Mercurial > jhg

comparison src/com/tmate/hgkit/fs/DataAccess.java @ 10:382cfe9463db

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Dirstate parsing. DataAccess refactored to allow reuse and control over constants
author Artem Tikhomirov <tikhomirov.artem@gmail.com>
date Sat, 25 Dec 2010 21:50:12 +0100
parents
children 9429c7bd1920
comparison
equal deleted inserted replaced
9:d6d2a630f4a6 10:382cfe9463db
1 /*
2 * Copyright (c) 2010 Artem Tikhomirov
3 */
4 package com.tmate.hgkit.fs;
5
6 import java.io.IOException;
7
8 /**
9 * relevant parts of DataInput, non-stream nature (seek operation), explicit check for end of data.
10 * convenient skip (+/- bytes)
11 * Primary goal - effective file read, so that clients don't need to care whether to call few
12 * distinct getInt() or readBytes(totalForFewInts) and parse themselves instead in an attempt to optimize.
13 */
14 public class DataAccess {
15 public boolean isEmpty() {
16 return true;
17 }
18 // absolute positioning
19 public void seek(long offset) throws IOException {
20 throw new UnsupportedOperationException();
21 }
22 // relative positioning
23 public void skip(int bytes) throws IOException {
24 throw new UnsupportedOperationException();
25 }
26 // shall be called once this object no longer needed
27 public void done() {
28 // no-op in this empty implementation
29 }
30 public int readInt() throws IOException {
31 byte[] b = new byte[4];
32 readBytes(b, 0, 4);
33 return b[0] << 24 | (b[1] & 0xFF) << 16 | (b[2] & 0xFF) << 8 | (b[3] & 0xFF);
34 }
35 public long readLong() throws IOException {
36 byte[] b = new byte[8];
37 readBytes(b, 0, 8);
38 int i1 = b[0] << 24 | (b[1] & 0xFF) << 16 | (b[2] & 0xFF) << 8 | (b[3] & 0xFF);
39 int i2 = b[4] << 24 | (b[5] & 0xFF) << 16 | (b[6] & 0xFF) << 8 | (b[7] & 0xFF);
40 return ((long) i1) << 32 | ((long) i2 & 0xFFFFFFFF);
41 }
42 public void readBytes(byte[] buf, int offset, int length) throws IOException {
43 throw new UnsupportedOperationException();
44 }
45 public byte readByte() throws IOException {
46 throw new UnsupportedOperationException();
47 }
48 }