forked from TrueCloudLab/restic
154 lines
3.4 KiB
Go
154 lines
3.4 KiB
Go
package chunker_test
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import (
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"bytes"
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"io"
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"math/rand"
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"testing"
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"github.com/fd0/khepri/chunker"
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)
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type chunk struct {
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Length int
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CutFP uint64
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}
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// created for 32MB of random data out of math/rand's Uint32() seeded by
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// constant 23
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//
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// chunking configuration:
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// window size 64, avg chunksize 1<<20, min chunksize 1<<19, max chunksize 1<<23
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// polynom 0x3DA3358B4DC173
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var chunks1 = []chunk{
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chunk{2163460, 0x000b98d4cdf00000},
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chunk{643703, 0x000d4e8364d00000},
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chunk{1528956, 0x0015a25c2ef00000},
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chunk{1955808, 0x00102a8242e00000},
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chunk{2222372, 0x00045da878000000},
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chunk{2538687, 0x00198a8179900000},
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chunk{609606, 0x001d4e8d17100000},
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chunk{1205738, 0x000a7204dd600000},
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chunk{959742, 0x00183e71e1400000},
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chunk{4036109, 0x001fec043c700000},
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chunk{1525894, 0x000b1574b1500000},
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chunk{1352720, 0x00018965f2e00000},
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chunk{811884, 0x00155628aa100000},
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chunk{1282314, 0x001909a0a1400000},
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chunk{1318021, 0x001cceb980000000},
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chunk{948640, 0x0011f7a470a00000},
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chunk{645464, 0x00030ce2d9400000},
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chunk{533758, 0x0004435c53c00000},
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chunk{1128303, 0x0000c48517800000},
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chunk{800374, 0x000968473f900000},
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chunk{2453512, 0x001e197c92600000},
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chunk{2651975, 0x000ae6c868000000},
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chunk{237392, 0x00184c5825e18636},
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}
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// test if nullbytes are correctly split, even if length is a multiple of MinSize.
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var chunks2 = []chunk{
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chunk{chunker.MinSize, 0},
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chunk{chunker.MinSize, 0},
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chunk{chunker.MinSize, 0},
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chunk{chunker.MinSize, 0},
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}
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func test_with_data(t *testing.T, chunker chunker.Chunker, chunks []chunk) {
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for i, chunk := range chunks {
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c, err := chunker.Next()
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if err != nil {
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t.Fatalf("Error returned with chunk %d: %v", i, err)
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}
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if c == nil {
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t.Fatalf("Nil chunk returned")
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}
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if c != nil {
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if c.Length != chunk.Length {
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t.Fatalf("Length for chunk %d does not match: expected %d, got %d",
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i, chunk.Length, c.Length)
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}
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if len(c.Data) != chunk.Length {
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t.Fatalf("Data length for chunk %d does not match: expected %d, got %d",
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i, chunk.Length, len(c.Data))
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}
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if c.Cut != chunk.CutFP {
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t.Fatalf("Cut fingerprint for chunk %d does not match: expected %016x, got %016x",
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i, chunk.CutFP, c.Cut)
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}
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}
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}
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c, err := chunker.Next()
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if c != nil {
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t.Fatal("additional non-nil chunk returned")
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}
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if err != io.EOF {
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t.Fatal("wrong error returned after last chunk")
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}
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}
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func get_random(seed, count int) []byte {
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buf := make([]byte, count)
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rnd := rand.New(rand.NewSource(23))
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for i := 0; i < count; i += 4 {
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r := rnd.Uint32()
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buf[i] = byte(r)
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buf[i+1] = byte(r >> 8)
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buf[i+2] = byte(r >> 16)
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buf[i+3] = byte(r >> 24)
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}
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return buf
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}
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func TestChunker(t *testing.T) {
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// setup data source
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buf := get_random(23, 32*1024*1024)
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ch := chunker.New(bytes.NewReader(buf))
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test_with_data(t, ch, chunks1)
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// setup nullbyte data source
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buf = bytes.Repeat([]byte{0}, len(chunks2)*chunker.MinSize)
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ch = chunker.New(bytes.NewReader(buf))
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test_with_data(t, ch, chunks2)
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}
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func BenchmarkChunker(b *testing.B) {
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size := 10 * 1024 * 1024
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buf := get_random(23, size)
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b.ResetTimer()
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b.SetBytes(int64(size))
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var chunks int
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for i := 0; i < b.N; i++ {
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chunks = 0
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ch := chunker.New(bytes.NewReader(buf))
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for {
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_, err := ch.Next()
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if err == io.EOF {
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break
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}
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if err != nil {
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b.Fatalf("Unexpected error occurred: %v", err)
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}
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chunks++
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}
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}
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b.Logf("%d chunks, average chunk size: %d bytes", chunks, size/chunks)
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}
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