mirror of
https://github.com/rclone/rclone
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35 lines
979 B
Go
35 lines
979 B
Go
// Package mmap implements a large block memory allocator using
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// anonymous memory maps.
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//go:build !plan9 && !windows && !js
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package mmap
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import (
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"fmt"
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"golang.org/x/sys/unix"
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)
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// Alloc allocates size bytes and returns a slice containing them. If
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// the allocation fails it will return with an error. This is best
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// used for allocations which are a multiple of the PageSize.
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func Alloc(size int) ([]byte, error) {
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mem, err := unix.Mmap(-1, 0, size, unix.PROT_READ|unix.PROT_WRITE, unix.MAP_PRIVATE|unix.MAP_ANON)
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if err != nil {
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return nil, fmt.Errorf("mmap: failed to allocate memory for buffer: %w", err)
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}
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return mem, nil
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}
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// Free frees buffers allocated by Alloc. Note it should be passed
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// the same slice (not a derived slice) that Alloc returned. If the
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// free fails it will return with an error.
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func Free(mem []byte) error {
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err := unix.Munmap(mem)
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if err != nil {
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return fmt.Errorf("mmap: failed to unmap memory: %w", err)
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}
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return nil
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}
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