Java > Open Source Codes > imageinfo > ImageInfo


1 /*
2  * ImageInfo.java
3  *
4  * Version 1.4
5  *
6  * A Java class to determine image width, height and color depth for
7  * a number of image file formats.
8  *
9  * Written by Marco Schmidt
10  * <http://www.geocities.com/marcoschmidt.geo/contact.html>.
11  *
12  * Contributed to the Public Domain.
13  *
14  * Last modification 2003-07-28
15  */
16
17 package imageinfo;
18 import java.io.DataInput ;
19 import java.io.FileInputStream ;
20 import java.io.InputStream ;
21 import java.io.IOException ;
22 import java.net.*;
23 import java.util.Vector ;
24
25 /**
26  * Get file format, image resolution, number of bits per pixel and optionally
27  * number of images, comments and physical resolution from
28  * JPEG, GIF, BMP, PCX, PNG, IFF, RAS, PBM, PGM, PPM, PSD and SWF files
29  * (or input streams).
30  * <p>
31  * Use the class like this:
32  * <pre>
33  * ImageInfo ii = new ImageInfo();
34  * ii.setInput(in); // in can be InputStream or RandomAccessFile
35  * ii.setDetermineImageNumber(true); // default is false
36  * ii.setCollectComments(true); // default is false
37  * if (!ii.check()) {
38  * System.err.println("Not a supported image file format.");
39  * return;
40  * }
41  * System.out.println(ii.getFormatName() + ", " + ii.getMimeType() +
42  * ", " + ii.getWidth() + " x " + ii.getHeight() + " pixels, " +
43  * ii.getBitsPerPixel() + " bits per pixel, " + ii.getNumberOfImages() +
44  * " image(s), " + ii.getNumberOfComments() + " comment(s).");
45  * </pre>
46  * You can also use this class as a command line program.
47  * Call it with a number of image file names as parameters:
48  * <pre>
49  * java ImageInfo *.jpg *.png *.gif
50  * </pre>
51  * or call it without parameters and pipe data to it:
52  * <pre>
53  * cat image.jpg | java ImageInfo
54  * </pre>
55  * <p>
56  * Known limitations:
57  * <ul>
58  * <li>When the determination of the number of images is turned off, GIF bits
59  * per pixel are only read from the global header.
60  * For some GIFs, local palettes change this to a typically larger
61  * value. To be certain to get the correct color depth, call
62  * setDetermineImageNumber(true) before calling check().
63  * The complete scan over the GIF file will take additional time.</li>
64  * <li>Transparency information is not included in the bits per pixel count.
65  * Actually, it was my decision not to include those bits, so it's a feature! ;-)</li>
66  * </ul>
67  * <p>
68  * Requirements:
69  * <ul>
70  * <li>Java 1.1 or higher</li>
71  * </ul>
72  * <p>
73  * The latest version can be found at <a HREF="http://www.geocities.com/marcoschmidt.geo/image-info.html">http://www.geocities.com/marcoschmidt.geo/image-info.html</a>.
74  * <p>
75  * Written by <a HREF="mailto:marcoschmidt@users.sourceforge.net">Marco Schmidt</a>.
76  * <p>
77  * This class is contributed to the Public Domain.
78  * Use it at your own risk.
79  * <p>
80  * Last modification 2003-07-28.
81  * <p>
82  * History:
83  * <ul>
84  * <li><strong>2001-08-24</strong> Initial version.</li>
85  * <li><strong>2001-10-13</strong> Added support for the file formats BMP and PCX.</li>
86  * <li><strong>2001-10-16</strong> Fixed bug in read(int[], int, int) that returned
87  * <li><strong>2002-01-22</strong> Added support for file formats Amiga IFF and Sun Raster (RAS).</li>
88  * <li><strong>2002-01-24</strong> Added support for file formats Portable Bitmap / Graymap / Pixmap (PBM, PGM, PPM) and Adobe Photoshop (PSD).
89  * Added new method getMimeType() to return the MIME type associated with a particular file format.</li>
90  * <li><strong>2002-03-15</strong> Added support to recognize number of images in file. Only works with GIF.
91  * Use {@link #setDetermineImageNumber} with <code>true</code> as argument to identify animated GIFs
92  * ({@link #getNumberOfImages()} will return a value larger than <code>1</code>).</li>
93  * <li><strong>2002-04-10</strong> Fixed a bug in the feature 'determine number of images in animated GIF' introduced with version 1.1.
94  * Thanks to Marcelo P. Lima for sending in the bug report.
95  * Released as 1.1.1.</li>
96  * <li><strong>2002-04-18</strong> Added {@link #setCollectComments(boolean)}.
97  * That new method lets the user specify whether textual comments are to be
98  * stored in an internal list when encountered in an input image file / stream.
99  * Added two methods to return the physical width and height of the image in dpi:
100  * {@link #getPhysicalWidthDpi()} and {@link #getPhysicalHeightDpi()}.
101  * If the physical resolution could not be retrieved, these methods return <code>-1</code>.
102  * </li>
103  * <li><strong>2002-04-23</strong> Added support for the new properties physical resolution and
104  * comments for some formats. Released as 1.2.</li>
105  * <li><strong>2002-06-17</strong> Added support for SWF, sent in by Michael Aird.
106  * Changed checkJpeg() so that other APP markers than APP0 will not lead to a failure anymore.
107  * Released as 1.3.</li>
108  * <li><strong>2003-07-28</strong> Bug fix - skip method now takes return values into consideration.
109  * Less bytes than necessary may have been skipped, leading to flaws in the retrieved information in some cases.
110  * Thanks to Bernard Bernstein for pointing that out.
111  * Released as 1.4.</li>
112  * </ul>
113  */
114 public class ImageInfo {
115     /**
116      * Return value of {@link #getFormat()} for JPEG streams.
117      * ImageInfo can extract physical resolution and comments
118      * from JPEGs (only from APP0 headers).
119      * Only one image can be stored in a file.
120      */
121     public static final int FORMAT_JPEG = 0;
122
123     /**
124      * Return value of {@link #getFormat()} for GIF streams.
125      * ImageInfo can extract comments from GIFs and count the number
126      * of images (GIFs with more than one image are animations).
127      * If you know of a place where GIFs store the physical resolution
128      * of an image, please
129      * <a HREF="http://www.geocities.com/marcoschmidt.geo/contact.html">send me a mail</a>!
130      */
131     public static final int FORMAT_GIF = 1;
132
133     /**
134      * Return value of {@link #getFormat()} for PNG streams.
135      * PNG only supports one image per file.
136      * Both physical resolution and comments can be stored with PNG,
137      * but ImageInfo is currently not able to extract those.
138      */
139     public static final int FORMAT_PNG = 2;
140
141     /**
142      * Return value of {@link #getFormat()} for BMP streams.
143      * BMP only supports one image per file.
144      * BMP does not allow for comments.
145      * The physical resolution can be stored.
146      * <em>The specification that I have says that the values must be
147      * interpreted as dots per meter. However, given that I only
148      * encounter typical dpi values like 72 or 300, I currently
149      * consider those values dpi. Maybe someone can shed some light
150      * on this, please send me a mail in that case.</em>
151      */
152     public static final int FORMAT_BMP = 3;
153
154     /**
155      * Return value of {@link #getFormat()} for PCX streams.
156      * PCX does not allow for comments or more than one image per file.
157      * However, the physical resolution can be stored.
158      */
159     public static final int FORMAT_PCX = 4;
160
161     /**
162      * Return value of {@link #getFormat()} for IFF streams.
163      */
164     public static final int FORMAT_IFF = 5;
165
166     /**
167      * Return value of {@link #getFormat()} for RAS streams.
168      * Sun Raster allows for one image per file only and is not able to
169      * store physical resolution or comments.
170      */
171     public static final int FORMAT_RAS = 6;
172
173     /** Return value of {@link #getFormat()} for PBM streams. */
174     public static final int FORMAT_PBM = 7;
175
176     /** Return value of {@link #getFormat()} for PGM streams. */
177     public static final int FORMAT_PGM = 8;
178
179     /** Return value of {@link #getFormat()} for PPM streams. */
180     public static final int FORMAT_PPM = 9;
181
182     /** Return value of {@link #getFormat()} for PSD streams. */
183     public static final int FORMAT_PSD = 10;
184
185     /** Return value of {@link #getFormat()} for SWF (Shockwave) streams. */
186     public static final int FORMAT_SWF = 11;
187
188     public static final int COLOR_TYPE_UNKNOWN = -1;
189     public static final int COLOR_TYPE_TRUECOLOR_RGB = 0;
190     public static final int COLOR_TYPE_PALETTED = 1;
191     public static final int COLOR_TYPE_GRAYSCALE= 2;
192     public static final int COLOR_TYPE_BLACK_AND_WHITE = 3;
193
194     /**
195      * The names of all supported file formats.
196      * The FORMAT_xyz int constants can be used as index values for
197      * this array.
198      */
199     private static final String [] FORMAT_NAMES =
200         {"JPEG", "GIF", "PNG", "BMP", "PCX",
201          "IFF", "RAS", "PBM", "PGM", "PPM",
202          "PSD", "SWF"};
203
204     /**
205      * The names of the MIME types for all supported file formats.
206      * The FORMAT_xyz int constants can be used as index values for
207      * this array.
208      */
209     private static final String [] MIME_TYPE_STRINGS =
210         {"image/jpeg", "image/gif", "image/png", "image/bmp", "image/pcx",
211          "image/iff", "image/ras", "image/x-portable-bitmap", "image/x-portable-graymap", "image/x-portable-pixmap",
212          "image/psd", "application/x-shockwave-flash"};
213
214     private int width;
215     private int height;
216     private int bitsPerPixel;
217     private int colorType = COLOR_TYPE_UNKNOWN;
218     private int format;
219     private InputStream in;
220     private DataInput din;
221     private boolean collectComments = true;
222     private Vector comments;
223     private boolean determineNumberOfImages;
224     private int numberOfImages;
225     private int physicalHeightDpi;
226     private int physicalWidthDpi;
227     private int bitBuf;
228     private int bitPos;
229
230     private void addComment(String s) {
231         if (comments == null) {
232             comments = new Vector ();
233         }
234         comments.addElement(s);
235     }
236
237     /**
238      * Call this method after you have provided an input stream or file
239      * using {@link #setInput(InputStream)} or {@link #setInput(DataInput)}.
240      * If true is returned, the file format was known and information
241      * on the file's content can be retrieved using the various getXyz methods.
242      * @return if information could be retrieved from input
243      */
244     public boolean check() {
245         format = -1;
246         width = -1;
247         height = -1;
248         bitsPerPixel = -1;
249         numberOfImages = 1;
250         physicalHeightDpi = -1;
251         physicalWidthDpi = -1;
252         comments = null;
253         try {
254             int b1 = read() & 0xff;
255             int b2 = read() & 0xff;
256             if (b1 == 0x47 && b2 == 0x49) {
257                 return checkGif();
258             }
259             else
260             if (b1 == 0x89 && b2 == 0x50) {
261                 return checkPng();
262             }
263             else
264             if (b1 == 0xff && b2 == 0xd8) {
265                 return checkJpeg();
266             }
267             else
268             if (b1 == 0x42 && b2 == 0x4d) {
269                 return checkBmp();
270             }
271             else
272             if (b1 == 0x0a && b2 < 0x06) {
273                 return checkPcx();
274             }
275             else
276             if (b1 == 0x46 && b2 == 0x4f) {
277                 return checkIff();
278             }
279             else
280             if (b1 == 0x59 && b2 == 0xa6) {
281                 return checkRas();
282             }
283             else
284             if (b1 == 0x50 && b2 >= 0x31 && b2 <= 0x36) {
285                 return checkPnm(b2 - '0');
286             }
287             else
288             if (b1 == 0x38 && b2 == 0x42) {
289                 return checkPsd();
290             }
291             else
292             if (b1 == 0x46 && b2 == 0x57) {
293                 return checkSwf();
294             }
295             else {
296                 return false;
297             }
298         } catch (IOException ioe) {
299             return false;
300         }
301     }
302
303     private boolean checkBmp() throws IOException {
304         byte[] a = new byte[44];
305         if (read(a) != a.length) {
306             return false;
307         }
308         width = getIntLittleEndian(a, 16);
309         height = getIntLittleEndian(a, 20);
310         if (width < 1 || height < 1) {
311             return false;
312         }
313         bitsPerPixel = getShortLittleEndian(a, 26);
314         if (bitsPerPixel != 1 && bitsPerPixel != 4 &&
315             bitsPerPixel != 8 && bitsPerPixel != 16 &&
316             bitsPerPixel != 24 && bitsPerPixel != 32) {
317             return false;
318         }
319         int x = getIntLittleEndian(a, 36);
320         if (x > 0) {
321             setPhysicalWidthDpi(x);
322         }
323         int y = getIntLittleEndian(a, 40);
324         if (y > 0) {
325             setPhysicalHeightDpi(y);
326         }
327         format = FORMAT_BMP;
328         return true;
329     }
330
331     private boolean checkGif() throws IOException {
332         final byte[] GIF_MAGIC_87A = {0x46, 0x38, 0x37, 0x61};
333         final byte[] GIF_MAGIC_89A = {0x46, 0x38, 0x39, 0x61};
334         byte[] a = new byte[11]; // 4 from the GIF signature + 7 from the global header
335 if (read(a) != 11) {
336             return false;
337         }
338         if ((!equals(a, 0, GIF_MAGIC_89A, 0, 4)) &&
339             (!equals(a, 0, GIF_MAGIC_87A, 0, 4))) {
340             return false;
341         }
342         format = FORMAT_GIF;
343         width = getShortLittleEndian(a, 4);
344         height = getShortLittleEndian(a, 6);
345         int flags = a[8] & 0xff;
346         bitsPerPixel = ((flags >> 4) & 0x07) + 1;
347         if (!determineNumberOfImages) {
348             return true;
349         }
350         // skip global color palette
351 if ((flags & 0x80) != 0) {
352             int tableSize = (1 << ((flags & 7) + 1)) * 3;
353             skip(tableSize);
354         }
355         numberOfImages = 0;
356         int blockType;
357         do
358         {
359             blockType = read();
360             switch(blockType)
361             {
362                 case(0x2c): // image separator
363 {
364                     if (read(a, 0, 9) != 9) {
365                         return false;
366                     }
367                     flags = a[8] & 0xff;
368                     int localBitsPerPixel = (flags & 0x07) + 1;
369                     if (localBitsPerPixel > bitsPerPixel) {
370                         bitsPerPixel = localBitsPerPixel;
371                     }
372                     if ((flags & 0x80) != 0) {
373                         skip((1 << localBitsPerPixel) * 3);
374                     }
375                     skip(1); // initial code length
376 int n;
377                     do
378                     {
379                         n = read();
380                         if (n > 0) {
381                             skip(n);
382                         }
383                         else
384                         if (n == -1) {
385                             return false;
386                         }
387                     }
388                     while (n > 0);
389                     numberOfImages++;
390                     break;
391                 }
392                 case(0x21): // extension
393 {
394                     int extensionType = read();
395                     if (collectComments && extensionType == 0xfe) {
396                         StringBuffer sb = new StringBuffer ();
397                         int n;
398                         do
399                         {
400                             n = read();
401                             if (n == -1) {
402                                 return false;
403                             }
404                             if (n > 0) {
405                                 for (int i = 0; i < n; i++) {
406                                     int ch = read();
407                                     if (ch == -1) {
408                                         return false;
409                                     }
410                                     sb.append((char)ch);
411                                 }
412                             }
413                         }
414                         while (n > 0);
415                     } else {
416                         int n;
417                         do
418                         {
419                             n = read();
420                             if (n > 0) {
421                                 skip(n);
422                             }
423                             else
424                             if (n == -1) {
425                                 return false;
426                             }
427                         }
428                         while (n > 0);
429                     }
430                     break;
431                 }
432                 case(0x3b): // end of file
433 {
434                     break;
435                 }
436                 default:
437                 {
438                     return false;
439                 }
440             }
441         }
442         while (blockType != 0x3b);
443         return true;
444     }
445
446     private boolean checkIff() throws IOException {
447         byte[] a = new byte[10];
448         // read remaining 2 bytes of file id, 4 bytes file size
449 // and 4 bytes IFF subformat
450 if (read(a, 0, 10) != 10) {
451             return false;
452         }
453         final byte[] IFF_RM = {0x52, 0x4d};
454         if (!equals(a, 0, IFF_RM, 0, 2)) {
455             return false;
456         }
457         int type = getIntBigEndian(a, 6);
458         if (type != 0x494c424d && // type must be ILBM...
459 type != 0x50424d20) { // ...or PBM
460 return false;
461         }
462         // loop chunks to find BMHD chunk
463 do {
464             if (read(a, 0, 8) != 8) {
465                 return false;
466             }
467             int chunkId = getIntBigEndian(a, 0);
468             int size = getIntBigEndian(a, 4);
469             if ((size & 1) == 1) {
470                 size++;
471             }
472             if (chunkId == 0x424d4844) { // BMHD chunk
473 if (read(a, 0, 9) != 9) {
474                     return false;
475                 }
476                 format = FORMAT_IFF;
477                 width = getShortBigEndian(a, 0);
478                 height = getShortBigEndian(a, 2);
479                 bitsPerPixel = a[8] & 0xff;
480                 return (width > 0 && height > 0 && bitsPerPixel > 0 && bitsPerPixel < 33);
481             } else {
482                 skip(size);
483             }
484         } while (true);
485     }
486
487     private boolean checkJpeg() throws IOException {
488         byte[] data = new byte[12];
489         while (true) {
490             if (read(data, 0, 4) != 4) {
491                 return false;
492             }
493             int marker = getShortBigEndian(data, 0);
494             int size = getShortBigEndian(data, 2);
495             if ((marker & 0xff00) != 0xff00) {
496                 return false; // not a valid marker
497 }
498             if (marker == 0xffe0) { // APPx
499 if (size < 14) {
500                     return false; // APPx header must be >= 14 bytes
501 }
502                 if (read(data, 0, 12) != 12) {
503                     return false;
504                 }
505                 final byte[] APP0_ID = {0x4a, 0x46, 0x49, 0x46, 0x00};
506                 if (equals(APP0_ID, 0, data, 0, 5)) {
507                     //System.out.println("data 7=" + data[7]);
508 if (data[7] == 1) {
509                         setPhysicalWidthDpi(getShortBigEndian(data, 8));
510                         setPhysicalHeightDpi(getShortBigEndian(data, 10));
511                     }
512                     else
513                     if (data[7] == 2) {
514                         int x = getShortBigEndian(data, 8);
515                         int y = getShortBigEndian(data, 10);
516                         setPhysicalWidthDpi((int)(x * 2.54f));
517                         setPhysicalHeightDpi((int)(y * 2.54f));
518                     }
519                 }
520                 skip(size - 14);
521             }
522             else
523             if (collectComments && size > 2 && marker == 0xfffe) { // comment
524 size -= 2;
525                 byte[] chars = new byte[size];
526                 if (read(chars, 0, size) != size) {
527                     return false;
528                 }
529                 String comment = new String (chars, "iso-8859-1");
530                 comment = comment.trim();
531                 //System.out.println(comment);
532 addComment(comment);
533             }
534             else
535             if (marker >= 0xffc0 && marker <= 0xffcf && marker != 0xffc4 && marker != 0xffc8) {
536                 if (read(data, 0, 6) != 6) {
537                     return false;
538                 }
539                 format = FORMAT_JPEG;
540                 bitsPerPixel = (data[0] & 0xff) * (data[5] & 0xff);
541                 width = getShortBigEndian(data, 3);
542                 height = getShortBigEndian(data, 1);
543                 return true;
544             } else {
545                 skip(size - 2);
546             }
547         }
548     }
549
550     private boolean checkPcx() throws IOException {
551         byte[] a = new byte[64];
552         if (read(a) != a.length) {
553             return false;
554         }
555         if (a[0] != 1) { // encoding, 1=RLE is only valid value
556 return false;
557         }
558         // width / height
559 int x1 = getShortLittleEndian(a, 2);
560         int y1 = getShortLittleEndian(a, 4);
561         int x2 = getShortLittleEndian(a, 6);
562         int y2 = getShortLittleEndian(a, 8);
563         if (x1 < 0 || x2 < x1 || y1 < 0 || y2 < y1) {
564             return false;
565         }
566         width = x2 - x1 + 1;
567         height = y2 - y1 + 1;
568         // color depth
569 int bits = a[1];
570         int planes = a[63];
571         if (planes == 1 &&
572             (bits == 1 || bits == 2 || bits == 4 || bits == 8)) {
573             // paletted
574 bitsPerPixel = bits;
575         } else
576         if (planes == 3 && bits == 8) {
577             // RGB truecolor
578 bitsPerPixel = 24;
579         } else {
580             return false;
581         }
582         setPhysicalWidthDpi(getShortLittleEndian(a, 10));
583         setPhysicalHeightDpi(getShortLittleEndian(a, 10));
584         format = FORMAT_PCX;
585         return true;
586     }
587
588     private boolean checkPng() throws IOException {
589         final byte[] PNG_MAGIC = {0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a};
590         byte[] a = new byte[24];
591         if (read(a) != 24) {
592             return false;
593         }
594         if (!equals(a, 0, PNG_MAGIC, 0, 6)) {
595             return false;
596         }
597         format = FORMAT_PNG;
598         width = getIntBigEndian(a, 14);
599         height = getIntBigEndian(a, 18);
600         bitsPerPixel = a[22] & 0xff;
601         int colorType = a[23] & 0xff;
602         if (colorType == 2 || colorType == 6) {
603             bitsPerPixel *= 3;
604         }
605         return true;
606     }
607
608     private boolean checkPnm(int id) throws IOException {
609         if (id < 1 || id > 6) {
610             return false;
611         }
612         final int[] PNM_FORMATS = {FORMAT_PBM, FORMAT_PGM, FORMAT_PPM};
613         format = PNM_FORMATS[(id - 1) % 3];
614         boolean hasPixelResolution = false;
615         String s;
616         while (true)
617         {
618             s = readLine();
619             if (s != null) {
620                 s = s.trim();
621             }
622             if (s == null || s.length() < 1) {
623                 continue;
624             }
625             if (s.charAt(0) == '#') { // comment
626 if (collectComments && s.length() > 1) {
627                     addComment(s.substring(1));
628                 }
629                 continue;
630             }
631             if (!hasPixelResolution) { // split "343 966" into width=343, height=966
632 int spaceIndex = s.indexOf(' ');
633                 if (spaceIndex == -1) {
634                     return false;
635                 }
636                 String widthString = s.substring(0, spaceIndex);
637                 spaceIndex = s.lastIndexOf(' ');
638                 if (spaceIndex == -1) {
639                     return false;
640                 }
641                 String heightString = s.substring(spaceIndex + 1);
642                 try {
643                     width = Integer.parseInt(widthString);
644                     height = Integer.parseInt(heightString);
645                 } catch (NumberFormatException nfe) {
646                     return false;
647                 }
648                 if (width < 1 || height < 1) {
649                     return false;
650                 }
651                 if (format == FORMAT_PBM) {
652                     bitsPerPixel = 1;
653                     return true;
654                 }
655                 hasPixelResolution = true;
656             }
657             else
658             {
659                 int maxSample;
660                 try {
661                     maxSample = Integer.parseInt(s);
662                 } catch (NumberFormatException nfe) {
663                     return false;
664                 }
665                 if (maxSample < 0) {
666                     return false;
667                 }
668                 for (int i = 0; i < 25; i++) {
669                     if (maxSample < (1 << (i + 1))) {
670                         bitsPerPixel = i + 1;
671                         if (format == FORMAT_PPM) {
672                             bitsPerPixel *= 3;
673                         }
674                         return true;
675                     }
676                 }
677                 return false;
678             }
679         }
680     }
681
682     private boolean checkPsd() throws IOException {
683         byte[] a = new byte[24];
684         if (read(a) != a.length) {
685             return false;
686         }
687         final byte[] PSD_MAGIC = {0x50, 0x53};
688         if (!equals(a, 0, PSD_MAGIC, 0, 2)) {
689             return false;
690         }
691         format = FORMAT_PSD;
692         width = getIntBigEndian(a, 16);
693         height = getIntBigEndian(a, 12);
694         int channels = getShortBigEndian(a, 10);
695         int depth = getShortBigEndian(a, 20);
696         bitsPerPixel = channels * depth;
697         return (width > 0 && height > 0 && bitsPerPixel > 0 && bitsPerPixel <= 64);
698     }
699
700     private boolean checkRas() throws IOException {
701         byte[] a = new byte[14];
702         if (read(a) != a.length) {
703             return false;
704         }
705         final byte[] RAS_MAGIC = {0x6a, (byte)0x95};
706         if (!equals(a, 0, RAS_MAGIC, 0, 2)) {
707             return false;
708         }
709         format = FORMAT_RAS;
710         width = getIntBigEndian(a, 2);
711         height = getIntBigEndian(a, 6);
712         bitsPerPixel = getIntBigEndian(a, 10);
713         return (width > 0 && height > 0 && bitsPerPixel > 0 && bitsPerPixel <= 24);
714     }
715
716     // Written by Michael Aird.
717 private boolean checkSwf() throws IOException {
718         //get rid of the last byte of the signature, the byte of the version and 4 bytes of the size
719 byte[] a = new byte[6];
720         if (read(a) != a.length) {
721             return false;
722         }
723         format = FORMAT_SWF;
724         int bitSize = (int)readUBits( 5 );
725         int minX = (int)readSBits( bitSize );
726         int maxX = (int)readSBits( bitSize );
727         int minY = (int)readSBits( bitSize );
728         int maxY = (int)readSBits( bitSize );
729         width = maxX/20; //cause we're in twips
730 height = maxY/20; //cause we're in twips
731 setPhysicalWidthDpi(72);
732         setPhysicalHeightDpi(72);
733         return (width > 0 && height > 0);
734     }
735
736     /**
737      * Run over String list, return false iff at least one of the arguments
738      * equals <code>-c</code>.
739      */
740     private static boolean determineVerbosity(String [] args) {
741         if (args != null && args.length > 0) {
742             for (int i = 0; i < args.length; i++) {
743                 if ("-c".equals(args[i])) {
744                     return false;
745                 }
746             }
747         }
748         return true;
749     }
750
751     private boolean equals(byte[] a1, int offs1, byte[] a2, int offs2, int num) {
752         while (num-- > 0) {
753             if (a1[offs1++] != a2[offs2++]) {
754                 return false;
755  &