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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"
"io/ioutil"
"strings"
"testing"
)
func TestUncompressedSource(t *testing.T) {
decoder := NewReader(bytes.NewReader([]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])
}
}
// The following test should not panic.
func TestIssue5915(t *testing.T) {
bits := []int{4, 0, 0, 6, 4, 3, 2, 3, 3, 4, 4, 5, 0, 0, 0, 0, 5, 5, 6,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 8, 6, 0, 11, 0, 8, 0, 6, 6, 10, 8}
var h huffmanDecoder
if h.init(bits) {
t.Fatalf("Given sequence of bits is bad, and should not succeed.")
}
}
// The following test should not panic.
func TestIssue5962(t *testing.T) {
bits := []int{4, 0, 0, 6, 4, 3, 2, 3, 3, 4, 4, 5, 0, 0, 0, 0,
5, 5, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11}
var h huffmanDecoder
if h.init(bits) {
t.Fatalf("Given sequence of bits is bad, and should not succeed.")
}
}
// The following test should not panic.
func TestIssue6255(t *testing.T) {
bits1 := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 11}
bits2 := []int{11, 13}
var h huffmanDecoder
if !h.init(bits1) {
t.Fatalf("Given sequence of bits is good and should succeed.")
}
if h.init(bits2) {
t.Fatalf("Given sequence of bits is bad and should not succeed.")
}
}
func TestInvalidEncoding(t *testing.T) {
// Initialize Huffman decoder to recognize "0".
var h huffmanDecoder
if !h.init([]int{1}) {
t.Fatal("Failed to initialize Huffman decoder")
}
// Initialize decompressor with invalid Huffman coding.
var f decompressor
f.r = bytes.NewReader([]byte{0xff})
_, err := f.huffSym(&h)
if err == nil {
t.Fatal("Should have rejected invalid bit sequence")
}
}
func TestInvalidBits(t *testing.T) {
oversubscribed := []int{1, 2, 3, 4, 4, 5}
incomplete := []int{1, 2, 4, 4}
var h huffmanDecoder
if h.init(oversubscribed) {
t.Fatal("Should reject oversubscribed bit-length set")
}
if h.init(incomplete) {
t.Fatal("Should reject incomplete bit-length set")
}
}
func TestDegenerateHuffmanCoding(t *testing.T) {
const (
want = "abcabc"
// This compressed form has a dynamic Huffman block, even though a
// sensible encoder would use a literal data block, as the latter is
// shorter. Still, it is a valid flate compression of "abcabc". It has
// a degenerate Huffman table with only one coded value: the one
// non-literal back-ref copy of the first "abc" to the second "abc".
//
// To verify that this is decompressible with zlib (the C library),
// it's easy to use the Python wrapper library:
// >>> import zlib
// >>> compressed = "\x0c\xc2...etc...\xff\xff"
// >>> zlib.decompress(compressed, -15) # negative means no GZIP header.
// 'abcabc'
compressed = "\x0c\xc2\x01\x0d\x00\x00\x00\x82\xb0\xac\x4a\xff\x0e\xb0\x7d\x27" +
"\x06\x00\x00\xff\xff"
)
b, err := ioutil.ReadAll(NewReader(strings.NewReader(compressed)))
if err != nil {
t.Fatal(err)
}
if got := string(b); got != want {
t.Fatalf("got %q, want %q", got, want)
}
}