
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offset::Integer=Int64(0); grow::Bool=true, shared::Bool=true) where {T<:Array,N} =
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open(io->mmap(io, T, dims, offset; grow=grow, shared=shared), file, isfile(file) ? "r+" : "w+")::Array{eltype(T),N}
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# using a length argument instead of dims
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mmap(io::IO, ::Type{T}, len::Integer, offset::Integer=position(io); grow::Bool=true, shared::Bool=true) where {T<:Array} =
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mmap(io, T, (len,), offset; grow=grow, shared=shared)
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mmap(file::AbstractString, ::Type{T}, len::Integer, offset::Integer=Int64(0); grow::Bool=true, shared::Bool=true) where {T<:Array} =
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open(io->mmap(io, T, (len,), offset; grow=grow, shared=shared), file, isfile(file) ? "r+" : "w+")::Vector{eltype(T)}
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# constructors for non-file-backed (anonymous) mmaps
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mmap(::Type{T}, dims::NTuple{N,Integer}; shared::Bool=true) where {T<:Array,N} = mmap(Anonymous(), T, dims, Int64(0); shared=shared)
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mmap(::Type{T}, i::Integer...; shared::Bool=true) where {T<:Array} = mmap(Anonymous(), T, convert(Tuple{Vararg{Int}},i), Int64(0); shared=shared)
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function mmap(io::IOStream, ::Type{<:BitArray}, dims::NTuple{N,Integer},
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offset::Int64=position(io); grow::Bool=true, shared::Bool=true) where N
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n = prod(dims)
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nc = Base.num_bit_chunks(n)
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chunks = mmap(io, Vector{UInt64}, (nc,), offset; grow=grow, shared=shared)
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if !isreadonly(io)
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chunks[end] &= Base._msk_end(n)
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else
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if chunks[end] != chunks[end] & Base._msk_end(n)
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throw(ArgumentError("the given file does not contain a valid BitArray of size $(join(dims, 'x')) (open with \"r+\" mode to override)"))
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end
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end
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B = BitArray{N}(ntuple(i->0,Val{N})...)
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B.chunks = chunks
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B.len = n
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if N != 1
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B.dims = dims
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end
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return B
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end
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mmap(file::AbstractString, ::Type{T}, dims::NTuple{N,Integer}, offset::Integer=Int64(0);grow::Bool=true, shared::Bool=true) where {T<:BitArray,N} =
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open(io->mmap(io, T, dims, offset; grow=grow, shared=shared), file, isfile(file) ? "r+" : "w+")::BitArray{N}
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# using a length argument instead of dims
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mmap(io::IO, ::Type{T}, len::Integer, offset::Integer=position(io); grow::Bool=true, shared::Bool=true) where {T<:BitArray} =
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mmap(io, T, (len,), offset; grow=grow, shared=shared)
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mmap(file::AbstractString, ::Type{T}, len::Integer, offset::Integer=Int64(0); grow::Bool=true, shared::Bool=true) where {T<:BitArray} =
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open(io->mmap(io, T, (len,), offset; grow=grow, shared=shared), file, isfile(file) ? "r+" : "w+")::BitVector
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# constructors for non-file-backed (anonymous) mmaps
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mmap(::Type{T}, dims::NTuple{N,Integer}; shared::Bool=true) where {T<:BitArray,N} = mmap(Anonymous(), T, dims, Int64(0); shared=shared)
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mmap(::Type{T}, i::Integer...; shared::Bool=true) where {T<:BitArray} = mmap(Anonymous(), T, convert(Tuple{Vararg{Int}},i), Int64(0); shared=shared)
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# msync flags for unix
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const MS_ASYNC = 1
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const MS_INVALIDATE = 2
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const MS_SYNC = 4
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function sync!(m::Array{T}, flags::Integer=MS_SYNC) where T
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offset = rem(UInt(pointer(m)), PAGESIZE)
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ptr = pointer(m) - offset
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@static if is_unix()
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systemerror("msync",
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ccall(:msync, Cint, (Ptr{Void}, Csize_t, Cint), ptr, length(m) * sizeof(T), flags) != 0)
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else
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systemerror("could not FlushViewOfFile: $(Libc.FormatMessage())",
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ccall(:FlushViewOfFile, stdcall, Cint, (Ptr{Void}, Csize_t), ptr, length(m)) == 0)
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end
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end
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sync!(B::BitArray, flags::Integer=MS_SYNC) = sync!(B.chunks, flags)
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end # module
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