return false // Negative values are never okay
		case cur.Offset > math.MaxInt64-cur.Length:
			return false // Integer overflow with large length
		case cur.endOffset() > size:
			return false // Region extends beyond the actual size
		case pre.endOffset() > cur.Offset:
			return false // Regions cannot overlap and must be in order
		}
		pre = cur
	}
	return true
}

		b = b[:sr.logicalRemaining()]
	}

	b0 := b
	endPos := sr.pos + int64(len(b))
	for endPos > sr.pos && err == nil {
		var nf int // Bytes read in fragment
		holeStart, holeEnd := sr.sp[0].Offset, sr.sp[0].endOffset()
		if sr.pos < holeStart { // In a data fragment
			bf := b[:min(int64(len(b)), holeStart-sr.pos)]
			nf, err = tryReadFull(sr.fr, bf)
		} else { // In a hole fragment
			bf := b[:min(int64(len(b)), holeEnd-sr.pos)]

		b = b[:sw.logicalRemaining()]
	}

	b0 := b
	endPos := sw.pos + int64(len(b))
	for endPos > sw.pos && err == nil {
		var nf int // Bytes written in fragment
		dataStart, dataEnd := sw.sp[0].Offset, sw.sp[0].endOffset()
		if sw.pos < dataStart { // In a hole fragment
			bf := b[:min(int64(len(b)), dataStart-sw.pos)]
			nf, err = zeroWriter{}.Write(bf)
		} else { // In a data fragment
			bf := b[:min(int64(len(b)), dataEnd-sw.pos)]

	encOff = encCumulativeSum + startPkgNum*sseDAREEncPackageBlockSize
	// Locate the part containing the end of the required range
	endOffset := off + length - 1
	for i1, size := range sizes[partStart:] {
		i := partStart + i1
		if endOffset < cumulativeSum+size {
			partEnd = i
			break
		}
		cumulativeSum += size
		encPartSize, _ := sio.EncryptedSize(uint64(size))

	if err != nil {
		return InvalidRange{startOffset, length, fi.Size}
	}

	// Calculate endOffset according to length
	endOffset := startOffset
	if length > 0 {
		endOffset += length - 1
	}

	// Get last part index to read given length.
	lastPartIndex, _, err := fi.ObjectToPartOffset(ctx, endOffset)
	if err != nil {
		return InvalidRange{startOffset, length, fi.Size}
	}

	var totalBytesRead int64