frostfs-api-go/util/proto/marshal.go
Alex Vanin f8482381fd Add stable marshaller helper for ints
Signed-off-by: Alex Vanin <alexey@nspcc.ru>
2020-09-18 10:41:01 +03:00

130 lines
2.7 KiB
Go

/*
This package contains help functions for stable marshaller. Their usage is
totally optional. One can implement fast stable marshaller without these
runtime function calls.
*/
package proto
import (
"encoding/binary"
"math/bits"
)
func BytesMarshal(field int, buf, v []byte) (int, error) {
if len(v) == 0 {
return 0, nil
}
prefix := field<<3 | 0x2
// buf length check can prevent panic at PutUvarint, but it will make
// marshaller a bit slower.
i := binary.PutUvarint(buf, uint64(prefix))
i += binary.PutUvarint(buf[i:], uint64(len(v)))
i += copy(buf[i:], v)
return i, nil
}
func BytesSize(field int, v []byte) int {
ln := len(v)
if ln == 0 {
return 0
}
prefix := field<<3 | 0x2
return VarUIntSize(uint64(prefix)) + VarUIntSize(uint64(ln)) + ln
}
func StringMarshal(field int, buf []byte, v string) (int, error) {
return BytesMarshal(field, buf, []byte(v))
}
func StringSize(field int, v string) int {
return BytesSize(field, []byte(v))
}
func BoolMarshal(field int, buf []byte, v bool) (int, error) {
if !v {
return 0, nil
}
prefix := field << 3
// buf length check can prevent panic at PutUvarint, but it will make
// marshaller a bit slower.
i := binary.PutUvarint(buf, uint64(prefix))
buf[i] = 0x1
return i + 1, nil
}
func BoolSize(field int, v bool) int {
if !v {
return 0
}
prefix := field << 3
return VarUIntSize(uint64(prefix)) + 1 // bool is always 1 byte long
}
func UInt64Marshal(field int, buf []byte, v uint64) (int, error) {
if v == 0 {
return 0, nil
}
prefix := field << 3
// buf length check can prevent panic at PutUvarint, but it will make
// marshaller a bit slower.
i := binary.PutUvarint(buf, uint64(prefix))
i += binary.PutUvarint(buf[i:], v)
return i, nil
}
func UInt64Size(field int, v uint64) int {
if v == 0 {
return 0
}
prefix := field << 3
return VarUIntSize(uint64(prefix)) + VarUIntSize(v)
}
func Int64Marshal(field int, buf []byte, v int64) (int, error) {
return UInt64Marshal(field, buf, uint64(v))
}
func Int64Size(field int, v int64) int {
return UInt64Size(field, uint64(v))
}
func UInt32Marshal(field int, buf []byte, v uint32) (int, error) {
return UInt64Marshal(field, buf, uint64(v))
}
func UInt32Size(field int, v uint32) int {
return UInt64Size(field, uint64(v))
}
func Int32Marshal(field int, buf []byte, v int32) (int, error) {
return UInt64Marshal(field, buf, uint64(v))
}
func Int32Size(field int, v int32) int {
return UInt64Size(field, uint64(v))
}
// varUIntSize returns length of varint byte sequence for uint64 value 'x'.
func VarUIntSize(x uint64) int {
return (bits.Len64(x|1) + 6) / 7
}
func NestedStructurePrefixSize(field int64) int {
return VarUIntSize(uint64(field<<3 | 0x02))
}