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package mem_virtual
import "core:sys/posix"
_reserve :: proc "contextless" (size: uint) -> (data: []byte, err: Allocator_Error) {
PROT_MAX :: proc "contextless" (flags: posix.Prot_Flags) -> posix.Prot_Flags {
_PROT_MAX_SHIFT :: 16
return transmute(posix.Prot_Flags)(transmute(i32)flags << _PROT_MAX_SHIFT)
}
result := posix.mmap(nil, size, PROT_MAX({.READ, .WRITE, .EXEC}), {.ANONYMOUS, .PRIVATE})
if result == posix.MAP_FAILED {
assert_contextless(posix.errno() == .ENOMEM)
return nil, .Out_Of_Memory
}
return ([^]byte)(uintptr(result))[:size], nil
}
_decommit :: proc "contextless" (data: rawptr, size: uint) {
MADV_FREE :: 5
posix.mprotect(data, size, {})
posix.posix_madvise(data, size, transmute(posix.MAdvice)i32(MADV_FREE))
}
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