jpg-source: add jpg source class

The jpg_source class is an implementation of the video_source class that
streams a still jpg image as video.

Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

2 files changed, 159 insertions, 0 deletions

diff --git a/lib/jpg-source.c b/lib/jpg-source.c
new file mode 100644
index 0000000..0bbe26f
--- /dev/null
+++ b/lib/jpg-source.c
@@ -0,0 +1,158 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * JPEG still image video source
+ *
+ * Copyright (C) 2018 Paul Elder
+ *
+ * Contact: Paul Elder <paul.elder@ideasonboard.com>
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <linux/videodev2.h>
+
+#include "events.h"
+#include "tools.h"
+#include "v4l2.h"
+#include "jpg-source.h"
+#include "video-buffers.h"
+
+struct jpg_source {
+	struct video_source src;
+
+	unsigned int imgsize;
+	void *imgdata;
+};
+
+#define to_jpg_source(s) container_of(s, struct jpg_source, src)
+
+static void jpg_source_destroy(struct video_source *s)
+{
+	struct jpg_source *src = to_jpg_source(s);
+
+	if (src->imgdata)
+		free(src->imgdata);
+
+	free(src);
+}
+
+static int jpg_source_set_format(struct video_source *s __attribute__((unused)),
+				  struct v4l2_pix_format *fmt)
+{
+	if (fmt->pixelformat != v4l2_fourcc('M', 'J', 'P', 'G')) {
+		printf("jpg-source: unsupported fourcc\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int jpg_source_set_frame_rate(struct video_source *s __attribute__((unused)),
+				     unsigned int fps __attribute__((unused)))
+{
+	return 0;
+}
+
+static int jpg_source_free_buffers(struct video_source *s __attribute__((unused)))
+{
+	return 0;
+}
+
+static int jpg_source_stream_on(struct video_source *s __attribute__((unused)))
+{
+	return 0;
+}
+
+static int jpg_source_stream_off(struct video_source *s __attribute__((unused)))
+{
+	return 0;
+}
+
+static void jpg_source_fill_buffer(struct video_source *s,
+				   struct video_buffer *buf)
+{
+	struct jpg_source *src = to_jpg_source(s);
+
+	memcpy(buf->mem, src->imgdata, src->imgsize);
+	buf->bytesused = src->imgsize;
+}
+
+static const struct video_source_ops jpg_source_ops = {
+	.destroy = jpg_source_destroy,
+	.set_format = jpg_source_set_format,
+	.set_frame_rate = jpg_source_set_frame_rate,
+	.alloc_buffers = NULL,
+	.export_buffers = NULL,
+	.free_buffers = jpg_source_free_buffers,
+	.stream_on = jpg_source_stream_on,
+	.stream_off = jpg_source_stream_off,
+	.queue_buffer = NULL,
+	.fill_buffer = jpg_source_fill_buffer,
+};
+
+struct video_source *jpg_video_source_create(const char *img_path)
+{
+	struct jpg_source *src;
+	int fd = -1;
+	int ret;
+
+	printf("using jpg video source\n");
+
+	if (img_path == NULL)
+		return NULL;
+
+	src = malloc(sizeof *src);
+	if (!src)
+		return NULL;
+
+	memset(src, 0, sizeof *src);
+	src->src.ops = &jpg_source_ops;
+
+	fd = open(img_path, O_RDONLY);
+	if (fd == -1) {
+		printf("Unable to open MJPEG image '%s'\n", img_path);
+		goto err_free_src;
+	}
+
+	src->imgsize = lseek(fd, 0, SEEK_END);
+	lseek(fd, 0, SEEK_SET);
+	src->imgdata = malloc(src->imgsize);
+	if (src->imgdata == NULL) {
+		printf("Unable to allocate memory for MJPEG image\n");
+		goto err_close_fd;
+	}
+
+	ret = read(fd, src->imgdata, src->imgsize);
+	if (ret < 0) {
+		fprintf(stderr, "error reading data from %s: %d\n", img_path, errno);
+		goto err_free_imgdata;
+	}
+
+	close(fd);
+
+	return &src->src;
+
+err_free_imgdata:
+	free(src->imgdata);
+err_close_fd:
+	close(fd);
+err_free_src:
+	free(src);
+
+	return NULL;
+}
+
+void jpg_video_source_init(struct video_source *s, struct events *events)
+{
+	struct jpg_source *src = to_jpg_source(s);
+
+	src->src.events = events;
+}
diff --git a/lib/meson.build b/lib/meson.build
index 2d9ad10..f6991d5 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -3,6 +3,7 @@
 libuvcgadget_sources = files([
   'configfs.c',
   'events.c',
+  'jpg-source.c',
   'stream.c',
   'test-source.c',
   'uvc.c',