manual: add documentation for new binary stream interfaces

src/clos/streams.lsp

@@ -113,7 +113,7 @@
 ;;; Extension
 (defgeneric stream-peek-byte (stream)
   (:documentation
-   "This is used to implement EXT:PEEK-BYTE; this corresponds to PEEK-TYPE of NIL.
+   "This is used to implement EXT:PEEK-BYTE.
   It returns either a byte or :EOF. The default method calls STREAM-READ-BYTE
   and STREAM-UNREAD-BYTE."))
 

src/doc/manual/extensions/gray-streams.txi

@@ -59,3 +59,17 @@ modification. The default method calls @code{stream-write-char} or
 @code{stream-element-type}. Element access to the sequence is done via
 @code{elt}.
 @end defun
+
+@subsection Gray Stream Extensions
+
+@defun {stream-unread-byte} stream byte
+Un-do the last call to @code{stream-read-byte}, as in @code{ext:unread-byte}.
+Return @code{nil}. Every subclass of @code{fundamental-binary-input-stream}
+should define a method for this function. A default method signals an error.
+@end defun
+
+@defun {stream-peek-byte} stream
+This is used to implement @code{ext:peek-byte}. It returns either a byte
+or @code{:eof}. A default method calls @code{stream-read-byte} and
+@code{stream-unread-byte}.
+@end defun

src/doc/manual/standards/streams.txi

@@ -150,6 +150,20 @@ happen.
 Return the POSIX file descriptor of @var{file-stream} as an integer
 @end defun
 
+@subsubsection Binary Stream Extensions
+
+@lspdef ext:unread-byte
+@defun ext:unread-byte stream byte
+Similar to @code{unread-char} but for unreading the last element to the
+input binary stream. See also @code{gray:stream-unread-byte}.
+@end defun
+
+@lspdef ext:peek-byte
+@defun ext:peek-byte stream eof-value
+Similar to @code{peek-char} but for peeking the next element from the
+output binary stream. See also @code{gray:stream-peek-byte}.
+@end defun
+
 @subsubsection External Format Extensions
 
 @lspdef ext:*default-external-format*