Add HW 3

homework/03-http-server/tests/gen_utils.go

@@ -0,0 +1,49 @@
+package hw3test
+
+import (
+	"io"
+	"math/rand"
+)
+
+func SimpleFilenameGenerator(maxLen int) func(r *rand.Rand) string {
+	return func(r *rand.Rand) string {
+		return GenFilename(r, maxLen)
+	}
+}
+
+func GenFilename(r *rand.Rand, maxLen int) string {
+	// TODO: better filename generation, right now it's only uppercase english letters
+	n := r.Intn(maxLen) + 1
+	b := make([]byte, n)
+	for i := 0; i < n; i++ {
+		b[i] = byte(r.Intn(26) + 65)
+	}
+	return string(b)
+}
+
+// TextReader is io.Reader filtering out non-text characters.
+type TextReader struct {
+	r io.Reader
+}
+
+func (t *TextReader) Read(p []byte) (n int, err error) {
+	for {
+		n, err = t.r.Read(p)
+		if n == 0 || err != nil {
+			return
+		}
+
+		m := 0
+		for i := 0; i < n; i++ {
+			// p[i] is a plain text character
+			if p[i] == '\n' || (p[i] >= 32 && p[i] <= 126) {
+				p[m] = p[i]
+				m++
+			}
+		}
+		if m == 0 {
+			continue
+		}
+		return m, nil
+	}
+}