"LOG_H" is a macro which is also used by ffmpeg/log.h.  This is
ffmpeg's fault, because short macros should be reserved for
applications, but since it's always a good idea to choose prefixed
macro names, even for applications, we are going to do that in MPD.

A frame contains one sample per channel, thus it is sample_size *
channels.  This patch includes some cleanup for various locations
where the sample size for 24 bit audio was still 3 bytes (instead of
4).

The last bit of CamelCase in audio_format.h.  Additionally, rename a
bunch of local variables.

"bits" and "channels" cannot be negative.

"bool" should be used in C99 programs for boolean values.

Since we use a C99 compiler now, we can assert that the C99 standard
headers are available, no need for complicated compile time checks.
Kill mpd_types.h.

Do full C99 integer type conversion in all modules which were not
touched by Eric's merged patch.

The inline function audio_format_sample_size() calculates how many
bytes each sample consumes.  This function already takes into account
that 24 bit samples are 4 bytes long, not 3.

audio_format_clear() sets an audio_format struct to an cleared
(undefined) state, which is both faster and smaller than memset(0).
audio_format_defined() checks if the audio_format struct actually has
a defined value (i.e. non-zero).  Both can be used to avoid pointers
to audio_format, replacing the "NULL" value with an "undefined"
audio_format.

Rename it to audio_format_equals() and return "true" if they are
equal.

Due to clumsy layout, the audio_format struct took 12 bytes.  Move the
"channels" to the end, so it can be merged into the same 32 bit slot
as "bits", which reduces the struct size to 8 bytes.

Get rid of CamelCase, and don't use a typedef, so we can
forward-declare it, and unclutter the include dependencies.

volatile provides absolutely no guarantee thread-safety in SMP
environments.  volatile was designed to access memory locations
in peripheral hardware directly; not for SMP.  If volatile is
needed to work properly on SMP, then it is only hiding subtle
bugs.

volatile only prevents the /compiler/ from making optimizations
when accessing variables.  CPUs do their own optimizations at
runtime so it cannot guarantee registers of CPUs are flushed
to memory cache-coherent access on different CPUs.

Furthermore, the thread-communication via condition variables
between threads sharing audio formats already results in memory
barriers.

Make the code more readable by hiding big formulas in an inline
function with a nice name.

We want to expose the AudioFormat structure to plugins; remove some
clutter by moving its declaration to a separate header file.

Try to only include headers which are really needed.  We should
particularly check all "headers including other headers".  The
long-term goal is to have a manageable, small API for plugins
(decoders, output) without so many mpd internals cluttering the
namespace.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7319 09075e82-0dd4-0310-85a5-a0d7c8717e4f

This will make refactoring features easier, especially now that
pthreads support and larger refactorings are on the horizon.

Hopefully, this will make porting to other platforms (even
non-UNIX-like ones for masochists) easier, too.

os_compat.h will house all the #includes for system headers
considered to be the "core" of MPD.  Headers for optional
features will be left to individual source files.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7130 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@6445 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@5834 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@5238 09075e82-0dd4-0310-85a5-a0d7c8717e4f

Add -Wmissing-prototypes if compiling with gcc
Static where possible

git-svn-id: https://svn.musicpd.org/mpd/trunk@4657 09075e82-0dd4-0310-85a5-a0d7c8717e4f

Indent the entire tree, hopefully we can keep
it indented.

git-svn-id: https://svn.musicpd.org/mpd/trunk@4410 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@4333 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@4331 09075e82-0dd4-0310-85a5-a0d7c8717e4f

the GPL header where necessary

git-svn-id: https://svn.musicpd.org/mpd/trunk@4317 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@3669 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@3067 09075e82-0dd4-0310-85a5-a0d7c8717e4f

also, should have better error reporting when failing to open playlist or
music directory's, or writing the db, etc

git-svn-id: https://svn.musicpd.org/mpd/trunk@3027 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@2501 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@2500 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@750 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@271 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@1 09075e82-0dd4-0310-85a5-a0d7c8717e4f