buf: new buffer stream.

* buf.c (struct buf_strm): New struct type.
(buf_strm_mark, int buf_strm_put_byte_callback,
buf_strm_put_string, buf_strm_put_char, buf_strm_put_byte,
buf_strm_get_byte_callback, buf_strm_get_char,
buf_strm_get_byte, buf_strm_unget_char, buf_strm_unget_byte,
buf_strm_seek, buf_strm_truncate, buf_strm_get_prop,
buf_strm_set_prop, buf_strm_get_error,
buf_strm_get_error_str): New static functions.
(buf_strm_ops): New static struct.
(buf_strm): New static function.
(make_buf_stream, get_buf_from_stream): New functions.
(buf_init): Register new intrinsic functiions make-buf-stream
and get-buf-from-stream.
Call fill_stream_ops on new buf_strm_ops to fill
default operations in place of function pointers
that have been left null.

* buf.h (make_buf_stream, get_buf_from_stream): Declared.

* lisplib.c (with_stream_set_entries): Add with-out-buf-stream
and with-in-buf-stream to auto-load symbols for with-stream.tl
module.

* share/txr/stdlib/with-stream.tl (with-out-buf-stream,
with-in-buf-stream): New macros.

* txr.1: New section about buffer streams.

1 files changed, 9 insertions, 0 deletions

diff --git a/share/txr/stdlib/with-stream.tl b/share/txr/stdlib/with-stream.tl
index 40043237..a422a07c 100644
--- a/share/txr/stdlib/with-stream.tl
+++ b/share/txr/stdlib/with-stream.tl
@@ -34,6 +34,11 @@
      ,*body
      (get-list-from-stream ,stream)))
 
+(defmacro with-out-buf-stream ((stream : buf) . body)
+  ^(let ((,stream (make-buf-stream ,*[[iff have list] buf])))
+     ,*body
+     (get-buf-from-stream ,stream)))
+
 (defmacro with-in-string-stream ((stream string) . body)
   ^(let ((,stream (make-string-input-stream ,string)))
      ,*body))
@@ -42,6 +47,10 @@
   ^(let ((,stream (make-string-byte-input-stream ,string)))
      ,*body))
 
+(defmacro with-in-buf-stream ((stream buf) . body)
+  ^(let ((,stream (make-buf-stream ,buf)))
+     ,*body))
+
 (defmacro with-stream ((var stream) . body)
   ^(let ((,var ,stream))
      (unwind-protect