xunsafe

README

XUnsafe

在go里面， []byte 和 string 的相互转换是非常频繁的，随之而来的是大量的内存分配，当长度越长时，对性能影响越大，所有提供了 unsafe 的转换方法。

当 []byte 是由 string 通过 unsafe 转换而来的话，将不能进行更改操作，否则会panic，且无法恢复。

StringToBytes

package main
import (
    "github.com/go-board/x-go/xunsafe"
)
func main()  {
    bs := xunsafe.StringToBytes("hello,world!")
    println(bs)
}

BytesToString

package main
import (
    "github.com/go-board/x-go/xunsafe"
)

func main()  {
    str := xunsafe.BytesToString([]byte{'h', 'e', 'l', 'l', 'o', ',', 'w', 'o', 'r', 'l', 'd', '!'})
    println(str)
}

Documentation

Index

• func BytesToString(data []byte) string
• func StringToBytes(str string) []byte
• func StringToBytesFast(s string) (b []byte)

Functions

func BytesToString

func BytesToString(data []byte) string

BytesToString use a quick way to cast []byte to string without any alloc, in a 6000 length test, this is faster than `string(bytes)` one 2200 times

func StringToBytes

func StringToBytes(str string) []byte

StringToBytes use a quick way to cast string to []byte without any alloc, in a 6000 length test, this is faster than `[]byte(string)` one 2200 times CAUTION: this is marked as unsafe so have limit, do not change the result. Generated asm code is: "".s2b STEXT nosplit size=88 args=0x28 locals=0x20 0x0000 00000 (main.go:33) TEXT "".s2b(SB), NOSPLIT|ABIInternal, $32-40 0x0000 00000 (main.go:33) SUBQ $32, SP 0x0004 00004 (main.go:33) MOVQ BP, 24(SP) 0x0009 00009 (main.go:33) LEAQ 24(SP), BP 0x000e 00014 (main.go:33) FUNCDATA $0, gclocals·9fad110d66c97cf0b58d28cccea80b12(SB) 0x000e 00014 (main.go:33) FUNCDATA $1, gclocals·7d2d5fca80364273fb07d5820a76fef4(SB) 0x000e 00014 (main.go:33) FUNCDATA $3, gclocals·ebb0e8ce1793da18f0378b883cb3e122(SB) 0x000e 00014 (main.go:33) FUNCDATA $4, "".s2b.stkobj(SB) 0x000e 00014 (main.go:35) PCDATA $2, $0 0x000e 00014 (main.go:35) PCDATA $0, $0 0x000e 00014 (main.go:35) XORPS X0, X0 0x0011 00017 (main.go:35) MOVUPS X0, "".bh(SP) 0x0015 00021 (main.go:35) MOVQ $0, "".bh+16(SP) 0x001e 00030 (main.go:36) MOVQ "".s+40(SP), AX 0x0023 00035 (main.go:36) MOVQ AX, "".bh(SP) 0x0027 00039 (main.go:37) MOVQ "".s+48(SP), AX 0x002c 00044 (main.go:37) MOVQ AX, "".bh+8(SP) 0x0031 00049 (main.go:38) PCDATA $0, $1 0x0031 00049 (main.go:38) MOVQ "".s+48(SP), CX 0x0036 00054 (main.go:38) MOVQ CX, "".bh+16(SP) 0x003b 00059 (main.go:40) PCDATA $2, $1 0x003b 00059 (main.go:40) MOVQ "".bh(SP), DX 0x003f 00063 (main.go:40) PCDATA $2, $0 0x003f 00063 (main.go:40) PCDATA $0, $2 0x003f 00063 (main.go:40) MOVQ DX, "".~r1+56(SP) 0x0044 00068 (main.go:40) MOVQ AX, "".~r1+64(SP) 0x0049 00073 (main.go:40) MOVQ CX, "".~r1+72(SP) 0x004e 00078 (main.go:40) MOVQ 24(SP), BP 0x0053 00083 (main.go:40) ADDQ $32, SP 0x0057 00087 (main.go:40) RET

func StringToBytesFast

func StringToBytesFast(s string) (b []byte)

StringToBytesFast is a faster version of StringToBytes. return stack space to store the final value, without the allocation of a temporary struct. Generated asm code is: "".s2bFast STEXT nosplit size=43 args=0x28 locals=0x0 0x0000 00000 (main.go:43) TEXT "".s2bV1(SB), NOSPLIT|ABIInternal, $0-40 0x0000 00000 (main.go:43) FUNCDATA $0, gclocals·39d1b96ca581879f548ad2c8aeb3a5fe(SB) 0x0000 00000 (main.go:43) FUNCDATA $1, gclocals·7d2d5fca80364273fb07d5820a76fef4(SB) 0x0000 00000 (main.go:43) FUNCDATA $3, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB) 0x0000 00000 (main.go:43) FUNCDATA $4, "".s2bV1.stkobj(SB) 0x0000 00000 (main.go:43) PCDATA $2, $0 0x0000 00000 (main.go:43) PCDATA $0, $1 0x0000 00000 (main.go:43) MOVQ $0, "".b+24(SP) 0x0009 00009 (main.go:43) XORPS X0, X0 0x000c 00012 (main.go:43) MOVUPS X0, "".b+32(SP) 0x0011 00017 (main.go:45) MOVQ "".s+16(SP), AX 0x0016 00022 (main.go:45) PCDATA $0, $2 0x0016 00022 (main.go:45) MOVQ "".s+8(SP), CX 0x001b 00027 (main.go:46) MOVQ CX, "".b+24(SP) 0x0020 00032 (main.go:47) MOVQ AX, "".b+32(SP) 0x0025 00037 (main.go:48) MOVQ AX, "".b+40(SP) 0x002a 00042 (main.go:49) RET