Check whether a file has alternative data stream in go

streamcheck.go

package checker

import (
	"golang.org/x/sys/windows"
	"syscall"
	"unsafe"
)

var kernel32 =  windows.NewLazyDLL("kernel32.dll")

var (
	findFirstStreamW = kernel32.NewProc("FindFirstStreamW")
	findNextStreamW  = kernel32.NewProc("FindNextStreamW")
)

/*
	HANDLE WINAPI FindFirstStreamW(
	__in        LPCWSTR lpFileName,
	__in        STREAM_INFO_LEVELS InfoLevel, (0 standard, 1 max infos)
	__out       LPVOID lpFindStreamData, (return information about file in a WIN32_FIND_STREAM_DATA if 0 is given in infos_level
	__reserved  DWORD dwFlags (Reserved for future use. This parameter must be zero.) cf: doc
	);
	https://msdn.microsoft.com/en-us/library/aa364424(v=vs.85).aspx
*/

func HasStream(f string) (bool, string) {
	buf := make([]uint16, 32)

	ret, _ , _ := findFirstStreamW.Call(
		uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(f))),
		0,
		uintptr(unsafe.Pointer(&buf[0])),
		0,
	)

	buf2 := make([]uint16, 32)

	ret2, _, _ := findNextStreamW.Call(
		uintptr(ret),
		uintptr(unsafe.Pointer(&buf2[0])),
	)

	streamName := syscall.UTF16ToString(buf2[4:])
	return ret2 != 0, streamName
}