Update to last common bleve (#3986)

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

@@ -0,0 +1,113 @@
+// +build 386 amd64,!appengine
+
+package roaring
+
+import (
+	"io"
+	"reflect"
+	"unsafe"
+)
+
+func (ac *arrayContainer) writeTo(stream io.Writer) (int, error) {
+	buf := uint16SliceAsByteSlice(ac.content)
+	return stream.Write(buf)
+}
+
+func (bc *bitmapContainer) writeTo(stream io.Writer) (int, error) {
+	buf := uint64SliceAsByteSlice(bc.bitmap)
+	return stream.Write(buf)
+}
+
+// readFrom reads an arrayContainer from stream.
+// PRE-REQUISITE: you must size the arrayContainer correctly (allocate b.content)
+// *before* you call readFrom. We can't guess the size in the stream
+// by this point.
+func (ac *arrayContainer) readFrom(stream io.Reader) (int, error) {
+	buf := uint16SliceAsByteSlice(ac.content)
+	return io.ReadFull(stream, buf)
+}
+
+func (bc *bitmapContainer) readFrom(stream io.Reader) (int, error) {
+	buf := uint64SliceAsByteSlice(bc.bitmap)
+	n, err := io.ReadFull(stream, buf)
+	bc.computeCardinality()
+	return n, err
+}
+
+func uint64SliceAsByteSlice(slice []uint64) []byte {
+	// make a new slice header
+	header := *(*reflect.SliceHeader)(unsafe.Pointer(&slice))
+
+	// update its capacity and length
+	header.Len *= 8
+	header.Cap *= 8
+
+	// return it
+	return *(*[]byte)(unsafe.Pointer(&header))
+}
+
+func uint16SliceAsByteSlice(slice []uint16) []byte {
+	// make a new slice header
+	header := *(*reflect.SliceHeader)(unsafe.Pointer(&slice))
+
+	// update its capacity and length
+	header.Len *= 2
+	header.Cap *= 2
+
+	// return it
+	return *(*[]byte)(unsafe.Pointer(&header))
+}
+
+func (bc *bitmapContainer) asLittleEndianByteSlice() []byte {
+	return uint64SliceAsByteSlice(bc.bitmap)
+}
+
+// Deserialization code follows
+
+func byteSliceAsUint16Slice(slice []byte) []uint16 {
+	if len(slice)%2 != 0 {
+		panic("Slice size should be divisible by 2")
+	}
+
+	// make a new slice header
+	header := *(*reflect.SliceHeader)(unsafe.Pointer(&slice))
+
+	// update its capacity and length
+	header.Len /= 2
+	header.Cap /= 2
+
+	// return it
+	return *(*[]uint16)(unsafe.Pointer(&header))
+}
+
+func byteSliceAsUint64Slice(slice []byte) []uint64 {
+	if len(slice)%8 != 0 {
+		panic("Slice size should be divisible by 8")
+	}
+
+	// make a new slice header
+	header := *(*reflect.SliceHeader)(unsafe.Pointer(&slice))
+
+	// update its capacity and length
+	header.Len /= 8
+	header.Cap /= 8
+
+	// return it
+	return *(*[]uint64)(unsafe.Pointer(&header))
+}
+
+func byteSliceAsInterval16Slice(slice []byte) []interval16 {
+	if len(slice)%4 != 0 {
+		panic("Slice size should be divisible by 4")
+	}
+
+	// make a new slice header
+	header := *(*reflect.SliceHeader)(unsafe.Pointer(&slice))
+
+	// update its capacity and length
+	header.Len /= 4
+	header.Cap /= 4
+
+	// return it
+	return *(*[]interval16)(unsafe.Pointer(&header))
+}