/* * * Copyright (c) 2013, 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. */ /* revised by S. Simmerman 2/25/08 */ #include #include #include #include "jerasure.h" #include "reed_sol.h" #define talloc(type, num) (type *) malloc(sizeof(type)*(num)) usage(char *s) { fprintf(stderr, "usage: reed_sol_01 k m w - Does a simple Reed-Solomon coding example in GF(2^w).\n"); fprintf(stderr, " \n"); fprintf(stderr, " w must be 8, 16 or 32. k+m must be <= 2^w. It sets up a classic\n"); fprintf(stderr, " Vandermonde-based distribution matrix and encodes k devices of\n"); fprintf(stderr, " %d bytes each with it. Then it decodes.\n", sizeof(long)); 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, " reed_sol_vandermonde_coding_matrix()\n"); if (s != NULL) fprintf(stderr, "%s\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; long l; 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) { long l; int k, w, i, j, m; int *matrix; char **data, **coding; int *erasures, *erased; int *decoding_matrix, *dm_ids; if (argc != 4) 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 <= 16 && k + m > (1 << w)) usage("k + m is too big"); matrix = reed_sol_vandermonde_coding_matrix(k, m, w); printf("Last m rows of the Distribution Matrix:\n\n"); jerasure_print_matrix(matrix, m, k, w); printf("\n"); srand48(0); data = talloc(char *, k); for (i = 0; i < k; i++) { data[i] = talloc(char, sizeof(long)); l = lrand48(); memcpy(data[i], &l, sizeof(long)); } coding = talloc(char *, m); for (i = 0; i < m; i++) { coding[i] = talloc(char, sizeof(long)); } jerasure_matrix_encode(k, m, w, matrix, data, coding, sizeof(long)); printf("Encoding Complete:\n\n"); print_data_and_coding(k, m, w, sizeof(long), data, coding); erasures = talloc(int, (m+1)); erased = talloc(int, (k+m)); for (i = 0; i < m+k; i++) erased[i] = 0; l = 0; for (i = 0; i < m; ) { erasures[i] = lrand48()%(k+m); if (erased[erasures[i]] == 0) { erased[erasures[i]] = 1; memcpy((erasures[i] < k) ? data[erasures[i]] : coding[erasures[i]-k], &l, sizeof(long)); i++; } } erasures[i] = -1; printf("Erased %d random devices:\n\n", m); print_data_and_coding(k, m, w, sizeof(long), data, coding); i = jerasure_matrix_decode(k, m, w, matrix, 1, erasures, data, coding, sizeof(long)); printf("State of the system after decoding:\n\n"); print_data_and_coding(k, m, w, sizeof(long), data, coding); return 0; }