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c91ef1a09f
* Add general purpose `setFileSize` (unexported for now). Use to simplify `memfiles.open` as well as make robust (via hard allocation, not merely `ftruncate` address space allocation) on systems with `posix_fallocate`. As part of this, fix a bad `closeHandle` return check bug on Windows and add `MemFile.resize` for Windows now that setFileSize makes that easier. * Adapt existing test to exercise newly portable `MemFile.resize`. * Since Apple has never provided `posix_fallocate`, provide a fallback. This is presently written in terms of `ftruncate`, but it can be improved to use `F_PREALLOCATE` instead, as mentioned in a comment.
44 lines
985 B
Nim
44 lines
985 B
Nim
discard """
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disabled: "Windows"
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output: '''Full read size: 20
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Half read size: 10 Data: Hello'''
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"""
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import memfiles, os
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import std/syncio
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const
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fn = "test.mmap"
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var
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mm, mm_full, mm_half: MemFile
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p: pointer
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if fileExists(fn): removeFile(fn)
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# Create a new file, data all zeros, starting at size 10
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mm = memfiles.open(fn, mode = fmReadWrite, newFileSize = 10, allowRemap=true)
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mm.resize 20 # resize up to 20
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mm.close()
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# read, change
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mm_full = memfiles.open(fn, mode = fmWrite, mappedSize = -1, allowRemap = true)
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let size = mm_full.size
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p = mm_full.mapMem(fmReadWrite, 20, 0)
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echo "Full read size: ", size
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var p2 = cast[cstring](p)
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p2[0] = 'H'
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p2[1] = 'e'
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p2[2] = 'l'
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p2[3] = 'l'
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p2[4] = 'o'
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p2[5] = '\0'
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mm_full.unmapMem(p, 20)
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mm_full.close()
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# read half, and verify data change
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mm_half = memfiles.open(fn, mode = fmRead, mappedSize = 10)
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echo "Half read size: ", mm_half.size, " Data: ", cast[cstring](mm_half.mem)
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mm_half.close()
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if fileExists(fn): removeFile(fn)
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