#!./miniperl -w

$config_pm = $ARGV[0] || 'lib/Config.pm';
@ARGV = "./config.sh";

# list names to put first (and hence lookup fastest)
@fast = qw(osname osvers so libpth archlib
	sharpbang startsh shsharp
	dynamic_ext static_ext extensions dl_src
	sig_name ccflags cppflags intsize);

# names of things which may need to have slashes changed to double-colons
@extensions = qw(dynamic_ext static_ext extensions known_extensions);


open CONFIG, ">$config_pm" or die "Can't open $config_pm: $!\n";
$myver = sprintf("%.3f", $]);
print CONFIG <<"ENDOFBEG";
package Config;
require Exporter;
\@ISA = (Exporter);
\@EXPORT = qw(%Config);

\$] == $myver or die sprintf
    "Perl lib version ($myver) doesn't match executable version (%.3f)\\n", \$];

# This file was created by configpm when Perl was built. Any changes
# made to this file will be lost the next time perl is built.

ENDOFBEG

@fast{@fast} = @fast;
@extensions{@extensions} = @extensions;
@non_v=();
@v_fast=();
@v_others=();

while (<>) {
    next if m:^#!/bin/sh:;
    # Catch CONFIG=true and PATCHLEVEL=n line from Configure.
    s/^(\w+)=(true|\d+)\s*$/$1='$2'\n/;
    unless (m/^(\w+)='(.*)'\s*$/){
	push(@non_v, "#$_"); # not a name='value' line
	next;
    }
    $name = $1;
    if ($extensions{$name}) { s,/,::,g }
    if (!$fast{$name}){ push(@v_others, $_); next; }
    push(@v_fast,$_);
}

foreach(@non_v){ print CONFIG $_ }

print CONFIG "\n",
    "\$config_sh=<<'!END!OF!CONFIG!';\n",
    join("", @v_fast, sort @v_others),
    "!END!OF!CONFIG!\n\n";


print CONFIG <<'ENDOFEND';

tie %Config, Config;
sub TIEHASH { bless {} }
sub FETCH { 
    # check for cached value (which maybe undef so we use exists not defined)
    return $_[0]->{$_[1]} if (exists $_[0]->{$_[1]});
 
    my($value); # search for the item in the big $config_sh string
    return undef unless (($value) = $config_sh =~ m/^$_[1]='(.*)'\s*$/m);
 
    $value = undef if $value eq 'undef'; # So we can say "if $Config{'foo'}".
    $_[0]->{$_[1]} = $value; # cache it
    return $value;
}
 
sub FIRSTKEY {
    $prevpos = 0;
    my $key;
    ($key) = $config_sh =~ m/^(.*)=/;
    $key;
}

sub NEXTKEY {
    my ($pos, $len);
    $pos = $prevpos;
    $pos = index( $config_sh, "\n", $pos) + 1;
    $prevpos = $pos;
    $len = index( $config_sh, "=", $pos) - $pos;
    $len > 0 ? substr( $config_sh, $pos, $len) : undef;
}

sub EXISTS{ 
     exists($_[0]->{$_[1]})  or  $config_sh =~ m/^$_[1]=/m; 
}

sub readonly { die "\%Config::Config is read-only\n" }

sub myconfig {
	my($output);
	
	$output = <<'END';
Summary of my $package (patchlevel $PATCHLEVEL) configuration:
  Platform:
    osname=$osname, osver=$osvers, archname=$archname
    uname='$myuname'
    hint=$hint
  Compiler:
    cc='$cc', optimize='$optimize'
    cppflags='$cppflags'
    ccflags ='$ccflags'
    ldflags ='$ldflags'
    stdchar='$stdchar', d_stdstdio=$d_stdstdio, usevfork=$usevfork
    voidflags=$voidflags, castflags=$castflags, d_casti32=$d_casti32, d_castneg=$d_castneg
    intsize=$intsize, alignbytes=$alignbytes, usemymalloc=$usemymalloc, randbits=$randbits
  Libraries:
    so=$so
    libpth=$libpth
    libs=$libs
    libc=$libc
  Dynamic Linking:
    dlsrc=$dlsrc, dlext=$dlext, d_dlsymun=$d_dlsymun
    cccdlflags='$cccdlflags', ccdlflags='$ccdlflags', lddlflags='$lddlflags'

END
	$output =~ s/\$(\w+)/$Config{$1}/ge;
	$output;
}

sub STORE { &readonly }
sub DELETE{ &readonly }
sub CLEAR { &readonly }


1;
ENDOFEND

close(CONFIG);

# Now do some simple tests on the Config.pm file we have created
unshift(@INC,'lib');
require $config_pm;
import Config;

die "$0: $config_pm not valid"
	unless $Config{'CONFIG'} eq 'true';

die "$0: error processing $config_pm"
	if defined($Config{'an impossible name'})
	or $Config{'CONFIG'} ne 'true' # test cache
	;

die "$0: error processing $config_pm"
	if eval '$Config{"cc"} = 1'
	or eval 'delete $Config{"cc"}'
	;


exit 0;