#------------------------------------------------------------------------------
# File: WriteRIFF.pl
#
# Description: Write RIFF-format files
#
# Revisions: 2020-09-26 - P. Harvey Created
#
# Notes: Currently writes only WEBP files
#
# References: https://developers.google.com/speed/webp/docs/riff_container
#------------------------------------------------------------------------------
package Image::ExifTool::RIFF;
use strict;
# map of where information is stored in WebP image
my %webpMap = (
'XMP ' => 'RIFF', # (the RIFF chunk name is 'XMP ')
EXIF => 'RIFF',
ICCP => 'RIFF',
C2PA => 'RIFF',
JUMBF => 'C2PA',
XMP => 'XMP ',
IFD0 => 'EXIF',
IFD1 => 'IFD0',
ICC_Profile => 'ICCP',
ExifIFD => 'IFD0',
GPS => 'IFD0',
SubIFD => 'IFD0',
GlobParamIFD => 'IFD0',
PrintIM => 'IFD0',
InteropIFD => 'ExifIFD',
MakerNotes => 'ExifIFD',
);
#------------------------------------------------------------------------------
# Write RIFF file (currently WebP-type only)
# Inputs: 0) ExifTool object ref, 1) dirInfo ref
# Returns: 1 on success, 0 if this wasn't a valid RIFF file, or -1 if
# an output file was specified and a write error occurred
sub WriteRIFF($$)
{
my ($et, $dirInfo) = @_;
$et or return 1; # allow dummy access to autoload this package
my $outfile = $$dirInfo{OutFile};
my $outsize = 0;
my $raf = $$dirInfo{RAF};
my ($buff, $err, $pass, %has, %dirDat, $imageWidth, $imageHeight);
# do this in 2 passes so we can set the size of the containing RIFF chunk
# without having to buffer the output (also to set the WebP_Flags)
for ($pass=0; ; ++$pass) {
my %doneDir;
# verify this is a valid RIFF file
return 0 unless $raf->Read($buff, 12) == 12;
return 0 unless $buff =~ /^(RIFF|RF64)....(.{4})/s;
unless ($1 eq 'RIFF' and $2 eq 'WEBP') {
my $type = $2;
$type =~ tr/-_a-zA-Z//dc;
$et->Error("Can't currently write $1 $type files");
return 1;
}
SetByteOrder('II');
# determine which directories we must write for this file type
$et->InitWriteDirs(\%webpMap);
my $addDirs = $$et{ADD_DIRS};
my $editDirs = $$et{EDIT_DIRS};
$$addDirs{IFD0} = 'EXIF' if $$addDirs{EXIF}; # set flag to add IFD0 if adding EXIF (don't ask)
my ($createVP8X, $deleteVP8X);
# write header
if ($pass) {
my $needsVP8X = ($has{ANIM} or $has{'XMP '} or $has{EXIF} or
$has{ALPH} or $has{ICCP});
if ($has{VP8X} and not $needsVP8X and $$et{CHANGED}) {
$deleteVP8X = 1; # delete the VP8X chunk
$outsize -= 18; # account for missing VP8X
} elsif ($needsVP8X and not $has{VP8X}) {
if (defined $imageWidth) {
++$$et{CHANGED};
$createVP8X = 1; # add VP8X chunk
$outsize += 18; # account for VP8X size
} else {
$et->Warn('Error getting image size for required VP8X chunk');
}
}
# finally we can set the overall RIFF chunk size:
Set32u($outsize - 8, \$buff, 4);
Write($outfile, $buff) or $err = 1;
# create VP8X chunk if necessary
if ($createVP8X) {
$et->VPrint(0," Adding required VP8X chunk (Extended WEBP)\n");
my $flags = 0;
$flags |= 0x02 if $has{ANIM};
$flags |= 0x04 if $has{'XMP '};
$flags |= 0x08 if $has{EXIF};
$flags |= 0x10 if $has{ALPH};
$flags |= 0x20 if $has{ICCP};
Write($outfile, 'VP8X', pack('V3v', 10, $flags,
($imageWidth-1) | ((($imageHeight-1) & 0xff) << 24),
($imageHeight-1) >> 8));
# write ICCP after VP8X
Write($outfile, $dirDat{ICCP}) or $err = 1 if $dirDat{ICCP};
}
} else {
$outsize += length $buff;
}
my $pos = 12;
#
# Read chunks in RIFF image
#
for (;;) {
my ($tag, $len);
my $num = $raf->Read($buff, 8);
if ($num < 8) {
$num and $et->Error('RIFF format error'), return 1;
# all done if we hit end of file unless we need to add EXIF or XMP
last unless $$addDirs{EXIF} or $$addDirs{'XMP '} or $$addDirs{ICCP};
# continue to add required EXIF or XMP chunks
$num = $len = 0;
$buff = $tag = '';
} else {
$pos += 8;
($tag, $len) = unpack('a4V', $buff);
if ($len <= 0) {
if ($len < 0) {
$et->Error('Invalid chunk length');
return 1;
} elsif ($tag eq "\0\0\0\0") {
# avoid reading through corrupted files filled with nulls because it takes forever
$et->Error('Encountered empty null chunk. Processing aborted');
return 1;
} else { # (just in case a tag may have no data)
if ($pass) {
Write($outfile, $buff) or $err = 1;
} else {
$outsize += length $buff;
}
next;
}
}
}
# RIFF chunks are padded to an even number of bytes
my $len2 = $len + ($len & 0x01);
# handle incorrect "XMP\0" chunk ID written by Google software
if ($tag eq "XMP\0") {
if ($$et{DEL_GROUP}{XMP}) {
# just ignore this chunk if deleting XMP
$raf->Seek($len2, 1) or $et->Error('Seek error'), last;
++$$et{CHANGED};
next;
} else {
$et->Warn('Incorrect XMP tag ID',1) if $pass;
}
}
# edit/add/delete necessary metadata chunks (EXIF must come before XMP)
if ($$editDirs{$tag} or $tag eq '' or ($tag eq 'XMP ' and $$addDirs{EXIF})) {
my $handledTag;
if ($len2) {
$et->Warn("Duplicate '${tag}' chunk") if $doneDir{$tag} and not $pass;
$doneDir{$tag} = 1;
$raf->Read($buff, $len2) == $len2 or $et->Error("Truncated '${tag}' chunk"), last;
$pos += $len2; # update current position
} else {
$buff = '';
}
#
# add/edit/delete EXIF/XMP/ICCP (note: EXIF must come before XMP, and ICCP is written elsewhere)
#
my %dirName = ( EXIF => 'IFD0', 'XMP ' => 'XMP', ICCP => 'ICC_Profile', C2PA => 'JUMBF' );
my %tblName = ( EXIF => 'Exif', 'XMP ' => 'XMP', ICCP => 'ICC_Profile', C2PA => 'Jpeg2000' );
my $dir;
foreach $dir ('EXIF', 'XMP ', 'ICCP', 'C2PA' ) {
next unless $tag eq $dir or ($$addDirs{$dir} and
($tag eq '' or ($tag eq 'XMP ' and $dir eq 'EXIF')));
my $start;
unless ($pass) {
# write the EXIF and save the result for the next pass
my $dataPt = \$buff;
if ($tag eq 'EXIF') {
# (only need to set directory $start for EXIF)
if ($buff =~ /^Exif\0\0/) {
if ($$et{DEL_GROUP}{EXIF}) {
# remove incorrect header if rewriting anyway
$buff = substr($buff, 6);
$len -= 6;
$len2 -= 6;
} else {
$et->Warn('Improper EXIF header',1) unless $pass;
$start = 6;
}
} else {
$start = 0;
}
} elsif ($dir ne $tag) {
# create from scratch
my $buf2 = '';
$dataPt = \$buf2;
}
# write the new directory to memory
my %dirInfo = (
DataPt => $dataPt,
DataPos => 0, # (relative to Base)
DirStart => $start,
Base => $pos - $len2,
Parent => $dir,
DirName => $dirName{$dir},
);
# must pass the TagInfo to enable deletion of C2PA information
if (ref $Image::ExifTool::RIFF::Main{$dir} eq 'HASH') {
$dirInfo{TagInfo} = $Image::ExifTool::RIFF::Main{$dir};
}
my $tagTablePtr = GetTagTable("Image::ExifTool::$tblName{$dir}::Main");
# (override writeProc for EXIF because it has the TIFF header)
my $writeProc = $dir eq 'EXIF' ? \&Image::ExifTool::WriteTIFF : undef;
$dirDat{$dir} = $et->WriteDirectory(\%dirInfo, $tagTablePtr, $writeProc);
}
delete $$addDirs{$dir}; # (don't try to add again)
if (defined $dirDat{$dir}) {
if ($dir eq $tag) {
$handledTag = 1; # set flag indicating we edited this tag
# increment CHANGED count if we are deleting the directory
++$$et{CHANGED} unless length $dirDat{$dir};
}
if (length $dirDat{$dir}) {
if ($pass) {
# write metadata chunk now (but not ICCP because it was added earlier)
Write($outfile, $dirDat{$dir}) or $err = 1 unless $dir eq 'ICCP';
} else {
# preserve (incorrect EXIF) header if it existed
my $hdr = $start ? substr($buff,0,$start) : '';
# (don't overwrite $len here because it may be XMP length)
my $dirLen = length($dirDat{$dir}) + length($hdr);
# add chunk header and padding
my $pad = $dirLen & 0x01 ? "\0" : '';
$dirDat{$dir} = $dir . Set32u($dirLen) . $hdr . $dirDat{$dir} . $pad;
$outsize += length($dirDat{$dir});
$has{$dir} = 1;
}
}
}
}
#
# just copy XMP, EXIF or ICC if nothing changed
#
if (not $handledTag and length $buff) {
# write the chunk without changes
if ($pass) {
Write($outfile, $tag, Set32u($len), $buff) or $err = 1;
} else {
$outsize += 8 + length($buff);
$has{$tag} = 1;
}
}
next;
}
$pos += $len2; # set read position at end of chunk data
#
# update necessary flags in VP8X chunk
#
if ($tag eq 'VP8X') {
my $buf2;
if ($len2 < 10 or $raf->Read($buf2, $len2) != $len2) {
$et->Error('Truncated VP8X chunk');
return 1;
}
if ($pass) {
if ($deleteVP8X) {
$et->VPrint(0," Deleting unnecessary VP8X chunk (Standard WEBP)\n");
next;
}
# ...but first set the VP8X flags
my $flags = Get32u(\$buf2, 0);
$flags &= ~0x2c; # (reset flags for everything we can write)
$flags |= 0x04 if $has{'XMP '};
$flags |= 0x08 if $has{EXIF};
$flags |= 0x20 if $has{ICCP};
Set32u($flags, \$buf2, 0);
Write($outfile, $buff, $buf2) or $err = 1;
} else {
# get the image size
$imageWidth = (Get32u(\$buf2, 4) & 0xffffff) + 1;
$imageHeight = (Get32u(\$buf2, 6) >> 8) + 1;
$outsize += 8 + $len2;
$has{$tag} = 1;
}
# write ICCP after VP8X
Write($outfile, $dirDat{ICCP}) or $err = 1 if $dirDat{ICCP};
next;
}
#
# just copy all other chunks
#
if ($pass) {
# write chunk header (still in $buff)
Write($outfile, $buff) or $err = 1;
} else {
$outsize += length $buff;
$has{$tag} = 1;
}
unless ($pass or defined $imageWidth) {
# get WebP image size from VP8 or VP8L header
if ($tag eq 'VP8 ' and $len2 >= 16) {
$raf->Read($buff, 16) == 16 or $et->Error('Truncated VP8 chunk'), return 1;
$outsize += 16;
if ($buff =~ /^...\x9d\x01\x2a/s) {
$imageWidth = Get16u(\$buff, 6) & 0x3fff;
$imageHeight = Get16u(\$buff, 8) & 0x3fff;
}
$len2 -= 16;
} elsif ($tag eq 'VP8L' and $len2 >= 6) {
$raf->Read($buff, 6) == 6 or $et->Error('Truncated VP8L chunk'), return 1;
$outsize += 6;
if ($buff =~ /^\x2f/s) {
$imageWidth = (Get16u(\$buff, 1) & 0x3fff) + 1;
$imageHeight = ((Get32u(\$buff, 2) >> 6) & 0x3fff) + 1;
}
$len2 -= 6;
}
}
if ($pass) {
# copy the chunk data in 64k blocks
while ($len2) {
my $num = $len2;
$num = 65536 if $num > 65536;
$raf->Read($buff, $num) == $num or $et->Error('Truncated RIFF chunk'), last;
Write($outfile, $buff) or $err = 1, last;
$len2 -= $num;
}
} else {
$raf->Seek($len2, 1) or $et->Error('Seek error'), last;
$outsize += $len2;
}
}
last if $pass;
$raf->Seek(0,0) or $et->Error('Seek error'), last;
}
return $err ? -1 : 1;
}
1; # end
__END__
=head1 NAME
Image::ExifTool::WriteRIFF.pl - Write RIFF-format files
=head1 SYNOPSIS
This file is autoloaded by Image::ExifTool::RIFF.
=head1 DESCRIPTION
This file contains routines to write metadata to RIFF-format files.
=head1 NOTES
Currently writes only WebP files.
=head1 AUTHOR
Copyright 2003-2023, Phil Harvey (philharvey66 at gmail.com)
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
=head1 REFERENCES
=over 4
=item L<https://developers.google.com/speed/webp/docs/riff_container>
=back
=head1 SEE ALSO
L<Image::ExifTool::Photoshop(3pm)|Image::ExifTool::RIFF>,
L<Image::ExifTool(3pm)|Image::ExifTool>
=cut