diff --git a/src/Bitpix.php b/src/Bitpix.php
new file mode 100644
index 0000000..96bf524
--- /dev/null
+++ b/src/Bitpix.php
@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Dumbastro\FitsPhp;
+
+/**
+* Valid BITPIX values
+*/
+enum Bitpix: int
+{
+ case Uint8 = 8;
+ case Uint16 = 16;
+ case Uint32 = 32;
+ case Uint64 = 64;
+ case Float32 = -32;
+ case Float64 = -64;
+
+ public function type(): string
+ {
+ return match($this) {
+ Bitpix::Uint8 => 'int8',
+ Bitpix::Uint16 => 'int16',
+ Bitpix::Uint32 => 'int32',
+ Bitpix::Uint64 => 'int64',
+ Bitpix::Float32 => 'float32',
+ Bitpix::Float64 => 'float64',
+ };
+ }
+
+ public function toString(): string
+ {
+ return match($this) {
+ Bitpix::Uint8 => 'Character or unsigned binary integer',
+ Bitpix::Uint16 => '16 bit two\'s complement binary integer',
+ Bitpix::Uint32 => '32 bit two\'s complement binary integer',
+ Bitpix::Uint64 => '64 bit two\'s complement binary integer',
+ Bitpix::Float32 => 'IEEE single-precision floating point',
+ Bitpix::Float64 => 'IEEE double-precision floating point',
+ };
+ }
+}
+
diff --git a/src/Exceptions/InvalidBitpixValue.php b/src/Exceptions/InvalidBitpixValue.php
new file mode 100644
index 0000000..87edaf8
--- /dev/null
+++ b/src/Exceptions/InvalidBitpixValue.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Dumbastro\FitsPhp\Exceptions;
+
+class InvalidBitpixValue extends \Exception
+{
+ public function __construct(int $bitpix)
+ {
+ $this->message = "The value $bitpix is not a valid BITPIX value";
+ }
+}
diff --git a/src/Exceptions/InvalidFitsException.php b/src/Exceptions/InvalidFits.php
similarity index 51%
rename from src/Exceptions/InvalidFitsException.php
rename to src/Exceptions/InvalidFits.php
index 55a287b..8137187 100644
--- a/src/Exceptions/InvalidFitsException.php
+++ b/src/Exceptions/InvalidFits.php
@@ -4,7 +4,7 @@ declare(strict_types=1);
namespace Dumbastro\FitsPhp\Exceptions;
-final class InvalidFitsException extends \Exception implements \Throwable
+final class InvalidFits extends \Exception implements \Throwable
{
}
diff --git a/src/Exceptions/InvalidPathException.php b/src/Exceptions/InvalidPath.php
similarity index 72%
rename from src/Exceptions/InvalidPathException.php
rename to src/Exceptions/InvalidPath.php
index 8563a0f..88b3bfe 100644
--- a/src/Exceptions/InvalidPathException.php
+++ b/src/Exceptions/InvalidPath.php
@@ -7,6 +7,6 @@ namespace Dumbastro\FitsPhp\Exceptions;
/**
* @todo Different exception if path is not writable?
*/
-final class InvalidPathException extends \Exception
+final class InvalidPath extends \Exception
{
}
diff --git a/src/Fits.php b/src/Fits.php
index f3d06b6..5e51584 100644
--- a/src/Fits.php
+++ b/src/Fits.php
@@ -5,38 +5,39 @@ declare(strict_types=1);
namespace Dumbastro\FitsPhp;
use Dumbastro\FitsPhp\Exceptions\{
- InvalidFitsException,
- InvalidPathException,
+ InvalidFits,
+ InvalidPath,
};
class Fits
{
- /**
- * @var resource $byteStream
- */
- private $byteStream;
+ private string $contents;
private string $path;
+ private FitsHeader $fitsHeader;
public readonly int $size;
public readonly string $headerBlock;
+ public readonly string $imageBlob;
/**
- * @throws InvalidFitsException, InvalidPathException
+ * @throws InvalidFits, InvalidPath
* @todo Check path for reading/writing errors
*/
public function __construct(string $path)
{
if (! is_readable($path) || ! is_file($path)) {
- throw new InvalidPathException("The path '$path' is not readable or is not a file.");
+ throw new InvalidPath("The path '$path' is not readable or is not a file.");
}
- $this->byteStream = fopen($path, 'rb');
+ $this->contents = file_get_contents($path);
$this->path = $path;
$this->size = filesize($this->path);
if (! $this->validate()) {
- throw new InvalidFitsException('The opened file is not a valid FITS image (invalid block size)');
+ throw new InvalidFits('The opened file is not a valid FITS image (invalid block size)');
}
$this->headerBlock = $this->extractHeader();
+ $this->fitsHeader = new FitsHeader($this->headerBlock);
+ $this->imageBlob = $this->extractImageBlob();
}
/**
* Validate the given FITS file based on block sizes
@@ -66,12 +67,29 @@ class Fits
*/
private function extractHeader(): string
{
- $contents = fread($this->byteStream, $this->size);
- $end = strpos($contents, 'END');
+ $end = strpos($this->contents, 'END');
// Determine minimum integer number of blocks including 'END' position
$headerEnd = (($end - ($end % 2880)) / 2880 + 1) * 2880;
- return substr($contents, 0, $headerEnd);
+ return substr($this->contents, 0, $headerEnd);
+ }
+ /**
+ * Extract the FITS image blob as a string;
+ * it uses the NAXIS1 and NAXIS2 keywords
+ * to compute the length of the main data table
+ */
+ private function extractImageBlob(): string
+ {
+ $naxis1 = (int)trim($this->fitsHeader->getKeywordValue('NAXIS1'));
+ $naxis2 = (int)trim($this->fitsHeader->getKeywordValue('NAXIS2'));
+
+ $blobEnd = $naxis1 * $naxis2;
+
+ return substr(
+ $this->contents,
+ strlen($this->headerBlock) + 1,
+ $blobEnd
+ );
}
public function writeTo(string $path): void
diff --git a/src/FitsHeader.php b/src/FitsHeader.php
index f36c071..64a08b8 100644
--- a/src/FitsHeader.php
+++ b/src/FitsHeader.php
@@ -71,5 +71,36 @@ class FitsHeader
return $keywordsString . $blanks;
}
+ /**
+ * Retrieve a Keyword object base on key name
+ */
+ public function keyword(string $key): ?Keyword
+ {
+ $keyword = null;
+
+ foreach ($this->keywords as $k) {
+ if (trim($k->name) === $key) {
+ $keyword = $k;
+ break;
+ }
+ }
+
+ return $keyword;
+ }
+ /**
+ * Note: the keyword key string is case-sensitive
+ */
+ public function getKeywordValue(string $key): string
+ {
+ $value = '';
+ foreach ($this->keywords as $keyword) {
+ if (trim($keyword->name) === $key) {
+ $value = $keyword->value;
+ break;
+ }
+ }
+
+ return $value;
+ }
}
diff --git a/src/ImageBlob.php b/src/ImageBlob.php
new file mode 100644
index 0000000..73192bd
--- /dev/null
+++ b/src/ImageBlob.php
@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Dumbastro\FitsPhp;
+
+use Dumbastro\FitsPhp\Exceptions\InvalidBitpixValue;
+use Dumbastro\FitsPhp\Bitpix;
+
+class ImageBlob
+{
+ private string $blob;
+ private FitsHeader $header;
+ public readonly Bitpix $bitpix;
+ public readonly int $dataBits;
+
+ /**
+ * @throws InvalidBitpixValue
+ * @todo Don't assume that NAXIS = 2...
+ */
+ public function __construct(FitsHeader $header, string $blob)
+ {
+ $this->header = $header;
+ $this->blob = $blob;
+ $bitpix = (int) $this->header->keyword('BITPIX')->value;
+ $this->bitpix = Bitpix::tryFrom($bitpix) ?? throw new InvalidBitpixValue($bitpix);
+ $naxis1 = (int) trim($this->header->keyword('NAXIS1')->value);
+ $naxis2 = (int) trim($this->header->keyword('NAXIS2')->value);
+ $this->dataBits = abs($this->bitpix->value) * $naxis1 * $naxis2;
+ }
+ /**
+ * Returns a generator that yields image data
+ * byte by byte
+ */
+ public function dataBytes(): \Generator
+ {
+ for ($i = 0; $i < strlen($this->blob); $i++) {
+ yield $this->blob[$i];
+ }
+ }
+ /**
+ * Convert to PNG
+ * @todo Manipulate bits and add PNG header to blob??
+ * Throw exception if gd fails?
+ */
+ public function toPNG(int $quality = -1): bool
+ {
+ $gdImg = imagecreatefromstring($this->blob);
+ return imagepng($gdImg, quality: $quality);
+ }
+}