From becfda202621418f2304649249d4437481b691c1 Mon Sep 17 00:00:00 2001
From: Paul Elder <paul.elder@ideasonboard.com>
Date: Wed, 23 Nov 2022 07:33:01 +0000
Subject: slideshow-source: add slideshow source class
The slideshow_source class is an implementation of the video_source
class that streams a set of images as video.
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
---
include/uvcgadget/slideshow-source.h | 20 ++
lib/meson.build | 1 +
lib/slideshow-source.c | 391 +++++++++++++++++++++++++++++++++++
3 files changed, 412 insertions(+)
create mode 100644 include/uvcgadget/slideshow-source.h
create mode 100644 lib/slideshow-source.c
diff --git a/include/uvcgadget/slideshow-source.h b/include/uvcgadget/slideshow-source.h
new file mode 100644
index 0000000..9b1d9f9
--- /dev/null
+++ b/include/uvcgadget/slideshow-source.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Slideshow video source
+ *
+ * Copyright (C) 2018 Paul Elder
+ *
+ * Contact: Paul Elder <paul.elder@ideasonboard.com>
+ */
+#ifndef __SLIDESHOW_VIDEO_SOURCE_H__
+#define __SLIDESHOW_VIDEO_SOURCE_H__
+
+#include "video-source.h"
+
+struct events;
+struct video_source;
+
+struct video_source *slideshow_video_source_create(const char *img_dir);
+void slideshow_video_source_init(struct video_source *src, struct events *events);
+
+#endif /* __SLIDESHOW_VIDEO_SOURCE_H__ */
diff --git a/lib/meson.build b/lib/meson.build
index a0d67d5..680be1c 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -4,6 +4,7 @@ libuvcgadget_sources = files([
'configfs.c',
'events.c',
'jpg-source.c',
+ 'slideshow-source.c',
'stream.c',
'test-source.c',
'timer.c',
diff --git a/lib/slideshow-source.c b/lib/slideshow-source.c
new file mode 100644
index 0000000..42a42a9
--- /dev/null
+++ b/lib/slideshow-source.c
@@ -0,0 +1,391 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Slideshow video source
+ *
+ * Copyright (C) 2018 Paul Elder
+ *
+ * Contact: Paul Elder <paul.elder@ideasonboard.com>
+ */
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <linux/limits.h>
+#include <linux/videodev2.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include "events.h"
+#include "list.h"
+#include "slideshow-source.h"
+#include "timer.h"
+#include "tools.h"
+#include "video-buffers.h"
+
+struct slide {
+ struct list_entry list;
+ unsigned int imgsize;
+ void *imgdata;
+};
+
+struct slideshow_source {
+ struct video_source src;
+
+ char img_dir[NAME_MAX];
+
+ struct slide *cur_slide;
+ struct list_entry slides;
+
+ struct timer *timer;
+ bool streaming;
+};
+
+#define to_slideshow_source(s) container_of(s, struct slideshow_source, src)
+
+static void slideshow_source_destroy(struct video_source *s)
+{
+ struct slideshow_source *src = to_slideshow_source(s);
+ struct slide *slide, *next;
+
+ list_for_each_entry_safe(slide, next, &src->slides, list) {
+ list_remove(&slide->list);
+ free(slide->imgdata);
+ free(slide);
+ }
+ timer_destroy(src->timer);
+ free(src);
+}
+
+char *v4l2_fourcc2s(__u32 fourcc, char *buf)
+{
+ buf[0] = fourcc & 0x7f;
+ buf[1] = (fourcc >> 8) & 0x7f;
+ buf[2] = (fourcc >> 16) & 0x7f;
+ buf[3] = (fourcc >> 24) & 0x7f;
+ if (fourcc & (1 << 31)) {
+ buf[4] = '-';
+ buf[5] = 'B';
+ buf[6] = 'E';
+ buf[7] = '\0';
+ } else {
+ buf[4] = '\0';
+ }
+ return buf;
+}
+
+/*
+ * slideshow_source_set_format - set the V4L2 format
+ *
+ * For this source, we require images stored in a directory structure with nodes
+ * for each format and framesize, for example:
+ *
+ * slideshow +
+ * |
+ * + MJPG +
+ * | |
+ * | + 1280x720 +
+ * | | |
+ * | | + 01.jpg
+ * | | |
+ * | | + 02.jpg
+ * | | |
+ * | | + 03.jpg
+ * | |
+ * | + 1920x1080
+ * |
+ * + YUYV +
+ * |
+ * + 1280x720
+ * |
+ * + 1920x1080
+ *
+ * The root directory will be passed as an argument to slideshow_source_create()
+ * and so is not fixed, but the second level directories must be named with the
+ * fourcc of the format the images within represent, and the third level's node
+ * names must be in the format "<width>x<height>".
+ */
+static int slideshow_source_set_format(struct video_source *s,
+ struct v4l2_pix_format *fmt)
+{
+ struct slideshow_source *src = to_slideshow_source(s);
+ char dirname[PATH_MAX];
+ struct slide *slide, *next;
+ struct dirent *file;
+ char fourcc_buf[8];
+ int fd = -1;
+ char *cwd;
+ DIR *dir;
+ int ret;
+
+ /*
+ * If the format is changed, we need to clear the existing list of
+ * slides before adding new ones.
+ */
+ list_for_each_entry_safe(slide, next, &src->slides, list) {
+ list_remove(&slide->list);
+ free(slide->imgdata);
+ free(slide);
+ }
+
+ ret = snprintf(dirname, sizeof(dirname), "%s/%s/%ux%u", src->img_dir,
+ v4l2_fourcc2s(fmt->pixelformat, fourcc_buf),
+ fmt->width, fmt->height);
+ if (ret < 0) {
+ fprintf(stderr, "failed to store directory name: %s (%d)\n",
+ strerror(ret), ret);
+ ret = errno;
+ goto err_dummy_slide;
+ }
+
+ dir = opendir(dirname);
+ if (!dir) {
+ fprintf(stderr, "unable to find directory %s\n", dirname);
+ ret = -ENOENT;
+ goto err_dummy_slide;
+ }
+
+ cwd = getcwd(NULL, 0);
+ if (!cwd) {
+ fprintf(stderr, "unable to allocate memory for cwd name\n");
+ ret = -ENOMEM;
+ goto err_dummy_slide;
+ }
+
+ ret = chdir(dirname);
+ if (ret) {
+ fprintf(stderr, "unable to cd to directory '%s': %s (%d)\n",
+ dirname, strerror(ret), ret);
+ goto err_close_dir;
+ }
+
+ while ((file = readdir(dir))) {
+ if (!strcmp(file->d_name, ".") ||
+ !strcmp(file->d_name, ".."))
+ continue;
+
+ fd = open(file->d_name, O_RDONLY);
+ if (fd == -1) {
+ fprintf(stderr, "Unable to open file '%s/%s'\n", dirname,
+ file->d_name);
+ ret = errno;
+ goto err_unwind;
+ }
+
+ slide = malloc(sizeof(*slide));
+ if (!slide) {
+ fprintf(stderr, "failed to allocate memory for slide\n");
+ ret = -ENOMEM;
+ goto err_close_fd;
+ }
+
+ slide->imgsize = lseek(fd, 0, SEEK_END);
+ lseek(fd, 0, SEEK_SET);
+
+ slide->imgdata = malloc(slide->imgsize);
+ if (!slide->imgdata) {
+ fprintf(stderr, "failed to allocate memory for image\n");
+ ret = -ENOMEM;
+ goto err_free_slide;
+ }
+
+ ret = read(fd, slide->imgdata, slide->imgsize);
+ if (ret < 0) {
+ fprintf(stderr, "failed to read from %s/%s: %u\n",
+ dirname, file->d_name, errno);
+ ret = errno;
+ goto err_free_imgdata;
+ }
+
+ list_append(&slide->list, &src->slides);
+ close(fd);
+ }
+
+ if (list_empty(&src->slides)) {
+ fprintf(stderr, "failed to find any images in %s\n", dirname);
+ ret = -ENOENT;
+ goto err_free_cwd;
+ }
+
+ ret = chdir(cwd);
+ if (ret) {
+ fprintf(stderr, "unable to cd to directory '%s': %s (%d)\n",
+ cwd, strerror(ret), ret);
+ goto err_free_cwd;
+ }
+
+ free(cwd);
+ closedir(dir);
+ src->cur_slide = list_first_entry(&src->slides, struct slide, list);
+
+ return 0;
+
+err_free_imgdata:
+ free(slide->imgdata);
+err_free_slide:
+ free(slide);
+err_close_fd:
+ close(fd);
+err_unwind:
+ list_for_each_entry_safe(slide, next, &src->slides, list) {
+ list_remove(&slide->list);
+ free(slide->imgdata);
+ free(slide);
+ }
+err_free_cwd:
+ chdir(cwd);
+ free(cwd);
+err_close_dir:
+ closedir(dir);
+err_dummy_slide:
+
+ /*
+ * At present, there is no means of stalling a USB SET_CUR control from
+ * the host; this means that the format passed here _must_ be accepted
+ * until this issue is resolved. To work around the issue for now simply
+ * use a single dummy slide... as long as we manage to allocate the
+ * memory for it at least.
+ */
+
+ printf("using dummy slideshow data\n");
+
+ slide = malloc(sizeof(*slide));
+ if (!slide) {
+ fprintf(stderr, "failed to allocate memory for slide\n");
+ return ret;
+ }
+
+ slide->imgsize = fmt->width * fmt->height * 2;
+
+ slide->imgdata = malloc(slide->imgsize);
+ if (!slide->imgdata) {
+ fprintf(stderr, "failed to allocate memory for image\n");
+ free(slide);
+ return -ENOMEM;
+ }
+
+ memset(slide->imgdata, 0, slide->imgsize);
+ list_append(&slide->list, &src->slides);
+ src->cur_slide = slide;
+
+ return ret;
+}
+
+static int slideshow_source_set_frame_rate(struct video_source *s,
+ unsigned int fps)
+{
+ struct slideshow_source *src = to_slideshow_source(s);
+
+ timer_set_fps(src->timer, fps);
+
+ return 0;
+}
+
+static int slideshow_source_free_buffers(struct video_source *s __attribute__((unused)))
+{
+ return 0;
+}
+
+static int slideshow_source_stream_on(struct video_source *s)
+{
+ struct slideshow_source *src = to_slideshow_source(s);
+ int ret;
+
+ ret = timer_arm(src->timer);
+ if (ret)
+ return ret;
+
+ src->streaming = true;
+ return 0;
+}
+
+static int slideshow_source_stream_off(struct video_source *s)
+{
+ struct slideshow_source *src = to_slideshow_source(s);
+
+ /*
+ * No error check here, because we want to flag that streaming is over
+ * even if the timer is still running due to the failure.
+ */
+ timer_disarm(src->timer);
+ src->streaming = false;
+
+ return 0;
+}
+
+static void slideshow_source_fill_buffer(struct video_source *s,
+ struct video_buffer *buf)
+{
+ struct slideshow_source *src = to_slideshow_source(s);
+
+ memcpy(buf->mem, src->cur_slide->imgdata, src->cur_slide->imgsize);
+ buf->bytesused = src->cur_slide->imgsize;
+
+ if (src->cur_slide == list_last_entry(&src->slides, struct slide, list))
+ src->cur_slide = list_first_entry(&src->slides, struct slide, list);
+ else
+ src->cur_slide = list_next_entry(&src->cur_slide->list, struct slide, list);
+
+ /*
+ * Wait for the timer to elapse to ensure that our configured frame rate
+ * is adhered to.
+ */
+ if (src->streaming)
+ timer_wait(src->timer);
+}
+
+static const struct video_source_ops slideshow_source_ops = {
+ .destroy = slideshow_source_destroy,
+ .set_format = slideshow_source_set_format,
+ .set_frame_rate = slideshow_source_set_frame_rate,
+ .free_buffers = slideshow_source_free_buffers,
+ .stream_on = slideshow_source_stream_on,
+ .stream_off = slideshow_source_stream_off,
+ .queue_buffer = NULL,
+ .fill_buffer = slideshow_source_fill_buffer,
+};
+
+struct video_source *slideshow_video_source_create(const char *img_dir)
+{
+ struct slideshow_source *src;
+
+ if (img_dir == NULL)
+ return NULL;
+
+ if (strlen(img_dir) > 31)
+ return NULL;
+
+ src = malloc(sizeof *src);
+ if (!src)
+ return NULL;
+
+ memset(src, 0, sizeof *src);
+ src->src.ops = &slideshow_source_ops;
+
+ strncpy(src->img_dir, img_dir, sizeof(src->img_dir));
+
+ src->timer = timer_new();
+ if (!src->timer)
+ goto err_free_src;
+
+ list_init(&src->slides);
+
+ return &src->src;
+
+err_free_src:
+ free(src);
+ return NULL;
+}
+
+void slideshow_video_source_init(struct video_source *s, struct events *events)
+{
+ struct slideshow_source *src = to_slideshow_source(s);
+
+ src->src.events = events;
+}
--
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