// reads file in 512KB chunks
func FileCRC64(fname string) (uint64, error) {
var checksum uint64
var bufSize = 1024 * 512
fp, err := os.Open(fname)
if err != nil {
return 0, err
//fmt.Printf("!Err-> can't read %s\n", fname)
//log.Panicf("!Err-> can't read %s %s\n", fname, err)
}
defer fp.Close()
bufr := make([]byte, bufSize)
checksum = 0
for {
n, err := io.ReadFull(fp, bufr)
if err != nil {
if n > 0 {
// fmt.Printf("not full block but read %d bytes\n",n)
}
}
if err == io.EOF {
if n != 0 {
return 0, err
} else {
break // normal end of file reached
}
}
// fmt.Printf(" read %d bytes\n",n)
checksum = crc64.Update(checksum, G_crcTable, bufr[0:n])
// checksum = crc64.Checksum(bufr[0:n],crcTable) if entire string in bufr
}
return checksum, nil
}
// TestContentEqual can be extremely slow (dozens of seconds) if
// GOMAXPROCS==1.
func TestContentEqual(t *testing.T) {
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(runtime.NumCPU()))
nConsumers := 10
done := make(chan uint64, nConsumers)
tab := crc64.MakeTable(crc64.ECMA)
sm := NewSourceMap()
defer sm.Close()
for i := 0; i < nConsumers; i++ {
go func() {
rdr := sm.NewReader("/dev/urandom", &Config{
SourceBuffer: 32,
FrameBytes: 65536,
CloseIdle: true,
Reopen: false,
})
defer rdr.Close()
var hash uint64
defer func() { done <- hash }()
var frame = make([]byte, 65536)
for f := 0; f < 130; f++ {
var err error
if _, err = rdr.Read(frame); err != nil && err != io.EOF {
t.Fatalf("rdr.Read(frame) at frame %d: %s", rdr.nextFrame, err)
}
hash = crc64.Update(hash, tab, frame)
}
}()
}
h0 := <-done
for i := 1; i < nConsumers; i++ {
hi := <-done
if h0 == 0 {
h0 = hi
} else if hi != h0 {
t.Errorf("hash mismatch: h0=%x, h%d=%x", h0, i, hi)
}
}
}