-
Notifications
You must be signed in to change notification settings - Fork 1
/
utils.go
323 lines (246 loc) · 7.11 KB
/
utils.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
package lowlevelfunctions
import (
"fmt"
"reflect"
"sync/atomic"
"unicode/utf8"
"unsafe"
"github.com/NikoMalik/low-level-functions/constants"
)
type ErrorSizeUnmatch struct {
fromLength int
fromSize int64
toSize int64
}
func (err *ErrorSizeUnmatch) Error() string {
return fmt.Sprintf(
"size mismatch: source length = '%d',"+
"source size = '%d', destination size = '%d'",
err.fromLength, err.fromSize, err.toSize)
}
func String(b []byte) string {
return unsafe.String(unsafe.SliceData(b), len(b))
}
func StringToBytes(s string) []byte {
return *(*[]byte)(unsafe.Pointer(&struct {
string
Cap int
}{s, len(s)},
))
}
func CopyString(s string) string {
c := MakeNoZero(len(s))
copy(c, StringToBytes(s))
return String(c)
}
func ConvertSlice[TFrom, TTo any](from []TFrom) ([]TTo, error) {
var (
zeroValFrom TFrom
zeroValTo TTo
)
maxSize := unsafe.Sizeof(zeroValFrom)
minSize := unsafe.Sizeof(zeroValTo)
if minSize > maxSize {
swap(&minSize, &maxSize)
}
if unsafe.Sizeof(zeroValFrom) == minSize {
if len(from)*int(minSize)%int(maxSize) != 0 {
return nil, &ErrorSizeUnmatch{
fromLength: len(from),
fromSize: int64(unsafe.Sizeof(zeroValFrom)),
toSize: int64(unsafe.Sizeof(zeroValTo)),
}
}
header := *(*reflect.SliceHeader)(unsafe.Pointer(&from))
header.Len = header.Len * int(minSize) / int(maxSize)
header.Cap = header.Cap * int(minSize) / int(maxSize)
result := *(*[]TTo)(unsafe.Pointer(&header))
return result, nil
} else {
if len(from)*int(maxSize)%int(minSize) != 0 {
return nil, &ErrorSizeUnmatch{
fromLength: len(from),
fromSize: int64(unsafe.Sizeof(zeroValFrom)),
toSize: int64(unsafe.Sizeof(zeroValTo)),
}
}
header := *(*reflect.SliceHeader)(unsafe.Pointer(&from))
header.Len = header.Len * int(maxSize) / int(minSize)
header.Cap = header.Cap * int(maxSize) / int(minSize)
result := *(*[]TTo)(unsafe.Pointer(&header))
return result, nil
}
}
//go:noinline
func swap[T any](a, b *T) {
tmp := *a
*a = *b
*b = tmp
}
//go:linkname mallocgc runtime.mallocgc
func mallocgc(size uintptr, typ unsafe.Pointer, needzero bool) unsafe.Pointer
func MakeNoZero(l int) []byte {
return unsafe.Slice((*byte)(mallocgc(uintptr(l), nil, false)), l) // standart
}
func MakeNoZeroCap(l int, c int) []byte {
return MakeNoZero(c)[:l]
}
type StringBuffer struct {
buf []byte
}
func NewStringBuffer(cap int) *StringBuffer {
return &StringBuffer{
buf: MakeNoZeroCap(0, cap),
}
}
func (b *StringBuffer) String() string {
return String(b.buf)
}
func (b *StringBuffer) Bytes() []byte {
return b.buf
}
func (b *StringBuffer) Len() int {
return len(b.buf)
}
func (b *StringBuffer) Cap() int {
return cap(b.buf)
}
func (b *StringBuffer) Reset() {
b.buf = b.buf[:0] // reuse the underlying storage
}
func (b *StringBuffer) grow(n int) {
buf := MakeNoZero(2*cap(b.buf) + n)[:len(b.buf)]
copy(buf, b.buf)
b.buf = buf
}
func (b *StringBuffer) Grow(n int) {
// Check if n is negative
if n < 0 {
// Panic with the message "fast.StringBuffer.Grow: negative count"
panic("fast.StringBuffer.Grow: negative count")
}
// Check if the buffer's available capacity is less than n
if cap(b.buf)-len(b.buf) < n {
// Call the grow method to increase the capacity
b.grow(n)
}
}
func (b *StringBuffer) Write(p []byte) (int, error) {
b.buf = append(b.buf, p...)
return len(p), nil
}
func (b *StringBuffer) WriteByte(c byte) error {
b.buf = append(b.buf, c)
return nil
}
func (b *StringBuffer) WriteRune(r rune) (int, error) {
n := len(b.buf)
b.buf = utf8.AppendRune(b.buf, r)
return len(b.buf) - n, nil
}
func (b *StringBuffer) WriteString(s string) (int, error) {
b.buf = append(b.buf, s...)
return len(s), nil
}
//go:linkname noescape runtime.noescape
func noescape(p unsafe.Pointer) unsafe.Pointer
func ConvertOne[TFrom, TTo any](from TFrom) (TTo, error) {
var (
zeroValFrom TFrom
zeroValTo TTo
)
if unsafe.Sizeof(zeroValFrom) != unsafe.Sizeof(zeroValTo) { // need same size to convert
return zeroValTo, &ErrorSizeUnmatch{
fromSize: int64(unsafe.Sizeof(zeroValFrom)),
toSize: int64(unsafe.Sizeof(zeroValTo)),
}
}
value := *(*TTo)(unsafe.Pointer(&from))
return value, nil
}
func MustConvertOne[TFrom, TTo any](from TFrom) TTo {
return *(*TTo)(unsafe.Pointer(&from))
}
func MakeZero[T any](l int) []T { // for now better works with big size
return unsafe.Slice((*T)(mallocgc(uintptr(l), nil, true)), l)
}
// in future i'll try to replace interface
func MakeZeroCap[T any](l int, c int) []T { // // for now better works with big size
return MakeZero[T](c)[:l]
}
func MakeNoZeroString(l int) []string {
return unsafe.Slice((*string)(mallocgc(uintptr(l), nil, false)), l)
}
func MakeNoZeroCapString(l int, c int) []string {
return MakeNoZeroString(c)[:l]
}
//go:linkname memequal runtime.memequal
func memequal(a, b unsafe.Pointer, size uintptr) bool
func Equal(a, b []byte) bool {
if len(a) != len(b) {
return false
}
return memequal(unsafe.Pointer(&a[0]), unsafe.Pointer(&b[0]), uintptr(len(a)))
}
func IsNil(v any) bool {
/*
var x *int
var y any
fmt.Println(x == nil) // false
fmt.Println(isNil(x)) // true
fmt.Println(x == nil) // true
fmt.Println(isNil(y)) // panic
*/
return reflect.ValueOf(v).IsNil()
}
// IsEqual checks if two variables point to the same memory location.
//
// It uses unsafe.Pointer to get the memory address of the variables.
// The equality check is performed by comparing the memory addresses.
//
// Parameters:
// - v1: The first variable.
// - v2: The second variable.
//
// Returns:
// - bool: True if the variables point to the same memory location, false otherwise.
func IsEqual(v1, v2 any) bool {
// Get the memory address of the variables using unsafe.Pointer.
// The & operator returns the memory address of a variable.
// The unsafe.Pointer type is used to store and manipulate untyped memory.
// It is commonly used in low-level programming to bypass type safety checks.
//
// The &v1 and &v2 expressions take the address of v1 and v2 variables respectively.
// The expressions return pointers to the variables.
return unsafe.Pointer(&v1) == unsafe.Pointer(&v2)
}
type CacheLinePadding struct {
_ [constants.CacheLinePadSize]byte
}
var CacheLinePadSize = constants.CacheLinePadSize
// Example of using cache line padding
type AtomicCounter struct {
_ CacheLinePadding // 64 or 32
value atomic.Int32
_ [constants.CacheLinePadSize - unsafe.Sizeof(atomic.Int32{})]byte
}
func (a *AtomicCounter) Increment(int) {
a.value.Add(1)
}
func (a *AtomicCounter) Get() int32 {
return a.value.Load()
}
func GetItem[T any](slice []T, idx int) T { // experimental same performance as original
if len(slice) == 0 || idx < 0 || idx >= len(slice) {
panic("index out of range")
}
ptr := unsafe.Pointer(uintptr(unsafe.Pointer(&slice[0])) + uintptr(idx)*unsafe.Sizeof(slice[0]))
return *(*T)(ptr)
}
func GetItemWithoutCheck[T any](slice []T, idx int) T { // clears the checks for idx and make it faster but not safe
ptr := unsafe.Pointer(uintptr(unsafe.Pointer(&slice[0])) + uintptr(idx)*unsafe.Sizeof(slice[0]))
return *(*T)(ptr)
}
func Pointer[T any](d T) *T {
return &d
}