cli/src/commands/org/jnode/command/file/CmpCommand.java

   1 package org.jnode.command.file;
   2
   3 import java.io.BufferedInputStream;
   4 import java.io.File;
   5 import java.io.FileInputStream;
   6 import java.io.IOException;
   7 import java.io.PrintWriter;
   8 import org.jnode.shell.AbstractCommand;
   9 import org.jnode.shell.syntax.Argument;
  10 import org.jnode.shell.syntax.FileArgument;
  11
  12 /**
  13  * Compare two files and report the first difference.
  14  *
  15  * @author Levente S\u00e1ntha
  16  */
  17 public class CmpCommand extends AbstractCommand {
  18
  19     private static final int BUFFER_SIZE = 64 * 1024;
  20
  21     private static final String HELP_SUPER = "Compare two files";
  22     private static final String HELP_FILE = "a file to compare";
  23     private static final String ERR_FILE_INVALID = "%s is not a file%n";
  24     private static final String MSG_DIFFER = "%s %s differ: byte %d, line %d%n";
  25     private static final String MSG_EOF = "cmp: EOF on %s%n";
  26
  27     private final FileArgument file1Arg;
  28     private final FileArgument file2Arg;
  29
  30     public CmpCommand() {
  31         super(HELP_SUPER);
  32
  33         file1Arg = new FileArgument("file1", Argument.MANDATORY | Argument.EXISTING, HELP_FILE);
  34         file2Arg = new FileArgument("file2", Argument.MANDATORY | Argument.EXISTING, HELP_FILE);
  35
  36         registerArguments(file1Arg, file2Arg);
  37     }
  38
  39     public static void main(String[] args) throws Exception {
  40         new CmpCommand().execute(args);
  41     }
  42
  43     @Override
  44     public void execute() throws IOException {
  45
  46         File file1 = file1Arg.getValue();
  47         File file2 = file2Arg.getValue();
  48
  49         PrintWriter err = getError().getPrintWriter();
  50
  51         if (!file1.isFile()) {
  52             err.format(ERR_FILE_INVALID, file1);
  53             exit(1);
  54         }
  55
  56         if (!file2.isFile()) {
  57             err.format(ERR_FILE_INVALID, file2);
  58             exit(1);
  59         }
  60
  61         BufferedInputStream bis1 = null;
  62         BufferedInputStream bis2 = null;
  63
  64         try {
  65             bis1 = new BufferedInputStream(new FileInputStream(file1), BUFFER_SIZE);
  66             bis2 = new BufferedInputStream(new FileInputStream(file2), BUFFER_SIZE);
  67
  68             long bc = 1;
  69             long lc = 1;
  70
  71             while (true) {
  72                 int b1 = bis1.read();
  73                 int b2 = bis2.read();
  74
  75                 if (b1 == -1 && b2 == -1)
  76                     //done
  77                     break;
  78
  79                 if (b1 == -1) {
  80                     PrintWriter out = getOutput().getPrintWriter();
  81                     out.format(MSG_EOF, file1.toString());
  82                     exit(1);
  83                     return;
  84                 }
  85
  86                 if (b2 == -1) {
  87                     PrintWriter out = getOutput().getPrintWriter();
  88                     out.format(MSG_EOF, file2.toString());
  89                     exit(1);
  90                     return;
  91                 }
  92
  93                 if (b1 != b2) {
  94                     PrintWriter out = getOutput().getPrintWriter();
  95                     out.format(MSG_DIFFER, file1.toString(), file2.toString(), bc, lc);
  96                     exit(1);
  97                     return;
  98                 }
  99
 100                 bc++;
 101
 102                 if (b1 == (byte) '\n')
 103                     lc++;
 104             }
 105         } finally {
 106             if (bis1 != null) {
 107                 try {
 108                     bis1.close();
 109                 } catch (IOException x) {
 110                     //ignore
 111                 }
 112             }
 113
 114             if (bis2 != null) {
 115                 try {
 116                     bis2.close();
 117                 } catch (IOException x) {
 118                     //ignore
 119                 }
 120             }
 121         }
 122     }
 123 }