This document provides an annotated comparison of the files $file1 and $file2. Specifically, it lists the additions and deletions made to $file1 in order to produce $file2.
It is recommended that you view this document in an HTML browser that supports cascading style sheets (CSS). Although additions and deletions are identified in the underlying HTML markup, most of the text annotations used to identify additions and deletions are visible only in a CSS-compliant browser.
Using Netscape Navigator version 4.x to print this document is not recommended, because Navigator's poor support for CSS may prevent document additions from being properly annotated in printed copies. Microsoft Internet Explorer version 3.x is not recommended for viewing or printing.
The examples below show how additions, deletions, and unchanged text are annotated in the document: $PrecedeAdditions
This is an addition.$FollowAdditions
This is unchanged text that appears in both files.$PrecedeDeletions
This is a deletion.$FollowDeletions
(Added)
'; $PrecedeDeletions = '(Deleted)
'; } elsif (/^-vv$/) { $PrecedeAdditions = '(Added)
'; $PrecedeDeletions = '(Deleted)
'; $FollowAdditions = '(End added)
'; $FollowDeletions = '(End deleted)
'; } elsif (/^-.*$/) { print "Invalid flag $ARGV[$i]\n"; PrintHelp (); return -1; } elsif ($file1 eq "") { $file1 = $ARGV[$i]; } else { $file2 = $ARGV[$i]; } } if (($file1 eq "") || ($file2 eq "")) { PrintHelp (); return -1; } return 0; } # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # Input file comparison and summary production subroutines # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # DumpLine # # Prints the supplied line to standard output, preceding it with the # current line number if desired. # # Parameters: # TBD # # Return Value: # The subroutine does not return a value. # # Remarks: # This subroutine prepends the line number to the line, if the user # has requested line numbers. # # Modification History: # 02 Oct 1999 - Created. CLT # sub DumpLine { my ($line, $line_segment); # This routine also uses $line_segment_length as a persistent # variable. $SummaryLineNum++; $line = $_[0]; chomp $line; # Set $line_segment_length first time through the routine if ($line_segment_length == 0) { if ($AddLineNumbers != 0) { # The magic number seven indicates five places for # line numbers, a colon, and a space, for a total of # seven columns. $line_segment_length = int $MaxCols - 7; } else { $line_segment_length = int $MaxCols; } } $line_segment = substr ($line, 0, $line_segment_length); $line = substr ($line, $line_segment_length); # Convert characters that might confuse an HTML user agent to # valid HTML entities ($line_segment = $line_segment) =~ s{\&}{&}g; ($line_segment = $line_segment) =~ s{\<}{<}g; ($line_segment = $line_segment) =~ s{\>}{>}g; # Dump the line to output if ($AddLineNumbers != 0) { printf "%5d: %s\n", $SummaryLineNum, $line_segment; } else { print "$line_segment\n"; } while ($line ne "") { $line_segment = substr ($line, 0, $line_segment_length); $line = substr ($line, $line_segment_length); # Convert characters that might confuse an HTML user agent to # valid HTML entities ($line_segment = $line_segment) =~ s{\&}{&}g; ($line_segment = $line_segment) =~ s{\<}{<}g; ($line_segment = $line_segment) =~ s{\>}{>}g; # Dump the line to output if ($AddLineNumbers != 0) { print " $line_segment\n"; } else { print "$line_segment\n"; } } } # # GenerateSummary # # Opens the source files and an input stream representing diff's # output, then produces the comparison summary. # # Parameters: # None. # # Return Value: # The subroutine does not return a value. # # Remarks: # The subroutine causes the script to exit immediately if # one of the files cannot be opened. # # Modification History: # 29 Sep 1999 - Created. CLT # sub GenerateSummary () { my ($difference, $current_diff, $ref_diff, $command, $following_line, $current_line, @cmdargs, $line, $i); open (FILE1, $file1) or die "Cannot open file $file1"; # Just make sure file2 is here. We won't be using it here, except # as input to diff. open (FILE2, $file2) or die "Cannot open file $file2"; close FILE2; open (DIFF, "diff -n $file1 $file2 |") or die "Cannot open diff"; $current_line = 0; $current_diff = 0; $difference =\n";
while ($current_line < ($following_line - 1)) {
$current_line++;
$line = ;
DumpLine $line;
}
if ($command eq "a") {
while ($current_line < $following_line) {
$current_line++;
$line = ;
DumpLine $line;
}
}
print " \n";
if (($AddLinks != 0) && ($current_diff > 1)) {
$ref_diff = $current_diff - 1;
print "\n";
}
if ($command eq "a") {
# Add new lines as directed by diff's output
print $PrecedeAdditions;
print "\n";
for ($i = 0; $i < $cmdargs[1]; $i++) {
# Don't increment $current_line here.
$line = ;
DumpLine $line;
}
print " \n";
print $FollowAdditions;
}
elsif ($command eq "d") {
# Show the deleted lines, beginning with the current line
print $PrecedeDeletions;
print "\n";
for ($i = 0; $i < $cmdargs[1]; $i++) {
$current_line++;
$line = ;
DumpLine $line;
}
print " \n";
print $FollowDeletions;
}
else {
print "I don't understand diff's output:\n"; print "
\n";
print $difference;
print "\n";
}
$difference = \n";
while ($line = ) {
$current_line++;
DumpLine $line;
}
print " \n";
close DIFF;
close FILE1;
}
#
# WriteDocument
#
# Compares the input files and produces the comparison document.
#
# Parameters:
# None.
#
# Return Value:
# The subroutine does not return a value.
#
# Remarks:
#
# Modification History:
# 29 Sep 1999 - Created. CLT
#
sub WriteDocument ()
{
PrintDocHeader ();
StartDocBody ();
if ($NoAddIntro == 0) {
WriteIntro ();
}
GenerateSummary ();
FinishDocBody ();
}
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
#
# Main routine
#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
#
# (Main entry point)
#
# Top-level executive routine for the script.
#
# Parameters:
# None.
#
# Return Value:
# The block does not return a value.
#
# Remarks:
#
# Modification History:
# 29 Sep 1999 - Created. CLT
#
BEGIN
{
# Set default values
$MaxCols = 80;
$AddLinks = 0;
$NoAddIntro = 0;
$AddLineNumbers = 0;
$SummaryLineNum = 0;
$StyleFile = "";
$PrecedeAdditions = "";
$FollowAdditions = "";
$PrecedeDeletions = "";
$FollowDeletions = "";
# This variable is used only in DumpLine, but it is declared globally
# so it will be persistent. It is initialized here and changed on
# the first run through DumpLine.
$line_segment_length = 0;
if (ProcessCommandLineArguments () != 0) {
exit;
}
WriteDocument ();
}