From 1bf591a5735068d1853be13c5a4255962835d5fe Mon Sep 17 00:00:00 2001 From: Simon Tatham Date: Tue, 5 Sep 2017 20:10:16 +0100 Subject: Support for saving games in Javascript puzzles. This is done by getting midend_serialise to produce the complete saved-game file as an in-memory string buffer, and then encoding that into a data: URI which we provide to the user as a hyperlink in a dialog box. The hyperlink has the 'download' attribute, which means clicking on it should automatically offer to save the file, and also lets me specify a not-too-silly default file name. --- emcc.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) (limited to 'emcc.c') diff --git a/emcc.c b/emcc.c index ca033cb..26e1ac2 100644 --- a/emcc.c +++ b/emcc.c @@ -757,6 +757,49 @@ void command(int n) } /* ---------------------------------------------------------------------- + * Called from JS to prepare a save-game file, and free one after it's + * been used. + */ + +struct savefile_write_ctx { + char *buffer; + size_t pos; +}; + +static void savefile_write(void *wctx, void *buf, int len) +{ + struct savefile_write_ctx *ctx = (struct savefile_write_ctx *)wctx; + if (ctx->buffer) + memcpy(ctx->buffer + ctx->pos, buf, len); + ctx->pos += len; +} + +char *get_save_file(void) +{ + struct savefile_write_ctx ctx; + size_t size; + + /* First pass, to count up the size */ + ctx.buffer = NULL; + ctx.pos = 0; + midend_serialise(me, savefile_write, &ctx); + size = ctx.pos; + + /* Second pass, to actually write out the data */ + ctx.buffer = snewn(size, char); + ctx.pos = 0; + midend_serialise(me, savefile_write, &ctx); + assert(ctx.pos == size); + + return ctx.buffer; +} + +void free_save_file(char *buffer) +{ + sfree(buffer); +} + +/* ---------------------------------------------------------------------- * Setup function called at page load time. It's called main() because * that's the most convenient thing in Emscripten, but it's not main() * in the usual sense of bounding the program's entire execution. -- cgit v1.1