--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/image.c	Wed Nov 25 21:13:03 2020 +0100
@@ -0,0 +1,82 @@
+/*
+ * image.c -- image definition
+ *
+ * Copyright (c) 2020 David Demelier <markand@malikania.fr>
+ * 
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <magic.h>
+
+#include "image.h"
+#include "log.h"
+#include "util.h"
+
+static const char *mimes[] = {
+	"image/bmp",
+	"image/jpeg",
+	"image/gif",
+	"image/png",
+	"image/svg+xml",
+	"image/tiff",
+	"image/webp"
+};
+
+void
+image_finish(struct image *image)
+{
+	assert(image);
+
+	free(image->id);
+	free(image->title);
+	free(image->author);
+	free(image->data);
+	free(image->filename);
+	memset(image, 0, sizeof (*image));
+}
+
+bool
+image_isvalid(const void *src, size_t srcsz)
+{
+	assert(src);
+
+	magic_t cookie;
+	bool ret = false;
+	const char *mime;
+
+	/*
+	 * If we're unable to load the libmagic we assume it's valid image and
+	 * let the browser show an invalid thing instead.
+	 */
+	if (!(cookie = magic_open(MAGIC_MIME_TYPE)))
+		return true;
+
+	magic_load(cookie, NULL);
+
+	if ((mime = magic_buffer(cookie, src, srcsz))) {
+		for (size_t i = 0; i < NELEM(mimes); ++i) {
+			if (strcmp(mime, mimes[i]) == 0) {
+				ret = true;
+				break;
+			}
+		}
+	}
+
+	magic_close(cookie);
+
+	return ret;
+}