Update to last common bleve (#3986)

vendor/github.com/RoaringBitmap/roaring/roaringarray.go

@@ -0,0 +1,893 @@
+package roaring
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"io/ioutil"
+
+	snappy "github.com/glycerine/go-unsnap-stream"
+	"github.com/tinylib/msgp/msgp"
+)
+
+//go:generate msgp -unexported
+
+type container interface {
+	clone() container
+	and(container) container
+	andCardinality(container) int
+	iand(container) container // i stands for inplace
+	andNot(container) container
+	iandNot(container) container // i stands for inplace
+	getCardinality() int
+	// rank returns the number of integers that are
+	// smaller or equal to x. rank(infinity) would be getCardinality().
+	rank(uint16) int
+
+	iadd(x uint16) bool                   // inplace, returns true if x was new.
+	iaddReturnMinimized(uint16) container // may change return type to minimize storage.
+
+	//addRange(start, final int) container  // range is [firstOfRange,lastOfRange) (unused)
+	iaddRange(start, endx int) container // i stands for inplace, range is [firstOfRange,endx)
+
+	iremove(x uint16) bool                   // inplace, returns true if x was present.
+	iremoveReturnMinimized(uint16) container // may change return type to minimize storage.
+
+	not(start, final int) container        // range is [firstOfRange,lastOfRange)
+	inot(firstOfRange, endx int) container // i stands for inplace, range is [firstOfRange,endx)
+	xor(r container) container
+	getShortIterator() shortIterable
+	getManyIterator() manyIterable
+	contains(i uint16) bool
+	maximum() uint16
+	minimum() uint16
+
+	// equals is now logical equals; it does not require the
+	// same underlying container types, but compares across
+	// any of the implementations.
+	equals(r container) bool
+
+	fillLeastSignificant16bits(array []uint32, i int, mask uint32)
+	or(r container) container
+	orCardinality(r container) int
+	isFull() bool
+	ior(r container) container   // i stands for inplace
+	intersects(r container) bool // whether the two containers intersect
+	lazyOR(r container) container
+	lazyIOR(r container) container
+	getSizeInBytes() int
+	//removeRange(start, final int) container  // range is [firstOfRange,lastOfRange) (unused)
+	iremoveRange(start, final int) container // i stands for inplace, range is [firstOfRange,lastOfRange)
+	selectInt(x uint16) int                  // selectInt returns the xth integer in the container
+	serializedSizeInBytes() int
+	readFrom(io.Reader) (int, error)
+	writeTo(io.Writer) (int, error)
+
+	numberOfRuns() int
+	toEfficientContainer() container
+	String() string
+	containerType() contype
+}
+
+type contype uint8
+
+const (
+	bitmapContype contype = iota
+	arrayContype
+	run16Contype
+	run32Contype
+)
+
+// careful: range is [firstOfRange,lastOfRange]
+func rangeOfOnes(start, last int) container {
+	if start > MaxUint16 {
+		panic("rangeOfOnes called with start > MaxUint16")
+	}
+	if last > MaxUint16 {
+		panic("rangeOfOnes called with last > MaxUint16")
+	}
+	if start < 0 {
+		panic("rangeOfOnes called with start < 0")
+	}
+	if last < 0 {
+		panic("rangeOfOnes called with last < 0")
+	}
+	return newRunContainer16Range(uint16(start), uint16(last))
+}
+
+type roaringArray struct {
+	keys            []uint16
+	containers      []container `msg:"-"` // don't try to serialize directly.
+	needCopyOnWrite []bool
+	copyOnWrite     bool
+
+	// conserz is used at serialization time
+	// to serialize containers. Otherwise empty.
+	conserz []containerSerz
+}
+
+// containerSerz facilitates serializing container (tricky to
+// serialize because it is an interface) by providing a
+// light wrapper with a type identifier.
+type containerSerz struct {
+	t contype  `msg:"t"` // type
+	r msgp.Raw `msg:"r"` // Raw msgpack of the actual container type
+}
+
+func newRoaringArray() *roaringArray {
+	return &roaringArray{}
+}
+
+// runOptimize compresses the element containers to minimize space consumed.
+// Q: how does this interact with copyOnWrite and needCopyOnWrite?
+// A: since we aren't changing the logical content, just the representation,
+//    we don't bother to check the needCopyOnWrite bits. We replace
+//    (possibly all) elements of ra.containers in-place with space
+//    optimized versions.
+func (ra *roaringArray) runOptimize() {
+	for i := range ra.containers {
+		ra.containers[i] = ra.containers[i].toEfficientContainer()
+	}
+}
+
+func (ra *roaringArray) appendContainer(key uint16, value container, mustCopyOnWrite bool) {
+	ra.keys = append(ra.keys, key)
+	ra.containers = append(ra.containers, value)
+	ra.needCopyOnWrite = append(ra.needCopyOnWrite, mustCopyOnWrite)
+}
+
+func (ra *roaringArray) appendWithoutCopy(sa roaringArray, startingindex int) {
+	mustCopyOnWrite := sa.needCopyOnWrite[startingindex]
+	ra.appendContainer(sa.keys[startingindex], sa.containers[startingindex], mustCopyOnWrite)
+}
+
+func (ra *roaringArray) appendCopy(sa roaringArray, startingindex int) {
+	// cow only if the two request it, or if we already have a lightweight copy
+	copyonwrite := (ra.copyOnWrite && sa.copyOnWrite) || sa.needsCopyOnWrite(startingindex)
+	if !copyonwrite {
+		// since there is no copy-on-write, we need to clone the container (this is important)
+		ra.appendContainer(sa.keys[startingindex], sa.containers[startingindex].clone(), copyonwrite)
+	} else {
+		ra.appendContainer(sa.keys[startingindex], sa.containers[startingindex], copyonwrite)
+		if !sa.needsCopyOnWrite(startingindex) {
+			sa.setNeedsCopyOnWrite(startingindex)
+		}
+	}
+}
+
+func (ra *roaringArray) appendWithoutCopyMany(sa roaringArray, startingindex, end int) {
+	for i := startingindex; i < end; i++ {
+		ra.appendWithoutCopy(sa, i)
+	}
+}
+
+func (ra *roaringArray) appendCopyMany(sa roaringArray, startingindex, end int) {
+	for i := startingindex; i < end; i++ {
+		ra.appendCopy(sa, i)
+	}
+}
+
+func (ra *roaringArray) appendCopiesUntil(sa roaringArray, stoppingKey uint16) {
+	// cow only if the two request it, or if we already have a lightweight copy
+	copyonwrite := ra.copyOnWrite && sa.copyOnWrite
+
+	for i := 0; i < sa.size(); i++ {
+		if sa.keys[i] >= stoppingKey {
+			break
+		}
+		thiscopyonewrite := copyonwrite || sa.needsCopyOnWrite(i)
+		if thiscopyonewrite {
+			ra.appendContainer(sa.keys[i], sa.containers[i], thiscopyonewrite)
+			if !sa.needsCopyOnWrite(i) {
+				sa.setNeedsCopyOnWrite(i)
+			}
+
+		} else {
+			// since there is no copy-on-write, we need to clone the container (this is important)
+			ra.appendContainer(sa.keys[i], sa.containers[i].clone(), thiscopyonewrite)
+
+		}
+	}
+}
+
+func (ra *roaringArray) appendCopiesAfter(sa roaringArray, beforeStart uint16) {
+	// cow only if the two request it, or if we already have a lightweight copy
+	copyonwrite := ra.copyOnWrite && sa.copyOnWrite
+
+	startLocation := sa.getIndex(beforeStart)
+	if startLocation >= 0 {
+		startLocation++
+	} else {
+		startLocation = -startLocation - 1
+	}
+
+	for i := startLocation; i < sa.size(); i++ {
+		thiscopyonewrite := copyonwrite || sa.needsCopyOnWrite(i)
+		if thiscopyonewrite {
+			ra.appendContainer(sa.keys[i], sa.containers[i], thiscopyonewrite)
+			if !sa.needsCopyOnWrite(i) {
+				sa.setNeedsCopyOnWrite(i)
+			}
+		} else {
+			// since there is no copy-on-write, we need to clone the container (this is important)
+			ra.appendContainer(sa.keys[i], sa.containers[i].clone(), thiscopyonewrite)
+
+		}
+	}
+}
+
+func (ra *roaringArray) removeIndexRange(begin, end int) {
+	if end <= begin {
+		return
+	}
+
+	r := end - begin
+
+	copy(ra.keys[begin:], ra.keys[end:])
+	copy(ra.containers[begin:], ra.containers[end:])
+	copy(ra.needCopyOnWrite[begin:], ra.needCopyOnWrite[end:])
+
+	ra.resize(len(ra.keys) - r)
+}
+
+func (ra *roaringArray) resize(newsize int) {
+	for k := newsize; k < len(ra.containers); k++ {
+		ra.containers[k] = nil
+	}
+
+	ra.keys = ra.keys[:newsize]
+	ra.containers = ra.containers[:newsize]
+	ra.needCopyOnWrite = ra.needCopyOnWrite[:newsize]
+}
+
+func (ra *roaringArray) clear() {
+	ra.resize(0)
+	ra.copyOnWrite = false
+	ra.conserz = nil
+}
+
+func (ra *roaringArray) clone() *roaringArray {
+
+	sa := roaringArray{}
+	sa.copyOnWrite = ra.copyOnWrite
+
+	// this is where copyOnWrite is used.
+	if ra.copyOnWrite {
+		sa.keys = make([]uint16, len(ra.keys))
+		copy(sa.keys, ra.keys)
+		sa.containers = make([]container, len(ra.containers))
+		copy(sa.containers, ra.containers)
+		sa.needCopyOnWrite = make([]bool, len(ra.needCopyOnWrite))
+
+		ra.markAllAsNeedingCopyOnWrite()
+		sa.markAllAsNeedingCopyOnWrite()
+
+		// sa.needCopyOnWrite is shared
+	} else {
+		// make a full copy
+
+		sa.keys = make([]uint16, len(ra.keys))
+		copy(sa.keys, ra.keys)
+
+		sa.containers = make([]container, len(ra.containers))
+		for i := range sa.containers {
+			sa.containers[i] = ra.containers[i].clone()
+		}
+
+		sa.needCopyOnWrite = make([]bool, len(ra.needCopyOnWrite))
+	}
+	return &sa
+}
+
+// unused function:
+//func (ra *roaringArray) containsKey(x uint16) bool {
+//	return (ra.binarySearch(0, int64(len(ra.keys)), x) >= 0)
+//}
+
+func (ra *roaringArray) getContainer(x uint16) container {
+	i := ra.binarySearch(0, int64(len(ra.keys)), x)
+	if i < 0 {
+		return nil
+	}
+	return ra.containers[i]
+}
+
+func (ra *roaringArray) getContainerAtIndex(i int) container {
+	return ra.containers[i]
+}
+
+func (ra *roaringArray) getFastContainerAtIndex(i int, needsWriteable bool) container {
+	c := ra.getContainerAtIndex(i)
+	switch t := c.(type) {
+	case *arrayContainer:
+		c = t.toBitmapContainer()
+	case *runContainer16:
+		if !t.isFull() {
+			c = t.toBitmapContainer()
+		}
+	case *bitmapContainer:
+		if needsWriteable && ra.needCopyOnWrite[i] {
+			c = ra.containers[i].clone()
+		}
+	}
+	return c
+}
+
+func (ra *roaringArray) getWritableContainerAtIndex(i int) container {
+	if ra.needCopyOnWrite[i] {
+		ra.containers[i] = ra.containers[i].clone()
+		ra.needCopyOnWrite[i] = false
+	}
+	return ra.containers[i]
+}
+
+func (ra *roaringArray) getIndex(x uint16) int {
+	// before the binary search, we optimize for frequent cases
+	size := len(ra.keys)
+	if (size == 0) || (ra.keys[size-1] == x) {
+		return size - 1
+	}
+	return ra.binarySearch(0, int64(size), x)
+}
+
+func (ra *roaringArray) getKeyAtIndex(i int) uint16 {
+	return ra.keys[i]
+}
+
+func (ra *roaringArray) insertNewKeyValueAt(i int, key uint16, value container) {
+	ra.keys = append(ra.keys, 0)
+	ra.containers = append(ra.containers, nil)
+
+	copy(ra.keys[i+1:], ra.keys[i:])
+	copy(ra.containers[i+1:], ra.containers[i:])
+
+	ra.keys[i] = key
+	ra.containers[i] = value
+
+	ra.needCopyOnWrite = append(ra.needCopyOnWrite, false)
+	copy(ra.needCopyOnWrite[i+1:], ra.needCopyOnWrite[i:])
+	ra.needCopyOnWrite[i] = false
+}
+
+func (ra *roaringArray) remove(key uint16) bool {
+	i := ra.binarySearch(0, int64(len(ra.keys)), key)
+	if i >= 0 { // if a new key
+		ra.removeAtIndex(i)
+		return true
+	}
+	return false
+}
+
+func (ra *roaringArray) removeAtIndex(i int) {
+	copy(ra.keys[i:], ra.keys[i+1:])
+	copy(ra.containers[i:], ra.containers[i+1:])
+
+	copy(ra.needCopyOnWrite[i:], ra.needCopyOnWrite[i+1:])
+
+	ra.resize(len(ra.keys) - 1)
+}
+
+func (ra *roaringArray) setContainerAtIndex(i int, c container) {
+	ra.containers[i] = c
+}
+
+func (ra *roaringArray) replaceKeyAndContainerAtIndex(i int, key uint16, c container, mustCopyOnWrite bool) {
+	ra.keys[i] = key
+	ra.containers[i] = c
+	ra.needCopyOnWrite[i] = mustCopyOnWrite
+}
+
+func (ra *roaringArray) size() int {
+	return len(ra.keys)
+}
+
+func (ra *roaringArray) binarySearch(begin, end int64, ikey uint16) int {
+	low := begin
+	high := end - 1
+	for low+16 <= high {
+		middleIndex := low + (high-low)/2 // avoid overflow
+		middleValue := ra.keys[middleIndex]
+
+		if middleValue < ikey {
+			low = middleIndex + 1
+		} else if middleValue > ikey {
+			high = middleIndex - 1
+		} else {
+			return int(middleIndex)
+		}
+	}
+	for ; low <= high; low++ {
+		val := ra.keys[low]
+		if val >= ikey {
+			if val == ikey {
+				return int(low)
+			}
+			break
+		}
+	}
+	return -int(low + 1)
+}
+
+func (ra *roaringArray) equals(o interface{}) bool {
+	srb, ok := o.(roaringArray)
+	if ok {
+
+		if srb.size() != ra.size() {
+			return false
+		}
+		for i, k := range ra.keys {
+			if k != srb.keys[i] {
+				return false
+			}
+		}
+
+		for i, c := range ra.containers {
+			if !c.equals(srb.containers[i]) {
+				return false
+			}
+		}
+		return true
+	}
+	return false
+}
+
+func (ra *roaringArray) headerSize() uint64 {
+	size := uint64(len(ra.keys))
+	if ra.hasRunCompression() {
+		if size < noOffsetThreshold { // for small bitmaps, we omit the offsets
+			return 4 + (size+7)/8 + 4*size
+		}
+		return 4 + (size+7)/8 + 8*size // - 4 because we pack the size with the cookie
+	}
+	return 4 + 4 + 8*size
+
+}
+
+// should be dirt cheap
+func (ra *roaringArray) serializedSizeInBytes() uint64 {
+	answer := ra.headerSize()
+	for _, c := range ra.containers {
+		answer += uint64(c.serializedSizeInBytes())
+	}
+	return answer
+}
+
+//
+// spec: https://github.com/RoaringBitmap/RoaringFormatSpec
+//
+func (ra *roaringArray) toBytes() ([]byte, error) {
+	stream := &bytes.Buffer{}
+	hasRun := ra.hasRunCompression()
+	isRunSizeInBytes := 0
+	cookieSize := 8
+	if hasRun {
+		cookieSize = 4
+		isRunSizeInBytes = (len(ra.keys) + 7) / 8
+	}
+	descriptiveHeaderSize := 4 * len(ra.keys)
+	preambleSize := cookieSize + isRunSizeInBytes + descriptiveHeaderSize
+
+	buf := make([]byte, preambleSize+4*len(ra.keys))
+
+	nw := 0
+
+	if hasRun {
+		binary.LittleEndian.PutUint16(buf[0:], uint16(serialCookie))
+		nw += 2
+		binary.LittleEndian.PutUint16(buf[2:], uint16(len(ra.keys)-1))
+		nw += 2
+
+		// compute isRun bitmap
+		var ir []byte
+
+		isRun := newBitmapContainer()
+		for i, c := range ra.containers {
+			switch c.(type) {
+			case *runContainer16:
+				isRun.iadd(uint16(i))
+			}
+		}
+		// convert to little endian
+		ir = isRun.asLittleEndianByteSlice()[:isRunSizeInBytes]
+		nw += copy(buf[nw:], ir)
+	} else {
+		binary.LittleEndian.PutUint32(buf[0:], uint32(serialCookieNoRunContainer))
+		nw += 4
+		binary.LittleEndian.PutUint32(buf[4:], uint32(len(ra.keys)))
+		nw += 4
+	}
+
+	// descriptive header
+	for i, key := range ra.keys {
+		binary.LittleEndian.PutUint16(buf[nw:], key)
+		nw += 2
+		c := ra.containers[i]
+		binary.LittleEndian.PutUint16(buf[nw:], uint16(c.getCardinality()-1))
+		nw += 2
+	}
+
+	startOffset := int64(preambleSize + 4*len(ra.keys))
+	if !hasRun || (len(ra.keys) >= noOffsetThreshold) {
+		// offset header
+		for _, c := range ra.containers {
+			binary.LittleEndian.PutUint32(buf[nw:], uint32(startOffset))
+			nw += 4
+			switch rc := c.(type) {
+			case *runContainer16:
+				startOffset += 2 + int64(len(rc.iv))*4
+			default:
+				startOffset += int64(getSizeInBytesFromCardinality(c.getCardinality()))
+			}
+		}
+	}
+
+	_, err := stream.Write(buf[:nw])
+	if err != nil {
+		return nil, err
+	}
+	for i, c := range ra.containers {
+		_ = i
+		_, err := c.writeTo(stream)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return stream.Bytes(), nil
+}
+
+//
+// spec: https://github.com/RoaringBitmap/RoaringFormatSpec
+//
+func (ra *roaringArray) writeTo(out io.Writer) (int64, error) {
+	by, err := ra.toBytes()
+	if err != nil {
+		return 0, err
+	}
+	n, err := out.Write(by)
+	if err == nil && n < len(by) {
+		err = io.ErrShortWrite
+	}
+	return int64(n), err
+}
+
+func (ra *roaringArray) fromBuffer(buf []byte) (int64, error) {
+	pos := 0
+	if len(buf) < 8 {
+		return 0, fmt.Errorf("buffer too small, expecting at least 8 bytes, was %d", len(buf))
+	}
+
+	cookie := binary.LittleEndian.Uint32(buf)
+	pos += 4
+	var size uint32 // number of containers
+	haveRunContainers := false
+	var isRunBitmap []byte
+
+	// cookie header
+	if cookie&0x0000FFFF == serialCookie {
+		haveRunContainers = true
+		size = uint32(uint16(cookie>>16) + 1) // number of containers
+
+		// create is-run-container bitmap
+		isRunBitmapSize := (int(size) + 7) / 8
+		if pos+isRunBitmapSize > len(buf) {
+			return 0, fmt.Errorf("malformed bitmap, is-run bitmap overruns buffer at %d", pos+isRunBitmapSize)
+		}
+
+		isRunBitmap = buf[pos : pos+isRunBitmapSize]
+		pos += isRunBitmapSize
+	} else if cookie == serialCookieNoRunContainer {
+		size = binary.LittleEndian.Uint32(buf[pos:])
+		pos += 4
+	} else {
+		return 0, fmt.Errorf("error in roaringArray.readFrom: did not find expected serialCookie in header")
+	}
+	if size > (1 << 16) {
+		return 0, fmt.Errorf("It is logically impossible to have more than (1<<16) containers.")
+	}
+	// descriptive header
+	// keycard - is {key, cardinality} tuple slice
+	if pos+2*2*int(size) > len(buf) {
+		return 0, fmt.Errorf("malfomred bitmap, key-cardinality slice overruns buffer at %d", pos+2*2*int(size))
+	}
+	keycard := byteSliceAsUint16Slice(buf[pos : pos+2*2*int(size)])
+	pos += 2 * 2 * int(size)
+
+	if !haveRunContainers || size >= noOffsetThreshold {
+		pos += 4 * int(size)
+	}
+
+	// Allocate slices upfront as number of containers is known
+	if cap(ra.containers) >= int(size) {
+		ra.containers = ra.containers[:size]
+	} else {
+		ra.containers = make([]container, size)
+	}
+	if cap(ra.keys) >= int(size) {
+		ra.keys = ra.keys[:size]
+	} else {
+		ra.keys = make([]uint16, size)
+	}
+	if cap(ra.needCopyOnWrite) >= int(size) {
+		ra.needCopyOnWrite = ra.needCopyOnWrite[:size]
+	} else {
+		ra.needCopyOnWrite = make([]bool, size)
+	}
+
+	for i := uint32(0); i < size; i++ {
+		key := uint16(keycard[2*i])
+		card := int(keycard[2*i+1]) + 1
+		ra.keys[i] = key
+		ra.needCopyOnWrite[i] = true
+
+		if haveRunContainers && isRunBitmap[i/8]&(1<<(i%8)) != 0 {
+			// run container
+			nr := binary.LittleEndian.Uint16(buf[pos:])
+			pos += 2
+			if pos+int(nr)*4 > len(buf) {
+				return 0, fmt.Errorf("malformed bitmap, a run container overruns buffer at %d:%d", pos, pos+int(nr)*4)
+			}
+			nb := runContainer16{
+				iv:   byteSliceAsInterval16Slice(buf[pos : pos+int(nr)*4]),
+				card: int64(card),
+			}
+			pos += int(nr) * 4
+			ra.containers[i] = &nb
+		} else if card > arrayDefaultMaxSize {
+			// bitmap container
+			nb := bitmapContainer{
+				cardinality: card,
+				bitmap:      byteSliceAsUint64Slice(buf[pos : pos+arrayDefaultMaxSize*2]),
+			}
+			pos += arrayDefaultMaxSize * 2
+			ra.containers[i] = &nb
+		} else {
+			// array container
+			nb := arrayContainer{
+				byteSliceAsUint16Slice(buf[pos : pos+card*2]),
+			}
+			pos += card * 2
+			ra.containers[i] = &nb
+		}
+	}
+
+	return int64(pos), nil
+}
+
+func (ra *roaringArray) readFrom(stream io.Reader) (int64, error) {
+	pos := 0
+	var cookie uint32
+	err := binary.Read(stream, binary.LittleEndian, &cookie)
+	if err != nil {
+		return 0, fmt.Errorf("error in roaringArray.readFrom: could not read initial cookie: %s", err)
+	}
+	pos += 4
+	var size uint32
+	haveRunContainers := false
+	var isRun *bitmapContainer
+	if cookie&0x0000FFFF == serialCookie {
+		haveRunContainers = true
+		size = uint32(uint16(cookie>>16) + 1)
+		bytesToRead := (int(size) + 7) / 8
+		numwords := (bytesToRead + 7) / 8
+		by := make([]byte, bytesToRead, numwords*8)
+		nr, err := io.ReadFull(stream, by)
+		if err != nil {
+			return 8 + int64(nr), fmt.Errorf("error in readFrom: could not read the "+
+				"runContainer bit flags of length %v bytes: %v", bytesToRead, err)
+		}
+		pos += bytesToRead
+		by = by[:cap(by)]
+		isRun = newBitmapContainer()
+		for i := 0; i < numwords; i++ {
+			isRun.bitmap[i] = binary.LittleEndian.Uint64(by)
+			by = by[8:]
+		}
+	} else if cookie == serialCookieNoRunContainer {
+		err = binary.Read(stream, binary.LittleEndian, &size)
+		if err != nil {
+			return 0, fmt.Errorf("error in roaringArray.readFrom: when reading size, got: %s", err)
+		}
+		pos += 4
+	} else {
+		return 0, fmt.Errorf("error in roaringArray.readFrom: did not find expected serialCookie in header")
+	}
+	if size > (1 << 16) {
+		return 0, fmt.Errorf("It is logically impossible to have more than (1<<16) containers.")
+	}
+	// descriptive header
+	keycard := make([]uint16, 2*size, 2*size)
+	err = binary.Read(stream, binary.LittleEndian, keycard)
+	if err != nil {
+		return 0, err
+	}
+	pos += 2 * 2 * int(size)
+	// offset header
+	if !haveRunContainers || size >= noOffsetThreshold {
+		io.CopyN(ioutil.Discard, stream, 4*int64(size)) // we never skip ahead so this data can be ignored
+		pos += 4 * int(size)
+	}
+	for i := uint32(0); i < size; i++ {
+		key := int(keycard[2*i])
+		card := int(keycard[2*i+1]) + 1
+		if haveRunContainers && isRun.contains(uint16(i)) {
+			nb := newRunContainer16()
+			nr, err := nb.readFrom(stream)
+			if err != nil {
+				return 0, err
+			}
+			pos += nr
+			ra.appendContainer(uint16(key), nb, false)
+		} else if card > arrayDefaultMaxSize {
+			nb := newBitmapContainer()
+			nr, err := nb.readFrom(stream)
+			if err != nil {
+				return 0, err
+			}
+			nb.cardinality = card
+			pos += nr
+			ra.appendContainer(keycard[2*i], nb, false)
+		} else {
+			nb := newArrayContainerSize(card)
+			nr, err := nb.readFrom(stream)
+			if err != nil {
+				return 0, err
+			}
+			pos += nr
+			ra.appendContainer(keycard[2*i], nb, false)
+		}
+	}
+	return int64(pos), nil
+}
+
+func (ra *roaringArray) hasRunCompression() bool {
+	for _, c := range ra.containers {
+		switch c.(type) {
+		case *runContainer16:
+			return true
+		}
+	}
+	return false
+}
+
+func (ra *roaringArray) writeToMsgpack(stream io.Writer) error {
+
+	ra.conserz = make([]containerSerz, len(ra.containers))
+	for i, v := range ra.containers {
+		switch cn := v.(type) {
+		case *bitmapContainer:
+			bts, err := cn.MarshalMsg(nil)
+			if err != nil {
+				return err
+			}
+			ra.conserz[i].t = bitmapContype
+			ra.conserz[i].r = bts
+		case *arrayContainer:
+			bts, err := cn.MarshalMsg(nil)
+			if err != nil {
+				return err
+			}
+			ra.conserz[i].t = arrayContype
+			ra.conserz[i].r = bts
+		case *runContainer16:
+			bts, err := cn.MarshalMsg(nil)
+			if err != nil {
+				return err
+			}
+			ra.conserz[i].t = run16Contype
+			ra.conserz[i].r = bts
+		default:
+			panic(fmt.Errorf("Unrecognized container implementation: %T", cn))
+		}
+	}
+	w := snappy.NewWriter(stream)
+	err := msgp.Encode(w, ra)
+	ra.conserz = nil
+	return err
+}
+
+func (ra *roaringArray) readFromMsgpack(stream io.Reader) error {
+	r := snappy.NewReader(stream)
+	err := msgp.Decode(r, ra)
+	if err != nil {
+		return err
+	}
+
+	if len(ra.containers) != len(ra.keys) {
+		ra.containers = make([]container, len(ra.keys))
+	}
+
+	for i, v := range ra.conserz {
+		switch v.t {
+		case bitmapContype:
+			c := &bitmapContainer{}
+			_, err = c.UnmarshalMsg(v.r)
+			if err != nil {
+				return err
+			}
+			ra.containers[i] = c
+		case arrayContype:
+			c := &arrayContainer{}
+			_, err = c.UnmarshalMsg(v.r)
+			if err != nil {
+				return err
+			}
+			ra.containers[i] = c
+		case run16Contype:
+			c := &runContainer16{}
+			_, err = c.UnmarshalMsg(v.r)
+			if err != nil {
+				return err
+			}
+			ra.containers[i] = c
+		default:
+			return fmt.Errorf("unrecognized contype serialization code: '%v'", v.t)
+		}
+	}
+	ra.conserz = nil
+	return nil
+}
+
+func (ra *roaringArray) advanceUntil(min uint16, pos int) int {
+	lower := pos + 1
+
+	if lower >= len(ra.keys) || ra.keys[lower] >= min {
+		return lower
+	}
+
+	spansize := 1
+
+	for lower+spansize < len(ra.keys) && ra.keys[lower+spansize] < min {
+		spansize *= 2
+	}
+	var upper int
+	if lower+spansize < len(ra.keys) {
+		upper = lower + spansize
+	} else {
+		upper = len(ra.keys) - 1
+	}
+
+	if ra.keys[upper] == min {
+		return upper
+	}
+
+	if ra.keys[upper] < min {
+		// means
+		// array
+		// has no
+		// item
+		// >= min
+		// pos = array.length;
+		return len(ra.keys)
+	}
+
+	// we know that the next-smallest span was too small
+	lower += (spansize >> 1)
+
+	mid := 0
+	for lower+1 != upper {
+		mid = (lower + upper) >> 1
+		if ra.keys[mid] == min {
+			return mid
+		} else if ra.keys[mid] < min {
+			lower = mid
+		} else {
+			upper = mid
+		}
+	}
+	return upper
+}
+
+func (ra *roaringArray) markAllAsNeedingCopyOnWrite() {
+	for i := range ra.needCopyOnWrite {
+		ra.needCopyOnWrite[i] = true
+	}
+}
+
+func (ra *roaringArray) needsCopyOnWrite(i int) bool {
+	return ra.needCopyOnWrite[i]
+}
+
+func (ra *roaringArray) setNeedsCopyOnWrite(i int) {
+	ra.needCopyOnWrite[i] = true
+}