contrib/pnglite/pnglite.c

35 file_read(png_t *png, void *out, size_t size, size_t numel)
44 		result = lseek(png->fd, offset, SEEK_CUR);
46 		result = read(png->fd, out, size * numel);
53 file_read_ul(png_t *png, unsigned *out)
57 	if (file_read(png, &buf, 1, 4) != 4)
72 png_get_bpp(png_t *png)
76 	switch (png->color_type) {
91 	bpp *= png->depth / 8;
97 png_read_ihdr(png_t *png)
104 	if (file_read_ul(png, &length) != PNG_NO_ERROR)
110 	if (file_read(png, ihdr, 1, 13+4) != 13+4)
113 	if (file_read_ul(png, &orig_crc) != PNG_NO_ERROR)
123 	png->width = get_ul(ihdr+4);
124 	png->height = get_ul(ihdr+8);
125 	png->depth = ihdr[12];
126 	png->color_type = ihdr[13];
127 	png->compression_method = ihdr[14];
128 	png->filter_method = ihdr[15];
129 	png->interlace_method = ihdr[16];
131 	if (png->color_type == PNG_INDEXED)
134 	if (png->depth != 8 && png->depth != 16)
137 	if (png->interlace_method)
144 png_print_info(png_t *png)
147 	printf("\twidth:\t\t%d\n", png->width);
148 	printf("\theight:\t\t%d\n", png->height);
149 	printf("\tdepth:\t\t%d\n", png->depth);
152 	switch (png->color_type) {
168 	    png->compression_method?
171 	    png->filter_method? "unknown, this is not good":"adaptive");
173 	    png->interlace_method? "interlace":"no interlace");
177 png_open(png_t *png, const char *filename)
182 	png->image = NULL;
183 	png->fd = open(filename, O_RDONLY);
184 	if (png->fd == -1)
187 	if (file_read(png, header, 1, 8) != 8) {
197 	result = png_read_ihdr(png);
199 		result = png_get_bpp(png);
201 			png->bpp = (uint8_t)result;
208 		uint64_t size = png->width * png->height * png->bpp;
211 			png->image = malloc(size);
212 		if (png->image == NULL)
217 		result = png_get_data(png, png->image);
220 		free(png->image);
221 		(void) close(png->fd);
222 		png->fd = -1;
230 png_close(png_t *png)
232 	(void) close(png->fd);
233 	png->fd = -1;
234 	free(png->image);
235 	png->image = NULL;
241 png_init_inflate(png_t *png)
244 	png->zs = calloc(1, sizeof (z_stream));
246 	stream = png->zs;
252 		free(png->zs);
253 		png->zs = NULL;
257 	stream->next_out = png->png_data;
258 	stream->avail_out = png->png_datalen;
264 png_end_inflate(png_t *png)
266 	z_stream *stream = png->zs;
277 	free(png->zs);
278 	png->zs = NULL;
284 png_inflate(png_t *png, uint8_t *data, int len)
287 	z_stream *stream = png->zs;
309 png_read_idat(png_t *png, unsigned length)
315 	if (!png->readbuf || png->readbuflen < length) {
316 		png->readbuf = realloc(png->readbuf, length);
317 		png->readbuflen = length;
320 	if (!png->readbuf)
323 	if (file_read(png, png->readbuf, 1, length) != len)
328 	calc_crc = crc32(calc_crc, (uint8_t *)png->readbuf, length);
330 	if (file_read_ul(png, &orig_crc) != PNG_NO_ERROR)
336 	return (png_inflate(png, png->readbuf, length));
340 png_process_chunk(png_t *png)
346 	if (file_read_ul(png, &length) != PNG_NO_ERROR)
349 	if (file_read_ul(png, &type) != PNG_NO_ERROR)
357 		if (!png->png_data) {	/* first IDAT */
358 			png->png_datalen = png->width * png->height *
359 			    png->bpp + png->height;
360 			png->png_data = malloc(png->png_datalen);
363 		if (!png->png_data)
366 		if (!png->zs) {
367 			result = png_init_inflate(png);
372 		return (png_read_idat(png, length));
376 		(void) file_read(png, 0, 1, length + 4); /* unknown chunk */
484 png_unfilter(png_t *png, uint8_t *data)
489 	uint8_t *filtered = png->png_data;
490 	unsigned stride = png->bpp;
492 	while (pos < png->png_datalen) {
497 		if (png->depth == 16) {
498 			for (i = 0; i < png->width * stride; i += 2) {
506 			memcpy(data+outpos, filtered+pos, png->width * stride);
510 			    png->width * stride);
515 				    data + outpos - (png->width*stride),
516 				    png->width*stride);
519 				    0, png->width*stride);
526 				    data + outpos - (png->width*stride),
527 				    png->width*stride);
530 				    data+outpos, 0, png->width*stride);
537 				    data + outpos - (png->width*stride),
538 				    png->width*stride);
541 				    data+outpos, 0, png->width*stride);
548 		outpos += png->width * stride;
549 		pos += png->width * stride;
556 png_get_data(png_t *png, uint8_t *data)
560 	png->zs = NULL;
561 	png->png_datalen = 0;
562 	png->png_data = NULL;
563 	png->readbuf = NULL;
564 	png->readbuflen = 0;
567 		result = png_process_chunk(png);
569 	if (png->readbuf) {
570 		free(png->readbuf);
571 		png->readbuflen = 0;
573 	if (png->zs)
574 		(void) png_end_inflate(png);
577 		free(png->png_data);
581 	result = png_unfilter(png, data);
583 	free(png->png_data);