1// Copyright (C) 2016 The Qt Company Ltd.
2// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
3
4#include "private/qppmhandler_p.h"
5
6#ifndef QT_NO_IMAGEFORMAT_PPM
7
8#include <qdebug.h>
9#include <qimage.h>
10#include <qlist.h>
11#include <qloggingcategory.h>
12#include <qrgba64.h>
13#include <qvariant.h>
14#include <private/qlocale_p.h>
15#include <private/qtools_p.h>
16
17QT_BEGIN_NAMESPACE
18
19Q_DECLARE_LOGGING_CATEGORY(lcImageIo)
20
21/*****************************************************************************
22 PBM/PGM/PPM (ASCII and RAW) image read/write functions
23 *****************************************************************************/
24
25static void discard_pbm_line(QIODevice *d)
26{
27 const int buflen = 100;
28 char buf[buflen];
29 int res = 0;
30 do {
31 res = d->readLine(data: buf, maxlen: buflen);
32 } while (res > 0 && buf[res-1] != '\n');
33}
34
35static int read_pbm_int(QIODevice *d, bool *ok, int maxDigits = -1)
36{
37 char c;
38 int val = -1;
39 bool digit;
40 bool hasOverflow = false;
41 for (;;) {
42 if (!d->getChar(c: &c)) // end of file
43 break;
44 digit = QtMiscUtils::isAsciiDigit(c);
45 if (val != -1) {
46 if (digit) {
47 const int cValue = c - '0';
48 if (val <= (INT_MAX - cValue) / 10) {
49 val = 10*val + cValue;
50 } else {
51 hasOverflow = true;
52 }
53 if (maxDigits > 0 && --maxDigits == 0)
54 break;
55 continue;
56 } else {
57 if (c == '#') // comment
58 discard_pbm_line(d);
59 break;
60 }
61 }
62 if (digit) // first digit
63 val = c - '0';
64 else if (ascii_isspace(c))
65 continue;
66 else if (c == '#')
67 discard_pbm_line(d);
68 else
69 break;
70 if (maxDigits > 0 && --maxDigits == 0)
71 break;
72 }
73 if (val < 0)
74 *ok = false;
75 return hasOverflow ? -1 : val;
76}
77
78static bool read_pbm_header(QIODevice *device, char& type, int& w, int& h, int& mcc)
79{
80 char buf[3];
81 if (device->read(data: buf, maxlen: 3) != 3) // read P[1-6]<white-space>
82 return false;
83
84 if (!(buf[0] == 'P' && QtMiscUtils::isAsciiDigit(c: buf[1]) && ascii_isspace(c: buf[2])))
85 return false;
86
87 type = buf[1];
88 if (type < '1' || type > '6')
89 return false;
90
91 bool ok = true;
92 w = read_pbm_int(d: device, ok: &ok); // get image width
93 h = read_pbm_int(d: device, ok: &ok); // get image height
94
95 if (type == '1' || type == '4')
96 mcc = 1; // ignore max color component
97 else
98 mcc = read_pbm_int(d: device, ok: &ok); // get max color component
99
100 if (!ok || w <= 0 || w > 32767 || h <= 0 || h > 32767 || mcc <= 0 || mcc > 0xffff)
101 return false; // weird P.M image
102
103 return true;
104}
105
106static inline QRgb scale_pbm_color(quint16 mx, quint16 rv, quint16 gv, quint16 bv)
107{
108 return QRgba64::fromRgba64(red: (rv * 0xffffu) / mx, green: (gv * 0xffffu) / mx, blue: (bv * 0xffffu) / mx, alpha: 0xffff).toArgb32();
109}
110
111static bool read_pbm_body(QIODevice *device, char type, int w, int h, int mcc, QImage *outImage)
112{
113 int nbits, y;
114 qsizetype pbm_bpl;
115 bool raw;
116
117 QImage::Format format;
118 switch (type) {
119 case '1': // ascii PBM
120 case '4': // raw PBM
121 nbits = 1;
122 format = QImage::Format_Mono;
123 break;
124 case '2': // ascii PGM
125 case '5': // raw PGM
126 nbits = 8;
127 format = QImage::Format_Grayscale8;
128 break;
129 case '3': // ascii PPM
130 case '6': // raw PPM
131 nbits = 32;
132 format = QImage::Format_RGB32;
133 break;
134 default:
135 return false;
136 }
137 raw = type >= '4';
138
139 if (!QImageIOHandler::allocateImage(size: QSize(w, h), format, image: outImage))
140 return false;
141
142 pbm_bpl = (qsizetype(w) * nbits + 7) / 8; // bytes per scanline in PBM
143
144 if (raw) { // read raw data
145 if (nbits == 32) { // type 6
146 pbm_bpl = mcc < 256 ? 3*w : 6*w;
147 uchar *buf24 = new uchar[pbm_bpl], *b;
148 QRgb *p;
149 QRgb *end;
150 for (y=0; y<h; y++) {
151 if (device->read(data: (char *)buf24, maxlen: pbm_bpl) != pbm_bpl) {
152 delete[] buf24;
153 return false;
154 }
155 p = (QRgb *)outImage->scanLine(y);
156 end = p + w;
157 b = buf24;
158 while (p < end) {
159 if (mcc < 256) {
160 if (mcc == 255)
161 *p++ = qRgb(r: b[0],g: b[1],b: b[2]);
162 else
163 *p++ = scale_pbm_color(mx: mcc, rv: b[0], gv: b[1], bv: b[2]);
164 b += 3;
165 } else {
166 quint16 rv = b[0] << 8 | b[1];
167 quint16 gv = b[2] << 8 | b[3];
168 quint16 bv = b[4] << 8 | b[5];
169 if (mcc == 0xffff)
170 *p++ = QRgba64::fromRgba64(red: rv, green: gv, blue: bv, alpha: 0xffff).toArgb32();
171 else
172 *p++ = scale_pbm_color(mx: mcc, rv, gv, bv);
173 b += 6;
174 }
175 }
176 }
177 delete[] buf24;
178 } else if (nbits == 8 && mcc > 255) { // type 5 16bit
179 pbm_bpl = 2*w;
180 uchar *buf16 = new uchar[pbm_bpl];
181 for (y=0; y<h; y++) {
182 if (device->read(data: (char *)buf16, maxlen: pbm_bpl) != pbm_bpl) {
183 delete[] buf16;
184 return false;
185 }
186 uchar *p = outImage->scanLine(y);
187 uchar *end = p + w;
188 uchar *b = buf16;
189 while (p < end) {
190 *p++ = (b[0] << 8 | b[1]) * 255 / mcc;
191 b += 2;
192 }
193 }
194 delete[] buf16;
195 } else { // type 4,5
196 for (y=0; y<h; y++) {
197 uchar *p = outImage->scanLine(y);
198 if (device->read(data: (char *)p, maxlen: pbm_bpl) != pbm_bpl)
199 return false;
200 if (nbits == 8 && mcc < 255) {
201 for (qsizetype i = 0; i < pbm_bpl; i++)
202 p[i] = (p[i] * 255) / mcc;
203 }
204 }
205 }
206 } else { // read ascii data
207 uchar *p;
208 qsizetype n;
209 bool ok = true;
210 for (y = 0; y < h && ok; y++) {
211 p = outImage->scanLine(y);
212 n = pbm_bpl;
213 if (nbits == 1) {
214 int b;
215 int bitsLeft = w;
216 while (n-- && ok) {
217 b = 0;
218 for (int i=0; i<8; i++) {
219 if (i < bitsLeft)
220 b = (b << 1) | (read_pbm_int(d: device, ok: &ok, maxDigits: 1) & 1);
221 else
222 b = (b << 1) | (0 & 1); // pad it our self if we need to
223 }
224 bitsLeft -= 8;
225 *p++ = b;
226 }
227 } else if (nbits == 8) {
228 if (mcc == 255) {
229 while (n-- && ok) {
230 *p++ = read_pbm_int(d: device, ok: &ok);
231 }
232 } else {
233 while (n-- && ok) {
234 *p++ = (read_pbm_int(d: device, ok: &ok) & 0xffff) * 255 / mcc;
235 }
236 }
237 } else { // 32 bits
238 n /= 4;
239 int r, g, b;
240 if (mcc == 255) {
241 while (n-- && ok) {
242 r = read_pbm_int(d: device, ok: &ok);
243 g = read_pbm_int(d: device, ok: &ok);
244 b = read_pbm_int(d: device, ok: &ok);
245 *((QRgb*)p) = qRgb(r, g, b);
246 p += 4;
247 }
248 } else {
249 while (n-- && ok) {
250 r = read_pbm_int(d: device, ok: &ok);
251 g = read_pbm_int(d: device, ok: &ok);
252 b = read_pbm_int(d: device, ok: &ok);
253 *((QRgb*)p) = scale_pbm_color(mx: mcc, rv: r, gv: g, bv: b);
254 p += 4;
255 }
256 }
257 }
258 }
259 if (!ok)
260 return false;
261 }
262
263 if (format == QImage::Format_Mono) {
264 outImage->setColorCount(2);
265 outImage->setColor(i: 0, c: qRgb(r: 255,g: 255,b: 255)); // white
266 outImage->setColor(i: 1, c: qRgb(r: 0,g: 0,b: 0)); // black
267 }
268
269 return true;
270}
271
272static bool write_pbm_image(QIODevice *out, const QImage &sourceImage, QByteArrayView sourceFormat)
273{
274 QByteArray str;
275 QImage image = sourceImage;
276 const QByteArrayView format = sourceFormat.left(n: 3); // ignore RAW part
277
278 bool gray = format == "pgm";
279
280 if (format == "pbm") {
281 image = image.convertToFormat(f: QImage::Format_Mono);
282 } else if (gray) {
283 image = image.convertToFormat(f: QImage::Format_Grayscale8);
284 } else {
285 switch (image.format()) {
286 case QImage::Format_Mono:
287 case QImage::Format_MonoLSB:
288 image = image.convertToFormat(f: QImage::Format_Indexed8);
289 break;
290 case QImage::Format_Indexed8:
291 case QImage::Format_RGB32:
292 case QImage::Format_ARGB32:
293 break;
294 default:
295 if (image.hasAlphaChannel())
296 image = image.convertToFormat(f: QImage::Format_ARGB32);
297 else
298 image = image.convertToFormat(f: QImage::Format_RGB32);
299 break;
300 }
301 }
302
303 if (image.depth() == 1 && image.colorCount() == 2) {
304 if (qGray(rgb: image.color(i: 0)) < qGray(rgb: image.color(i: 1))) {
305 // 0=dark/black, 1=light/white - invert
306 image.detach();
307 for (int y=0; y<image.height(); y++) {
308 uchar *p = image.scanLine(y);
309 uchar *end = p + image.bytesPerLine();
310 while (p < end)
311 *p++ ^= 0xff;
312 }
313 }
314 }
315
316 uint w = image.width();
317 uint h = image.height();
318
319 str = "P\n";
320 str += QByteArray::number(w);
321 str += ' ';
322 str += QByteArray::number(h);
323 str += '\n';
324
325 switch (image.depth()) {
326 case 1: {
327 str.insert(i: 1, c: '4');
328 if (out->write(data: str, len: str.size()) != str.size())
329 return false;
330 w = (w+7)/8;
331 for (uint y=0; y<h; y++) {
332 uchar* line = image.scanLine(y);
333 if (w != (uint)out->write(data: (char*)line, len: w))
334 return false;
335 }
336 }
337 break;
338
339 case 8: {
340 str.insert(i: 1, c: gray ? '5' : '6');
341 str.append(s: "255\n");
342 if (out->write(data: str, len: str.size()) != str.size())
343 return false;
344 qsizetype bpl = qsizetype(w) * (gray ? 1 : 3);
345 uchar *buf = new uchar[bpl];
346 if (image.format() == QImage::Format_Indexed8) {
347 const QList<QRgb> color = image.colorTable();
348 for (uint y=0; y<h; y++) {
349 const uchar *b = image.constScanLine(y);
350 uchar *p = buf;
351 uchar *end = buf+bpl;
352 if (gray) {
353 while (p < end) {
354 uchar g = (uchar)qGray(rgb: color[*b++]);
355 *p++ = g;
356 }
357 } else {
358 while (p < end) {
359 QRgb rgb = color[*b++];
360 *p++ = qRed(rgb);
361 *p++ = qGreen(rgb);
362 *p++ = qBlue(rgb);
363 }
364 }
365 if (bpl != (qsizetype)out->write(data: (char*)buf, len: bpl))
366 return false;
367 }
368 } else {
369 for (uint y=0; y<h; y++) {
370 const uchar *b = image.constScanLine(y);
371 uchar *p = buf;
372 uchar *end = buf + bpl;
373 if (gray) {
374 while (p < end)
375 *p++ = *b++;
376 } else {
377 while (p < end) {
378 uchar color = *b++;
379 *p++ = color;
380 *p++ = color;
381 *p++ = color;
382 }
383 }
384 if (bpl != (qsizetype)out->write(data: (char*)buf, len: bpl))
385 return false;
386 }
387 }
388 delete [] buf;
389 break;
390 }
391
392 case 32: {
393 str.insert(i: 1, c: '6');
394 str.append(s: "255\n");
395 if (out->write(data: str, len: str.size()) != str.size())
396 return false;
397 qsizetype bpl = qsizetype(w) * 3;
398 uchar *buf = new uchar[bpl];
399 for (uint y=0; y<h; y++) {
400 const QRgb *b = reinterpret_cast<const QRgb *>(image.constScanLine(y));
401 uchar *p = buf;
402 uchar *end = buf+bpl;
403 while (p < end) {
404 QRgb rgb = *b++;
405 *p++ = qRed(rgb);
406 *p++ = qGreen(rgb);
407 *p++ = qBlue(rgb);
408 }
409 if (bpl != (qsizetype)out->write(data: (char*)buf, len: bpl))
410 return false;
411 }
412 delete [] buf;
413 break;
414 }
415
416 default:
417 return false;
418 }
419
420 return true;
421}
422
423QPpmHandler::QPpmHandler()
424 : state(Ready)
425{
426}
427
428bool QPpmHandler::readHeader()
429{
430 state = Error;
431 if (!read_pbm_header(device: device(), type, w&: width, h&: height, mcc))
432 return false;
433 state = ReadHeader;
434 return true;
435}
436
437bool QPpmHandler::canRead() const
438{
439 if (state == Ready && !canRead(device: device(), subType: &subType))
440 return false;
441
442 if (state != Error) {
443 setFormat(subType);
444 return true;
445 }
446
447 return false;
448}
449
450bool QPpmHandler::canRead(QIODevice *device, QByteArray *subType)
451{
452 if (!device) {
453 qCWarning(lcImageIo, "QPpmHandler::canRead() called with no device");
454 return false;
455 }
456
457 char head[2];
458 if (device->peek(data: head, maxlen: sizeof(head)) != sizeof(head))
459 return false;
460
461 if (head[0] != 'P')
462 return false;
463
464 if (head[1] == '1' || head[1] == '4') {
465 if (subType)
466 *subType = "pbm";
467 } else if (head[1] == '2' || head[1] == '5') {
468 if (subType)
469 *subType = "pgm";
470 } else if (head[1] == '3' || head[1] == '6') {
471 if (subType)
472 *subType = "ppm";
473 } else {
474 return false;
475 }
476 return true;
477}
478
479bool QPpmHandler::read(QImage *image)
480{
481 if (state == Error)
482 return false;
483
484 if (state == Ready && !readHeader()) {
485 state = Error;
486 return false;
487 }
488
489 if (!read_pbm_body(device: device(), type, w: width, h: height, mcc, outImage: image)) {
490 state = Error;
491 return false;
492 }
493
494 state = Ready;
495 return true;
496}
497
498bool QPpmHandler::write(const QImage &image)
499{
500 return write_pbm_image(out: device(), sourceImage: image, sourceFormat: subType);
501}
502
503bool QPpmHandler::supportsOption(ImageOption option) const
504{
505 return option == SubType
506 || option == Size
507 || option == ImageFormat;
508}
509
510QVariant QPpmHandler::option(ImageOption option) const
511{
512 if (option == SubType) {
513 return subType;
514 } else if (option == Size) {
515 if (state == Error)
516 return QVariant();
517 if (state == Ready && !const_cast<QPpmHandler*>(this)->readHeader())
518 return QVariant();
519 return QSize(width, height);
520 } else if (option == ImageFormat) {
521 if (state == Error)
522 return QVariant();
523 if (state == Ready && !const_cast<QPpmHandler*>(this)->readHeader())
524 return QVariant();
525 QImage::Format format = QImage::Format_Invalid;
526 switch (type) {
527 case '1': // ascii PBM
528 case '4': // raw PBM
529 format = QImage::Format_Mono;
530 break;
531 case '2': // ascii PGM
532 case '5': // raw PGM
533 format = QImage::Format_Grayscale8;
534 break;
535 case '3': // ascii PPM
536 case '6': // raw PPM
537 format = QImage::Format_RGB32;
538 break;
539 default:
540 break;
541 }
542 return format;
543 }
544 return QVariant();
545}
546
547void QPpmHandler::setOption(ImageOption option, const QVariant &value)
548{
549 if (option == SubType)
550 subType = value.toByteArray().toLower();
551}
552
553QT_END_NAMESPACE
554
555#endif // QT_NO_IMAGEFORMAT_PPM
556

source code of qtbase/src/gui/image/qppmhandler.cpp