be_test.go

package bytebits

import (
	"bytes"
	"testing"
	"encoding/hex"
)


type rotTest struct{ s []byte; n, d int; z []byte }
var rotTests = []rotTest{

	// Zero-byte slices
	{ []byte{}, 0, 0, []byte{}}, 
	{ []byte{}, 0, 1, []byte{0}}, 
	{ []byte{}, 1, 0, []byte{}}, 
	{ []byte{}, 1, 5, []byte{0,0,0,0,0}}, 
	{ []byte{}, -1, 0, []byte{}}, 
	{ []byte{}, 7, 0, []byte{}}, 
	{ []byte{}, -7, 0, []byte{}}, 
	{ []byte{}, 8, 0, []byte{}}, 
	{ []byte{}, -8, 0, []byte{}}, 
	{ []byte{}, 15, 0, []byte{}}, 
	{ []byte{}, -15, 0, []byte{}}, 

	// One-byte slices
	{ []byte{0xac}, 0, 0, []byte{0xac}}, 
	{ []byte{0xac}, 0, 1, []byte{0xac}}, 
	{ []byte{0xac}, 1, 0, []byte{0x59}}, 
	{ []byte{0xac}, 1, 5, []byte{0x59,0,0,0,0}}, 
	{ []byte{0xac}, -1, 0, []byte{0x56}}, 
	{ []byte{0xac}, 7, 0, []byte{0x56}}, 
	{ []byte{0xac}, -7, 0, []byte{0x59}}, 
	{ []byte{0xac}, 8, 0, []byte{0xac}}, 
	{ []byte{0xac}, -8, 0, []byte{0xac}}, 
	{ []byte{0xac}, 15, 0, []byte{0x56}}, 
	{ []byte{0xac}, -15, 0, []byte{0x59}}, 

	// 4-byte slices
	{ []byte{0xde,0xad,0xbe,0xef}, 0, 0, []byte{0xde,0xad,0xbe,0xef} },
	{ []byte{0xde,0xad,0xbe,0xef}, 0, 4, []byte{0xde,0xad,0xbe,0xef} },
	{ []byte{0xde,0xad,0xbe,0xef}, 0, 5, []byte{0xde,0xad,0xbe,0xef,0} },
	{ []byte{0xde,0xad,0xbe,0xef}, 1, 0, []byte{0xbd,0x5b,0x7d,0xdf} },
	{ []byte{0xde,0xad,0xbe,0xef}, -1, 0, []byte{0xef,0x56,0xdf,0x77} },
	{ []byte{0xde,0xad,0xbe,0xef}, 4, 0, []byte{0xea,0xdb,0xee,0xfd} },
	{ []byte{0xde,0xad,0xbe,0xef}, -4, 0, []byte{0xfd,0xea,0xdb,0xee} },
	{ []byte{0xde,0xad,0xbe,0xef}, 8, 0, []byte{0xad,0xbe,0xef,0xde} },
	{ []byte{0xde,0xad,0xbe,0xef}, -8, 0, []byte{0xef,0xde,0xad,0xbe} },
	{ []byte{0xde,0xad,0xbe,0xef}, 9, 0, []byte{0x5b,0x7d,0xdf,0xbd} },
	{ []byte{0xde,0xad,0xbe,0xef}, -9, 0, []byte{0x77,0xef,0x56,0xdf} },
	{ []byte{0xde,0xad,0xbe,0xef}, 12, 0, []byte{0xdb,0xee,0xfd,0xea} },
	{ []byte{0xde,0xad,0xbe,0xef}, -12, 0, []byte{0xee,0xfd,0xea,0xdb} },
	{ []byte{0xde,0xad,0xbe,0xef}, 15, 0, []byte{0xdf,0x77,0xef,0x56} },
	{ []byte{0xde,0xad,0xbe,0xef}, -15, 0, []byte{0x7d,0xdf,0xbd,0x5b} },
}

func TestRotateLeft(t *testing.T) {

	for i, rt := range(rotTests) {
		var d []byte
		if rt.d > 0 {
			d = make([]byte, rt.d)
		}
		d = BigEndian.RotateLeft(d, rt.s, rt.n)
		if bytes.Compare(d, rt.z) != 0 {
			t.Errorf("Rotate test %v failed %v << %v: %v != %v",
				i, hex.EncodeToString(rt.s), rt.n,
				hex.EncodeToString(d),
				hex.EncodeToString(rt.z))
		}
	}
}