libublio is a small library with the aim of providing a buffered I/O
layer in userspace. It's primary motivation is to make it easy to fulfil
the I/O alignment constraints of disk devices on FreeBSD (and derivative
OS-es). (These exist since FreeBSD chose to ditch block devices and
make all disks and alike character devices). However, libublio is
generic code and might prove to be useful in other cases as well.

libublio provides a random positioned I/O API which is translated into
blocksize aligned I/O (where blocksize is defined by the user).
libublio also caches data; the caching algorithm uses red/black trees
and puts emphasis on making all cache operations logarithmic (in terms
of the number of cache entries).

Note that libublio is _not_ thread safe.

Usage:

- Take a look at the ublio_conf.h to see if you want to make any compile
  time cusomization (you can tune there some diagnostic features and
  some platform specific settings which could be much better determined by
  autotools if I have taken the effort to use autotools).

- Compile either a static libublio.a with the help of the provided
  Makefile or throw directly ublio.c among your source files (in the
  latter case make sure that it can include the ublio.h and ublio_conf.h
  header files).

- See ublio.h for the API and runtime tunables. Include ublio.h to your
  program, compile, enjoy.

Feedback, bugreports is to be sent to csaba.henk creo.hu .
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libublio uses BSD style data structure macros via queue.h and tree.h,
something which is present in a form in all four major BSD variants.

Upon trying to compile libublio on xBSD, one may ask: how do libublio's
{quee,tree}.h headers relate to those of xBSD, and is it possible to use
the native xBSD versions of these header files indeed?

Briefly: you can use the native queue.h on all BSDs but you can use the
native tree.h only on FreeBSD.

In details:

- queue.h is taken from OpenBSD as is. I choose the OpenBSD version because
  that seemed to be the least stuffed with system-specific stuff. However,
  those macros of queue.h which I use do the same on all BSDs.

- tree.h was taken from FreeBSD with some modifications. I choose the FreeBSD
  version for two features:
  - it can generate a static tree function kit;
  - it has the RB_NFIND macro which looks up the least upper bound of a sample
    node.

  I made some adjustments on both features.
  - regarding the static functions: I made the code a bit more portable;
  - regarding RB_NFIND: I replaced the FreeBSD implementation with a more
    streamlined and optimized one.