gitea/vendor/github.com/tinylib/msgp/msgp/elsize.go
2018-05-19 20:49:46 +08:00

99 lines
3.4 KiB
Go

package msgp
// size of every object on the wire,
// plus type information. gives us
// constant-time type information
// for traversing composite objects.
//
var sizes = [256]bytespec{
mnil: {size: 1, extra: constsize, typ: NilType},
mfalse: {size: 1, extra: constsize, typ: BoolType},
mtrue: {size: 1, extra: constsize, typ: BoolType},
mbin8: {size: 2, extra: extra8, typ: BinType},
mbin16: {size: 3, extra: extra16, typ: BinType},
mbin32: {size: 5, extra: extra32, typ: BinType},
mext8: {size: 3, extra: extra8, typ: ExtensionType},
mext16: {size: 4, extra: extra16, typ: ExtensionType},
mext32: {size: 6, extra: extra32, typ: ExtensionType},
mfloat32: {size: 5, extra: constsize, typ: Float32Type},
mfloat64: {size: 9, extra: constsize, typ: Float64Type},
muint8: {size: 2, extra: constsize, typ: UintType},
muint16: {size: 3, extra: constsize, typ: UintType},
muint32: {size: 5, extra: constsize, typ: UintType},
muint64: {size: 9, extra: constsize, typ: UintType},
mint8: {size: 2, extra: constsize, typ: IntType},
mint16: {size: 3, extra: constsize, typ: IntType},
mint32: {size: 5, extra: constsize, typ: IntType},
mint64: {size: 9, extra: constsize, typ: IntType},
mfixext1: {size: 3, extra: constsize, typ: ExtensionType},
mfixext2: {size: 4, extra: constsize, typ: ExtensionType},
mfixext4: {size: 6, extra: constsize, typ: ExtensionType},
mfixext8: {size: 10, extra: constsize, typ: ExtensionType},
mfixext16: {size: 18, extra: constsize, typ: ExtensionType},
mstr8: {size: 2, extra: extra8, typ: StrType},
mstr16: {size: 3, extra: extra16, typ: StrType},
mstr32: {size: 5, extra: extra32, typ: StrType},
marray16: {size: 3, extra: array16v, typ: ArrayType},
marray32: {size: 5, extra: array32v, typ: ArrayType},
mmap16: {size: 3, extra: map16v, typ: MapType},
mmap32: {size: 5, extra: map32v, typ: MapType},
}
func init() {
// set up fixed fields
// fixint
for i := mfixint; i < 0x80; i++ {
sizes[i] = bytespec{size: 1, extra: constsize, typ: IntType}
}
// nfixint
for i := uint16(mnfixint); i < 0x100; i++ {
sizes[uint8(i)] = bytespec{size: 1, extra: constsize, typ: IntType}
}
// fixstr gets constsize,
// since the prefix yields the size
for i := mfixstr; i < 0xc0; i++ {
sizes[i] = bytespec{size: 1 + rfixstr(i), extra: constsize, typ: StrType}
}
// fixmap
for i := mfixmap; i < 0x90; i++ {
sizes[i] = bytespec{size: 1, extra: varmode(2 * rfixmap(i)), typ: MapType}
}
// fixarray
for i := mfixarray; i < 0xa0; i++ {
sizes[i] = bytespec{size: 1, extra: varmode(rfixarray(i)), typ: ArrayType}
}
}
// a valid bytespsec has
// non-zero 'size' and
// non-zero 'typ'
type bytespec struct {
size uint8 // prefix size information
extra varmode // extra size information
typ Type // type
_ byte // makes bytespec 4 bytes (yes, this matters)
}
// size mode
// if positive, # elements for composites
type varmode int8
const (
constsize varmode = 0 // constant size (size bytes + uint8(varmode) objects)
extra8 = -1 // has uint8(p[1]) extra bytes
extra16 = -2 // has be16(p[1:]) extra bytes
extra32 = -3 // has be32(p[1:]) extra bytes
map16v = -4 // use map16
map32v = -5 // use map32
array16v = -6 // use array16
array32v = -7 // use array32
)
func getType(v byte) Type {
return sizes[v].typ
}