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package glacier_test
import (
"bytes"
"crypto/sha256"
"fmt"
"io"
"github.com/aws/aws-sdk-go/service/glacier"
)
func ExampleComputeHashes() {
r := testCreateReader()
h := glacier.ComputeHashes(r)
n, _ := r.Seek(0, 1) // Check position after checksumming
fmt.Printf("linear: %x\n", h.LinearHash)
fmt.Printf("tree: %x\n", h.TreeHash)
fmt.Printf("pos: %d\n", n)
// Output:
// linear: 68aff0c5a91aa0491752bfb96e3fef33eb74953804f6a2f7b708d5bcefa8ff6b
// tree: 154e26c78fd74d0c2c9b3cc4644191619dc4f2cd539ae2a74d5fd07957a3ee6a
// pos: 0
}
func testCreateReader() io.ReadSeeker {
buf := make([]byte, 5767168) // 5.5MB buffer
for i := range buf {
buf[i] = '0' // Fill with zero characters
}
return bytes.NewReader(buf)
}
func ExampleComputeTreeHash() {
r := testCreateReader()
const chunkSize = 1024 * 1024 // 1MB
buf := make([]byte, chunkSize)
hashes := [][]byte{}
for {
// Reach 1MB chunks from reader to generate hashes from
n, err := io.ReadAtLeast(r, buf, chunkSize)
if n == 0 {
break
}
tmpHash := sha256.Sum256(buf[:n])
hashes = append(hashes, tmpHash[:])
if err != nil {
break // last chunk
}
}
treeHash := glacier.ComputeTreeHash(hashes)
fmt.Printf("TreeHash: %x\n", treeHash)
// Output:
// TreeHash: 154e26c78fd74d0c2c9b3cc4644191619dc4f2cd539ae2a74d5fd07957a3ee6a
}
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