1 package org.ibex.nestedvm.util;
5 public abstract class Seekable {
6 public abstract int read(byte[] buf, int offset, int length) throws IOException;
7 public abstract int write(byte[] buf, int offset, int length) throws IOException;
8 public abstract int length() throws IOException;
9 public abstract void seek(int pos) throws IOException;
10 public abstract void close() throws IOException;
11 public abstract int pos() throws IOException;
13 public int read() throws IOException {
14 byte[] buf = new byte[1];
15 int n = read(buf,0,1);
16 return n == -1 ? -1 : buf[0]&0xff;
19 public static class ByteArray extends Seekable {
20 protected byte[] data;
22 private final boolean writable;
24 public ByteArray(byte[] data, boolean writable) {
27 this.writable = writable;
30 public int read(byte[] buf, int off, int len) {
31 len = Math.min(len,data.length-pos);
32 if(len <= 0) return -1;
33 System.arraycopy(data,pos,buf,off,len);
38 public int write(byte[] buf, int off, int len) throws IOException {
39 if(!writable) throw new IOException("read-only data");
40 len = Math.min(len,data.length-pos);
41 if(len <= 0) throw new IOException("no space");
42 System.arraycopy(buf,off,data,pos,len);
47 public int length() { return data.length; }
48 public int pos() { return pos; }
49 public void seek(int pos) { this.pos = pos; }
50 public void close() { /*noop*/ }
53 public static class File extends Seekable {
54 private final RandomAccessFile raf;
56 public File(String fileName) throws IOException { this(fileName,false); }
57 public File(String fileName, boolean writable) throws IOException { this(new java.io.File(fileName),writable); }
59 public File(java.io.File file, boolean writable) throws IOException {
60 raf = new RandomAccessFile(file,writable ? "rw" : "r");
63 // NOTE: RandomAccessFile.setLength() is a Java2 function
64 public void setLength(int n) throws IOException { raf.setLength(n); }
66 public int read(byte[] buf, int offset, int length) throws IOException { return raf.read(buf,offset,length); }
67 public int write(byte[] buf, int offset, int length) throws IOException { raf.write(buf,offset,length); return length; }
68 public void seek(int pos) throws IOException{ raf.seek(pos); }
69 public int pos() throws IOException { return (int) raf.getFilePointer(); }
70 public int length() throws IOException { return (int)raf.length(); }
71 public void close() throws IOException { raf.close(); }
74 public static class InputStream extends Seekable {
75 private byte[] buffer = new byte[4096];
76 private int bytesRead = 0;
77 private boolean eof = false;
79 private java.io.InputStream is;
81 public InputStream(java.io.InputStream is) { this.is = is; }
83 public int read(byte[] outbuf, int off, int len) throws IOException {
84 if(pos >= bytesRead && !eof) readTo(pos + 1);
85 len = Math.min(len,bytesRead-pos);
86 if(len <= 0) return -1;
87 System.arraycopy(buffer,pos,outbuf,off,len);
92 private void readTo(int target) throws IOException {
93 if(target >= buffer.length) {
94 byte[] buf2 = new byte[Math.max(buffer.length+Math.min(buffer.length,65536),target)];
95 System.arraycopy(buffer,0,buf2,0,bytesRead);
98 while(bytesRead < target) {
99 int n = is.read(buffer,bytesRead,buffer.length-bytesRead);
108 public int length() throws IOException {
109 while(!eof) readTo(bytesRead+4096);
113 public int write(byte[] buf, int off, int len) throws IOException { throw new IOException("read-only"); }
114 public void seek(int pos) { this.pos = pos; }
115 public int pos() { return pos; }
116 public void close() throws IOException { is.close(); }