Adding Peter Thatcher to the owners file.

[chromium-blink-merge.git] / third_party / lcov / contrib / galaxy / genflat.pl

#!/usr/bin/perl -w
#
#   Copyright (c) International Business Machines  Corp., 2002
#
#   This program is free software;  you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation; either version 2 of the License, or (at
#   your option) any later version.
#
#   This program is distributed in the hope that it will be useful, but
#   WITHOUT ANY WARRANTY;  without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#   General Public License for more details.                 
#
#   You should have received a copy of the GNU General Public License
#   along with this program;  if not, write to the Free Software
#   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
#
# genflat
#
#   This script generates std output from .info files as created by the
#   geninfo script. Call it with --help to get information on usage and 
#   available options.  This code is based on the lcov genhtml script
#   by Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com>
#
#
# History:
#   2003-08-19 ripped up Peter's script James M Kenefick Jr. <jkenefic@us.ibm.com>
#

use strict;
use File::Basename; 
use Getopt::Long;
# Constants
our $lcov_version = "";
our $lcov_url = "";

# Specify coverage rate limits (in %) for classifying file entries
# HI:   $hi_limit <= rate <= 100          graph color: green
# MED: $med_limit <= rate <  $hi_limit    graph color: orange
# LO:          0  <= rate <  $med_limit   graph color: red
our $hi_limit   = 50;
our $med_limit  = 15;

# Data related prototypes
sub print_usage(*);
sub gen_html();
sub process_dir($);
sub process_file($$$);
sub info(@);
sub read_info_file($);
sub get_info_entry($);
sub set_info_entry($$$$;$$);
sub get_prefix(@);
sub shorten_prefix($);
sub get_dir_list(@);
sub get_relative_base_path($);
sub get_date_string();
sub split_filename($);
sub subtract_counts($$);
sub add_counts($$);
sub apply_baseline($$);
sub combine_info_files($$);
sub combine_info_entries($$);
sub apply_prefix($$);
sub escape_regexp($);


# HTML related prototypes


sub write_file_table(*$$$$);


# Global variables & initialization
our %info_data;         # Hash containing all data from .info file
our $dir_prefix;        # Prefix to remove from all sub directories
our %test_description;  # Hash containing test descriptions if available
our $date = get_date_string();

our @info_filenames;    # List of .info files to use as data source
our $test_title;        # Title for output as written to each page header
our $output_directory;  # Name of directory in which to store output
our $base_filename;     # Optional name of file containing baseline data
our $desc_filename;     # Name of file containing test descriptions
our $css_filename;      # Optional name of external stylesheet file to use
our $quiet;             # If set, suppress information messages
our $help;              # Help option flag
our $version;           # Version option flag
our $show_details;      # If set, generate detailed directory view
our $no_prefix;         # If set, do not remove filename prefix
our $frames;            # If set, use frames for source code view
our $keep_descriptions; # If set, do not remove unused test case descriptions
our $no_sourceview;     # If set, do not create a source code view for each file
our $tab_size = 8;      # Number of spaces to use in place of tab

our $cwd = `pwd`;       # Current working directory
chomp($cwd);
our $tool_dir = dirname($0);    # Directory where genhtml tool is installed


#
# Code entry point
#

# Add current working directory if $tool_dir is not already an absolute path
if (! ($tool_dir =~ /^\/(.*)$/))
{
        $tool_dir = "$cwd/$tool_dir";
}

# Parse command line options
if (!GetOptions("output-directory=s"    => \$output_directory,
                "css-file=s"            => \$css_filename,
                "baseline-file=s"       => \$base_filename,
                "prefix=s"              => \$dir_prefix,
                "num-spaces=i"          => \$tab_size,
                "no-prefix"             => \$no_prefix,
                "quiet"                 => \$quiet,
                "help"                  => \$help,
                "version"               => \$version
                ))
{
        print_usage(*STDERR);
        exit(1);
}

@info_filenames = @ARGV;

# Check for help option
if ($help)
{
        print_usage(*STDOUT);
        exit(0);
}

# Check for version option
if ($version)
{
        print($lcov_version."\n");
        exit(0);
}

# Check for info filename
if (!@info_filenames)
{
        print(STDERR "No filename specified\n");
        print_usage(*STDERR);
        exit(1);
}

# Generate a title if none is specified
if (!$test_title)
{
        if (scalar(@info_filenames) == 1)
        {
                # Only one filename specified, use it as title
                $test_title = basename($info_filenames[0]);
        }
        else
        {
                # More than one filename specified, used default title
                $test_title = "unnamed";
        }
}

# Make sure tab_size is within valid range
if ($tab_size < 1)
{
        print(STDERR "ERROR: invalid number of spaces specified: ".
                     "$tab_size!\n");
        exit(1);
}

# Do something
gen_html();

exit(0);



#
# print_usage(handle)
#
# Print usage information.
#

sub print_usage(*)
{
        local *HANDLE = $_[0];
        my $executable_name = basename($0);

        print(HANDLE <<END_OF_USAGE);
Usage: $executable_name [OPTIONS] INFOFILE(S)

Create HTML output for coverage data found in INFOFILE. Note that INFOFILE
may also be a list of filenames.

  -h, --help                        Print this help, then exit
  -v, --version                     Print version number, then exit
  -q, --quiet                       Do not print progress messages
  -b, --baseline-file BASEFILE      Use BASEFILE as baseline file
  -p, --prefix PREFIX               Remove PREFIX from all directory names
      --no-prefix                   Do not remove prefix from directory names
      --no-source                   Do not create source code view
      --num-spaces NUM              Replace tabs with NUM spaces in source view

See $lcov_url for more information about this tool.
END_OF_USAGE
        ;
}


#
# gen_html()
#
# Generate a set of HTML pages from contents of .info file INFO_FILENAME.
# Files will be written to the current directory. If provided, test case
# descriptions will be read from .tests file TEST_FILENAME and included
# in ouput.
#
# Die on error.
#

sub gen_html()
{
        local *HTML_HANDLE;
        my %overview;
        my %base_data;
        my $lines_found;
        my $lines_hit;
        my $overall_found = 0;
        my $overall_hit = 0;
        my $dir_name;
        my $link_name;
        my @dir_list;
        my %new_info;

        # Read in all specified .info files
        foreach (@info_filenames)
        {
                info("Reading data file $_\n");
                %new_info = %{read_info_file($_)};

                # Combine %new_info with %info_data
                %info_data = %{combine_info_files(\%info_data, \%new_info)};
        }

        info("Found %d entries.\n", scalar(keys(%info_data)));

        # Read and apply baseline data if specified
        if ($base_filename)
        {
                # Read baseline file
                info("Reading baseline file $base_filename\n");
                %base_data = %{read_info_file($base_filename)};
                info("Found %d entries.\n", scalar(keys(%base_data)));

                # Apply baseline
                info("Subtracting baseline data.\n");
                %info_data = %{apply_baseline(\%info_data, \%base_data)};
        }

        @dir_list = get_dir_list(keys(%info_data));

        if ($no_prefix)
        {
                # User requested that we leave filenames alone
                info("User asked not to remove filename prefix\n");
        }
        elsif (!defined($dir_prefix))
        {
                # Get prefix common to most directories in list
                $dir_prefix = get_prefix(@dir_list);

                if ($dir_prefix)
                {
                        info("Found common filename prefix \"$dir_prefix\"\n");
                }
                else
                {
                        info("No common filename prefix found!\n");
                        $no_prefix=1;
                }
        }
        else
        {
                info("Using user-specified filename prefix \"".
                     "$dir_prefix\"\n");
        }

        # Process each subdirectory and collect overview information
        foreach $dir_name (@dir_list)
        {
                ($lines_found, $lines_hit) = process_dir($dir_name);

                $overview{$dir_name} = "$lines_found,$lines_hit, ";
                $overall_found  += $lines_found;
                $overall_hit    += $lines_hit;
        }


        if ($overall_found == 0)
        {
                info("Warning: No lines found!\n");
        }
        else
        {
                info("Overall coverage rate: %d of %d lines (%.1f%%)\n",
                     $overall_hit, $overall_found,
                     $overall_hit*100/$overall_found);
        }
}


#
# process_dir(dir_name)
#

sub process_dir($)
{
        my $abs_dir = $_[0];
        my $trunc_dir;
        my $rel_dir = $abs_dir;
        my $base_dir;
        my $filename;
        my %overview;
        my $lines_found;
        my $lines_hit;
        my $overall_found=0;
        my $overall_hit=0;
        my $base_name;
        my $extension;
        my $testdata;
        my %testhash;
        local *HTML_HANDLE;

        # Remove prefix if applicable
        if (!$no_prefix)
        {
                # Match directory name beginning with $dir_prefix
                $rel_dir = apply_prefix($rel_dir, $dir_prefix);
        }

        $trunc_dir = $rel_dir;

        # Remove leading /
        if ($rel_dir =~ /^\/(.*)$/)
        {
                $rel_dir = substr($rel_dir, 1);
        }

        $base_dir = get_relative_base_path($rel_dir);

        $abs_dir = escape_regexp($abs_dir);

        # Match filenames which specify files in this directory, not including
        # sub-directories
        foreach $filename (grep(/^$abs_dir\/[^\/]*$/,keys(%info_data)))
        {
                ($lines_found, $lines_hit, $testdata) =
                        process_file($trunc_dir, $rel_dir, $filename);

                $base_name = basename($filename);

                $overview{$base_name} = "$lines_found,$lines_hit";

                $testhash{$base_name} = $testdata;

                $overall_found  += $lines_found;
                $overall_hit    += $lines_hit;
        }
        write_file_table($abs_dir, "./linux/", \%overview, \%testhash, 4);


        # Calculate resulting line counts
        return ($overall_found, $overall_hit);
}


#
# process_file(trunc_dir, rel_dir, filename)
#

sub process_file($$$)
{
        info("Processing file ".apply_prefix($_[2], $dir_prefix)."\n");
        my $trunc_dir = $_[0];
        my $rel_dir = $_[1];
        my $filename = $_[2];
        my $base_name = basename($filename);
        my $base_dir = get_relative_base_path($rel_dir);
        my $testdata;
        my $testcount;
        my $sumcount;
        my $funcdata;
        my $lines_found;
        my $lines_hit;
        my @source;
        my $pagetitle;

        ($testdata, $sumcount, $funcdata, $lines_found, $lines_hit) =
                get_info_entry($info_data{$filename});
        return ($lines_found, $lines_hit, $testdata);
}


#
# read_info_file(info_filename)
#
# Read in the contents of the .info file specified by INFO_FILENAME. Data will
# be returned as a reference to a hash containing the following mappings:
#
# %result: for each filename found in file -> \%data
#
# %data: "test"  -> \%testdata
#        "sum"   -> \%sumcount
#        "func"  -> \%funcdata
#        "found" -> $lines_found (number of instrumented lines found in file)
#        "hit"   -> $lines_hit (number of executed lines in file)
#
# %testdata: name of test affecting this file -> \%testcount
#
# %testcount: line number -> execution count for a single test
# %sumcount : line number -> execution count for all tests
# %funcdata : line number -> name of function beginning at that line
# 
# Note that .info file sections referring to the same file and test name
# will automatically be combined by adding all execution counts.
#
# Note that if INFO_FILENAME ends with ".gz", it is assumed that the file
# is compressed using GZIP. If available, GUNZIP will be used to decompress
# this file.
#
# Die on error
#

sub read_info_file($)
{
        my $tracefile = $_[0];          # Name of tracefile
        my %result;                     # Resulting hash: file -> data
        my $data;                       # Data handle for current entry
        my $testdata;                   #       "             "
        my $testcount;                  #       "             "
        my $sumcount;                   #       "             "
        my $funcdata;                   #       "             "
        my $line;                       # Current line read from .info file
        my $testname;                   # Current test name
        my $filename;                   # Current filename
        my $hitcount;                   # Count for lines hit
        my $count;                      # Execution count of current line
        my $negative;                   # If set, warn about negative counts
        local *INFO_HANDLE;             # Filehandle for .info file

        # Check if file exists and is readable
        stat($_[0]);
        if (!(-r _))
        {
                die("ERROR: cannot read file $_[0]!\n");
        }

        # Check if this is really a plain file
        if (!(-f _))
        {
                die("ERROR: not a plain file: $_[0]!\n");
        }

        # Check for .gz extension
        if ($_[0] =~ /^(.*)\.gz$/)
        {
                # Check for availability of GZIP tool
                system("gunzip -h >/dev/null 2>/dev/null")
                        and die("ERROR: gunzip command not available!\n");

                # Check integrity of compressed file
                system("gunzip -t $_[0] >/dev/null 2>/dev/null")
                        and die("ERROR: integrity check failed for ".
                                "compressed file $_[0]!\n");

                # Open compressed file
                open(INFO_HANDLE, "gunzip -c $_[0]|")
                        or die("ERROR: cannot start gunzip to uncompress ".
                               "file $_[0]!\n");
        }
        else
        {
                # Open uncompressed file
                open(INFO_HANDLE, $_[0])
                        or die("ERROR: cannot read file $_[0]!\n");
        }

        $testname = "";
        while (<INFO_HANDLE>)
        {
                chomp($_);
                $line = $_;

                # Switch statement
                foreach ($line)
                {
                        /^TN:(\w+)/ && do
                        {
                                # Test name information found
                                $testname = $1;
                                last;
                        };

                        /^[SK]F:(.*)/ && do
                        {
                                # Filename information found
                                # Retrieve data for new entry
                                $filename = $1;

                                $data = $result{$filename};
                                ($testdata, $sumcount, $funcdata) =
                                        get_info_entry($data);

                                if (defined($testname))
                                {
                                        $testcount = $testdata->{$testname};
                                }
                                else
                                {
                                        my %new_hash;
                                        $testcount = \%new_hash;
                                }
                                last;
                        };

                        /^DA:(\d+),(-?\d+)/ && do
                        {
                                # Fix negative counts
                                $count = $2 < 0 ? 0 : $2;
                                if ($2 < 0)
                                {
                                        $negative = 1;
                                }
                                # Execution count found, add to structure
                                # Add summary counts
                                $sumcount->{$1} += $count;

                                # Add test-specific counts
                                if (defined($testname))
                                {
                                        $testcount->{$1} += $count;
                                }
                                last;
                        };

                        /^FN:(\d+),([^,]+)/ && do
                        {
                                # Function data found, add to structure
                                $funcdata->{$1} = $2;
                                last;
                        };

                        /^end_of_record/ && do
                        {
                                # Found end of section marker
                                if ($filename)
                                {
                                        # Store current section data
                                        if (defined($testname))
                                        {
                                                $testdata->{$testname} =
                                                        $testcount;
                                        }
                                        set_info_entry($data, $testdata,
                                                       $sumcount, $funcdata);
                                        $result{$filename} = $data;
                                }

                        };

                        # default
                        last;
                }
        }
        close(INFO_HANDLE);

        # Calculate lines_found and lines_hit for each file
        foreach $filename (keys(%result))
        {
                $data = $result{$filename};

                ($testdata, $sumcount, $funcdata) = get_info_entry($data);

                $data->{"found"} = scalar(keys(%{$sumcount}));
                $hitcount = 0;

                foreach (keys(%{$sumcount}))
                {
                        if ($sumcount->{$_} >0) { $hitcount++; }
                }

                $data->{"hit"} = $hitcount;

                $result{$filename} = $data;
        }

        if (scalar(keys(%result)) == 0)
        {
                die("ERROR: No valid records found in tracefile $tracefile\n");
        }
        if ($negative)
        {
                warn("WARNING: Negative counts found in tracefile ".
                     "$tracefile\n");
        }

        return(\%result);
}


#
# get_info_entry(hash_ref)
#
# Retrieve data from an entry of the structure generated by read_info_file().
# Return a list of references to hashes:
# (test data hash ref, sum count hash ref, funcdata hash ref, lines found,
#  lines hit)
#

sub get_info_entry($)
{
        my $testdata_ref = $_[0]->{"test"};
        my $sumcount_ref = $_[0]->{"sum"};
        my $funcdata_ref = $_[0]->{"func"};
        my $lines_found  = $_[0]->{"found"};
        my $lines_hit    = $_[0]->{"hit"};

        return ($testdata_ref, $sumcount_ref, $funcdata_ref, $lines_found,
                $lines_hit);
}


#
# set_info_entry(hash_ref, testdata_ref, sumcount_ref, funcdata_ref[,
#                lines_found, lines_hit])
#
# Update the hash referenced by HASH_REF with the provided data references.
#

sub set_info_entry($$$$;$$)
{
        my $data_ref = $_[0];

        $data_ref->{"test"} = $_[1];
        $data_ref->{"sum"} = $_[2];
        $data_ref->{"func"} = $_[3];

        if (defined($_[4])) { $data_ref->{"found"} = $_[4]; }
        if (defined($_[5])) { $data_ref->{"hit"} = $_[5]; }
}


#
# get_prefix(filename_list)
#
# Search FILENAME_LIST for a directory prefix which is common to as many
# list entries as possible, so that removing this prefix will minimize the
# sum of the lengths of all resulting shortened filenames.
#

sub get_prefix(@)
{
        my @filename_list = @_;         # provided list of filenames
        my %prefix;                     # mapping: prefix -> sum of lengths
        my $current;                    # Temporary iteration variable

        # Find list of prefixes
        foreach (@filename_list)
        {
                # Need explicit assignment to get a copy of $_ so that
                # shortening the contained prefix does not affect the list
                $current = shorten_prefix($_);
                while ($current = shorten_prefix($current))
                {
                        # Skip rest if the remaining prefix has already been
                        # added to hash
                        if ($prefix{$current}) { last; }

                        # Initialize with 0
                        $prefix{$current}="0";
                }

        }

        # Calculate sum of lengths for all prefixes
        foreach $current (keys(%prefix))
        {
                foreach (@filename_list)
                {
                        # Add original length
                        $prefix{$current} += length($_);

                        # Check whether prefix matches
                        if (substr($_, 0, length($current)) eq $current)
                        {
                                # Subtract prefix length for this filename
                                $prefix{$current} -= length($current);
                        }
                }
        }

        # Find and return prefix with minimal sum
        $current = (keys(%prefix))[0];

        foreach (keys(%prefix))
        {
                if ($prefix{$_} < $prefix{$current})
                {
                        $current = $_;
                }
        }

        return($current);
}


#
# shorten_prefix(prefix)
#
# Return PREFIX shortened by last directory component.
#

sub shorten_prefix($)
{
        my @list = split("/", $_[0]);

        pop(@list);
        return join("/", @list);
}



#
# get_dir_list(filename_list)
#
# Return sorted list of directories for each entry in given FILENAME_LIST.
#

sub get_dir_list(@)
{
        my %result;

        foreach (@_)
        {
                $result{shorten_prefix($_)} = "";
        }

        return(sort(keys(%result)));
}


#
# get_relative_base_path(subdirectory)
#
# Return a relative path string which references the base path when applied
# in SUBDIRECTORY.
#
# Example: get_relative_base_path("fs/mm") -> "../../"
#

sub get_relative_base_path($)
{
        my $result = "";
        my $index;

        # Make an empty directory path a special case
        if (!$_[0]) { return(""); }

        # Count number of /s in path
        $index = ($_[0] =~ s/\//\//g);

        # Add a ../ to $result for each / in the directory path + 1
        for (; $index>=0; $index--)
        {
                $result .= "../";
        }

        return $result;
}


#
# get_date_string()
#
# Return the current date in the form: yyyy-mm-dd
#

sub get_date_string()
{
        my $year;
        my $month;
        my $day;

        ($year, $month, $day) = (localtime())[5, 4, 3];

        return sprintf("%d-%02d-%02d", $year+1900, $month+1, $day);
}


#
# split_filename(filename)
#
# Return (path, filename, extension) for a given FILENAME.
#

sub split_filename($)
{
        if (!$_[0]) { return(); }
        my @path_components = split('/', $_[0]);
        my @file_components = split('\.', pop(@path_components));
        my $extension = pop(@file_components);

        return (join("/",@path_components), join(".",@file_components),
                $extension);
}


#
# write_file_table(filehandle, base_dir, overview, testhash, fileview)
#
# Write a complete file table. OVERVIEW is a reference to a hash containing
# the following mapping:
#
#   filename -> "lines_found,lines_hit,page_link"
#
# TESTHASH is a reference to the following hash:
#
#   filename -> \%testdata
#   %testdata: name of test affecting this file -> \%testcount
#   %testcount: line number -> execution count for a single test
#
# Heading of first column is "Filename" if FILEVIEW is true, "Directory name"
# otherwise.
#

sub write_file_table(*$$$$)
{
        my $dir = $_[0];
        my $base_dir = $_[1];
        my %overview = %{$_[2]};
        my %testhash = %{$_[3]};
        my $fileview = $_[4];
        my $filename;
        my $hit;
        my $found;
        my $classification;
        my $rate_string;
        my $rate;
        my $junk;


        foreach $filename (sort(keys(%overview)))
        {
                ($found, $hit, $junk) = split(",", $overview{$filename});
#James I think this is right
                $rate = $hit * 100 / $found;
                $rate_string = sprintf("%.1f", $rate);

                if ($rate < 0.001)                      { $classification = "None"; }
                elsif ($rate < $med_limit)      { $classification = "Lo"; }
                elsif ($rate < $hi_limit)       { $classification = "Med"; }
                else                            { $classification = "Hi"; }

                print "$dir/$filename\t$classification\t$rate_string\n";

        }
}


#
# info(printf_parameter)
#
# Use printf to write PRINTF_PARAMETER to stdout only when the $quiet flag
# is not set.
#

sub info(@)
{
        if (!$quiet)
        {
                # Print info string
                printf(STDERR @_);
        }
}


#
# subtract_counts(data_ref, base_ref)
#

sub subtract_counts($$)
{
        my %data = %{$_[0]};
        my %base = %{$_[1]};
        my $line;
        my $data_count;
        my $base_count;
        my $hit = 0;
        my $found = 0;

        foreach $line (keys(%data))
        {
                $found++;
                $data_count = $data{$line};
                $base_count = $base{$line};

                if (defined($base_count))
                {
                        $data_count -= $base_count;

                        # Make sure we don't get negative numbers
                        if ($data_count<0) { $data_count = 0; }
                }

                $data{$line} = $data_count;
                if ($data_count > 0) { $hit++; }
        }

        return (\%data, $found, $hit);
}


#
# add_counts(data1_ref, data2_ref)
#
# DATA1_REF and DATA2_REF are references to hashes containing a mapping
#
#   line number -> execution count
#
# Return a list (RESULT_REF, LINES_FOUND, LINES_HIT) where RESULT_REF
# is a reference to a hash containing the combined mapping in which
# execution counts are added.
#

sub add_counts($$)
{
        my %data1 = %{$_[0]};   # Hash 1
        my %data2 = %{$_[1]};   # Hash 2
        my %result;             # Resulting hash
        my $line;               # Current line iteration scalar
        my $data1_count;        # Count of line in hash1
        my $data2_count;        # Count of line in hash2
        my $found = 0;          # Total number of lines found
        my $hit = 0;            # Number of lines with a count > 0

        foreach $line (keys(%data1))
        {
                $data1_count = $data1{$line};
                $data2_count = $data2{$line};

                # Add counts if present in both hashes
                if (defined($data2_count)) { $data1_count += $data2_count; }

                # Store sum in %result
                $result{$line} = $data1_count;

                $found++;
                if ($data1_count > 0) { $hit++; }
        }

        # Add lines unique to data2
        foreach $line (keys(%data2))
        {
                # Skip lines already in data1
                if (defined($data1{$line})) { next; }

                # Copy count from data2
                $result{$line} = $data2{$line};

                $found++;
                if ($result{$line} > 0) { $hit++; }
        }

        return (\%result, $found, $hit);
}


#
# apply_baseline(data_ref, baseline_ref)
#
# Subtract the execution counts found in the baseline hash referenced by
# BASELINE_REF from actual data in DATA_REF.
#

sub apply_baseline($$)
{
        my %data_hash = %{$_[0]};
        my %base_hash = %{$_[1]};
        my $filename;
        my $testname;
        my $data;
        my $data_testdata;
        my $data_funcdata;
        my $data_count;
        my $base;
        my $base_testdata;
        my $base_count;
        my $sumcount;
        my $found;
        my $hit;

        foreach $filename (keys(%data_hash))
        {
                # Get data set for data and baseline
                $data = $data_hash{$filename};
                $base = $base_hash{$filename};

                # Get set entries for data and baseline
                ($data_testdata, undef, $data_funcdata) =
                        get_info_entry($data);
                ($base_testdata, $base_count) = get_info_entry($base);

                # Sumcount has to be calculated anew
                $sumcount = {};

                # For each test case, subtract test specific counts
                foreach $testname (keys(%{$data_testdata}))
                {
                        # Get counts of both data and baseline
                        $data_count = $data_testdata->{$testname};

                        $hit = 0;

                        ($data_count, undef, $hit) =
                                subtract_counts($data_count, $base_count);

                        # Check whether this test case did hit any line at all
                        if ($hit > 0)
                        {
                                # Write back resulting hash
                                $data_testdata->{$testname} = $data_count;
                        }
                        else
                        {
                                # Delete test case which did not impact this
                                # file
                                delete($data_testdata->{$testname});
                        }

                        # Add counts to sum of counts
                        ($sumcount, $found, $hit) =
                                add_counts($sumcount, $data_count);
                }

                # Write back resulting entry
                set_info_entry($data, $data_testdata, $sumcount,
                               $data_funcdata, $found, $hit);

                $data_hash{$filename} = $data;
        }

        return (\%data_hash);
}


#
# combine_info_entries(entry_ref1, entry_ref2)
#
# Combine .info data entry hashes referenced by ENTRY_REF1 and ENTRY_REF2.
# Return reference to resulting hash.
#

sub combine_info_entries($$)
{
        my $entry1 = $_[0];     # Reference to hash containing first entry
        my $testdata1;
        my $sumcount1;
        my $funcdata1;

        my $entry2 = $_[1];     # Reference to hash containing second entry
        my $testdata2;
        my $sumcount2;
        my $funcdata2;

        my %result;             # Hash containing combined entry
        my %result_testdata;
        my $result_sumcount = {};
        my %result_funcdata;
        my $lines_found;
        my $lines_hit;

        my $testname;

        # Retrieve data
        ($testdata1, $sumcount1, $funcdata1) = get_info_entry($entry1);
        ($testdata2, $sumcount2, $funcdata2) = get_info_entry($entry2);

        # Combine funcdata
        foreach (keys(%{$funcdata1}))
        {
                $result_funcdata{$_} = $funcdata1->{$_};
        }

        foreach (keys(%{$funcdata2}))
        {
                $result_funcdata{$_} = $funcdata2->{$_};
        }
        
        # Combine testdata
        foreach $testname (keys(%{$testdata1}))
        {
                if (defined($testdata2->{$testname}))
                {
                        # testname is present in both entries, requires
                        # combination
                        ($result_testdata{$testname}) =
                                add_counts($testdata1->{$testname},
                                           $testdata2->{$testname});
                }
                else
                {
                        # testname only present in entry1, add to result
                        $result_testdata{$testname} = $testdata1->{$testname};
                }

                # update sum count hash
                ($result_sumcount, $lines_found, $lines_hit) =
                        add_counts($result_sumcount,
                                   $result_testdata{$testname});
        }

        foreach $testname (keys(%{$testdata2}))
        {
                # Skip testnames already covered by previous iteration
                if (defined($testdata1->{$testname})) { next; }

                # testname only present in entry2, add to result hash
                $result_testdata{$testname} = $testdata2->{$testname};

                # update sum count hash
                ($result_sumcount, $lines_found, $lines_hit) =
                        add_counts($result_sumcount,
                                   $result_testdata{$testname});
        }
        
        # Calculate resulting sumcount

        # Store result
        set_info_entry(\%result, \%result_testdata, $result_sumcount,
                       \%result_funcdata, $lines_found, $lines_hit);

        return(\%result);
}


#
# combine_info_files(info_ref1, info_ref2)
#
# Combine .info data in hashes referenced by INFO_REF1 and INFO_REF2. Return
# reference to resulting hash.
#

sub combine_info_files($$)
{
        my %hash1 = %{$_[0]};
        my %hash2 = %{$_[1]};
        my $filename;

        foreach $filename (keys(%hash2))
        {
                if ($hash1{$filename})
                {
                        # Entry already exists in hash1, combine them
                        $hash1{$filename} =
                                combine_info_entries($hash1{$filename},
                                                     $hash2{$filename});
                }
                else
                {
                        # Entry is unique in both hashes, simply add to
                        # resulting hash
                        $hash1{$filename} = $hash2{$filename};
                }
        }

        return(\%hash1);
}


#
# apply_prefix(filename, prefix)
#
# If FILENAME begins with PREFIX, remove PREFIX from FILENAME and return
# resulting string, otherwise return FILENAME.
#

sub apply_prefix($$)
{
        my $filename = $_[0];
        my $prefix = $_[1];
        my $clean_prefix = escape_regexp($prefix);

        if (defined($prefix) && ($prefix ne ""))
        {
                if ($filename =~ /^$clean_prefix\/(.*)$/)
                {
                        return substr($filename, length($prefix) + 1);
                }
        }

        return $filename;
}


#
# escape_regexp(string)
#
# Escape special characters in STRING which would be incorrectly interpreted
# in a PERL regular expression.
#

sub escape_regexp($)
{
        my $string = $_[0];
        
        # Escape special characters
        $string =~ s/\\/\\\\/g;
        $string =~ s/\^/\\\^/g;
        $string =~ s/\$/\\\$/g;
        $string =~ s/\./\\\./g;
        $string =~ s/\|/\\\|/g;
        $string =~ s/\(/\\\(/g;
        $string =~ s/\)/\\\)/g;
        $string =~ s/\[/\\\[/g;
        $string =~ s/\]/\\\]/g;
        $string =~ s/\*/\\\*/g;
        $string =~ s/\?/\\\?/g;
        $string =~ s/\{/\\\{/g;
        $string =~ s/\}/\\\}/g;
        $string =~ s/\+/\\\+/g;

        return $string;
}