# adler32

***

**1. Hashing a File**

```
import (
    "crypto/adler32"
    "fmt"
    "io"
)

func hashFile(file string) (uint32, error) {
    f, err := os.Open(file)
    if err != nil {
        return 0, err
    }
    defer f.Close()

    h := adler32.New()
    if _, err := io.Copy(h, f); err != nil {
        return 0, err
    }

    return h.Sum32(), nil
}
```

**2. Hashing a String**

```
import (
    "crypto/adler32"
    "fmt"
)

func hashString(str string) uint32 {
    h := adler32.New()
    h.Write([]byte(str))

    return h.Sum32()
}
```

**3. Hashing a Byte Slice**

```
import (
    "crypto/adler32"
    "fmt"
)

func hashBytes(data []byte) uint32 {
    h := adler32.New()
    h.Write(data)

    return h.Sum32()
}
```

**4. Hashing a Reader**

```
import (
    "crypto/adler32"
    "fmt"
    "io"
)

func hashReader(r io.Reader) (uint32, error) {
    h := adler32.New()
    if _, err := io.Copy(h, r); err != nil {
        return 0, err
    }

    return h.Sum32(), nil
}
```

**5. Hashing a Map**

```
import (
    "crypto/adler32"
    "fmt"
)

func hashMap(m map[string]string) uint32 {
    h := adler32.New()
    for k, v := range m {
        h.Write([]byte(k))
        h.Write([]byte(v))
    }

    return h.Sum32()
}
```

**6. Hashing a Struct**

```
import (
    "crypto/adler32"
    "fmt"
)

type Person struct {
    Name string
    Age int
}

func hashStruct(p Person) uint32 {
    h := adler32.New()
    h.Write([]byte(p.Name))
    h.Write([]byte(strconv.Itoa(p.Age)))

    return h.Sum32()
}
```

**7. Using Adler32 as a Key for a Cache**

```
import (
    "crypto/adler32"
    "fmt"
)

var cache = map[uint32][]byte

func getFromCache(key []byte) []byte {
    h := adler32.New()
    h.Write(key)

    return cache[h.Sum32()]
}

func setToCache(key, value []byte) {
    h := adler32.New()
    h.Write(key)

    cache[h.Sum32()] = value
}
```

**8. Using Adler32 for Data Integrity**

```
import (
    "crypto/adler32"
    "fmt"
)

func sendData(data []byte, checksum uint32) {
    // Send data to the receiver.
}

func receiveData(data []byte, checksum uint32) error {
    h := adler32.New()
    h.Write(data)

    if checksum != h.Sum32() {
        return fmt.Errorf("data integrity failed")
    }

    return nil
}
```

**9. Using Adler32 for Compression**

```
import (
    "compress/zlib"
    "crypto/adler32"
    "fmt"
)

func compressData(data []byte) ([]byte, error) {
    z, err := zlib.NewWriter(nil)
    if err != nil {
        return nil, err
    }

    h := adler32.New()
    h.Write(data)

    z.Write(h.Sum32())
    z.Write(data)
    z.Close()

    return z.Bytes(), nil
}

func decompressData(data []byte) ([]byte, error) {
    z, err := zlib.NewReader(bytes.NewReader(data))
    if err != nil {
        return nil, err
    }

    var checksum uint32
    if _, err := fmt.Fscan(z, &checksum); err != nil {
        return nil, err
    }

    h := adler32.New()
    if _, err := io.Copy(h, z); err != nil {
        return nil, err
    }

    if checksum != h.Sum32() {
        return nil, fmt.Errorf("data integrity failed")
    }

    return io.ReadAll(z)
}
```

**10. Using Adler32 for Encryption**

```
import (
    "crypto/aes"
    "crypto/adler32"
    "crypto/cipher"
    "fmt"
)

func encryptData(key, data []byte) ([]byte, error) {
    block, err := aes.NewCipher(key)
    if err != nil {
        return nil, err
    }

    h := adler32.New()
    h.Write(data)

    cipher

```