lua-ApeTag
----------

lua-ApeTag is a lua library for reading and writing APEv2 tags.  If called from
the command line, it prints out the contents of the APEv2 tag for the given
filename arguments.

It aims for standards compliance with the APE spec (1). APEv2 is the standard
tagging format for Musepack (.mpc) and Monkey's Audio files (.ape), and it can
also be used with mp3s as an alternative to ID3v2.x (technically, it can be
used on any file type and is not limited to storing just audio file metadata).

The module is in written mostly in pure Lua.  It does require a small C
extension because file truncation is not supported in the Lua standard library.
It should be useable on all platforms that Lua supports, though the C file may
need to be modified (it assumes ftruncate is found in unistd.h).  It is
developed and tested on OpenBSD.  It has only been tested on Lua 5.1.1.  It
includes a full unit test suite.

(1) http://wiki.hydrogenaudio.org/index.php?title=APEv2_specification

Installation
------------

First, you need to build the C extension:

  make

Second, you should probably run the unit tests:

  make regress

Finally, you should install it by copying apetag.lua and io_truncate.so to
somewhere in Lua's path.  There isn't a make target for this.

Example Usage
-------------

require('apetag')
a = ApeTag:new('file.mp3')
a:exists() # if it already has an APEv2 tag 
a:raw() # the raw APEv2+ID3v1 tag string in the file
a:fields() # a table of fields (type ApeFields), keys are strings, values are
           # tables (type ApeItem).  You shouldn't pay attention to the keys. 
           # Use value.key to get the real key.
a:pretty_print() # string suitable for pretty printing
a:update(function(fields) fields.Artist='Test Artist' fields.Year = nil end)
  # Update the tag with the added/changed/deleted fields 
  # Note that you should NOT do: 
  #    a:update(function(fields) fields = {Artist='Test Artist'} end)
  # OR: 
  #    a:update(function(fields) return {Artist='Test Artist'} end) 
  # You need to update/modify the fields given, not reassign it
a:remove() # remove the APEv2 and ID3v1 tags.

API Documentation
-----------------

The documentation for the library is in luadoc format.  You'll have to install
luadoc and its dependencies to generate it.

Bugs
----

If you find any bugs, would like additional documentation, or want to submit a
patch, please use Sourceforge (http://sf.net/projects/pylibape/).

The most current source code can be accessed via github
(http://github.com/jeremyevans/ape_tag_libs/tree/master).  Note that the library
isn't modified on a regular basis, so it is unlikely to be different from the
latest release.

Changelog
---------

1.0.1
- Allow use of read only flag on tag itself
- Make any bad footer flags an error instead of assuming no tag exists

1.0.0
- Initial Public Release