colorful_items.go

package main

import "fmt"

func fcolor(r, g, b byte) string {
        return fmt.Sprintf("\x1b[38;2;%d;%d;%dm", r, g, b)
}

func bcolor(r, g, b byte) string {
        return fmt.Sprintf("\x1b[48;2;%d;%d;%dm", r, g, b)
}

const resetColor = "\x1b[0m"

func swap(a, b *uint64) {
        *a, *b = *b, *a
}

func strItemColor(s string) string {
        r := 12345 - 777*uint64(len(s))
        g := 34567 + 999*uint64(len(s))
        b := 56789 ^ (333 / (3 + uint64(len(s))))
        a := []uint64{0x80, 0x40, 0x20, 0x10}

        for i, _c := range []rune(s) {
                c := uint64(_c)
                r = r ^ (r << (i & 7)) ^ (c * ^uint64(i))
                g = g ^ (g >> (i & 7)) ^ (c * uint64(-i))
                b = (b * r) ^ (b * g) ^ (b * 333)
                if (r & 0xff) > (b & 0xff) {
                        swap(&a[0], &a[1])
                        swap(&a[2], &a[3])
                        swap(&a[0], &a[3])
                } else {
                        swap(&a[0], &a[2])
                        swap(&a[1], &a[3])
                }

                if (g & 0xff) > (r & 0xff) {
                        swap(&a[0], &a[3])
                        swap(&a[1], &a[2])
                } else {
                        swap(&a[1], &a[3])
                }
        }
        return fcolor(byte(r|a[0]), byte(g|a[1]), byte(b|a[2])) + s + resetColor
}

func intItemColor(s uint64) string {
        s0 := s
        r := 12345 - 777*s
        g := 34567 + 999*s
        b := 56789 ^ (333 / (3 + s))
        a := []uint64{0x80, 0x40, 0x20, 0x10}

        for i := uint64(0); i < 16; i++ {
                s = s ^ (s >> 9) ^ (s>>3)*9999
                s = ^s * 99999999

                r = r ^ (r << (i & 7)) ^ (s * ^i)
                g = g ^ (g >> (i & 7)) ^ (s * -i)
                b = (b * r) ^ (b * g) ^ (b * 333)
                if (r & 0xff) > (b & 0xff) {
                        swap(&a[0], &a[1])
                        swap(&a[2], &a[3])
                        swap(&a[0], &a[3])
                } else {
                        swap(&a[0], &a[2])
                        swap(&a[1], &a[3])
                }

                if (g & 0xff) > (r & 0xff) {
                        swap(&a[0], &a[3])
                        swap(&a[1], &a[2])
                } else {
                        swap(&a[1], &a[3])
                }
        }
        return fmt.Sprintf("%s0x%x%s", fcolor(byte(r|a[0]), byte(g|a[1]), byte(b|a[2])), s0, resetColor)
}

func main() {
        for i := uint64(0); i < 100; i++ {
                fmt.Print(intItemColor(i) + " ")
        }
        fmt.Println(strItemColor("\n0"))
        fmt.Println(strItemColor("Hello, World"))
}