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1
5 package org.h2.compress;
6
7 import java.io.IOException  ;
8 import java.io.InputStream ;
9
10 public class LZFInputStream extends InputStream {
11
12 private InputStream in;
13 private CompressLZF decompress = new CompressLZF();
14 private int pos;
15 private int bufferLength;
16 private byte[] inBuffer;
17 private byte[] buffer;
18
19 public LZFInputStream(InputStream in) throws IOException {
20 this.in = in;
21 if(readInt() != LZFOutputStream.MAGIC) {
22 throw new IOException ("Not an LZFInputStream");
23 }
24 }
25
26 private byte[] ensureSize(byte[] buff, int len) {
27 return buff == null || buff.length < len ? new byte[len] : buff;
28 }
29
30 private void fillBuffer() throws IOException {
31 if(buffer != null && pos < bufferLength) {
32 return;
33 }
34 int len = readInt();
35 if(decompress == null) {
36 this.bufferLength = 0;
38 } else if(len < 0) {
39 len = -len;
40 buffer = ensureSize(buffer, len);
41 readFully(buffer, len);
42 this.bufferLength = len;
43 } else {
44 inBuffer = ensureSize(inBuffer, len);
45 int size = readInt();
46 readFully(inBuffer, len);
47 buffer = ensureSize(buffer, size);
48 try {
49 decompress.expand(inBuffer, 0, len, buffer, 0, size);
50 } catch(Exception e) {
51 throw new IOException ("Error decompressing bytes");
52 }
53 this.bufferLength = size;
54 }
55 pos = 0;
56 }
57
58 private void readFully(byte[] buff, int len) throws IOException {
59 int off = 0;
60 while(len > 0) {
61 int l = in.read(buff, off, len);
62 len -= l;
63 off += l;
64 }
65 }
66
67 private int readInt() throws IOException {
68 int x = in.read();
69 if(x<0) {
70 close();
71 decompress = null;
72 return 0;
73 }
74 x = (x<< 24) + (in.read() << 16) + (in.read() << 8) + in.read();
75 return x;
76 }
77
78 public int read() throws IOException {
79 fillBuffer();
80 if(pos >= bufferLength) {
81 return -1;
82 }
83 return buffer[pos++] & 255;
84 }
85
86 public int read(byte[] b) throws IOException {
87 return read(b, 0, b.length);
88 }
89
90 public int read(byte[] b, int off, int len) throws IOException {
91 if(len == 0) {
92 return 0;
93 }
94 int read = 0;
95 while(len > 0) {
96 int r = readBlock(b, off, len);
97 if(r < 0) {
98 break;
99 }
100 read += r;
101 off += r;
102 len -= r;
103 }
104 return read == 0 ? -1 : read;
105 }
106
107 public int readBlock(byte[] b, int off, int len) throws IOException {
108 fillBuffer();
109 if(pos >= bufferLength) {
110 return -1;
111 }
112 int max = Math.min(len, bufferLength - pos);
113 max = Math.min(max, b.length - off);
114 System.arraycopy(buffer, pos, b, off, max);
115 pos += max;
116 return max;
117 }
118
119 public void close() throws IOException {
120 in.close();
121 }
122
123 }
124 |
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