photoprism/pkg/fastwalk/fastwalk_dirent_namlen_linux.go

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// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build linux && !appengine
// +build linux,!appengine
package fastwalk
import (
"bytes"
"syscall"
"unsafe"
)
func direntNamlen(dirent *syscall.Dirent) uint64 {
const fixedHdr = uint16(unsafe.Offsetof(syscall.Dirent{}.Name))
nameBuf := (*[unsafe.Sizeof(dirent.Name)]byte)(unsafe.Pointer(&dirent.Name[0]))
const nameBufLen = uint16(len(nameBuf))
limit := dirent.Reclen - fixedHdr
if limit > nameBufLen {
limit = nameBufLen
}
nameLen := bytes.IndexByte(nameBuf[:limit], 0)
if nameLen < 0 {
panic("failed to find terminating 0 byte in dirent")
}
return uint64(nameLen)
}