package chunker_test import ( "bytes" "io" "math/rand" "testing" "github.com/restic/restic/chunker" ) type chunk struct { Length int CutFP uint64 } // created for 32MB of random data out of math/rand's Uint32() seeded by // constant 23 // // chunking configuration: // window size 64, avg chunksize 1<<20, min chunksize 1<<19, max chunksize 1<<23 // polynom 0x3DA3358B4DC173 var chunks1 = []chunk{ chunk{2163460, 0x000b98d4cdf00000}, chunk{643703, 0x000d4e8364d00000}, chunk{1528956, 0x0015a25c2ef00000}, chunk{1955808, 0x00102a8242e00000}, chunk{2222372, 0x00045da878000000}, chunk{2538687, 0x00198a8179900000}, chunk{609606, 0x001d4e8d17100000}, chunk{1205738, 0x000a7204dd600000}, chunk{959742, 0x00183e71e1400000}, chunk{4036109, 0x001fec043c700000}, chunk{1525894, 0x000b1574b1500000}, chunk{1352720, 0x00018965f2e00000}, chunk{811884, 0x00155628aa100000}, chunk{1282314, 0x001909a0a1400000}, chunk{1318021, 0x001cceb980000000}, chunk{948640, 0x0011f7a470a00000}, chunk{645464, 0x00030ce2d9400000}, chunk{533758, 0x0004435c53c00000}, chunk{1128303, 0x0000c48517800000}, chunk{800374, 0x000968473f900000}, chunk{2453512, 0x001e197c92600000}, chunk{2651975, 0x000ae6c868000000}, chunk{237392, 0x0000000000000001}, } // test if nullbytes are correctly split, even if length is a multiple of MinSize. var chunks2 = []chunk{ chunk{chunker.MinSize, 0}, chunk{chunker.MinSize, 0}, chunk{chunker.MinSize, 0}, chunk{chunker.MinSize, 0}, } func test_with_data(t *testing.T, chnker *chunker.Chunker, chunks []chunk) { buf := make([]byte, chunker.MaxSize) for i, chunk := range chunks { c, err := chnker.Next(buf) if err != nil { t.Fatalf("Error returned with chunk %d: %v", i, err) } if c == nil { t.Fatalf("Nil chunk returned") } if c != nil { if c.Length != chunk.Length { t.Fatalf("Length for chunk %d does not match: expected %d, got %d", i, chunk.Length, c.Length) } if len(c.Data) != chunk.Length { t.Fatalf("Data length for chunk %d does not match: expected %d, got %d", i, chunk.Length, len(c.Data)) } if c.Cut != chunk.CutFP { t.Fatalf("Cut fingerprint for chunk %d/%d does not match: expected %016x, got %016x", i, len(chunks)-1, chunk.CutFP, c.Cut) } } } c, err := chnker.Next(buf) if c != nil { t.Fatal("additional non-nil chunk returned") } if err != io.EOF { t.Fatal("wrong error returned after last chunk") } } func get_random(seed, count int) []byte { buf := make([]byte, count) rnd := rand.New(rand.NewSource(23)) for i := 0; i < count; i += 4 { r := rnd.Uint32() buf[i] = byte(r) buf[i+1] = byte(r >> 8) buf[i+2] = byte(r >> 16) buf[i+3] = byte(r >> 24) } return buf } func TestChunker(t *testing.T) { // setup data source buf := get_random(23, 32*1024*1024) ch := chunker.New(bytes.NewReader(buf)) test_with_data(t, ch, chunks1) ch.Free() // setup nullbyte data source buf = bytes.Repeat([]byte{0}, len(chunks2)*chunker.MinSize) ch = chunker.New(bytes.NewReader(buf)) test_with_data(t, ch, chunks2) ch.Free() } func TestChunkerReuse(t *testing.T) { // test multiple uses of the same chunker for i := 0; i < 4; i++ { buf := get_random(23, 32*1024*1024) ch := chunker.New(bytes.NewReader(buf)) test_with_data(t, ch, chunks1) ch.Free() } } func BenchmarkChunker(b *testing.B) { size := 10 * 1024 * 1024 buf := get_random(23, size) dst := make([]byte, chunker.MaxSize) b.ResetTimer() b.SetBytes(int64(size)) var chunks int for i := 0; i < b.N; i++ { chunks = 0 ch := chunker.New(bytes.NewReader(buf)) for { _, err := ch.Next(dst) if err == io.EOF { break } if err != nil { b.Fatalf("Unexpected error occurred: %v", err) } chunks++ } } b.Logf("%d chunks, average chunk size: %d bytes", chunks, size/chunks) }