From ed0bfb4b8eb40d8a4efc65e528e477a2314b34aa Mon Sep 17 00:00:00 2001 From: Kaz Kylheku Date: Wed, 22 Apr 2020 06:20:05 -0700 Subject: streams: put_buf and fill_buf become lower-level. In this commit, the put_buf and fill_buf stream virtual functions are changed to operate directly on a low-level buffer, rather than a stream. This will allow these functions to be used for improving the performance of I/O operations that are not related to buffer objects. * stream.h (struct strm_ops): Change type signature of put_buf and fill_buf members. The lengths and iszes are ucnum. The return value is ucnum. The buffer is passed as a pointer and length, rather than a buffer object. * stream.c (unimpl_put_buf, unimpl_fill_buf, generic_put_buf, generic_fill_buf, stdio_put_buf, stdio_fill_buf, delegate_put_buf, delegate_fill_buf): Adjust to new interface. (put_buf, fill_buf, fill_buf_adjust): Pull the poitner and size from the buffer and pass those down to the virtual functions rather than the buffer itself. Convert ucnum return value to val. * strudel.c (strudel_put_buf, strudel_get_buf): The struct delegate interface doesn't change. The put-buf and fill-buf methods still operate on buffer objects. To glue that with the new low-level interface, we use the init_borrowed_buf trick that is was first used in ffi.c: temporary buf objects are efficiently allocated on the stack, pointing to the same memory that is coming down from the stream operation. * txr.1: Document the new restrictions on the buf argument of the put-buf and fill-buf stream delegate methods. Since the buf not a heap object, it cannot be used after the method returns. --- stream.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'stream.h') diff --git a/stream.h b/stream.h index 3cfb0f8b..ba905871 100644 --- a/stream.h +++ b/stream.h @@ -69,8 +69,8 @@ struct strm_ops { val (*get_byte)(val); val (*unget_char)(val, val); val (*unget_byte)(val, int); - val (*put_buf)(val, val, cnum); - val (*fill_buf)(val, val, cnum); + ucnum (*put_buf)(val, mem_t *, ucnum len, ucnum pos); + ucnum (*fill_buf)(val, mem_t *, ucnum len, ucnum pos); val (*close)(val, val); val (*flush)(val); val (*seek)(val, val, enum strm_whence); -- cgit v1.2.3