// Returns nil if no checksum.
func (c ChecksumType) Hasher() hash.Hash {
	switch {
	case c.Is(ChecksumCRC32):
		return crc32.NewIEEE()
	case c.Is(ChecksumCRC32C):
		return crc32.New(crc32.MakeTable(crc32.Castagnoli))
	case c.Is(ChecksumSHA1):
		return sha1.New()
	case c.Is(ChecksumSHA256):
		return sha256.New()
	case c.Is(ChecksumCRC64NVME):
		return crc64.New(crc64Table)

func TestChecksumAddToHeader(t *testing.T) {
	tests := []struct {
		name     string
		checksum ChecksumType
		fullobj  bool
		wantErr  bool
	}{
		{"CRC32-composite", ChecksumCRC32, false, false},
		{"CRC32-full-object", ChecksumCRC32, true, false},
		{"CRC32C-composite", ChecksumCRC32C, false, false},
		{"CRC32C-full-object", ChecksumCRC32C, true, false},

			fv:      defaultFormVals.Clone().Set(http.CanonicalHeaderKey(xhttp.AmzChecksumCRC32), "crc32-val"),
			wantErr: `Each form field that you specify in a form must appear in the list of policy conditions. "X-Amz-Checksum-Crc32" not specified in the policy.`,
		},
		{
			name:    "unknown key XAmzChecksumCRC32C is error as it does not appear in policy",

func hashOrder(key string, cardinality int) []int {
	if cardinality <= 0 {
		// Returns an empty int slice for cardinality < 0.
		return nil
	}

	nums := make([]int, cardinality)
	keyCrc := crc32.Checksum([]byte(key), crc32.IEEETable)

	start := int(keyCrc % uint32(cardinality))
	for i := 1; i <= cardinality; i++ {
		nums[i-1] = 1 + ((start + i) % cardinality)
	}
	return nums
}

			wantHeaders:        map[string]string{"x-amz-checksum-crc32": checksumData(bytesData, crc32.New(crc32.IEEETable))},
		},
		// Correct crc32c
		10: {
			bucketName:         bucketName,
			objectName:         objectName,
			headers:            map[string]string{"x-amz-checksum-crc32c": checksumData(bytesData, crc32.New(crc32.MakeTable(crc32.Castagnoli)))},
			data:               bytesData,

	defer timeout(60 * time.Second)()
	const debug = false

	var readBytes int
	var wroteBytes int
	var readBuf bytes.Buffer
	var wroteBuf bytes.Buffer
	readHash := crc32.NewIEEE()
	wroteHash := crc32.NewIEEE()
	read := io.Writer(readHash)
	wrote := io.Writer(wroteHash)
	if debug {
		read = io.MultiWriter(read, &readBuf)
		wrote = io.MultiWriter(wrote, &wroteBuf)
	}

		// Corrupt one of the CRC32s in the data descriptor:
		b[0x2d]++
	})
}

func returnCorruptNotStreamedZip() (r io.ReaderAt, size int64) {
	return messWith("crc32-not-streamed.zip", func(b []byte) {
		// Corrupt foo.txt's final crc32 byte, in both
		// the file header and TOC. (0x7e -> 0x7f)
		b[0x11]++
		b[0x9d]++

		// TODO(bradfitz): add a new test that only corrupts

	sum64 := siphash.Hash(k0, k1, []byte(key))
	return int(sum64 % uint64(cardinality))
}

func crcHashMod(key string, cardinality int) int {
	if cardinality <= 0 {
		return -1
	}
	keyCrc := crc32.Checksum([]byte(key), crc32.IEEETable)
	return int(keyCrc % uint32(cardinality))
}

func hashKey(algo string, key string, cardinality int, id [16]byte) int {
	switch algo {
	case formatErasureVersionV2DistributionAlgoV1:

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package tar

import (
	"bytes"
	"compress/bzip2"
	"errors"
	"fmt"
	"hash/crc32"
	"internal/obscuretestdata"
	"io"
	"maps"
	"math"
	"os"
	"path"
	"reflect"
	"slices"
	"strconv"
	"strings"
	"testing"
	"time"
)

func TestReader(t *testing.T) {

		ETag:              partInfo.ETag,
		LastModified:      partInfo.ModTime,
		Size:              partInfo.Size,
		ActualSize:        partInfo.ActualSize,
		ChecksumCRC32:     partInfo.Checksums["CRC32"],
		ChecksumCRC32C:    partInfo.Checksums["CRC32C"],
		ChecksumSHA1:      partInfo.Checksums["SHA1"],
		ChecksumSHA256:    partInfo.Checksums["SHA256"],
		ChecksumCRC64NVME: partInfo.Checksums["CRC64NVME"],
	}, nil