primint.c

来自「用C语言编写的交织器」· C语言 代码 · 共 142 行

// ------------------------------------------------------------------------

// File: primint.c

// Description: Generate a PRIMITIVE interleaver. Output is the interleaver

// array in a files with name specified at command line

//

// The permuted position is computed as a recursion:

//

//          position[i] = ( position[i-1] + root ) modulo N

//

// Care must be taken in selecting N and root to obtain a valid interlaver


#include <stdio.h>

#include <math.h>

#include <float.h>

#include <limits.h>

#define NMAX 16384



main(int argc, char *argv[])

{



int interleaver[NMAX];

int deinterleaver[NMAX];

int check[NMAX];

int i, j, position;

int N;                                 // Interleaver length

int root;                              // Primitive root modulo N

char name1[40];

FILE *fp1;



  // Command line processing

  if (argc != 4)

    {

      printf("Usage %s N  primitive_root  INT_file\n", argv[0]);

      exit(0);

    }



  sscanf(argv[1],"%d", &N);

  sscanf(argv[2],"%d", &root);

  sscanf(argv[3],"%s", name1);



  fp1 = fopen(name1,"w");



  interleaver[0] = 0;

  deinterleaver[0] = 0;

  position = 0;



  for (i=1; i<N; i++)

    {

      position = (position + root) % N;

      interleaver[i] = position;

    }    



  // Check if a valid interleaver is obtained ...

  for (i=0; i<N; i++) check[i] = 0;

  for (i=0; i<N; i++) check[interleaver[i]] = 1;

  for (i=0; i<N; i++) 

    if (!check[i]) {

        printf("This is not a valid interleaver!\n");

        exit(0);

      }



  for (i=0; i<N; i++)

    {

      fprintf(fp1, "%d\n", interleaver[i]);

      printf("%5d -> %5d\n",i,interleaver[i]);

    }



  fclose(fp1);



}