ham84.c

sloedgy open sip stack source code

/*

$Log: ham84.c,v $
Revision 1.1  2006/06/26 03:02:53  joegenbaclor
I have decided to include the latest development realease  of OPAL tagged Deimos Devel 1 (June 8 2006) as inegrated classes to opensipstack to avoid future version conflicts due to the fast pace in OPAL development.   This move is also aimed to reduce the size of projects using OPAL componets such as the soon to be relased OpenSIPPhone.

Revision 2.2  2005/08/08 03:28:42  dereksmithies
Eradicate all "/ * within comments" messages from GCC compilations.

Revision 2.1  2003/03/14 09:53:27  robertj
Updated to openH323 v1.11.7

Revision 1.1  2000/06/05 04:45:12  robertj
Added LPC-10 2400bps codec

 * Revision 1.1  1996/08/19  22:32:07  jaf
 * Initial revision
 *

*/

#ifdef P_R_O_T_O_T_Y_P_E_S
extern int ham84_(integer *input, integer *output, integer *errcnt);
#endif

/*  -- translated by f2c (version 19951025).
   You must link the resulting object file with the libraries:
	-lf2c -lm   (in that order)
*/

#include "f2c.h"

/* ***************************************************************** */

/* 	HAM84 Version 45G */

/*
 * $Log: ham84.c,v $
 * Revision 1.1  2006/06/26 03:02:53  joegenbaclor
 * I have decided to include the latest development realease  of OPAL tagged Deimos Devel 1 (June 8 2006) as inegrated classes to opensipstack to avoid future version conflicts due to the fast pace in OPAL development.   This move is also aimed to reduce the size of projects using OPAL componets such as the soon to be relased OpenSIPPhone.
 *
 * Revision 2.2  2005/08/08 03:28:42  dereksmithies
 * Eradicate all "/ * within comments" messages from GCC compilations.
 *
 * Revision 2.1  2003/03/14 09:53:27  robertj
 * Updated to openH323 v1.11.7
 *
 * Revision 1.1  2000/06/05 04:45:12  robertj
 * Added LPC-10 2400bps codec
 *
 * Revision 1.1  1996/08/19  22:32:07  jaf
 * Initial revision
 * */
/* Revision 1.3  1996/03/21  15:26:00  jaf */
/* Put comment header in standard form. */

/* Revision 1.2  1996/03/13  22:00:13  jaf */
/* Comments added explaining that none of the local variables of this */
/* subroutine need to be saved from one invocation to the next. */

/* Revision 1.1  1996/02/07 14:47:04  jaf */
/* Initial revision */


/* ***************************************************************** */

/*  Hamming 8,4 Decoder - can correct 1 out of seven bits */
/*   and can detect up to two errors. */

/* Input: */
/*  INPUT  - Seven bit data word, 4 bits parameter and */
/*           4 bits parity information */
/* Input/Output: */
/*  ERRCNT - Sums errors detected by Hamming code */
/* Output: */
/*  OUTPUT - 4 corrected parameter bits */

/* This subroutine is entered with an eight bit word in INPUT.  The 8th */
/* bit is parity and is stripped off.  The remaining 7 bits address the */
/* hamming 8,4 table and the output OUTPUT from the table gives the 4 */
/* bits of corrected data.  If bit 4 is set, no error was detected. */
/* ERRCNT is the number of errors counted. */

/* This subroutine has no local state. */

/* Subroutine */ int ham84_(integer *input, integer *output, integer *errcnt)
{
    /* Initialized data */

    static integer dactab[128] = { 16,0,0,3,0,5,14,7,0,9,14,11,14,13,30,14,0,
	    9,2,7,4,7,7,23,9,25,10,9,12,9,14,7,0,5,2,11,5,21,6,5,8,11,11,27,
	    12,5,14,11,2,1,18,2,12,5,2,7,12,9,2,11,28,12,12,15,0,3,3,19,4,13,
	    6,3,8,13,10,3,13,29,14,13,4,1,10,3,20,4,4,7,10,9,26,10,4,13,10,15,
	    8,1,6,3,6,5,22,6,24,8,8,11,8,13,6,15,1,17,2,1,4,1,6,15,8,1,10,15,
	    12,15,15,31 };

    integer i__, j, parity;

/*       Arguments */
/*       Parameters/constants */
/*       Local variables that need not be saved */
/*  Determine parity of input word */
    parity = *input & 255;
    parity ^= parity / 16;
    parity ^= parity / 4;
    parity ^= parity / 2;
    parity &= 1;
    i__ = dactab[*input & 127];
    *output = i__ & 15;
    j = i__ & 16;
    if (j != 0) {
/*          No errors detected in seven bits */
	if (parity != 0) {
	    ++(*errcnt);
	}
    } else {
/*          One or two errors detected */
	++(*errcnt);
	if (parity == 0) {
/*             Two errors detected */
	    ++(*errcnt);
	    *output = -1;
	}
    }
    return 0;
} /* ham84_ */