encoding/binary: add examples for varint functions

Change-Id: I191f6e46b452fadde9f641140445d843b0c7d534
Reviewed-on: https://go-review.googlesource.com/48604
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

diff --git a/src/encoding/binary/example_test.go b/src/encoding/binary/example_test.go
index 2b52a47d129cf7a0968680874ad714251a4238b5..a8b8dba6507706da837ddb1b68761d1abf21e308 100644 (file)
--- a/src/encoding/binary/example_test.go
+++ b/src/encoding/binary/example_test.go
@@ -68,3 +68,94 @@ func ExampleByteOrder_get() {
        // Output:
        // 0x03e8 0x07d0
 }
+
+func ExamplePutUvarint() {
+       buf := make([]byte, binary.MaxVarintLen64)
+
+       for _, x := range []uint64{1, 2, 127, 128, 255, 256} {
+               n := binary.PutUvarint(buf, x)
+               fmt.Printf("%x\n", buf[:n])
+       }
+       // Output:
+       // 01
+       // 02
+       // 7f
+       // 8001
+       // ff01
+       // 8002
+}
+
+func ExamplePutVarint() {
+       buf := make([]byte, binary.MaxVarintLen64)
+
+       for _, x := range []int64{-65, -64, -2, -1, 0, 1, 2, 63, 64} {
+               n := binary.PutVarint(buf, x)
+               fmt.Printf("%x\n", buf[:n])
+       }
+       // Output:
+       // 8101
+       // 7f
+       // 03
+       // 01
+       // 00
+       // 02
+       // 04
+       // 7e
+       // 8001
+}
+
+func ExampleUvarint() {
+       inputs := [][]byte{
+               []byte{0x01},
+               []byte{0x02},
+               []byte{0x7f},
+               []byte{0x80, 0x01},
+               []byte{0xff, 0x01},
+               []byte{0x80, 0x02},
+       }
+       for _, b := range inputs {
+               x, n := binary.Uvarint(b)
+               if n != len(b) {
+                       fmt.Println("Uvarint did not consume all of in")
+               }
+               fmt.Println(x)
+       }
+       // Output:
+       // 1
+       // 2
+       // 127
+       // 128
+       // 255
+       // 256
+}
+
+func ExampleVarint() {
+       inputs := [][]byte{
+               []byte{0x81, 0x01},
+               []byte{0x7f},
+               []byte{0x03},
+               []byte{0x01},
+               []byte{0x00},
+               []byte{0x02},
+               []byte{0x04},
+               []byte{0x7e},
+               []byte{0x80, 0x01},
+       }
+       for _, b := range inputs {
+               x, n := binary.Varint(b)
+               if n != len(b) {
+                       fmt.Println("Varint did not consume all of in")
+               }
+               fmt.Println(x)
+       }
+       // Output:
+       // -65
+       // -64
+       // -2
+       // -1
+       // 0
+       // 1
+       // 2
+       // 63
+       // 64
+}