media/v4l2-core/v4l2-jpeg.c

41 #define SOS	0xffda	/* start of stream */
56  * struct jpeg_stream - JPEG byte stream
57  * @curr: current position in stream
66 static int jpeg_get_byte(struct jpeg_stream *stream)
68 	if (stream->curr >= stream->end)
71 	return *stream->curr++;
75 static int jpeg_get_word_be(struct jpeg_stream *stream)
79 	if (stream->curr + sizeof(__be16) > stream->end)
82 	word = get_unaligned_be16(stream->curr);
83 	stream->curr += sizeof(__be16);
88 static int jpeg_skip(struct jpeg_stream *stream, size_t len)
90 	if (stream->curr + len > stream->end)
93 	stream->curr += len;
98 static int jpeg_next_marker(struct jpeg_stream *stream)
103 	while ((byte = jpeg_get_byte(stream)) >= 0) {
113 /* this does not advance the current position in the stream */
114 static int jpeg_reference_segment(struct jpeg_stream *stream,
119 	if (stream->curr + sizeof(__be16) > stream->end)
122 	len = get_unaligned_be16(stream->curr);
123 	if (stream->curr + len > stream->end)
126 	segment->start = stream->curr;
155 static int jpeg_parse_frame_header(struct jpeg_stream *stream, u16 sof_marker,
158 	int len = jpeg_get_word_be(stream);
171 		p = jpeg_get_byte(stream);
181 		y = jpeg_get_word_be(stream);
187 		x = jpeg_get_word_be(stream);
193 		nf = jpeg_get_byte(stream);
214 			c = jpeg_get_byte(stream);
218 			h_v = jpeg_get_byte(stream);
233 			tq = jpeg_get_byte(stream);
245 		return jpeg_skip(stream, len - 2);
251 static int jpeg_parse_scan_header(struct jpeg_stream *stream,
255 	int len = jpeg_get_word_be(stream);
267 		ns = jpeg_get_byte(stream);
279 			cs = jpeg_get_byte(stream);
283 			td_ta = jpeg_get_byte(stream);
300 	return jpeg_skip(stream, skip);
304 static int jpeg_parse_quantization_tables(struct jpeg_stream *stream,
308 	int len = jpeg_get_word_be(stream);
320 		int pq_tq = jpeg_get_byte(stream);
341 		qk = stream->curr;
342 		ret = jpeg_skip(stream, pq ? 128 : 64);
358 static int jpeg_parse_huffman_tables(struct jpeg_stream *stream,
362 	int len = jpeg_get_word_be(stream);
372 		int tc_th = jpeg_get_byte(stream);
390 		table = stream->curr;
395 			li = jpeg_get_byte(stream);
402 		ret = jpeg_skip(stream, mt);
408 			tables[(tc << 1) | th].length = stream->curr - table;
412 	return jpeg_skip(stream, len - 2);
416 static int jpeg_parse_restart_interval(struct jpeg_stream *stream,
419 	int len = jpeg_get_word_be(stream);
427 	ri = jpeg_get_word_be(stream);
436 static int jpeg_skip_segment(struct jpeg_stream *stream)
438 	int len = jpeg_get_word_be(stream);
445 	return jpeg_skip(stream, len - 2);
449 static int jpeg_parse_app14_data(struct jpeg_stream *stream,
456 	lp = jpeg_get_word_be(stream);
461 	if (stream->curr + 6 > stream->end ||
462 	    strncmp(stream->curr, "Adobe\0", 6))
463 		return jpeg_skip(stream, lp - 2);
466 	ret = jpeg_skip(stream, 11);
470 	ret = jpeg_get_byte(stream);
478 	return jpeg_skip(stream, skip);
496 	struct jpeg_stream stream;
500 	stream.curr = buf;
501 	stream.end = stream.curr + len;
507 	if (jpeg_get_word_be(&stream) != SOI)
514 	while ((marker = jpeg_next_marker(&stream)) >= 0) {
518 			ret = jpeg_reference_segment(&stream, &out->sof);
521 			ret = jpeg_parse_frame_header(&stream, marker,
536 			ret = jpeg_reference_segment(&stream,
541 				ret = jpeg_skip_segment(&stream);
544 			ret = jpeg_parse_huffman_tables(&stream,
548 			ret = jpeg_reference_segment(&stream,
553 				ret = jpeg_skip_segment(&stream);
556 			ret = jpeg_parse_quantization_tables(&stream,
561 			ret = jpeg_parse_restart_interval(&stream,
565 			ret = jpeg_parse_app14_data(&stream,
569 			ret = jpeg_reference_segment(&stream, &out->sos);
572 			ret = jpeg_parse_scan_header(&stream, out->scan);
577 			out->ecs_offset = stream.curr - (u8 *)buf;
588 			ret = jpeg_skip_segment(&stream);
610 	struct jpeg_stream stream;
612 	stream.curr = buf;
613 	stream.end = stream.curr + len;
614 	return jpeg_parse_frame_header(&stream, SOF0, frame_header);
629 	struct jpeg_stream stream;
631 	stream.curr = buf;
632 	stream.end = stream.curr + len;
633 	return jpeg_parse_scan_header(&stream, scan_header);
650 	struct jpeg_stream stream;
652 	stream.curr = buf;
653 	stream.end = stream.curr + len;
654 	return jpeg_parse_quantization_tables(&stream, precision, q_tables);
671 	struct jpeg_stream stream;
673 	stream.curr = buf;
674 	stream.end = stream.curr + len;
675 	return jpeg_parse_huffman_tables(&stream, huffman_tables);