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128 lines
4.1 KiB
C
128 lines
4.1 KiB
C
/*
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* Mini Object Storage, (C) 2014 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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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 <erasure-code.h>
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#include "common.h"
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static
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int32_t _minio_src_index_in_error (int r, int32_t *error_index)
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{
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int i;
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for (i = 0; error_index[i] != -1; i++) {
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if (error_index[i] == r) {
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// true
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return 1;
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}
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}
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// false
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return 0;
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}
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int32_t minio_get_source_target (int errs, int k, int m,
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int32_t *error_index,
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uint32_t *decode_index,
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uint8_t **buffs,
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uint8_t ***source,
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uint8_t ***target)
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{
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int i;
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uint8_t *tmp_source[k];
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uint8_t *tmp_target[m];
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memset (tmp_source, 0, k);
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memset (tmp_target, 0, m);
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for (i = 0; i < k; i++) {
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tmp_source[i] = (uint8_t *) buffs[decode_index[i]];
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}
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for (i = 0; i < m; i++) {
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if (i < errs)
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tmp_target[i] = (uint8_t *) buffs[error_index[i]];
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}
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*source = tmp_source;
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*target = tmp_target;
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}
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/*
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Generate decode matrix during the decoding phase
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*/
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int minio_init_decoder (int32_t *error_index,
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int k, int n, int errs,
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uint8_t *encode_matrix,
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uint8_t **decode_matrix,
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uint8_t **decode_tbls,
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uint32_t **decode_index)
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{
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int i, j, r, s, l, z;
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uint8_t input_matrix[k * n];
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uint8_t inverse_matrix[k * n];
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uint8_t tmp_decode_matrix[k * n];
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uint8_t tmp_decode_tbls[k * n * 32];
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uint32_t tmp_decode_index[k];
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for (i = 0, r = 0; i < k; i++, r++) {
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while (_minio_src_index_in_error(r, error_index))
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r++;
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for (j = 0; j < k; j++) {
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input_matrix[k * i + j] = encode_matrix[k * r + j];
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}
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tmp_decode_index[i] = r;
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}
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// Not all Vandermonde matrix can be inverted
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if (gf_invert_matrix(input_matrix, inverse_matrix, k) < 0) {
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return -1;
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}
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for (l = 0; l < errs; l++) {
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if (error_index[l] < k) {
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// decoding matrix elements for data chunks
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for (j = 0; j < k; j++) {
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tmp_decode_matrix[k * l + j] =
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inverse_matrix[k *
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error_index[l] + j];
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}
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} else {
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int s = 0;
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// decoding matrix element for coding chunks
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for (i = 0; i < k; i++) {
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s = 0;
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for (j = 0; j < k; j++) {
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s ^= gf_mul(inverse_matrix[j * k + i],
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encode_matrix[k *
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error_index[l] + j]);
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}
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tmp_decode_matrix[k * l + i] = s;
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}
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}
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}
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ec_init_tables (k, errs, tmp_decode_matrix, tmp_decode_tbls);
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*decode_matrix = tmp_decode_matrix;
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*decode_tbls = tmp_decode_tbls;
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*decode_index = tmp_decode_index;
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return 0;
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}
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