text: /* *
   * Copyright (c) 2014, James S. Plank and Kevin Greenan
   * All rights reserved.
   *
   * Jerasure - A C/C++ Library for a Variety of Reed-Solomon and RAID-6 Erasure
   * Coding Techniques
   *
   * Revision 2.0: Galois Field backend now links to GF-Complete
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   *  - Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   *  - Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   *  - Neither the name of the University of Tennessee nor the names of its
   *    contributors may be used to endorse or promote products derived
   *    from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
   * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  
  /* Jerasure's authors:
  
     Revision 2.x - 2014: James S. Plank and Kevin M. Greenan.
     Revision 1.2 - 2008: James S. Plank, Scott Simmerman and Catherine D. Schuman.
     Revision 1.0 - 2007: James S. Plank.
   */
  
  #include <stdint.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <strings.h>
  #include <gf_rand.h>
  #include "jerasure.h"
  
  #define talloc(type, num) (type *) malloc(sizeof(type)*(num))
  
  static void usage(char *s)
  {
    fprintf(stderr, "usage: jerasure_05 k m w size seed - Does a simple Reed-Solomon coding example in GF(2^w).\n");
    fprintf(stderr, "       \n");
    fprintf(stderr, "       k+m must be <= 2^w.  w can be 8, 16 or 32.\n");
    fprintf(stderr, "       It sets up a Cauchy generator matrix and encodes\n");
    fprintf(stderr, "       k devices of size bytes with it.  Then it decodes.\n");
    fprintf(stderr, "       After that, it decodes device 0 by using jerasure_make_decoding_matrix()\n");
    fprintf(stderr, "       and jerasure_matrix_dotprod().\n");
    fprintf(stderr, "       \n");
    fprintf(stderr, "This demonstrates: jerasure_matrix_encode()\n");
    fprintf(stderr, "                   jerasure_matrix_decode()\n");
    fprintf(stderr, "                   jerasure_print_matrix()\n");
    fprintf(stderr, "                   jerasure_make_decoding_matrix()\n");
    fprintf(stderr, "                   jerasure_matrix_dotprod()\n");
    if (s != NULL) fprintf(stderr, "\n%s\n\n", s);
    exit(1);
  }
  
  static void print_data_and_coding(int k, int m, int w, int size, 
  		char **data, char **coding) 
  {
    int i, j, x;
    int n, sp;
  
    if(k > m) n = k;
    else n = m;
    sp = size * 2 + size/(w/8) + 8;
  
    printf("%-*sCoding\n", sp, "Data");
    for(i = 0; i < n; i++) {
  	  if(i < k) {
  		  printf("D%-2d:", i);
  		  for(j=0;j< size; j+=(w/8)) { 
  			  printf(" ");
  			  for(x=0;x < w/8;x++){
  				printf("%02x", (unsigned char)data[i][j+x]);
  			  }
  		  }
  		  printf("    ");
  	  }
  	  else printf("%*s", sp, "");
  	  if(i < m) {
  		  printf("C%-2d:", i);
  		  for(j=0;j< size; j+=(w/8)) { 
  			  printf(" ");
  			  for(x=0;x < w/8;x++){
  				printf("%02x", (unsigned char)coding[i][j+x]);
  			  }
  		  }
  	  }
  	  printf("\n");
    }
  	printf("\n");
  }
  
  int main(int argc, char **argv)
  {
    int k, m, w, size;
    int i, j;
    int *matrix;
    char **data, **coding;
    int *erasures, *erased;
    int *decoding_matrix, *dm_ids;
    uint32_t seed;
    
    if (argc != 6) usage(NULL);
    if (sscanf(argv[1], "%d", &k) == 0 || k <= 0) usage("Bad k");
    if (sscanf(argv[2], "%d", &m) == 0 || m <= 0) usage("Bad m");
    if (sscanf(argv[3], "%d", &w) == 0 || (w != 8 && w != 16 && w != 32)) usage("Bad w");
    if (w < 32 && k + m > (1 << w)) usage("k + m must be <= 2 ^ w");
    if (sscanf(argv[4], "%d", &size) == 0 || size % sizeof(long) != 0) 
  		usage("size must be multiple of sizeof(long)");
    if (sscanf(argv[5], "%d", &seed) == 0) usage("Bad seed");
  
    matrix = talloc(int, m*k);
    for (i = 0; i < m; i++) {
      for (j = 0; j < k; j++) {
        matrix[i*k+j] = galois_single_divide(1, i ^ (m + j), w);
      }
    }
  
    printf("<HTML><TITLE>jerasure_05");
    for (i = 1; i < argc; i++) printf(" %s", argv[i]);
    printf("</TITLE>\n");
    printf("<h3>jerasure_05");
    for (i = 1; i < argc; i++) printf(" %s", argv[i]);
    printf("</h3>\n");
    printf("<pre>\n");
  
    printf("The Coding Matrix (the last m rows of the Generator Matrix G^T):\n\n");
    jerasure_print_matrix(matrix, m, k, w);
    printf("\n");
  
    MOA_Seed(seed);
    data = talloc(char *, k);
    for (i = 0; i < k; i++) {
      data[i] = talloc(char, size);
      MOA_Fill_Random_Region(data[i], size);
    }
  
    coding = talloc(char *, m);
    for (i = 0; i < m; i++) {
      coding[i] = talloc(char, size);
    }
  
    jerasure_matrix_encode(k, m, w, matrix, data, coding, size);
    
    printf("Encoding Complete:\n\n");
    print_data_and_coding(k, m, w, size, data, coding);
  
    erasures = talloc(int, (m+1));
    erased = talloc(int, (k+m));
    for (i = 0; i < m+k; i++) erased[i] = 0;
    for (i = 0; i < m; ) {
      erasures[i] = (MOA_Random_W(w, 1))%(k+m);
      if (erased[erasures[i]] == 0) {
        erased[erasures[i]] = 1;
  	  
        bzero((erasures[i] < k) ? data[erasures[i]] : coding[erasures[i]-k], size);
        i++;
      }
    }
    erasures[i] = -1;
  
    printf("Erased %d random devices:\n\n", m);
    print_data_and_coding(k, m, w, size, data, coding);
    
    i = jerasure_matrix_decode(k, m, w, matrix, 0, erasures, data, coding, size);
  
    printf("State of the system after decoding:\n\n");
    print_data_and_coding(k, m, w, size, data, coding);
    
    decoding_matrix = talloc(int, k*k);
    dm_ids = talloc(int, k);
  
    for (i = 0; i < m; i++) erased[i] = 1;
    for (; i < k+m; i++) erased[i] = 0;
  
    jerasure_make_decoding_matrix(k, m, w, matrix, erased, decoding_matrix, dm_ids);
  
    printf("Suppose we erase the first %d devices.  Here is the decoding matrix:\n\n", m);
    jerasure_print_matrix(decoding_matrix, k, k, w);
    printf("\n");
    printf("And dm_ids:\n\n");
    jerasure_print_matrix(dm_ids, 1, k, w);
  
    bzero(data[0], size);
    jerasure_matrix_dotprod(k, w, decoding_matrix, dm_ids, 0, data, coding, size);
  
    printf("\nAfter calling jerasure_matrix_dotprod, we calculate the value of device #0 to be:\n\n");
    printf("D0 :");
    for(i=0;i< size; i+=(w/8)) {
  	  printf(" ");
  	  for(j=0;j < w/8;j++){
  		printf("%02x", (unsigned char)data[0][i+j]);
  	  }
    }
    printf("\n\n");
  
    return 0;
  }
  