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+/* *
+ * 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 <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;
+}
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