/*************************************************************************** *   biterror.c  - Software Radio channel simulation module *                           ------------------- *   begin                :  Oct 17th, 2002 *   authors              :  Roman Hofer *   emails               :  roman.hofer@epfl.ch ***************************************************************************//*************************************************************************** *                                Changes *                                ------- * date - name - description * Oct.17th, 2002  - Creation of class -  * 04/03/05 - ineiti - adjusted documentation * **************************************************************************//*************************************************************************** *                                                                         * *   This program is free software; you can redistribute it and/or modify  * *   it under the terms of the GNU General Public License as published by  * *   the Free Software Foundation; either version 2 of the License, or     * *   (at your option) any later version.                                   * *                                                                         * ***************************************************************************//** * A simple channel simulation which can be used in a test * Simply inverts some bits with a predefined probability */#include <stdlib.h>#include "spc.h"#define DBG_LVL 0typedef struct {  // Bit Error Rate  double ber; // 0.01}config_t;typedef struct {}stats_t;typedef struct {  double ber;}private_t;/* * The initialisation function, or constructor, * is called the first time this module is instantiated. */int spc_init( swr_sdb_t *context ) {  // Definition of variables - don't touch if you're not an expert  config_t *config;  stats_t *stats;  context->private_data = swr_malloc( sizeof( private_t ) );  swr_sdb_get_config_struct( context->id, (void**)&config );  swr_sdb_get_stats_struct( context->id, (void**)&stats );  config->ber = 0.01;  // Definition - don't touch  swr_sdb_free_config_struct( context->id, (void**)&config );  swr_sdb_free_stats_struct( context->id, (void**)&stats );  return 0;}int spc_configure_inputs( swr_sdb_t *context ) {  // Definition of variables - don't touch  config_t *config;  swr_sdb_get_config_struct( context->id, (void**)&config );  size_in(0) = size_out(0);  // Definition - don't touch  swr_sdb_free_config_struct( context->id, (void**)&config );  return 0;}/* * This is called when the input-sizes change * It configures the outputs */int spc_configure_outputs( swr_sdb_t *context ) {  // Definition of variables - don't touch  config_t *config;  swr_sdb_get_config_struct( context->id, (void**)&config );  size_out( 0 ) = size_in(0);  // Definition - don't touch  swr_sdb_free_config_struct( context->id, (void**)&config );  return 0;}/* * Every time modules from the outside change the value of a configuration parameter, * this function is called. */int spc_reconfig( swr_sdb_t *context ) {  // Definition of variables - don't touch  config_t *config;  swr_sdb_get_config_struct( context->id, (void**)&config );  private->ber = config->ber;  // Definition - don't touch  swr_sdb_free_config_struct( context->id, (void**)&config );  return(0);}/* * This is function that impements the `main method' of the class * Every class has got just ONE method/working-mode. */int spc_pdata( swr_sdb_t *context ) {  // Definition of variables - don't touch  int n;  U8 *out;  U8 *in;  PR_DBG( 4, "rnd: in spc_pdata\n");  out = buffer_out(0);  in = buffer_in(0);  // This for-loop  // inverts a few bits  for (n=0;n<size_in(0);n++) {    U8 invertPattern=0x00;    int i;    for (i=0;i<8;i++) {      if ( ((double)random())/RAND_MAX < private->ber ) {        invertPattern += 1 << i;      }    }    //invert these bits...    out[n]=in[n]^invertPattern;    if (invertPattern!=0) {      PR_DBG( 4, "Modifying Byte #%d: Inverting Bits: %x. %x-->%x\n",              n,invertPattern,in[n],out[n]);    }  }  return(0);}int spc_custom_msg( swr_sdb_t *context, swr_usr_msg_t* msg_data, swr_msgq ret ) {  spc_pdata( context );  return 0;}/* * This is the `destructor'. */int spc_finalize( swr_sdb_t *context ) {  swr_free( private );  MOD_DEC_USE_COUNT;  return(0);}/* * This function is called upon "insmod" and is used to register the * different parts of the module to the SPM. */swr_spc_id_t cdb_id;int spc_module_init(void) {  swr_spc_desc_t *desc;  // Get a description-part from SPM  // Give the following parameters:  // Input-ports, output-ports, config-params, stat-params  desc = swr_spc_get_new_desc( 1, 1, 1, 0 );  if ( !desc ) {    PR_DBG( 0, "Can't initialise the module. This is BAD!\n" );    return -1;  }  // Define the different parts of config and stats  UM_CONFIG_DOUBLE( "ber" );  UM_INPUT( SIG_U8, 0 );  UM_OUTPUT( SIG_U8, 0 );  // Initialise the callback-functions. NULL for not-used functions  desc->fn_init         = spc_init;  desc->fn_reconfigure  = spc_reconfig;  desc->fn_process_data = spc_pdata;  desc->fn_finalize     = spc_finalize;  desc->fn_custom_msg   = spc_custom_msg;  desc->fn_configure_inputs  = spc_configure_inputs;  desc->fn_configure_outputs = spc_configure_outputs;  // And register the module in the SPM  cdb_id = swr_cdb_register_spc( &desc, "biterror" );  if ( cdb_id == SWR_SPM_INVALID_ID ) {    swr_spc_free_desc( desc );    PR_DBG( 0, "Couldn't register the module!\n" );    return 1;  }  PR_DBG( 4, "Ready to generate random iid equiprobable u8\n");  return 0;}/* * This is called upon rmmod */void spc_module_exit( void ) {  PR_DBG( 2, "Freeing id: %i\n", cdb_id );  if ( swr_cdb_unregister_spc( cdb_id ) < 0 ) {    PR_DBG( 0, "Still in use somewhere\n" );  }}// Do not touch!module_init( spc_module_init );module_exit( spc_module_exit );