+PDCLib - Public Domain C Library
+================================
+
+License
+-------
+
+Permission is granted to use, modify, and / or redistribute at will.
+
+This includes removing authorship notices, re-use of code parts in
+other software (with or without giving credit), and / or creating a
+commercial product based on it.
+
+This software is provided as-is. Use it at your own risk. There is
+no warranty whatsoever, neither expressed nor implied, and by using
+this software you accept that the author(s) shall not be held liable
+for any loss of data, loss of service, or other damages, be they
+incidential or consequential. Your only option other than accepting
+this is not to use the software at all.
+
+A case for Public Domain
+------------------------
+
+There was a time when you could just post a piece of code to usenet
+and say, "I give it away for free; perhaps it's useful for you."
+
+Then came the lawyers.
+
+There are building blocks in software engineering that are so basic
+that everyone should have free access to them without having to
+employ a complete legal department for advice. They should be FREE.
+Available for free, free of licensing implications, free of attached
+propaganda, free of everything but their useful self.
+
+Today, even the term "free" has to be defined by several paragraphs
+of legal blah-blah.
+
+Sick and tired of it, the author brought you this piece of software
+under a "license" that should not be neccessary in the first place:
+"Free" should have been enough.
+
+What is it
+----------
+
+This is a C Standard Library. Nothing more, nothing less. No POSIX
+or other extensions, just what's defined in ISO/IEC 9899.
+
+(Well, this is what it will be when the 1.0 release comes out. See
+the "Development Status" section to see what's implemented so far.)
+
+Internals
+---------
+
+As a namespace convention, everything (files, typedefs, functions,
+macros) not defined in ISO/IEC 9899 is prefixed with _PDCLIB_*.
+As identifiers starting with '_' and a capital letter are reserved
+for the implementation, and the chances of you compiler using an
+identifier in the _PDCLIB_* range are slim, any strictly conforming
+application should work with PDCLib.
+
+PDCLib consists of several parts:
+
+1) standard headers;
+2) implementation files for standard functions;
+3) internal header files keeping complex stuff out of the standard
+ headers;
+4) the central, platform-specific file _PDCLIB_config.h;
+5) optimization overlay implementation files (optional).
+
+The standard headers only contain what they are defined to contain.
+Where additional logic or macro magic is necessary, that is deferred
+to the internal files. This has been done so that the headers are
+actually educational as to what they provide (as opposed to how the
+library does it).
+
+There is a seperate implementation file for every function defined
+by the standard, named {function}.c. Not only does this avoid linking
+in huge amounts of unused code when you use but a single function,
+it also allows the optimization overlay to work (see below).
+
+Then there are internal header files, which contain all the "black
+magic" and "code fu" that were kept out of the standard headers. You
+should not have to touch them if you want to adapt PDCLib to a new
+platform. If you do, note that the PDCLib author would consider it
+a serious design flaw, and would be happy to fix it in the next PDCLib
+release. Any adaption work should be covered by the config header
+(and, possibly, the optimization overlay).
+
+For adapting PDCLib to a new platform (the trinity of CPU, operating
+system, and compiler), open _PDCLIB_config.h in your favourite text
+editor, have a look at the comments, and modify it as appropriate for
+your platform. That should be all that is actually required for such
+an adaption (see previous paragraph).
+
+Of course, your platform might provide more efficient replacements
+for the generic implementations offered by PDCLib. The math functions
+are an especially "juicy" target for optimization - while PDCLib does
+provide generic implementations for each of them, there are usually
+FPU opcodes that do the same job, only orders of magnitude faster. For
+this, you might want to create an "optimization overlay" for PDCLib.
+
+Optimization Overlay
+--------------------
+
+The idea is to provide a generic implementation that is useable even
+on platforms the author never heard of - for example, the OS and/or
+compiler *you* just wrote and now need a C library for. That is
+actually what PDCLib was written for: To provide a C library for
+compiler and OS builders that do not want the usual baggage of POSIX
+and GNU extensions, licensing considerations etc. etc.
+
+Thus, PDCLib provides generic implementations. They do work, and do
+so correctly, but they are not very efficient when compared to hand-
+crafted assembler or compiler build-ins. So the author wanted to
+provide a means to modify PDCLib to run more efficiently on a given
+platform, without cluttering the main branch with tons of #ifdef
+statements and "featureset defines" that grow stale quickly.
+
+The solution is the "optimization overlay". Every function has its
+own implementation file, and _PDCLIB_config.h should be the only
+header that must be modified. So, a platform-specific overlay is
+copied over the main PDCLib branch - replacing _PDCLIB_config.h and
+any number of implementation files - to create a PDCLib adapted /
+optimized for the platform in question. That overlay could be part
+of the PDCLib source tree (for established platforms where maintainers
+won't bother with PDCLib), or part of that platform's source tree
+(for under-development platforms PDCLib maintainers won't bother with).
+
+So, to use PDCLib on your given platform, you unpack PDCLib (as you
+obviously have done already since you are reading this), and copy
+the overlay for your platform over the PDCLib source tree structure.
+
projects / pdclib / commitdiff