CBLibrary
CBLibrary | Dynamic Areas tutorial | FontLib | Joystick emulation module | Loader demo | LongStr BASIC library | SlidingHeap module
These programming resources are intended for ARM powered computers running RISC OS. The title and icon of each package are linked to the relevant Zip archive for download. On RISC OS computers Zip files may be opened using SparkPlug, SparkFS (commercial) or Infozip.
CBLibrary
(Also available without source code - smaller download.)
This is yet another C library for RISC OS. Actually, it is more like a personal collection of modules that happen to be common to many of my applications. It has a large number of external dependencies, including most of the libraries supplied with the Acorn C/C++ development suite.
I do not seriously expect many other programmers to use CBLibrary, but it has to be in the public domain in order that the programs that use it can meaningfully be released under the GNU General Public Licence.
The most interesting library modules are probably Drag, Entity, Loader2, Saver, Scheduler and PseudoFlex. The first four provide a complete implementation of the data transfer, drag and drop, and clipboard protocols described in the RISC OS 3 PRM and application notes 240 and 241. The Scheduler module is a system for managing null events and scheduling functions to be called in the future. The PseudoFlex module usurps Acorn's flex library and redirects calls to Simon P. Bullen's fortified memory allocation shell (for debugging).
Release 29 (27 Jan 2008)
#include "PseudoFlex.h" when
compiled with FORTIFY defined, to allow
debugging with Fortify.
get_date_stamp function which was revealed by
Fortify: *UTC[4] means the fifth
os_date_and_time (i.e. at offset +20), whereas
(*UTC)[4] means the fifth uint8_t
array element (i.e. at offset +4).
"DateStamp.h" now defines
os_date_and_time as an array of uint8_t
rather than unsigned char.
_ent_datarequest_msg_handler function, for entities
with non-persistent data (i.e. should be freed when no
longer required):
EntityDataMethod function
if it could not be re-anchored.
saver_send_data function
failed.
saver_send_data function by passing a pointer to a
WimpMessage structure instead of individually
specifying the file type, leaf name, drag destination and
message ID to reply to. Updated the
_ent_datarequest_msg_handler function to allocate
and partially populate a WimpMessage for
saver_send_data.
_svr_datasaveack_msg_handler function, when compiled
with SLOW_TEST defined; if
scheduler_register_delay returned an error then the
SaveOpData record was never destroyed. It now
calls _svr_save_as_file directly as a fallback
(i.e. non-SLOW_TEST behaviour).
_ldr2_decapitate_list
function called flex_free with a direct
pointer to the RAM fetch buffer, instead of a
flex_ptr to its anchor. Caused the flex
library to blow up if loader2_receive_data
allocated this buffer and then failed to create or send the
RAMFetch message.
Dynamic Areas
tutorial
A short introduction to using dynamic areas in BASIC programs, including two small example programs.
Release 1 (8th May 1999)
FontLib/FontTest
This is a sample application which attempts to demonstrate various aspects of using outline fonts in a WIMP application. It is assumed that the user is reasonably familiar with the basic principles of writing multi-tasking WIMP applications. Harriet has tried to hide away as much of the 'workings' as she can in the FONT_Lib library file.
February 2000
Joystick emulation
module
(Note: requires APCS-32 supporting C library)
It is difficult for games programmers to implement support for joysticks without access to actual hardware. This module has been written to help - specifically, to allow me to test the new joystick support in Star Fighter 3000.
The cost of an interface and a decent joystick to go with it is quite expensive. If, like me, you are too miserly to pay for the real thing, this module may provide the solution. It allows games to be tested against a 'virtual' (emulated) joystick, which is controlled using the numeric keypad. Not particularly useful for playing games, but for testing purposes certainly far better than nothing.
Various emulation modes are supported, including "switched" (emulates an Atari-type joystick), "analogue" (emulates a PC-type joystick) and "damped" (uses a gradual decay function to make keyboard control of an analogue stick easier).
Version 2.01 (15th March 2003)
Loader demo and
documentation
(Note: example application requires Toolbox modules)
The Loader component is part of CBLibrary, which is distributed separately from this demo, with source code under the Lesser General Public License. You will need to obtain CBLibrary in order to recompile this demo or use Loader in your own programs. Acorn's Flex, Toolbox and Event libraries are also a requirement.
Essentially a layer on top of Eventlib's message handlers, Loader centrally handles incoming data transfers for all parts of your application. A client-supplied handler function is called when a data transfer is successfully concluded.
The client application registers an interest in listening for certain file types dragged to particular areas of the user interface. This approach fits well with an object-oriented programming style, as listeners may be registered when a Toolbox object is created or shown and deregistered when it is deleted or hidden.
This example application is supplied with full source code. There is also extensive documentation as an HTML/EasiWriter document.
Version 0.15 (28 Oct 2006)
LoaderFinishedHandler function
arguments to include the drop coordinates, for
compatibility with recent versions of
CBLibrary.
LongStr BASIC library
In BBC BASIC, it is impossible to use text strings of greater than 255 characters in length. This can be frustrating if you want to allow for long file paths in your program, or you need to manipulate some data that originated in a less restricted environment.
My LongStr library is quite slow and was hastily written, but
it does a fair job of bypassing this limit. Virtually all
BASIC's string handling keywords (with the
exception of INSTR) are replicated by equivalent
library functions.
The library functions are described in some detail in the accompanying documentation, which also contains guidelines and advice for use. There is also an example program.
Release 6 (11th September 2003)
record%'.
ls_',
to increase their uniqueness and make it easier to avoid
name clashes.
SlidingHeap
module
The SlidingHeap module creates and manages a sliding heap of blocks of memory claimed from a program's Wimpslot as necessary, thus avoiding the fragmentation caused by repeatedly claiming and releasing memory from the RMA. The order of blocks in the heap may change and their location will vary as other blocks grow and shrink. It is rather like Acorn C's 'flex' library, but is suitable for use from BASIC/ARM code programs.
This new release of SlidingHeap has been reconstructed from a disassembly, in the absence of the original source code. Apart from being 32-bit compatible (for use on RISC OS 5) other improvements include a new SWI to increase the maximum number of blocks.
The module is distributed under the GNU Public Licence with full source code, demonstration programs and extensive documentation in both text and StrongHelp format.
Steven Haslam (32-bit compatibility by Chris Bazley, much additional work by Harriet Bazley)
Module: Version 2.12 (13 Oct 2002)
BASIC support library: 3rd December 2002
SlidingHeap_ExtendBlock now rounds requested
block sizes up to the nearest word, just as
SlidingHeap_NewBlock always has.... Optimised this
to use single BIC in place of AND NOT
construction.
SlidingHeap_ScrapBlock (as far as I know, never
called during entire history of module) dealing with the
possibility of non-word-aligned blocks.
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Designed by
Christopher James Bazley using a
RISC OS workstation and HTML³.
Background pattern is © Sophia Field. |
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