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// Copyright 2009 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.
// This test tests some internals of the flate package.
// The tests in package compress/gzip serve as the
// end-to-end test of the decompressor.
package flate
import (
"bytes"
"reflect"
"testing"
)
// The Huffman code lengths used by the fixed-format Huffman blocks.
var fixedHuffmanBits = [...]int{
// 0-143 length 8
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
// 144-255 length 9
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
// 256-279 length 7
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7,
// 280-287 length 8
8, 8, 8, 8, 8, 8, 8, 8,
}
type InitDecoderTest struct {
in []int
out huffmanDecoder
ok bool
}
var initDecoderTests = []*InitDecoderTest{
// Example from Connell 1973,
&InitDecoderTest{
[]int{3, 5, 2, 4, 3, 5, 5, 4, 4, 3, 4, 5},
huffmanDecoder{
2, 5,
[maxCodeLen + 1]int{2: 0, 4, 13, 31},
[maxCodeLen + 1]int{2: 0, 1, 6, 20},
// Paper used different code assignment:
// 2, 9, 4, 0, 10, 8, 3, 7, 1, 5, 11, 6
// Reordered here so that codes of same length
// are assigned to increasing numbers.
[]int{2, 0, 4, 9, 3, 7, 8, 10, 1, 5, 6, 11},
},
true,
},
// Example from RFC 1951 section 3.2.2
&InitDecoderTest{
[]int{2, 1, 3, 3},
huffmanDecoder{
1, 3,
[maxCodeLen + 1]int{1: 0, 2, 7},
[maxCodeLen + 1]int{1: 0, 1, 4},
[]int{1, 0, 2, 3},
},
true,
},
// Second example from RFC 1951 section 3.2.2
&InitDecoderTest{
[]int{3, 3, 3, 3, 3, 2, 4, 4},
huffmanDecoder{
2, 4,
[maxCodeLen + 1]int{2: 0, 6, 15},
[maxCodeLen + 1]int{2: 0, 1, 8},
[]int{5, 0, 1, 2, 3, 4, 6, 7},
},
true,
},
// Static Huffman codes (RFC 1951 section 3.2.6)
&InitDecoderTest{
fixedHuffmanBits[0:],
fixedHuffmanDecoder,
true,
},
// Illegal input.
&InitDecoderTest{
[]int{},
huffmanDecoder{},
false,
},
// Illegal input.
&InitDecoderTest{
[]int{0, 0, 0, 0, 0, 0, 0},
huffmanDecoder{},
false,
},
}
func TestInitDecoder(t *testing.T) {
for i, tt := range initDecoderTests {
var h huffmanDecoder
if h.init(tt.in) != tt.ok {
t.Errorf("test %d: init = %v", i, !tt.ok)
continue
}
if !reflect.DeepEqual(&h, &tt.out) {
t.Errorf("test %d:\nhave %v\nwant %v", i, h, tt.out)
}
}
}
func TestUncompressedSource(t *testing.T) {
decoder := NewReader(bytes.NewBuffer([]byte{0x01, 0x01, 0x00, 0xfe, 0xff, 0x11}))
output := make([]byte, 1)
n, error := decoder.Read(output)
if n != 1 || error != nil {
t.Fatalf("decoder.Read() = %d, %v, want 1, nil", n, error)
}
if output[0] != 0x11 {
t.Errorf("output[0] = %x, want 0x11", output[0])
}
}
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