add: strings and projects

20-project-spam-masker/03-step-2-no-append/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+/*
+✅ #1- Get and check the input
+✅ #2- Create a byte buffer and use it as the output
+✅ #3- Write input to the buffer as it is and print it
+✅ #4- Detect the link
+✅ #5- Mask the link
+✅ #6- Stop masking when whitespace is detected
+✅ #7- Put a http:// prefix in front of the masked link
+*/
+
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+const (
+	link  = "http://"
+	nlink = len(link)
+	mask  = '*'
+)
+
+func main() {
+	args := os.Args[1:]
+	if len(args) != 1 {
+		fmt.Println("gimme somethin' to mask!")
+		return
+	}
+
+	var (
+		text = args[0]
+		size = len(text)
+
+		// create a byte buffer directly from the string (text)
+		buf = []byte(text)
+
+		in bool
+	)
+
+	for i := 0; i < size; i++ {
+		// no need to add an artificial http:// prefix
+		// it's already there
+		if len(text[i:]) >= nlink && text[i:i+nlink] == link {
+			in = true
+			i += nlink
+		}
+
+		switch text[i] {
+		case ' ', '\t', '\n': // try -> unicode.IsSpace
+			in = false
+		}
+
+		// when censoring mode: on
+		// directly manipulate the bytes on the buffer
+		if in {
+			buf[i] = mask
+		}
+	}
+	fmt.Println(string(buf))
+}