1. heap-o-rama
    1. Introduction
    2. Usage
    3. Requirements
    4. Documentation
      1. setup-low-level-stuff
      2. gc-happened?
      3. do-the-dance
    5. Author
    6. License
    7. Version History

heap-o-rama

Introduction

Filter the heap after a major garbage collection for objects of a particular type.

Usage

(require-extension heap-o-rama)

Requirements

This extension runs only on CHICKEN 4.5.7 or newer.

Documentation

setup-low-level-stuff

[procedure] (setup-low-level-stuff MINSIZE MAXSIZE)

Sets up a GC hook that records whether a major garbage collection has been performed. Any previously installed hooks are retained. MINSIZE and MAXSIZE specify the minimum and maximum size of objects (in elements) that should be extracted from the heap.

gc-happened?

[procedure] (gc-happened?)

Returns true if a major GC was triggered after the last call to do-the-dance (see below).

do-the-dance

[procedure] (do-the-dance COUNT PROTOS)

Performs another major garbage collection and collects at most COUNT non-immediate objects still live on the heap after the collection. PROTOS should be a vector of prototype objects - live objects in the heap that are of identical type are collected and returned. Structure objects ("records") in PROTOS specify record objects that should be matched.

Returns 3 values: the "object vector", the "link table" and a count of how many objects are stored in the object vector and link table, respectively.

The object vector holds the actual objects filtered from the heap. The link table contains sub-vectors of the form #(LINKCOUNT LINKINDEX1 ...) where LINKCOUNT gives the number of links between the object at the same index in the object vector and LINKINDEX1 ... gives the index of objects that where filtered and who are references by that object. The sub-vector may hold additional elements of value #f and has the same size as the filtered object.

Note that this procedure does very little error checking.

Author

Felix Winkelmann

License

Copyright (c) 2010, Felix L. Winkelmann
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. The name of the authors may not be used to endorse or promote products
   derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 

Version History

0.1
initial release