freeswitch/libs/codec/lpc10

Tue Aug 20 16:19:51 CDT 1996

Andy Fingerhut (jaf@arl.wustl.edu)



In release 1.4, there are quite a few hand modifications to the C code

that was automatically created from the Fortran code with f2c.  They

are all summarized in change log comments at the beginning of the

changed files.  All of the original files from f2c were checked in to

RCS before modification, so it is possible to see exactly what changes

were made, for the extremely curious.  That precaution was also for my

benefit, in case I ever recompile the Fortran sources, and want to

make similar changes to that new C source code.



Below is the README file for this directory included with the 1.3

release of the LPC-10 package.  A few parts of it are a little out of

date, but it is correct for the most part.





Sun Jul  7 15:30:31 CDT 1996

Andy Fingerhut (jaf@arl.wustl.edu)



To create the LPC-10 library, copy the appropriate makefile to the

proper name for easy use, e.g., for Unix, copy makefile.unx to the

file "Makefile".  The file makefile.dos has been used with some

version of the 'nmake' utility that comes with the Microsoft C

compiler (the same one used for Nautilus v1.5a, which I believe

specifies Microsoft C version 7.0 or later).



Then edit the file lpc10.h in the directory above.  It should already

be set up to work properly on any Unix compiler for which "int" is 32

bits and "short" is 16 bits, and under the Microsoft C compiler

configured so that "long" is 32 bits and "int" is 16 bits.  There must

be a typedef for the two types INT32 and INT16 in that file.  You

should choose types that compile to those sizes using your compiler,

because there are places in the LPC-10 code that expect INT16's to

have exactly 16 bits (at least, I *think* they must be no larger), and

INT32's to have exactly 32 bits.





A few notes on how these files were created

-------------------------------------------



(This section is mostly for my benefit, so I can remember what I did.

You don't need to read it if you just want to use this package.  It

might be useful to read it if you change the Fortran sources and want

to recreate a usable library of C sources.  -- Andy)



These C sources were created automatically from the Fortran sources

using f2c, for the most part.  Listed below are the extra

modifications that were made after this automatic conversion.  Many of

them were made so that it was not necessary to install f2c in order to

use this LPC-10 coder.



1.



Put all of those files that were necessary for only the coder, rather

than an application that uses the coder, into this subdirectory called

lpc10.



2.



Copied f2c.h from the f2c distribution into this subdirectory.  Some

modifications were made to the "typedef" statements in this file, to

explicitly indicate the sizes (in bits) that different integer types

should be.  The types INT32 and INT16 must be defined in a file called

lpc10.h in the directory above.  Created the file f2clib.c, containing

only the functions pow_ii(), r_sign(), and i_nint() from the f2c

library.



3.



The f2c output originally had a file called contrl_com.c, that defined

a small structure containing a few variables that were used in many

different functions of the LPC10 code.  Every file containing

functions that used it defined it as "extern", while contrl_com.c

actually allocated storage for the structure.  Bill Dorsey, one of the

lead developers of Nautilus, said that the Microsoft C compiler had

problems either compiling this file, or linking it with all of the

other compiled files, so he just eliminated that file and removed the

"extern" keyword from the one of the files that declared it that way.

The file chosen (arbitrarily) was analys.c.



4.



Copied the makefiles for Unix and Microsoft C from the Nautilus v1.5a

distribution into the lpc10 directory.  Modified them to take out

references to Nautilus.  These makefiles don't create an executable,

but a library of compiled functions called liblpc10.a (Unix) or

LPC10.LIB (DOS).  This library can be used when linking an executable

that calls the functions lpcini_(), lpcenc_(), and lpcdec_().