Source file
src/bytes/boundary_test.go
Documentation: bytes
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8 package bytes_test
9
10 import (
11 . "bytes"
12 "syscall"
13 "testing"
14 )
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26
27 func dangerousSlice(t *testing.T) []byte {
28 pagesize := syscall.Getpagesize()
29 b, err := syscall.Mmap(0, 0, 3*pagesize, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANONYMOUS|syscall.MAP_PRIVATE)
30 if err != nil {
31 t.Fatalf("mmap failed %s", err)
32 }
33 err = syscall.Mprotect(b[:pagesize], syscall.PROT_NONE)
34 if err != nil {
35 t.Fatalf("mprotect low failed %s\n", err)
36 }
37 err = syscall.Mprotect(b[2*pagesize:], syscall.PROT_NONE)
38 if err != nil {
39 t.Fatalf("mprotect high failed %s\n", err)
40 }
41 return b[pagesize : 2*pagesize]
42 }
43
44 func TestEqualNearPageBoundary(t *testing.T) {
45 t.Parallel()
46 b := dangerousSlice(t)
47 for i := range b {
48 b[i] = 'A'
49 }
50 for i := 0; i <= len(b); i++ {
51 Equal(b[:i], b[len(b)-i:])
52 Equal(b[len(b)-i:], b[:i])
53 }
54 }
55
56 func TestIndexByteNearPageBoundary(t *testing.T) {
57 t.Parallel()
58 b := dangerousSlice(t)
59 for i := range b {
60 idx := IndexByte(b[i:], 1)
61 if idx != -1 {
62 t.Fatalf("IndexByte(b[%d:])=%d, want -1\n", i, idx)
63 }
64 }
65 }
66
67 func TestIndexNearPageBoundary(t *testing.T) {
68 t.Parallel()
69 var q [64]byte
70 b := dangerousSlice(t)
71 if len(b) > 256 {
72
73 b = b[len(b)-256:]
74 }
75 for j := 1; j < len(q); j++ {
76 q[j-1] = 1
77 for i := range b {
78 idx := Index(b[i:], q[:j])
79 if idx != -1 {
80 t.Fatalf("Index(b[%d:], q[:%d])=%d, want -1\n", i, j, idx)
81 }
82 }
83 q[j-1] = 0
84 }
85 }
86
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