unsafe_slice.go raw
1 package reflect2
2
3 import (
4 "reflect"
5 "unsafe"
6 )
7
8 // sliceHeader is a safe version of SliceHeader used within this package.
9 type sliceHeader struct {
10 Data unsafe.Pointer
11 Len int
12 Cap int
13 }
14
15 type UnsafeSliceType struct {
16 unsafeType
17 elemRType unsafe.Pointer
18 pElemRType unsafe.Pointer
19 elemSize uintptr
20 }
21
22 func newUnsafeSliceType(cfg *frozenConfig, type1 reflect.Type) SliceType {
23 elemType := type1.Elem()
24 return &UnsafeSliceType{
25 unsafeType: *newUnsafeType(cfg, type1),
26 pElemRType: unpackEFace(reflect.PtrTo(elemType)).data,
27 elemRType: unpackEFace(elemType).data,
28 elemSize: elemType.Size(),
29 }
30 }
31
32 func (type2 *UnsafeSliceType) Set(obj interface{}, val interface{}) {
33 objEFace := unpackEFace(obj)
34 assertType("Type.Set argument 1", type2.ptrRType, objEFace.rtype)
35 valEFace := unpackEFace(val)
36 assertType("Type.Set argument 2", type2.ptrRType, valEFace.rtype)
37 type2.UnsafeSet(objEFace.data, valEFace.data)
38 }
39
40 func (type2 *UnsafeSliceType) UnsafeSet(ptr unsafe.Pointer, val unsafe.Pointer) {
41 *(*sliceHeader)(ptr) = *(*sliceHeader)(val)
42 }
43
44 func (type2 *UnsafeSliceType) IsNil(obj interface{}) bool {
45 if obj == nil {
46 return true
47 }
48 objEFace := unpackEFace(obj)
49 assertType("Type.IsNil argument 1", type2.ptrRType, objEFace.rtype)
50 return type2.UnsafeIsNil(objEFace.data)
51 }
52
53 func (type2 *UnsafeSliceType) UnsafeIsNil(ptr unsafe.Pointer) bool {
54 if ptr == nil {
55 return true
56 }
57 return (*sliceHeader)(ptr).Data == nil
58 }
59
60 func (type2 *UnsafeSliceType) SetNil(obj interface{}) {
61 objEFace := unpackEFace(obj)
62 assertType("SliceType.SetNil argument 1", type2.ptrRType, objEFace.rtype)
63 type2.UnsafeSetNil(objEFace.data)
64 }
65
66 func (type2 *UnsafeSliceType) UnsafeSetNil(ptr unsafe.Pointer) {
67 header := (*sliceHeader)(ptr)
68 header.Len = 0
69 header.Cap = 0
70 header.Data = nil
71 }
72
73 func (type2 *UnsafeSliceType) MakeSlice(length int, cap int) interface{} {
74 return packEFace(type2.ptrRType, type2.UnsafeMakeSlice(length, cap))
75 }
76
77 func (type2 *UnsafeSliceType) UnsafeMakeSlice(length int, cap int) unsafe.Pointer {
78 header := &sliceHeader{unsafe_NewArray(type2.elemRType, cap), length, cap}
79 return unsafe.Pointer(header)
80 }
81
82 func (type2 *UnsafeSliceType) LengthOf(obj interface{}) int {
83 objEFace := unpackEFace(obj)
84 assertType("SliceType.Len argument 1", type2.ptrRType, objEFace.rtype)
85 return type2.UnsafeLengthOf(objEFace.data)
86 }
87
88 func (type2 *UnsafeSliceType) UnsafeLengthOf(obj unsafe.Pointer) int {
89 header := (*sliceHeader)(obj)
90 return header.Len
91 }
92
93 func (type2 *UnsafeSliceType) SetIndex(obj interface{}, index int, elem interface{}) {
94 objEFace := unpackEFace(obj)
95 assertType("SliceType.SetIndex argument 1", type2.ptrRType, objEFace.rtype)
96 elemEFace := unpackEFace(elem)
97 assertType("SliceType.SetIndex argument 3", type2.pElemRType, elemEFace.rtype)
98 type2.UnsafeSetIndex(objEFace.data, index, elemEFace.data)
99 }
100
101 func (type2 *UnsafeSliceType) UnsafeSetIndex(obj unsafe.Pointer, index int, elem unsafe.Pointer) {
102 header := (*sliceHeader)(obj)
103 elemPtr := arrayAt(header.Data, index, type2.elemSize, "i < s.Len")
104 typedmemmove(type2.elemRType, elemPtr, elem)
105 }
106
107 func (type2 *UnsafeSliceType) GetIndex(obj interface{}, index int) interface{} {
108 objEFace := unpackEFace(obj)
109 assertType("SliceType.GetIndex argument 1", type2.ptrRType, objEFace.rtype)
110 elemPtr := type2.UnsafeGetIndex(objEFace.data, index)
111 return packEFace(type2.pElemRType, elemPtr)
112 }
113
114 func (type2 *UnsafeSliceType) UnsafeGetIndex(obj unsafe.Pointer, index int) unsafe.Pointer {
115 header := (*sliceHeader)(obj)
116 return arrayAt(header.Data, index, type2.elemSize, "i < s.Len")
117 }
118
119 func (type2 *UnsafeSliceType) Append(obj interface{}, elem interface{}) {
120 objEFace := unpackEFace(obj)
121 assertType("SliceType.Append argument 1", type2.ptrRType, objEFace.rtype)
122 elemEFace := unpackEFace(elem)
123 assertType("SliceType.Append argument 2", type2.pElemRType, elemEFace.rtype)
124 type2.UnsafeAppend(objEFace.data, elemEFace.data)
125 }
126
127 func (type2 *UnsafeSliceType) UnsafeAppend(obj unsafe.Pointer, elem unsafe.Pointer) {
128 header := (*sliceHeader)(obj)
129 oldLen := header.Len
130 type2.UnsafeGrow(obj, oldLen+1)
131 type2.UnsafeSetIndex(obj, oldLen, elem)
132 }
133
134 func (type2 *UnsafeSliceType) Cap(obj interface{}) int {
135 objEFace := unpackEFace(obj)
136 assertType("SliceType.Cap argument 1", type2.ptrRType, objEFace.rtype)
137 return type2.UnsafeCap(objEFace.data)
138 }
139
140 func (type2 *UnsafeSliceType) UnsafeCap(ptr unsafe.Pointer) int {
141 return (*sliceHeader)(ptr).Cap
142 }
143
144 func (type2 *UnsafeSliceType) Grow(obj interface{}, newLength int) {
145 objEFace := unpackEFace(obj)
146 assertType("SliceType.Grow argument 1", type2.ptrRType, objEFace.rtype)
147 type2.UnsafeGrow(objEFace.data, newLength)
148 }
149
150 func (type2 *UnsafeSliceType) UnsafeGrow(obj unsafe.Pointer, newLength int) {
151 header := (*sliceHeader)(obj)
152 if newLength <= header.Cap {
153 header.Len = newLength
154 return
155 }
156 newCap := calcNewCap(header.Cap, newLength)
157 newHeader := (*sliceHeader)(type2.UnsafeMakeSlice(header.Len, newCap))
158 typedslicecopy(type2.elemRType, *newHeader, *header)
159 header.Data = newHeader.Data
160 header.Cap = newHeader.Cap
161 header.Len = newLength
162 }
163
164 func calcNewCap(cap int, expectedCap int) int {
165 if cap == 0 {
166 cap = expectedCap
167 } else {
168 for cap < expectedCap {
169 if cap < 1024 {
170 cap += cap
171 } else {
172 cap += cap / 4
173 }
174 }
175 }
176 return cap
177 }
178