Another way to display strings in Go
Once sitting at work, and writing code on Go, I remembered the old puzzle, the essence of which was that we needed to implement the division of any number by a predetermined in the condition of the problem. It would seem simple, but there were two limitations:
1. You cannot use numbers explicitly, except for 0.
2. The number of allowed mathematical operations was also limited.
I did not repeat it on Go, but decided to apply one of the solutions to display the string. This idea is not new, and I do not claim full-fledged authorship, I just decided to share it.
The bottom line is that the string is divided into bytes, and each byte is converted into a sequence of bit-wise shifts, and XOR and OR operations with one.
')
It looks like this:
So, let's begin. The unsafe module is only needed for the sizeof function. If anyone knows how to get the size of the structure in Go in other ways, I will be glad if you share it.
Next, you need a function that will be for a given byte, to find and generate such a combination. The simplest and most obvious option was to first calculate the pattern, of the form [0,1,1,0,1,1, ...]. Where 0 means that the number is even, 1 means odd. Decreasing the number each time, performing a bitwise right shift by 1.
Thus, the length of the slice arr will be equal to the number of steps that must be performed to obtain the initial number.
Running through the slice of arr, we generate a string of “shifts”, and if we meet an odd number, then randomly execute an OR or XOR operation with 1 on this number.
It remains to write the function, which in fact will turn the given string into a sequence of such shifts. As an example, I decided to display the code, executing which you can get the specified string.
That's all. After starting, for the line: “Author: GH0st3rs ” we get the following result:
"The source code of the project is available on GitHub
1. You cannot use numbers explicitly, except for 0.
2. The number of allowed mathematical operations was also limited.
I did not repeat it on Go, but decided to apply one of the solutions to display the string. This idea is not new, and I do not claim full-fledged authorship, I just decided to share it.
The bottom line is that the string is divided into bytes, and each byte is converted into a sequence of bit-wise shifts, and XOR and OR operations with one.
')
It looks like this:
EAX = uint8(unsafe.Sizeof(true)) (((EAX<<EAX^EAX)<<EAX|EAX)<<EAX<<EAX<<EAX^EAX)<<EAX) So, let's begin. The unsafe module is only needed for the sizeof function. If anyone knows how to get the size of the structure in Go in other ways, I will be glad if you share it.
We make out the sections Import and Const
import ( "fmt" "math/rand" "time" "unsafe" ) const ( EAX = uint8(unsafe.Sizeof(true)) ONE = "EAX" ) Next, you need a function that will be for a given byte, to find and generate such a combination. The simplest and most obvious option was to first calculate the pattern, of the form [0,1,1,0,1,1, ...]. Where 0 means that the number is even, 1 means odd. Decreasing the number each time, performing a bitwise right shift by 1.
Write this in code
func getNumber(n byte) (buf string) { var arr []byte for n > EAX { if n%2 == EAX { arr = append(arr, EAX) } else { arr = append(arr, 0) } n = n >> EAX } } Thus, the length of the slice arr will be equal to the number of steps that must be performed to obtain the initial number.
Let's add the getNumber function
buf = ONE rand.Seed(time.Now().Unix()) for i := len(arr) - 1; i >= 0; i-- { buf = fmt.Sprintf("%s<<%s", buf, ONE) if arr[i] == EAX { if rand.Intn(2) == 0 { buf = fmt.Sprintf("(%s^%s)", buf, ONE) } else { buf = fmt.Sprintf("(%s|%s)", buf, ONE) } } } Running through the slice of arr, we generate a string of “shifts”, and if we meet an odd number, then randomly execute an OR or XOR operation with 1 on this number.
It remains to write the function, which in fact will turn the given string into a sequence of such shifts. As an example, I decided to display the code, executing which you can get the specified string.
Another function
func TextToCode(txt string) string { b := []byte(txt) tmp := "var str []byte\n" for _, item := range b { tmp = fmt.Sprintf("%s\nstr = append(str, %s)", tmp, getNumber(item)) } tmp += "\nfmt.Println(string(str))" return tmp } That's all. After starting, for the line: “Author: GH0st3rs ” we get the following result:
not to look nervous
var str []byte str = append(str, (EAX<<EAX<<EAX<<EAX<<EAX<<EAX<<EAX^EAX)) str = append(str, ((((EAX<<EAX^EAX)<<EAX|EAX)<<EAX<<EAX^EAX)<<EAX<<EAX^EAX)) str = append(str, (((EAX<<EAX^EAX)<<EAX|EAX)<<EAX<<EAX^EAX)<<EAX<<EAX) str = append(str, ((EAX<<EAX^EAX)<<EAX<<EAX|EAX)<<EAX<<EAX<<EAX) str = append(str, (((((EAX<<EAX^EAX)<<EAX<<EAX|EAX)<<EAX^EAX)<<EAX^EAX)<<EAX|EAX)) str = append(str, (((EAX<<EAX^EAX)<<EAX|EAX)<<EAX<<EAX<<EAX^EAX)<<EAX) str = append(str, (((EAX<<EAX^EAX)<<EAX|EAX)<<EAX<<EAX^EAX)<<EAX) str = append(str, EAX<<EAX<<EAX<<EAX<<EAX<<EAX) str = append(str, EAX<<EAX<<EAX<<EAX<<EAX<<EAX<<EAX) str = append(str, (((EAX<<EAX<<EAX<<EAX<<EAX^EAX)<<EAX|EAX)<<EAX^EAX)) str = append(str, (EAX<<EAX<<EAX<<EAX^EAX)<<EAX<<EAX<<EAX) str = append(str, (EAX<<EAX^EAX)<<EAX<<EAX<<EAX<<EAX) str = append(str, ((((EAX<<EAX^EAX)<<EAX|EAX)<<EAX<<EAX<<EAX^EAX)<<EAX^EAX)) str = append(str, (((EAX<<EAX^EAX)<<EAX|EAX)<<EAX<<EAX^EAX)<<EAX<<EAX) str = append(str, (((EAX<<EAX^EAX)<<EAX<<EAX<<EAX|EAX)<<EAX^EAX)) str = append(str, (((EAX<<EAX^EAX)<<EAX|EAX)<<EAX<<EAX<<EAX^EAX)<<EAX) str = append(str, ((((EAX<<EAX^EAX)<<EAX|EAX)<<EAX<<EAX<<EAX^EAX)<<EAX^EAX)) fmt.Println(string(str)) "The source code of the project is available on GitHub
Source: https://habr.com/ru/post/313486/
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