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1
5 package org.h2.store;
6
7 import java.io.IOException  ;
8 import java.io.InputStream ;
9 import java.sql.SQLException ;
10
11 import org.h2.engine.Constants;
12 import org.h2.message.Message;
13 import org.h2.tools.CompressTool;
14
15 public class FileStoreInputStream extends InputStream {
16
17 private FileStore store;
18 private DataPage page;
19 private int remaining;
20 private CompressTool compress;
21
22 public FileStoreInputStream(FileStore store, DataHandler handler, boolean compression) throws SQLException {
23 this.store = store;
24 if(compression) {
25 compress = CompressTool.getInstance();
26 }
27 page = DataPage.create(handler, Constants.FILE_BLOCK_SIZE);
28 try {
29 if(store.length() <= FileStore.HEADER_LENGTH) {
30 close();
31 } else {
32 fillBuffer();
33 }
34 } catch(IOException e) {
35 throw Message.convert(e);
36 }
37 }
38
39 public int available() {
40 return remaining <= 0 ? 0 : remaining;
41 }
42
43 public int read(byte[] buff) throws IOException {
44 return read(buff, 0, buff.length);
45 }
46
47 public int read(byte[] b, int off, int len) throws IOException {
48 if(len == 0) {
49 return 0;
50 }
51 int read = 0;
52 while(len > 0) {
53 int r = readBlock(b, off, len);
54 if(r < 0) {
55 break;
56 }
57 read += r;
58 off += r;
59 len -= r;
60 }
61 return read == 0 ? -1 : read;
62 }
63
64 public int readBlock(byte[] buff, int off, int len) throws IOException {
65 fillBuffer();
66 if(store == null) {
67 return -1;
68 }
69 int l = Math.min(remaining, len);
70 page.read(buff, off, l);
71 remaining -= l;
72 return l;
73 }
74
75 private void fillBuffer() throws IOException {
76 if(remaining > 0 || store==null) {
77 return;
78 }
79 page.reset();
80 try {
81 if(store.length() == store.getFilePointer()) {
82 close();
83 return;
84 }
85 store.readFully(page.getBytes(), 0, Constants.FILE_BLOCK_SIZE);
86 } catch(SQLException e) {
87 throw Message.convertToIOException(e);
88 }
89 page.reset();
90 remaining = page.readInt();
91 if(remaining<0) {
92 close();
93 return;
94 }
95 page.checkCapacity(remaining);
96 if(compress != null) {
98 page.checkCapacity(page.getIntLen());
99 page.readInt();
100 }
101 page.setPos(page.length() + remaining);
102 page.fillAligned();
103 int len = page.length() - Constants.FILE_BLOCK_SIZE;
104 page.reset();
105 page.readInt();
106 try {
107 store.readFully(page.getBytes(), Constants.FILE_BLOCK_SIZE, len);
108 page.reset();
109 page.readInt();
110 if(compress != null) {
111 int uncompressed = page.readInt();
112 byte[] buff = new byte[remaining];
113 page.read(buff, 0, remaining);
114 page.reset();
115 page.checkCapacity(uncompressed);
116 compress.expand(buff, page.getBytes(), 0);
117 remaining = uncompressed;
118 }
119 } catch(SQLException e) {
120 throw Message.convertToIOException(e);
121 }
122 }
123
124 public void close() throws IOException {
125 if(store != null) {
126 try {
127 store.close();
128 } finally {
129 store = null;
130 }
131 }
132 }
133
134 protected void finalize() {
135 if (!Constants.RUN_FINALIZERS) {
136 return;
137 }
138 try {
139 close();
140 } catch(IOException e) {
141 }
143 }
144
145 public int read() throws IOException {
146 fillBuffer();
147 if(store == null) {
148 return -1;
149 }
150 int i = page.readByte() & 0xff;
151 remaining--;
152 return i;
153 }
154
155 }
156 |
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