package predictor
import (
diff "0dev.org/diff"
"bytes"
"fmt"
"io/ioutil"
"testing"
)
// Sample input from RFC1978 - PPP Predictor Compression Protocol
var input = []byte{0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x0a,
0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x0a,
0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x0a,
0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x0a,
0x41, 0x42, 0x41, 0x42, 0x41, 0x42, 0x41, 0x0a,
0x42, 0x41, 0x42, 0x41, 0x42, 0x41, 0x42, 0x0a,
0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x0a}
// Sample output from RFC1978 - PPP Predictor Compression Protocol
var output = []byte{0x60, 0x41, 0x41, 0x41, 0x41, 0x41, 0x0a, 0x60,
0x41, 0x41, 0x41, 0x41, 0x41, 0x0a, 0x6f, 0x41,
0x0a, 0x6f, 0x41, 0x0a, 0x41, 0x42, 0x41, 0x42,
0x41, 0x42, 0x0a, 0x60, 0x42, 0x41, 0x42, 0x41,
0x42, 0x0a, 0x60, 0x78, 0x78, 0x78, 0x78, 0x78, 0x0a}
func TestCompressorSample(t *testing.T) {
var (
buf bytes.Buffer
err error
)
out := Compressor(&buf)
_, err = out.Write(input)
if err != nil {
t.Error(err)
}
_, err = out.Write(nil)
if err != nil {
t.Error(err)
}
result := buf.Bytes()
delta := diff.Diff(diff.D{len(result), len(output), func(i, j int) bool { return result[i] == output[j] }})
if len(delta.Added) > 0 || len(delta.Removed) > 0 {
t.Error("Unexpected compressed output", delta)
}
}
func TestDecompressorSample(t *testing.T) {
in := Decompressor(bytes.NewReader(output))
result, err := ioutil.ReadAll(in)
if err != nil {
t.Error("Unexpected error while decompressing", err)
}
delta := diff.Diff(diff.D{len(result), len(input),
func(i, j int) bool { return result[i] == input[j] }})
if len(delta.Added) > 0 || len(delta.Removed) > 0 {
t.Error("Unexpected decompressed output", delta)
}
}
var testData = [][]byte{
[]byte{},
[]byte{0, 1, 2, 3},
[]byte{0, 1, 2, 3, 4, 5, 6, 7},
[]byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11},
[]byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15},
}
func TestCycle(t *testing.T) {
for i := 0; i < len(testData); i++ {
if err := cycle(testData[i], len(testData[i])); err != nil {
t.Error(err)
}
}
}
func TestStepCycle(t *testing.T) {
for i := 0; i < len(testData); i++ {
for j := 1; j < len(testData); j++ {
if err := cycle(testData[i], j); err != nil {
t.Error("Error for testData[", i, "], step[", j, "] ", err)
}
}
}
}
func cycle(input []byte, step int) error {
var (
buf bytes.Buffer
err error
)
if step > len(input) {
return nil
}
// Create a compressor and write the given data
compressor := Compressor(&buf)
var data []byte = input
var trace []byte = make([]byte, 0)
for len(data) > 0 {
if step <= len(data) {
trace = append(trace, data[:step]...)
_, err = compressor.Write(data[:step])
if err != nil {
return err
}
data = data[step:]
} else {
step = len(data)
}
}
// Flush the compressor
_, err = compressor.Write(nil)
if err != nil {
return err
}
// Attempt to decompress the data
compressed := buf.Bytes()
decompressed, err := ioutil.ReadAll(Decompressor(bytes.NewReader(compressed)))
if err != nil {
return err
}
// Diff the result against the initial input
delta := diff.Diff(diff.D{len(input), len(decompressed),
func(i, j int) bool { return input[i] == decompressed[j] }})
// Return a well-formated error if any differences are found
if len(delta.Added) > 0 || len(delta.Removed) > 0 {
return fmt.Errorf("Unexpected decompressed output %v\ninput: (%d) %#x\ntrace: (%d) %#x\noutput: (%d) %#x\n",
delta, len(input), input, len(trace), trace, len(decompressed), decompressed)
}
// All is good :)
return nil
}