YAPC::EU 2018 Glasgow Update!

Task/Bitwise-IO/Go/bitwise-io-2.go

@@ -0,0 +1,65 @@
+package bit
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"log"
+)
+
+func ExampleWriter_WriteBits() {
+	var buf bytes.Buffer
+	bw := NewWriter(&buf, MSB)
+	bw.WriteBits(0x0f, 4) // Writes 1111
+	bw.WriteBits(0x00, 1) //        0
+	bw.WriteBits(0x13, 5) //        1001 1
+	// Close will flush with zero bits, in this case
+	//                              0000 00
+	if err := bw.Close(); err != nil {
+		log.Fatal(err)
+	}
+	fmt.Printf("%08b", buf.Bytes())
+	// Output:
+	// [11110100 11000000]
+}
+
+func Example() {
+	const message = "This is a test."
+	fmt.Printf("%q as bytes: % 02[1]X\n", message, []byte(message))
+	fmt.Printf("    original bits: %08b\n", []byte(message))
+
+	// Re-write in 7 bit chunks to buf:
+	var buf bytes.Buffer
+	bw := NewWriter(&buf, MSB)
+	for _, r := range message {
+		bw.WriteBits(uint16(r), 7) // nolint: errcheck
+	}
+	if err := bw.Close(); err != nil {
+		log.Fatal(err)
+	}
+	fmt.Printf("Written bitstream: %08b\n", buf.Bytes())
+	fmt.Printf("Written bytes: % 02X\n", buf.Bytes())
+
+	// Read back in 7 bit chunks:
+	br := NewReader(&buf, MSB)
+	var result []byte
+	for {
+		v, err := br.ReadBits(7)
+		if err != nil {
+			if err != io.EOF {
+				log.Fatal(err)
+			}
+			break
+		}
+		if v != 0 {
+			result = append(result, byte(v))
+		}
+	}
+	fmt.Printf("Read back as \"%s\"\n", result)
+	// Output:
+	// "This is a test." as bytes: 54 68 69 73 20 69 73 20 61 20 74 65 73 74 2E
+	//     original bits: [01010100 01101000 01101001 01110011 00100000 01101001 01110011 00100000 01100001 00100000 01110100 01100101 01110011 01110100 00101110]
+	// Written bitstream: [10101001 10100011 01001111 00110100 00011010 01111001 10100000 11000010 10000011 10100110 01011110 01111101 00010111 00000000]
+	// Written bytes: A9 A3 4F 34 1A 79 A0 C2 83 A6 5E 7D 17 00
+	// Read back as "This is a test."
+}