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1 package com.thoughtworks.xstream.io.path;
2
3 import com.thoughtworks.xstream.core.util.StringStack;
4
5 import java.util.ArrayList  ;
6 import java.util.List ;
7
8 public class RelativePathCalculator {
9
10 public String relativePath(String from, String to) {
11 String [] fromBits = split(from);
12 String [] toBits = split(to);
13 StringBuffer result = new StringBuffer ();
14 boolean nothingWrittenYet = true;
15
16 int depthOfPathDivergence = depthOfPathDivergence(fromBits, toBits);
17
18 for (int i = depthOfPathDivergence; i < fromBits.length; i++) {
19 if (nothingWrittenYet) {
20 nothingWrittenYet = false;
21 } else {
22 result.append('/');
23 }
24 result.append("..");
25 }
26
27 for (int j = depthOfPathDivergence; j < toBits.length; j++) {
28 if (nothingWrittenYet) {
29 nothingWrittenYet = false;
30 } else {
31 result.append('/');
32 }
33 result.append(toBits[j]);
34 }
35
36 if (nothingWrittenYet) {
37 return ".";
38 } else {
39 return result.toString();
40 }
41 }
42
43 private String [] split(String str) {
44 List result = new ArrayList ();
46 int currentIndex = 0;
47 int nextSeperator;
48 while ((nextSeperator = str.indexOf('/', currentIndex)) != -1) {
49 result.add(str.substring(currentIndex, nextSeperator));
50 currentIndex = nextSeperator + 1;
51 }
52 result.add(str.substring(currentIndex));
53 String [] arr = new String [result.size()];
54 result.toArray(arr);
55 return arr;
56 }
57
58 private int depthOfPathDivergence(String [] path1, String [] path2) {
59 int minLength = Math.min(path1.length, path2.length);
60 for (int i = 0; i < minLength; i++) {
61 if (!path1[i].equals(path2[i])) {
62 return i;
63 }
64 }
65 return minLength;
66 }
67
68 public String absolutePath(String currentPath, String relativePathOfReference) {
69 StringStack absoluteStack = new StringStack(16);
70
71 String [] currentPathChunks = split(currentPath);
72 for (int i = 0; i < currentPathChunks.length; i++) {
73 absoluteStack.push(currentPathChunks[i]);
74 }
75
76 String [] relativeChunks = split(relativePathOfReference);
77 for (int i = 0; i < relativeChunks.length; i++) {
78 String relativeChunk = relativeChunks[i];
79 if (relativeChunk.equals("..")) {
80 absoluteStack.pop();
81 } else if (!relativeChunk.equals(".")) {
82 absoluteStack.push(relativeChunk);
83 }
84 }
85
86 StringBuffer result = new StringBuffer ();
87 int size = absoluteStack.size();
88 for (int i = 0; i < size; i++) {
89 if (i > 0) {
90 result.append('/');
91 }
92 result.append(absoluteStack.get(i));
93 }
94
95 return result.toString();
96 }
97
98 }
99 |
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