diff options
Diffstat (limited to 'vendor/github.com/RoaringBitmap/roaring/serialization_littleendian.go')
-rw-r--r-- | vendor/github.com/RoaringBitmap/roaring/serialization_littleendian.go | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/vendor/github.com/RoaringBitmap/roaring/serialization_littleendian.go b/vendor/github.com/RoaringBitmap/roaring/serialization_littleendian.go new file mode 100644 index 0000000000..c1d3ad3046 --- /dev/null +++ b/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)) +} |