status-go/vendor/github.com/segmentio/asm/ascii/valid_print_default.go

47 lines
1.0 KiB
Go

//go:build purego || !amd64
// +build purego !amd64
package ascii
import "unsafe"
// ValidString returns true if s contains only printable ASCII characters.
func ValidPrintString(s string) bool {
p := *(*unsafe.Pointer)(unsafe.Pointer(&s))
i := uintptr(0)
n := uintptr(len(s))
for i+8 <= n {
if hasLess64(*(*uint64)(unsafe.Pointer(uintptr(p) + i)), 0x20) || hasMore64(*(*uint64)(unsafe.Pointer(uintptr(p) + i)), 0x7e) {
return false
}
i += 8
}
if i+4 <= n {
if hasLess32(*(*uint32)(unsafe.Pointer(uintptr(p) + i)), 0x20) || hasMore32(*(*uint32)(unsafe.Pointer(uintptr(p) + i)), 0x7e) {
return false
}
i += 4
}
if i == n {
return true
}
p = unsafe.Pointer(uintptr(p) + i)
var x uint32
switch n - i {
case 3:
x = 0x20000000 | uint32(*(*uint16)(p)) | uint32(*(*uint8)(unsafe.Pointer(uintptr(p) + 2)))<<16
case 2:
x = 0x20200000 | uint32(*(*uint16)(p))
case 1:
x = 0x20202000 | uint32(*(*uint8)(p))
default:
return true
}
return !(hasLess32(x, 0x20) || hasMore32(x, 0x7e))
}