cmd/xurls: don't use bufio.Scanner to scan the input

It was a convenient way to obtain the input in chunks, so that the tool
could print urls incrementally without having to read the entirety of
the input at once.

Unfortunately, we failed to notie that bufio.Scanner has a hard limit on
the size of each "token". In our particular case, it meant that any
sequence of many thousands of input bytes without any whitespace could
make the tool error out.

Instead, use bufio.Reader, which grows a buffer to fit the data being
read. Go back to reading one line at a time, as it can only stop at one
specific byte like '\n', and not many of them like all whitespace
characters.

Fixes #28.

cmd/xurls/main.go

@@ -7,6 +7,7 @@ import (
 	"bufio"
 	"flag"
 	"fmt"
+	"io"
 	"os"
 	"regexp"
 
@@ -41,15 +42,19 @@ func scanPath(re *regexp.Regexp, path string) error {
 		defer f.Close()
 		r = f
 	}
-	scanner := bufio.NewScanner(r)
-	scanner.Split(bufio.ScanWords)
-	for scanner.Scan() {
-		word := scanner.Text()
-		for _, match := range re.FindAllString(word, -1) {
-			fmt.Println(match)
+	bufr := bufio.NewReader(r)
+	for {
+		line, err := bufr.ReadBytes('\n')
+		for _, match := range re.FindAll(line, -1) {
+			fmt.Printf("%s\n", match)
+		}
+		if err == io.EOF {
+			break
+		} else if err != nil {
+			return err
 		}
 	}
-	return scanner.Err()
+	return nil
 }
 
 func main() {

generate/schemesgen/main.go

@@ -34,7 +34,7 @@ func schemeList() []string {
 	}
 	defer resp.Body.Close()
 	r := csv.NewReader(resp.Body)
-	r.Read() //ignore headers
+	r.Read() // ignore headers
 	schemes := make([]string, 0)
 	for {
 		record, err := r.Read()