hackutils

README

hackutils

Various hacky utils for Go

Please don't use this code in production. It's meant for writing quick "scripts" in Go, eschewing proper error handling etc.

Documentation

Index

• func HammingDistance(b1, b2 []byte) int64
• func HexReaderToBytes(r io.Reader) []byte
• func HexToBytes(h []byte) []byte
• func KLDivergence(p, q []float64) float64
• func XorBytes(b1, b2 []byte) []byte
• func XorBytesWithVal(bs []byte, b byte) []byte
• func XorWithRepeatingMask(bs []byte, mask []byte) []byte

Functions

func HammingDistance

func HammingDistance(b1, b2 []byte) int64

HammingDistance computes the hamming distance (number of bits that are different) between b1 and b2.

func HexReaderToBytes

func HexReaderToBytes(r io.Reader) []byte

HexReaderToBytes converts all hexadecimal-encoded data in r to raw bytes. The input has to consist of (possibly whitespace-separated) hexadecimal daat only - for example a file with some hexa data per line (newline separated). The returned byte buffer is the concatenation of all input found in the reader.

func HexToBytes

func HexToBytes(h []byte) []byte

HexToBytes converts hexadecimal encoded bytes to raw bytes, failing the program in case of errors. For example, []byte{"aa18"} is converted to []byte{0xaa, 0x18}.

func KLDivergence

func KLDivergence(p, q []float64) float64

KLDivergence computes the Kullback-Leibler divergence between two probability distributions p and q. p and q are expected to have the same length and contain numbers that sum up to 1.0; The KL divergence is close to 0 if the two distributions are deemed "similar" and gets larger the more different they are. See https://en.wikipedia.org/wiki/Kullback%E2%80%93Leibler_divergence

func XorBytes

func XorBytes(b1, b2 []byte) []byte

XorBytes performs a binary XOR between two byte slices of the same length. If the length is different it fails. Returns a new byte slice with the result.

func XorBytesWithVal

func XorBytesWithVal(bs []byte, b byte) []byte

XorBytesWithVal performs a binary XOR between every byte in bs with b. Returns a new byte slice with the result.

func XorWithRepeatingMask

func XorWithRepeatingMask(bs []byte, mask []byte) []byte

XorWithRepeatingMask performs a binary XOR between bs and mask, with mask repeated enough times to cover the length of bs. For example, with a 10-byte bs and the mask "XYZ", bs will be XOR-ed with "XYZXYZXYZX". Note that just enough of the mask is taken to cover the leftovers.