ArUtils


1   package de.masters_of_disaster.ant.tasks.ar;
2   
3   /**
4    * This class provides static utility methods to work with byte streams.
5    */
6   public class ArUtils {
7       /**
8        * Parse an octal string from a header buffer. This is used for the
9        * file permission mode value.
10       *
11       * @param header The header buffer from which to parse.
12       * @param offset The offset into the buffer from which to parse.
13       * @param length The number of header bytes to parse.
14       * @return The long value of the octal string.
15       */
16      public static long parseOctal(byte[] header, int offset, int length) {
17          long    result = 0;
18          int     end = offset + length;
19  
20          for (int i=offset ; i<end ; i++) {
21              if (header[i] == (byte) ' ') {
22                  break;
23              }
24              result = (result << 3) + (header[i] - '0');
25          }
26  
27          return result;
28      }
29  
30      /**
31       * Parse an entry name from a header buffer.
32       *
33       * @param header The header buffer from which to parse.
34       * @param offset The offset into the buffer from which to parse.
35       * @param length The number of header bytes to parse.
36       * @return The header's entry name.
37       */
38      public static StringBuffer   parseName(byte[] header, int offset, int length) {
39          StringBuffer   result = new StringBuffer  (length);
40          int          end = offset + length;
41  
42          for (int i=offset ; i<end ; i++) {
43              if (header[i] == ' ') {
44                  break;
45              }
46  
47              result.append((char) header[i]);
48          }
49  
50          return result;
51      }
52  
53      /**
54       * Write a name into a byte array.
55       *
56       * @param name The name to write.
57       * @param buf The byte array into which to write.
58       * @param offset The offset into the buffer from which to write.
59       * @param length The number of header bytes to write.
60       * @return The number of bytes written to the buffer.
61       */
62      public static int getNameBytes(StringBuffer   name, byte[] buf, int offset, int length) {
63          int i;
64          int c = name.length();
65  
66          for (i=0 ; i<length && i<c ; i++) {
67              buf[offset+i] = (byte) name.charAt(i);
68          }
69  
70          while (i<length) {
71              buf[offset+i] = (byte) ' ';
72              i++;
73          }
74  
75          return offset + length;
76      }
77  
78      /**
79       * Write a long value into a byte array.
80       *
81       * @param value The value to write.
82       * @param buf The byte array into which to write.
83       * @param offset The offset into the buffer from which to write.
84       * @param length The number of header bytes to write.
85       * @return The number of bytes written to the buffer.
86       */
87      public static int getLongBytes(long value, byte[] buf, int offset, int length) {
88          int i;
89          String   tmp = Long.toString(value);
90          int c = tmp.length();
91  
92          for (i=0 ; i<length && i<c ; i++) {
93              buf[offset+i] = (byte) tmp.charAt(i);
94          }
95  
96          while (i<length) {
97              buf[offset+i] = (byte) ' ';
98              i++;
99          }
100 
101         return offset + length;
102     }
103 
104     /**
105      * Write an int value into a byte array.
106      *
107      * @param value The value to write.
108      * @param buf The byte array into which to write.
109      * @param offset The offset into the buffer from which to write.
110      * @param length The number of header bytes to write.
111      * @return The number of bytes written to the buffer.
112      */
113     public static int getIntegerBytes(int value, byte[] buf, int offset, int length) {
114         int i;
115         String   tmp = Integer.toString(value);
116         int c = tmp.length();
117 
118         for (i=0 ; i<length && i<c ; i++) {
119             buf[offset+i] = (byte) tmp.charAt(i);
120         }
121 
122         while (i<length) {
123             buf[offset+i] = (byte) ' ';
124             i++;
125         }
126 
127         return offset + length;
128     }
129 
130     /**
131      * Write an octal value into a byte array.
132      *
133      * @param value The value to write.
134      * @param buf The byte array into which to write.
135      * @param offset The offset into the buffer from which to write.
136      * @param length The number of header bytes to write.
137      * @return The number of bytes written to the buffer.
138      */
139     public static int getOctalBytes(long value, byte[] buf, int offset, int length) {
140         int i;
141         String   tmp = Long.toOctalString(value);
142         int c = tmp.length();
143 
144         for (i=0 ; i<length && i<c ; i++) {
145             buf[offset+i] = (byte) tmp.charAt(i);
146         }
147 
148         while (i<length) {
149             buf[offset+i] = (byte) ' ';
150             i++;
151         }
152 
153         return offset + length;
154     }
155 }
156
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