| // Copyright 2018 The gVisor Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package state |
| |
| import ( |
| "reflect" |
| "unsafe" |
| ) |
| |
| // arrayFromSlice constructs a new pointer to the slice data. |
| // |
| // It would be similar to the following: |
| // |
| // x := make([]Foo, l, c) |
| // a := ([l]Foo*)(unsafe.Pointer(x[0])) |
| // |
| func arrayFromSlice(obj reflect.Value) reflect.Value { |
| return reflect.NewAt( |
| reflect.ArrayOf(obj.Cap(), obj.Type().Elem()), |
| unsafe.Pointer(obj.Pointer())) |
| } |
| |
| // pbSlice returns a protobuf-supported slice of the array and erase the |
| // original element type (which could be a defined type or non-supported type). |
| func pbSlice(obj reflect.Value) reflect.Value { |
| var typ reflect.Type |
| switch obj.Type().Elem().Kind() { |
| case reflect.Uint8: |
| typ = reflect.TypeOf(byte(0)) |
| case reflect.Uint16: |
| typ = reflect.TypeOf(uint16(0)) |
| case reflect.Uint32: |
| typ = reflect.TypeOf(uint32(0)) |
| case reflect.Uint64: |
| typ = reflect.TypeOf(uint64(0)) |
| case reflect.Uintptr: |
| typ = reflect.TypeOf(uint64(0)) |
| case reflect.Int8: |
| typ = reflect.TypeOf(byte(0)) |
| case reflect.Int16: |
| typ = reflect.TypeOf(int16(0)) |
| case reflect.Int32: |
| typ = reflect.TypeOf(int32(0)) |
| case reflect.Int64: |
| typ = reflect.TypeOf(int64(0)) |
| case reflect.Bool: |
| typ = reflect.TypeOf(bool(false)) |
| case reflect.Float32: |
| typ = reflect.TypeOf(float32(0)) |
| case reflect.Float64: |
| typ = reflect.TypeOf(float64(0)) |
| default: |
| panic("slice element is not of basic value type") |
| } |
| return reflect.NewAt( |
| reflect.ArrayOf(obj.Len(), typ), |
| unsafe.Pointer(obj.Slice(0, obj.Len()).Pointer()), |
| ).Elem().Slice(0, obj.Len()) |
| } |
| |
| func castSlice(obj reflect.Value, elemTyp reflect.Type) reflect.Value { |
| if obj.Type().Elem().Size() != elemTyp.Size() { |
| panic("cannot cast slice into other element type of different size") |
| } |
| return reflect.NewAt( |
| reflect.ArrayOf(obj.Len(), elemTyp), |
| unsafe.Pointer(obj.Slice(0, obj.Len()).Pointer()), |
| ).Elem() |
| } |