//       purge:
//           # retainVersions: 0 # (default) delete all versions of the object. This option is the fastest.
//           # retainVersions: 5 # keep the latest 5 versions of the object.
//
//     - type: deleted # objects with delete marker as their latest version
//       name: NAME # match object names that satisfy the wildcard expression.

import (
	"bytes"
	"encoding/binary"
	"fmt"
	"hash/crc32"
	"net/http"
	"strconv"
	"sync/atomic"
	"time"
)

// A message is in the format specified in
// https://docs.aws.amazon.com/AmazonS3/latest/API/images/s3select-frame-diagram-frame-overview.png
// hence the calculation is made accordingly.
func totalByteLength(headerLength, payloadLength int) int {
	return 4 + 4 + 4 + headerLength + payloadLength + 4
}

	IsDir bool

	// Hex encoded unique entity tag of the object.
	ETag string

	// Version ID of this object.
	VersionID string

	// IsLatest indicates if this is the latest current version
	// latest can be true for delete marker or a version.
	IsLatest bool

	// DeleteMarker indicates if the versionId corresponds
	// to a delete marker on an object.
	DeleteMarker bool

	// Transitioned object information

			if !modTime.Equal(test.expectedTime) {
				t.Fatalf("Expected modTime to be equal to %v but was found to be %v",
					test.expectedTime, modTime)
			}
			availableDisks, newErrs, _ := disksWithAllParts(ctx, onlineDisks, partsMetadata,
				test.errs, fi, bucket, object, madmin.HealDeepScan)
			test.errs = newErrs

			if test._tamperBackend != noTamper {

					return ObjectLocked{}
				}

				if !ret.RetainUntilDate.Before(t) {
					return ObjectLocked{}
				}
				return nil
			}
			// https://docs.aws.amazon.com/AmazonS3/latest/dev/object-lock-overview.html#object-lock-retention-modes
			// If you try to delete objects protected by governance mode and have s3:BypassGovernanceRetention, the operation will succeed.

	"versions",
	"website",
}

// Signature and API related constants.
const (
	signV2Algorithm = "AWS"
)

// AWS S3 Signature V2 calculation rule is give here:
// http://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAuthentication.html#RESTAuthenticationStringToSign
func doesPolicySignatureV2Match(formValues http.Header) (auth.Credentials, APIErrorCode) {
	accessKey := formValues.Get(xhttp.AmzAccessKeyID)

func (r *Reader) SetExpectedMax(expectedMax int64) {
	r.expectedMax = expectedMax
}

// AddChecksum will add checksum checks as specified in
// https://docs.aws.amazon.com/AmazonS3/latest/userguide/checking-object-integrity.html
// Returns ErrInvalidChecksum if a problem with the checksum is found.
func (r *Reader) AddChecksum(req *http.Request, ignoreValue bool) error {
	cs, err := GetContentChecksum(req.Header)

	ext := strings.TrimPrefix(e.name, dir)
	if len(ext) != len(e.name) {
		idx := strings.Index(ext, separator)
		// If separator is not found or is last entry, ok.
		return idx == -1 || idx == len(ext)-len(separator)
	}
	return false
}

// isLatestDeletemarker returns whether the latest version is a delete marker.
// If metadata is NOT versioned false will always be returned.
// If v2 and UNABLE to load metadata true will be returned.

//msgp:tuple FileInfoVersions
type FileInfoVersions struct {
	// Name of the volume.
	Volume string `msg:"v,omitempty"`

	// Name of the file.
	Name string `msg:"n,omitempty"`

	// Represents the latest mod time of the
	// latest version.
	LatestModTime time.Time `msg:"lm"`

	Versions     []FileInfo `msg:"vs"`
	FreeVersions []FileInfo `msg:"fvs"`
}

// findVersionIndex will return the version index where the version

		if err != nil {
			return nil, nil, fmt.Errorf("Drive %s: %w", export, err)
		}
		// Migrate successful v2 => v3, v3 is latest
		// version = formatXLVersionV3
		return migrate(formatPath, formatData)
	case formatErasureVersionV3:
		// v3 is the latest version, return.
		return formatData, formatFi, nil
	}
	return nil, nil, fmt.Errorf(`Disk %s: unknown format version %s`, export, version)
}