// https://github.com/php/php-src/blob/0029d2b08bbd3cb3aa293d9c8d55bf31faa9e203/ext/standard/image.c#L917
static int php_get_wbmp(php_stream *stream, struct gfxinfo **result, int check)
{
	int i, width = 0, height = 0;

	if (php_stream_rewind(stream)) {
		return 0;
	}

	/* get type */
	if (php_stream_getc(stream) != 0) {
		return 0;
	}

	/* skip header */
	do {
		i = php_stream_getc(stream);
		if (i < 0) {
			return 0;
		}
	} while (i & 0x80);

	/* get width */
	do {
		i = php_stream_getc(stream);
		if (i < 0) {
			return 0;
		}
		width = (width << 7) | (i & 0x7f);
		/* maximum valid width for wbmp (although 127 may be a more accurate one) */
		if (width > 2048) {
			return 0;
		}
	} while (i & 0x80);

	/* get height */
	do {
		i = php_stream_getc(stream);
		if (i < 0) {
			return 0;
		}
		height = (height << 7) | (i & 0x7f);
		/* maximum valid height for wbmp (although 127 may be a more accurate one) */
		if (height > 2048) {
			return 0;
		}
	} while (i & 0x80);

	if (!height || !width) {
		return 0;
	}

	if (!check) {
		(*result)->width = width;
		(*result)->height = height;
	}

	return IMAGE_FILETYPE_WBMP;
}