--- /dev/null
+// SPDX-License-Identifier: BSD-2-Clause
+/**********************************************************************
+ * Copyright(c) 2011-2015 Intel Corporation All rights reserved.
+ *
+ * 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 Intel Corporation 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
+ * OWNER 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.
+ */
+
+#include <linux/limits.h>
+#include <linux/string.h> /* for memset */
+#include <libcfs/libcfs.h>
+#include "erasure_code.h"
+
+/* Global GF(256) tables */
+static const unsigned char gff_base[] = {
+ 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1d, 0x3a,
+ 0x74, 0xe8, 0xcd, 0x87, 0x13, 0x26, 0x4c, 0x98, 0x2d, 0x5a,
+ 0xb4, 0x75, 0xea, 0xc9, 0x8f, 0x03, 0x06, 0x0c, 0x18, 0x30,
+ 0x60, 0xc0, 0x9d, 0x27, 0x4e, 0x9c, 0x25, 0x4a, 0x94, 0x35,
+ 0x6a, 0xd4, 0xb5, 0x77, 0xee, 0xc1, 0x9f, 0x23, 0x46, 0x8c,
+ 0x05, 0x0a, 0x14, 0x28, 0x50, 0xa0, 0x5d, 0xba, 0x69, 0xd2,
+ 0xb9, 0x6f, 0xde, 0xa1, 0x5f, 0xbe, 0x61, 0xc2, 0x99, 0x2f,
+ 0x5e, 0xbc, 0x65, 0xca, 0x89, 0x0f, 0x1e, 0x3c, 0x78, 0xf0,
+ 0xfd, 0xe7, 0xd3, 0xbb, 0x6b, 0xd6, 0xb1, 0x7f, 0xfe, 0xe1,
+ 0xdf, 0xa3, 0x5b, 0xb6, 0x71, 0xe2, 0xd9, 0xaf, 0x43, 0x86,
+ 0x11, 0x22, 0x44, 0x88, 0x0d, 0x1a, 0x34, 0x68, 0xd0, 0xbd,
+ 0x67, 0xce, 0x81, 0x1f, 0x3e, 0x7c, 0xf8, 0xed, 0xc7, 0x93,
+ 0x3b, 0x76, 0xec, 0xc5, 0x97, 0x33, 0x66, 0xcc, 0x85, 0x17,
+ 0x2e, 0x5c, 0xb8, 0x6d, 0xda, 0xa9, 0x4f, 0x9e, 0x21, 0x42,
+ 0x84, 0x15, 0x2a, 0x54, 0xa8, 0x4d, 0x9a, 0x29, 0x52, 0xa4,
+ 0x55, 0xaa, 0x49, 0x92, 0x39, 0x72, 0xe4, 0xd5, 0xb7, 0x73,
+ 0xe6, 0xd1, 0xbf, 0x63, 0xc6, 0x91, 0x3f, 0x7e, 0xfc, 0xe5,
+ 0xd7, 0xb3, 0x7b, 0xf6, 0xf1, 0xff, 0xe3, 0xdb, 0xab, 0x4b,
+ 0x96, 0x31, 0x62, 0xc4, 0x95, 0x37, 0x6e, 0xdc, 0xa5, 0x57,
+ 0xae, 0x41, 0x82, 0x19, 0x32, 0x64, 0xc8, 0x8d, 0x07, 0x0e,
+ 0x1c, 0x38, 0x70, 0xe0, 0xdd, 0xa7, 0x53, 0xa6, 0x51, 0xa2,
+ 0x59, 0xb2, 0x79, 0xf2, 0xf9, 0xef, 0xc3, 0x9b, 0x2b, 0x56,
+ 0xac, 0x45, 0x8a, 0x09, 0x12, 0x24, 0x48, 0x90, 0x3d, 0x7a,
+ 0xf4, 0xf5, 0xf7, 0xf3, 0xfb, 0xeb, 0xcb, 0x8b, 0x0b, 0x16,
+ 0x2c, 0x58, 0xb0, 0x7d, 0xfa, 0xe9, 0xcf, 0x83, 0x1b, 0x36,
+ 0x6c, 0xd8, 0xad, 0x47, 0x8e, 0x01
+};
+
+static const unsigned char gflog_base[] = {
+ 0x00, 0xff, 0x01, 0x19, 0x02, 0x32, 0x1a, 0xc6, 0x03, 0xdf,
+ 0x33, 0xee, 0x1b, 0x68, 0xc7, 0x4b, 0x04, 0x64, 0xe0, 0x0e,
+ 0x34, 0x8d, 0xef, 0x81, 0x1c, 0xc1, 0x69, 0xf8, 0xc8, 0x08,
+ 0x4c, 0x71, 0x05, 0x8a, 0x65, 0x2f, 0xe1, 0x24, 0x0f, 0x21,
+ 0x35, 0x93, 0x8e, 0xda, 0xf0, 0x12, 0x82, 0x45, 0x1d, 0xb5,
+ 0xc2, 0x7d, 0x6a, 0x27, 0xf9, 0xb9, 0xc9, 0x9a, 0x09, 0x78,
+ 0x4d, 0xe4, 0x72, 0xa6, 0x06, 0xbf, 0x8b, 0x62, 0x66, 0xdd,
+ 0x30, 0xfd, 0xe2, 0x98, 0x25, 0xb3, 0x10, 0x91, 0x22, 0x88,
+ 0x36, 0xd0, 0x94, 0xce, 0x8f, 0x96, 0xdb, 0xbd, 0xf1, 0xd2,
+ 0x13, 0x5c, 0x83, 0x38, 0x46, 0x40, 0x1e, 0x42, 0xb6, 0xa3,
+ 0xc3, 0x48, 0x7e, 0x6e, 0x6b, 0x3a, 0x28, 0x54, 0xfa, 0x85,
+ 0xba, 0x3d, 0xca, 0x5e, 0x9b, 0x9f, 0x0a, 0x15, 0x79, 0x2b,
+ 0x4e, 0xd4, 0xe5, 0xac, 0x73, 0xf3, 0xa7, 0x57, 0x07, 0x70,
+ 0xc0, 0xf7, 0x8c, 0x80, 0x63, 0x0d, 0x67, 0x4a, 0xde, 0xed,
+ 0x31, 0xc5, 0xfe, 0x18, 0xe3, 0xa5, 0x99, 0x77, 0x26, 0xb8,
+ 0xb4, 0x7c, 0x11, 0x44, 0x92, 0xd9, 0x23, 0x20, 0x89, 0x2e,
+ 0x37, 0x3f, 0xd1, 0x5b, 0x95, 0xbc, 0xcf, 0xcd, 0x90, 0x87,
+ 0x97, 0xb2, 0xdc, 0xfc, 0xbe, 0x61, 0xf2, 0x56, 0xd3, 0xab,
+ 0x14, 0x2a, 0x5d, 0x9e, 0x84, 0x3c, 0x39, 0x53, 0x47, 0x6d,
+ 0x41, 0xa2, 0x1f, 0x2d, 0x43, 0xd8, 0xb7, 0x7b, 0xa4, 0x76,
+ 0xc4, 0x17, 0x49, 0xec, 0x7f, 0x0c, 0x6f, 0xf6, 0x6c, 0xa1,
+ 0x3b, 0x52, 0x29, 0x9d, 0x55, 0xaa, 0xfb, 0x60, 0x86, 0xb1,
+ 0xbb, 0xcc, 0x3e, 0x5a, 0xcb, 0x59, 0x5f, 0xb0, 0x9c, 0xa9,
+ 0xa0, 0x51, 0x0b, 0xf5, 0x16, 0xeb, 0x7a, 0x75, 0x2c, 0xd7,
+ 0x4f, 0xae, 0xd5, 0xe9, 0xe6, 0xe7, 0xad, 0xe8, 0x74, 0xd6,
+ 0xf4, 0xea, 0xa8, 0x50, 0x58, 0xaf
+};
+
+void ec_init_tables(int k, int rows, unsigned char *a, unsigned char *g_tbls)
+{
+ int i, j;
+
+ for (i = 0; i < rows; i++) {
+ for (j = 0; j < k; j++) {
+ gf_vect_mul_init(*a++, g_tbls);
+ g_tbls += 32;
+ }
+ }
+}
+EXPORT_SYMBOL(ec_init_tables);
+
+unsigned char gf_mul(unsigned char a, unsigned char b)
+{
+ int i;
+
+ if ((a == 0) || (b == 0))
+ return 0;
+
+ i = gflog_base[a] + gflog_base[b];
+ return gff_base[i > 254 ? i - 255 : i];
+}
+
+unsigned char gf_inv(unsigned char a)
+{
+ if (a == 0)
+ return 0;
+
+ return gff_base[255 - gflog_base[a]];
+}
+
+void gf_gen_cauchy1_matrix(unsigned char *a, int m, int k)
+{
+ int i, j;
+ unsigned char *p;
+
+ /* Identity matrix in high position */
+ memset(a, 0, k * m);
+ for (i = 0; i < k; i++)
+ a[k * i + i] = 1;
+
+ /* For the rest choose 1/(i + j) | i != j */
+ p = &a[k * k];
+ for (i = k; i < m; i++)
+ for (j = 0; j < k; j++)
+ *p++ = gf_inv(i ^ j);
+
+}
+EXPORT_SYMBOL(gf_gen_cauchy1_matrix);
+
+int gf_invert_matrix(unsigned char *in_mat, unsigned char *out_mat, const int n)
+{
+ int i, j, k;
+ unsigned char temp;
+
+ /* Set out_mat[] to the identity matrix */
+ for (i = 0; i < n * n; i++) /* memset(out_mat, 0, n*n) */
+ out_mat[i] = 0;
+
+ for (i = 0; i < n; i++)
+ out_mat[i * n + i] = 1;
+
+ /* Inverse */
+ for (i = 0; i < n; i++) {
+ /* Check for 0 in pivot element */
+ if (in_mat[i * n + i] == 0) {
+ /* Find a row with non-zero in current column and swap */
+ for (j = i + 1; j < n; j++)
+ if (in_mat[j * n + i])
+ break;
+
+ if (j == n) /* Couldn't find means it's singular */
+ return -1;
+
+ for (k = 0; k < n; k++) { /* Swap rows i,j */
+ temp = in_mat[i * n + k];
+ in_mat[i * n + k] = in_mat[j * n + k];
+ in_mat[j * n + k] = temp;
+
+ temp = out_mat[i * n + k];
+ out_mat[i * n + k] = out_mat[j * n + k];
+ out_mat[j * n + k] = temp;
+ }
+ }
+
+ temp = gf_inv(in_mat[i * n + i]); /* 1/pivot */
+ for (j = 0; j < n; j++) { /* Scale row i by 1/pivot */
+ in_mat[i * n + j] = gf_mul(in_mat[i * n + j], temp);
+ out_mat[i * n + j] = gf_mul(out_mat[i * n + j], temp);
+ }
+
+ for (j = 0; j < n; j++) {
+ if (j == i)
+ continue;
+
+ temp = in_mat[j * n + i];
+ for (k = 0; k < n; k++) {
+ out_mat[j * n + k] ^= gf_mul(temp, out_mat[i * n + k]);
+ in_mat[j * n + k] ^= gf_mul(temp, in_mat[i * n + k]);
+ }
+ }
+ }
+ return 0;
+}
+EXPORT_SYMBOL(gf_invert_matrix);
+
+/* Calculates const table gftbl in GF(2^8) from single input A
+ * gftbl(A) = {A{00}, A{01}, A{02}, ... , A{0f} }, {A{00}, A{10}, A{20}, ... ,
+ * A{f0} }
+ */
+void gf_vect_mul_init(unsigned char c, unsigned char *tbl)
+{
+ unsigned char c2 = (c << 1) ^ ((c & 0x80) ? 0x1d : 0); /* Mult by
+ * GF{2}
+ */
+ unsigned char c4 = (c2 << 1) ^ ((c2 & 0x80) ? 0x1d : 0); /* Mult by
+ * GF{2}
+ */
+ unsigned char c8 = (c4 << 1) ^ ((c4 & 0x80) ? 0x1d : 0); /* Mult by
+ * GF{2}
+ */
+#if BITS_PER_LONG == 64
+ unsigned long long v1, v2, v4, v8, *t;
+ unsigned long long v10, v20, v40, v80;
+ unsigned char c17, c18, c20, c24;
+
+ t = (unsigned long long *)tbl;
+
+ v1 = c * 0x0100010001000100ull;
+ v2 = c2 * 0x0101000001010000ull;
+ v4 = c4 * 0x0101010100000000ull;
+ v8 = c8 * 0x0101010101010101ull;
+
+ v4 = v1 ^ v2 ^ v4;
+ t[0] = v4;
+ t[1] = v8 ^ v4;
+
+ c17 = (c8 << 1) ^ ((c8 & 0x80) ? 0x1d : 0); //Mult by GF{2}
+ c18 = (c17 << 1) ^ ((c17 & 0x80) ? 0x1d : 0); //Mult by GF{2}
+ c20 = (c18 << 1) ^ ((c18 & 0x80) ? 0x1d : 0); //Mult by GF{2}
+ c24 = (c20 << 1) ^ ((c20 & 0x80) ? 0x1d : 0); //Mult by GF{2}
+
+ v10 = c17 * 0x0100010001000100ull;
+ v20 = c18 * 0x0101000001010000ull;
+ v40 = c20 * 0x0101010100000000ull;
+ v80 = c24 * 0x0101010101010101ull;
+
+ v40 = v10 ^ v20 ^ v40;
+ t[2] = v40;
+ t[3] = v80 ^ v40;
+
+#else /* 32-bit or other */
+ unsigned char c3, c5, c6, c7, c9, c10, c11, c12, c13, c14, c15;
+ unsigned char c17, c18, c19, c20, c21, c22, c23, c24, c25, c26;
+ unsigned char c27, c28, c29, c30, c31;
+
+ c3 = c2 ^ c;
+ c5 = c4 ^ c;
+ c6 = c4 ^ c2;
+ c7 = c4 ^ c3;
+
+ c9 = c8 ^ c;
+ c10 = c8 ^ c2;
+ c11 = c8 ^ c3;
+ c12 = c8 ^ c4;
+ c13 = c8 ^ c5;
+ c14 = c8 ^ c6;
+ c15 = c8 ^ c7;
+
+ tbl[0] = 0;
+ tbl[1] = c;
+ tbl[2] = c2;
+ tbl[3] = c3;
+ tbl[4] = c4;
+ tbl[5] = c5;
+ tbl[6] = c6;
+ tbl[7] = c7;
+ tbl[8] = c8;
+ tbl[9] = c9;
+ tbl[10] = c10;
+ tbl[11] = c11;
+ tbl[12] = c12;
+ tbl[13] = c13;
+ tbl[14] = c14;
+ tbl[15] = c15;
+
+ c17 = (c8 << 1) ^ ((c8 & 0x80) ? 0x1d : 0); /* Mult by GF{2} */
+ c18 = (c17 << 1) ^ ((c17 & 0x80) ? 0x1d : 0); /* Mult by GF{2} */
+ c19 = c18 ^ c17;
+ c20 = (c18 << 1) ^ ((c18 & 0x80) ? 0x1d : 0); /* Mult by GF{2} */
+ c21 = c20 ^ c17;
+ c22 = c20 ^ c18;
+ c23 = c20 ^ c19;
+ c24 = (c20 << 1) ^ ((c20 & 0x80) ? 0x1d : 0); /* Mult by GF{2} */
+ c25 = c24 ^ c17;
+ c26 = c24 ^ c18;
+ c27 = c24 ^ c19;
+ c28 = c24 ^ c20;
+ c29 = c24 ^ c21;
+ c30 = c24 ^ c22;
+ c31 = c24 ^ c23;
+
+ tbl[16] = 0;
+ tbl[17] = c17;
+ tbl[18] = c18;
+ tbl[19] = c19;
+ tbl[20] = c20;
+ tbl[21] = c21;
+ tbl[22] = c22;
+ tbl[23] = c23;
+ tbl[24] = c24;
+ tbl[25] = c25;
+ tbl[26] = c26;
+ tbl[27] = c27;
+ tbl[28] = c28;
+ tbl[29] = c29;
+ tbl[30] = c30;
+ tbl[31] = c31;
+
+#endif /* BITS_PER_LONG == 64 */
+}
+
+void ec_encode_data(int len, int srcs, int dests, unsigned char *v,
+ unsigned char **src, unsigned char **dest)
+{
+ int i, j, l;
+ unsigned char s;
+
+ for (l = 0; l < dests; l++) {
+ for (i = 0; i < len; i++) {
+ s = 0;
+ for (j = 0; j < srcs; j++)
+ s ^= gf_mul(src[j][i], v[j * 32 + l * srcs * 32 + 1]);
+
+ dest[l][i] = s;
+ }
+ }
+}
+EXPORT_SYMBOL(ec_encode_data);
+
+static int __init ec_init(void)
+{
+ return 0;
+}
+
+static void __exit ec_exit(void)
+{
+}
+
+MODULE_AUTHOR("Intel Corporation");
+MODULE_DESCRIPTION("M to N erasure code handling");
+MODULE_VERSION("1.0.0");
+MODULE_LICENSE("Dual BSD/GPL");
+
+module_init(ec_init);
+module_exit(ec_exit);
--- /dev/null
+// SPDX-License-Identifier: BSD-2-Clause
+/**********************************************************************
+ * Copyright(c) 2011-2015 Intel Corporation All rights reserved.
+ *
+ * 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 Intel Corporation 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
+ * OWNER 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.
+ */
+
+#ifndef _ERASURE_CODE_H_
+#define _ERASURE_CODE_H_
+
+/**
+ * @file erasure_code.h
+ * @brief Interface to functions supporting erasure code encode and decode.
+ *
+ * This file defines the interface to optimized functions used in erasure
+ * codes. Encode and decode of erasures in GF(2^8) are made by calculating the
+ * dot product of the symbols (bytes in GF(2^8)) across a set of buffers and a
+ * set of coefficients. Values for the coefficients are determined by the type
+ * of erasure code. Using a general dot product means that any sequence of
+ * coefficients may be used including erasure codes based on random
+ * coefficients.
+ * Multiple versions of dot product are supplied to calculate 1-6 output
+ * vectors in one pass.
+ * Base GF multiply and divide functions can be sped up by defining
+ * GF_LARGE_TABLES at the expense of memory size.
+ *
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Initialize 32-byte constant array for GF(2^8) vector multiply
+ *
+ * Calculates array {C{00}, C{01}, C{02}, ... , C{0f} }, {C{00}, C{10},
+ * C{20}, ... , C{f0} } as required by other fast vector multiply
+ * functions.
+ * @param c Constant input.
+ * @param gftbl Table output.
+ */
+void gf_vect_mul_init(unsigned char c, unsigned char *gftbl);
+
+/**
+ * @brief Initialize tables for fast Erasure Code encode and decode.
+ *
+ * Generates the expanded tables needed for fast encode or decode for erasure
+ * codes on blocks of data. 32bytes is generated for each input coefficient.
+ *
+ * @param k The number of vector sources or rows in the generator matrix
+ * for coding.
+ * @param rows The number of output vectors to concurrently encode/decode.
+ * @param a Pointer to sets of arrays of input coefficients used to encode
+ * or decode data.
+ * @param gftbls Pointer to start of space for concatenated output tables
+ * generated from input coefficients. Must be of size 32*k*rows.
+ * @returns none
+ */
+void ec_init_tables(int k, int rows, unsigned char *a, unsigned char *gftbls);
+
+/**
+ * @brief Generate or decode erasure codes on blocks of data, runs appropriate
+ * version.
+ *
+ * Given a list of source data blocks, generate one or multiple blocks of
+ * encoded data as specified by a matrix of GF(2^8) coefficients. When given a
+ * suitable set of coefficients, this function will perform the fast generation
+ * or decoding of Reed-Solomon type erasure codes.
+ *
+ * This function determines what instruction sets are enabled and
+ * selects the appropriate version at runtime.
+ *
+ * @param len Length of each block of data (vector) of source or dest data.
+ * @param k The number of vector sources or rows in the generator matrix
+ * for coding.
+ * @param rows The number of output vectors to concurrently encode/decode.
+ * @param gftbls Pointer to array of input tables generated from coding
+ * coefficients in ec_init_tables(). Must be of size 32*k*rows
+ * @param data Array of pointers to source input buffers.
+ * @param coding Array of pointers to coded output buffers.
+ * @returns none
+ */
+void ec_encode_data(int len, int k, int rows, unsigned char *gftbls,
+ unsigned char **data, unsigned char **coding);
+
+/**
+ * @brief Generate a Cauchy matrix of coefficients to be used for encoding.
+ *
+ * Cauchy matrix example of encoding coefficients where high portion of matrix
+ * is identity matrix I and lower portion is constructed as 1/(i + j) | i != j,
+ * i:{0,k-1} j:{k,m-1}. Any sub-matrix of a Cauchy matrix should be invertable.
+ *
+ * @param a [m x k] array to hold coefficients
+ * @param m number of rows in matrix corresponding to srcs + parity.
+ * @param k number of columns in matrix corresponding to srcs.
+ * @returns none
+ */
+void gf_gen_cauchy1_matrix(unsigned char *a, int m, int k);
+
+/**
+ * @brief Invert a matrix in GF(2^8)
+ *
+ * Attempts to construct an n x n inverse of the input matrix. Returns non-zero
+ * if singular. Will always destroy input matrix in process.
+ *
+ * @param in input matrix, destroyed by invert process
+ * @param out output matrix such that [in] x [out] = [I] - identity matrix
+ * @param n size of matrix [nxn]
+ * @returns 0 successful, other fail on singular input matrix
+ */
+int gf_invert_matrix(unsigned char *in, unsigned char *out, const int n);
+
+/*************************************************************/
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _ERASURE_CODE_H_ */
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