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// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ccitt
import (
"bytes"
"reflect"
"testing"
)
func testEncode(t *testing.T, o Order) {
t.Helper()
values := []uint32{0, 1, 256, 7, 128, 3, 2560, 2240, 2368, 2048}
decTable := whiteDecodeTable[:]
encTableSmall := whiteEncodeTable2[:]
encTableBig := whiteEncodeTable3[:]
// Encode values to bit stream.
var bb bytes.Buffer
w := &bitWriter{w: &bb, order: o}
for _, v := range values {
encTable := encTableSmall
if v < 64 {
// No-op.
} else if v&63 != 0 {
t.Fatalf("writeCode: cannot encode %d: large but not a multiple of 64", v)
} else {
encTable = encTableBig
v = v/64 - 1
}
if err := w.writeCode(encTable[v]); err != nil {
t.Fatalf("writeCode: %v", err)
}
}
if err := w.close(); err != nil {
t.Fatalf("close: %v", err)
}
// Decode bit stream to values.
got := []uint32(nil)
r := &bitReader{
r: bytes.NewReader(bb.Bytes()),
order: o,
}
finalValue := values[len(values)-1]
for {
v, err := decode(r, decTable)
if err != nil {
t.Fatalf("after got=%d: %v", got, err)
}
got = append(got, v)
if v == finalValue {
break
}
}
// Check that the round-tripped values were unchanged.
if !reflect.DeepEqual(got, values) {
t.Fatalf("\ngot: %v\nwant: %v", got, values)
}
}
func TestEncodeLSB(t *testing.T) { testEncode(t, LSB) }
func TestEncodeMSB(t *testing.T) { testEncode(t, MSB) }
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