mirror of https://github.com/minio/minio.git
148 lines
5.2 KiB
C
148 lines
5.2 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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int32_t minio_src_in_err (int r, int *src_err_list)
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{
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int i;
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for (i = 0; src_err_list[i] != -1; i++) {
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if (src_err_list[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 *src_err_list,
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int errs, int k, int m,
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unsigned char **data,
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unsigned char **coding,
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unsigned char ***source,
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unsigned char ***target)
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{
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int i, j, l;
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unsigned char *tmp_source[k];
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unsigned char *tmp_target[m];
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// Fill zeroes
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memset (tmp_source, 0, sizeof(tmp_source));
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memset (tmp_target, 0, sizeof(tmp_target));
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// Separate out source and target buffers from input data/coding chunks
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// This separation needs to happen at error chunks from input chunks
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for (i = 0, j = 0, l = 0;
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((l < k) || (j < errs)) && (i < (k + m)); i++) {
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if (!minio_src_in_err(i, src_err_list)) {
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if (l < k) {
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if (i < k)
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tmp_source[l] =
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(unsigned char *) data[i];
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else
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tmp_source[l] =
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(unsigned char *) coding[i - k];
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l++;
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}
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} else {
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if (j < m) {
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if (i < k)
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tmp_target[j] =
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(unsigned char *) data[i];
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else
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tmp_target[j] =
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(unsigned char *) coding[i - k];
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j++;
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}
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}
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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 (int *src_err_list,
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unsigned char *encode_matrix,
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unsigned char **decode_matrix,
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unsigned char **decode_tbls,
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int k, int n, int errs)
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{
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int i, j, r, s, l, z;
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unsigned char input_matrix[k * n];
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unsigned char inverse_matrix[k * n];
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unsigned char *tmp_decode_matrix;
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unsigned char *tmp_decode_tbls;
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tmp_decode_matrix = (unsigned char *) malloc (k * n);
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if (!tmp_decode_matrix)
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return -1;
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tmp_decode_tbls = (unsigned char *) malloc (k * n * 32);
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if (!tmp_decode_tbls)
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return -1;
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for (i = 0, r = 0; i < k; i++, r++) {
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while (minio_src_in_err(r, src_err_list))
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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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}
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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 (src_err_list[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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src_err_list[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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src_err_list[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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return 0;
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}
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