357 lines
9.7 KiB
C
357 lines
9.7 KiB
C
/* *
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* Copyright (c) 2013, James S. Plank and Kevin Greenan
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* All rights reserved.
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*
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* Jerasure - A C/C++ Library for a Variety of Reed-Solomon and RAID-6 Erasure
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* Coding Techniques
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*
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* Revision 2.0: Galois Field backend now links to GF-Complete
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* - Neither the name of the University of Tennessee nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
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* WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "galois.h"
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#define MAX_GF_INSTANCES 64
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gf_t *gfp_array[MAX_GF_INSTANCES] = { 0 };
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int gfp_is_composite[MAX_GF_INSTANCES] = { 0 };
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gf_t *galois_get_field_ptr(int w)
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{
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if (gfp_array[w] != NULL) {
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return gfp_array[w];
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}
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return NULL;
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}
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gf_t* galois_init_field(int w,
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int mult_type,
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int region_type,
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int divide_type,
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uint64_t prim_poly,
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int arg1,
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int arg2)
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{
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int scratch_size;
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void *scratch_memory;
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gf_t *gfp;
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if (w <= 0 || w > 32) {
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fprintf(stderr, "ERROR -- cannot init default Galois field for w=%d\n", w);
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exit(1);
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}
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gfp = (gf_t *) malloc(sizeof(gf_t));
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if (!gfp) {
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fprintf(stderr, "ERROR -- cannot allocate memory for Galois field w=%d\n", w);
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exit(1);
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}
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scratch_size = gf_scratch_size(w, mult_type, region_type, divide_type, arg1, arg2);
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if (!scratch_size) {
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fprintf(stderr, "ERROR -- cannot get scratch size for base field w=%d\n", w);
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exit(1);
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}
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scratch_memory = malloc(scratch_size);
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if (!scratch_memory) {
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fprintf(stderr, "ERROR -- cannot get scratch memory for base field w=%d\n", w);
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exit(1);
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}
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if(!gf_init_hard(gfp,
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w,
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mult_type,
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region_type,
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divide_type,
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prim_poly,
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arg1,
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arg2,
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NULL,
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scratch_memory))
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{
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fprintf(stderr, "ERROR -- cannot init default Galois field for w=%d\n", w);
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exit(1);
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}
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gfp_is_composite[w] = 0;
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return gfp;
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}
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gf_t* galois_init_composite_field(int w,
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int region_type,
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int divide_type,
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int degree,
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gf_t* base_gf)
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{
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int scratch_size;
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void *scratch_memory;
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gf_t *gfp;
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if (w <= 0 || w > 32) {
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fprintf(stderr, "ERROR -- cannot init composite field for w=%d\n", w);
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exit(1);
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}
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gfp = (gf_t *) malloc(sizeof(gf_t));
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if (!gfp) {
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fprintf(stderr, "ERROR -- cannot allocate memory for Galois field w=%d\n", w);
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exit(1);
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}
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scratch_size = gf_scratch_size(w, GF_MULT_COMPOSITE, region_type, divide_type, degree, 0);
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if (!scratch_size) {
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fprintf(stderr, "ERROR -- cannot get scratch size for composite field w=%d\n", w);
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exit(1);
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}
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scratch_memory = malloc(scratch_size);
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if (!scratch_memory) {
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fprintf(stderr, "ERROR -- cannot get scratch memory for composite field w=%d\n", w);
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exit(1);
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}
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if(!gf_init_hard(gfp,
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w,
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GF_MULT_COMPOSITE,
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region_type,
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divide_type,
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0,
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degree,
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0,
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base_gf,
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scratch_memory))
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{
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fprintf(stderr, "ERROR -- cannot init default composite field for w=%d\n", w);
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exit(1);
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}
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gfp_is_composite[w] = 1;
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return gfp;
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}
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static void galois_init_default_field(int w)
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{
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if (w <= 0 || w > 32) {
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fprintf(stderr, "ERROR -- cannot init default Galois field for w=%d\n", w);
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exit(1);
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}
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if (gfp_array[w] == NULL) {
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gfp_array[w] = (gf_t*)malloc(sizeof(gf_t));
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if (gfp_array[w] == NULL) {
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fprintf(stderr, "ERROR -- cannot allocate memory for Galois field w=%d\n", w);
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exit(1);
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}
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}
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if (!gf_init_easy(gfp_array[w], w)) {
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fprintf(stderr, "ERROR -- cannot init default Galois field for w=%d\n", w);
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exit(1);
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}
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}
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static int is_valid_gf(gf_t *gf, int w)
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{
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// TODO: I assume we may eventually
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// want to do w=64 and 128, so w
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// will be needed to perform this check
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(void)w;
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if (gf == NULL) {
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return 0;
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}
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if (gf->multiply.w32 == NULL) {
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return 0;
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}
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if (gf->multiply_region.w32 == NULL) {
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return 0;
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}
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if (gf->divide.w32 == NULL) {
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return 0;
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}
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if (gf->inverse.w32 == NULL) {
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return 0;
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}
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if (gf->extract_word.w32 == NULL) {
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return 0;
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}
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return 1;
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}
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void galois_change_technique(gf_t *gf, int w)
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{
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if (w <= 0 || w > 32) {
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fprintf(stderr, "ERROR -- cannot support Galois field for w=%d\n", w);
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exit(1);
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}
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if (!is_valid_gf(gf, w)) {
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fprintf(stderr, "ERROR -- overriding with invalid Galois field for w=%d\n", w);
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exit(1);
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}
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if (gfp_array[w] != NULL) {
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gf_free(gfp_array[w], gfp_is_composite[w]);
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}
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gfp_array[w] = gf;
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}
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int galois_single_multiply(int x, int y, int w)
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{
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if (x == 0 || y == 0) return 0;
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if (gfp_array[w] == NULL) {
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galois_init_default_field(w);
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}
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if (w <= 32) {
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return gfp_array[w]->multiply.w32(gfp_array[w], x, y);
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} else {
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fprintf(stderr, "ERROR -- Galois field not implemented for w=%d\n", w);
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}
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}
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int galois_single_divide(int x, int y, int w)
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{
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if (x == 0) return 0;
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if (y == 0) return -1;
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if (gfp_array[w] == NULL) {
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galois_init_default_field(w);
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}
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if (w <= 32) {
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return gfp_array[w]->divide.w32(gfp_array[w], x, y);
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} else {
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fprintf(stderr, "ERROR -- Galois field not implemented for w=%d\n", w);
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}
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}
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void galois_w08_region_multiply(char *region, /* Region to multiply */
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int multby, /* Number to multiply by */
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int nbytes, /* Number of bytes in region */
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char *r2, /* If r2 != NULL, products go here */
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int add)
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{
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if (gfp_array[8] == NULL) {
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galois_init_default_field(8);
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}
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gfp_array[8]->multiply_region.w32(gfp_array[8], region, r2, multby, nbytes, add);
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}
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void galois_w16_region_multiply(char *region, /* Region to multiply */
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int multby, /* Number to multiply by */
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int nbytes, /* Number of bytes in region */
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char *r2, /* If r2 != NULL, products go here */
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int add)
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{
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if (gfp_array[16] == NULL) {
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galois_init_default_field(16);
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}
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gfp_array[16]->multiply_region.w32(gfp_array[16], region, r2, multby, nbytes, add);
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}
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void galois_w32_region_multiply(char *region, /* Region to multiply */
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int multby, /* Number to multiply by */
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int nbytes, /* Number of bytes in region */
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char *r2, /* If r2 != NULL, products go here */
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int add)
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{
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if (gfp_array[32] == NULL) {
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galois_init_default_field(32);
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}
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gfp_array[32]->multiply_region.w32(gfp_array[32], region, r2, multby, nbytes, add);
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}
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void galois_w8_region_xor(void *src, void *dest, int nbytes)
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{
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if (gfp_array[8] == NULL) {
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galois_init_default_field(8);
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}
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gfp_array[8]->multiply_region.w32(gfp_array[32], src, dest, 1, nbytes, 1);
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}
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void galois_w16_region_xor(void *src, void *dest, int nbytes)
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{
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if (gfp_array[16] == NULL) {
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galois_init_default_field(16);
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}
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gfp_array[16]->multiply_region.w32(gfp_array[16], src, dest, 1, nbytes, 1);
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}
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void galois_w32_region_xor(void *src, void *dest, int nbytes)
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{
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if (gfp_array[32] == NULL) {
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galois_init_default_field(32);
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}
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gfp_array[32]->multiply_region.w32(gfp_array[32], src, dest, 1, nbytes, 1);
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}
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void galois_region_xor(char *r1, /* Region 1 */
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char *r2, /* Region 2 */
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char *r3, /* Sum region (r3 = r1 ^ r2) -- can be r1 or r2 */
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int nbytes) /* Number of bytes in region */
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{
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long *l1;
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long *l2;
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long *l3;
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long *ltop;
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char *ctop;
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ctop = r1 + nbytes;
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ltop = (long *) ctop;
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l1 = (long *) r1;
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l2 = (long *) r2;
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l3 = (long *) r3;
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while (l1 < ltop) {
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*l3 = ((*l1) ^ (*l2));
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l1++;
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l2++;
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l3++;
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}
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}
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int galois_inverse(int y, int w)
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{
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if (y == 0) return -1;
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return galois_single_divide(1, y, w);
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}
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