/**
* Make a new entry from a bunch of bytes.
*
* This method will create the proper subclass of {@link PelEntry}
* corresponding to the {@link PelTag} and {@link PelFormat} given.
* The entry will be initialized with the data given.
*
* Please note that the data you pass to this method should come
* from an image, that is, it should be raw bytes. If instead you
* want to create an entry for holding, say, an short integer, then
* create a {@link PelEntryShort} object directly and load the data
* into it.
*
* A {@link PelUnexpectedFormatException} is thrown if a mismatch is
* discovered between the tag and format, and likewise a {@link
* PelWrongComponentCountException} is thrown if the number of
* components does not match the requirements of the tag. The
* requirements for a given tag (if any) can be found in the
* documentation for {@link PelTag}.
*
* @param PelTag the tag of the entry.
*
* @param PelFormat the format of the entry.
*
* @param int the components in the entry.
*
* @param PelDataWindow the data which will be used to construct the
* entry.
*
* @return PelEntry a newly created entry, holding the data given.
*/
function newEntryFromData($tag, $format, $components, PelDataWindow $data)
{
/* First handle tags for which we have a specific PelEntryXXX
* class. */
switch ($this->type) {
case self::IFD0:
case self::IFD1:
case self::EXIF:
case self::INTEROPERABILITY:
switch ($tag) {
case PelTag::DATE_TIME:
case PelTag::DATE_TIME_ORIGINAL:
case PelTag::DATE_TIME_DIGITIZED:
if ($format != PelFormat::ASCII) {
throw new PelUnexpectedFormatException($this->type, $tag, $format, PelFormat::ASCII);
}
if ($components != 20) {
throw new PelWrongComponentCountException($this->type, $tag, $components, 20);
}
// TODO: handle timezones.
return new PelEntryTime($tag, $data->getBytes(0, -1), PelEntryTime::EXIF_STRING);
case PelTag::COPYRIGHT:
if ($format != PelFormat::ASCII) {
throw new PelUnexpectedFormatException($this->type, $tag, $format, PelFormat::ASCII);
}
$v = explode("", trim($data->getBytes(), ' '));
return new PelEntryCopyright($v[0], $v[1]);
case PelTag::EXIF_VERSION:
case PelTag::FLASH_PIX_VERSION:
case PelTag::INTEROPERABILITY_VERSION:
if ($format != PelFormat::UNDEFINED) {
throw new PelUnexpectedFormatException($this->type, $tag, $format, PelFormat::UNDEFINED);
}
return new PelEntryVersion($tag, $data->getBytes() / 100);
case PelTag::USER_COMMENT:
if ($format != PelFormat::UNDEFINED) {
throw new PelUnexpectedFormatException($this->type, $tag, $format, PelFormat::UNDEFINED);
}
if ($data->getSize() < 8) {
return new PelEntryUserComment();
} else {
return new PelEntryUserComment($data->getBytes(8), rtrim($data->getBytes(0, 8)));
}
case PelTag::XP_TITLE:
case PelTag::XP_COMMENT:
case PelTag::XP_AUTHOR:
case PelTag::XP_KEYWORDS:
case PelTag::XP_SUBJECT:
if ($format != PelFormat::BYTE) {
throw new PelUnexpectedFormatException($this->type, $tag, $format, PelFormat::BYTE);
}
$v = '';
for ($i = 0; $i < $components; $i++) {
$b = $data->getByte($i);
/* Convert the byte to a character if it is non-null ---
* information about the character encoding of these entries
* would be very nice to have! So far my tests have shown
* that characters in the Latin-1 character set are stored in
* a single byte followed by a NULL byte. */
if ($b != 0) {
$v .= chr($b);
}
}
return new PelEntryWindowsString($tag, $v);
}
case self::GPS:
default:
/* Then handle the basic formats. */
switch ($format) {
case PelFormat::BYTE:
$v = new PelEntryByte($tag);
for ($i = 0; $i < $components; $i++) {
$v->addNumber($data->getByte($i));
}
return $v;
case PelFormat::SBYTE:
$v = new PelEntrySByte($tag);
for ($i = 0; $i < $components; $i++) {
$v->addNumber($data->getSByte($i));
}
return $v;
case PelFormat::ASCII:
return new PelEntryAscii($tag, $data->getBytes(0, -1));
case PelFormat::SHORT:
$v = new PelEntryShort($tag);
for ($i = 0; $i < $components; $i++) {
$v->addNumber($data->getShort($i * 2));
}
return $v;
case PelFormat::SSHORT:
$v = new PelEntrySShort($tag);
for ($i = 0; $i < $components; $i++) {
$v->addNumber($data->getSShort($i * 2));
}
return $v;
case PelFormat::LONG:
$v = new PelEntryLong($tag);
for ($i = 0; $i < $components; $i++) {
$v->addNumber($data->getLong($i * 4));
}
return $v;
case PelFormat::SLONG:
$v = new PelEntrySLong($tag);
for ($i = 0; $i < $components; $i++) {
$v->addNumber($data->getSLong($i * 4));
}
return $v;
case PelFormat::RATIONAL:
$v = new PelEntryRational($tag);
for ($i = 0; $i < $components; $i++) {
$v->addNumber($data->getRational($i * 8));
}
return $v;
case PelFormat::SRATIONAL:
$v = new PelEntrySRational($tag);
for ($i = 0; $i < $components; $i++) {
$v->addNumber($data->getSRational($i * 8));
}
return $v;
case PelFormat::UNDEFINED:
return new PelEntryUndefined($tag, $data->getBytes());
default:
throw new PelException('Unsupported format: %s', PelFormat::getName($format));
}
}
}