minio/pkg/storage/erasure/ec-code.h

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#ifndef _ERASURE_CODE_H_
#define _ERASURE_CODE_H_

#include <stdint.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.
 *
 */

#include "ec-vect-mul.h"

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @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, uint8_t* a, uint8_t* gftbls);

/**
 * @brief Generate or decode erasure codes on blocks of data.
 *
 * 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.
 *
 * @requires SSE4.1
 * @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_sse(int len, int k, int rows, uint8_t *gftbls, uint8_t **data, uint8_t **coding);


/**
 * @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, uint8_t *gftbls, uint8_t **data, uint8_t **coding);


/**
 * @brief Generate or decode erasure codes on blocks of data, runs baseline 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.
 *
 * @param len    Length of each block of data (vector) of source or dest data.
 * @param srcs   The number of vector sources or rows in the generator matrix
 * 		 for coding.
 * @param dests  The number of output vectors to concurrently encode/decode.
 * @param v      Pointer to array of input tables generated from coding
 * 		 coefficients in ec_init_tables(). Must be of size 32*k*rows
 * @param src    Array of pointers to source input buffers.
 * @param dest   Array of pointers to coded output buffers.
 * @returns none
 */

void ec_encode_data_base(int len, int srcs, int dests, uint8_t *v, uint8_t **src, uint8_t **dest);


/**
 * @brief GF(2^8) vector dot product.
 *
 * Does a GF(2^8) dot product across each byte of the input array and a constant
 * set of coefficients to produce each byte of the output. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 32*vlen byte constant array based on the input coefficients.
 *
 * @requires SSE4.1
 * @param len    Length of each vector in bytes. Must be >= 16.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 32*vlen byte array of pre-calculated constants based
 *               on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Pointer to destination data array.
 * @returns none
 */

void gf_vect_dot_prod_sse(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t *dest);

/**
 * @brief GF(2^8) vector dot product.
 *
 * Does a GF(2^8) dot product across each byte of the input array and a constant
 * set of coefficients to produce each byte of the output. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 32*vlen byte constant array based on the input coefficients.
 *
 * @requires AVX
 * @param len    Length of each vector in bytes. Must be >= 16.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 32*vlen byte array of pre-calculated constants based
 *               on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Pointer to destination data array.
 * @returns none
 */

void gf_vect_dot_prod_avx(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t *dest);

/**
 * @brief GF(2^8) vector dot product.
 *
 * Does a GF(2^8) dot product across each byte of the input array and a constant
 * set of coefficients to produce each byte of the output. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 32*vlen byte constant array based on the input coefficients.
 *
 * @requires AVX2
 * @param len    Length of each vector in bytes. Must be >= 32.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 32*vlen byte array of pre-calculated constants based
 *               on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Pointer to destination data array.
 * @returns none
 */

void gf_vect_dot_prod_avx2(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t *dest);

/**
 * @brief GF(2^8) vector dot product with two outputs.
 *
 * Vector dot product optimized to calculate two ouputs at a time. Does two
 * GF(2^8) dot products across each byte of the input array and two constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 2*32*vlen byte constant array based on the two sets of input coefficients.
 *
 * @requires SSE4.1
 * @param len    Length of each vector in bytes. Must be >= 16.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 2*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_2vect_dot_prod_sse(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product with two outputs.
 *
 * Vector dot product optimized to calculate two ouputs at a time. Does two
 * GF(2^8) dot products across each byte of the input array and two constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 2*32*vlen byte constant array based on the two sets of input coefficients.
 *
 * @requires AVX
 * @param len    Length of each vector in bytes. Must be >= 16.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 2*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_2vect_dot_prod_avx(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product with two outputs.
 *
 * Vector dot product optimized to calculate two ouputs at a time. Does two
 * GF(2^8) dot products across each byte of the input array and two constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 2*32*vlen byte constant array based on the two sets of input coefficients.
 *
 * @requires AVX2
 * @param len    Length of each vector in bytes. Must be >= 32.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 2*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_2vect_dot_prod_avx2(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product with three outputs.
 *
 * Vector dot product optimized to calculate three ouputs at a time. Does three
 * GF(2^8) dot products across each byte of the input array and three constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 3*32*vlen byte constant array based on the three sets of input coefficients.
 *
 * @requires SSE4.1
 * @param len    Length of each vector in bytes. Must be >= 16.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 3*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_3vect_dot_prod_sse(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product with three outputs.
 *
 * Vector dot product optimized to calculate three ouputs at a time. Does three
 * GF(2^8) dot products across each byte of the input array and three constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 3*32*vlen byte constant array based on the three sets of input coefficients.
 *
 * @requires AVX
 * @param len    Length of each vector in bytes. Must be >= 16.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 3*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_3vect_dot_prod_avx(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product with three outputs.
 *
 * Vector dot product optimized to calculate three ouputs at a time. Does three
 * GF(2^8) dot products across each byte of the input array and three constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 3*32*vlen byte constant array based on the three sets of input coefficients.
 *
 * @requires AVX2
 * @param len    Length of each vector in bytes. Must be >= 32.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 3*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_3vect_dot_prod_avx2(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product with four outputs.
 *
 * Vector dot product optimized to calculate four ouputs at a time. Does four
 * GF(2^8) dot products across each byte of the input array and four constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 4*32*vlen byte constant array based on the four sets of input coefficients.
 *
 * @requires SSE4.1
 * @param len    Length of each vector in bytes. Must be >= 16.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 4*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_4vect_dot_prod_sse(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product with four outputs.
 *
 * Vector dot product optimized to calculate four ouputs at a time. Does four
 * GF(2^8) dot products across each byte of the input array and four constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 4*32*vlen byte constant array based on the four sets of input coefficients.
 *
 * @requires AVX
 * @param len    Length of each vector in bytes. Must be >= 16.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 4*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_4vect_dot_prod_avx(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product with four outputs.
 *
 * Vector dot product optimized to calculate four ouputs at a time. Does four
 * GF(2^8) dot products across each byte of the input array and four constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 4*32*vlen byte constant array based on the four sets of input coefficients.
 *
 * @requires AVX2
 * @param len    Length of each vector in bytes. Must be >= 32.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 4*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_4vect_dot_prod_avx2(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product with five outputs.
 *
 * Vector dot product optimized to calculate five ouputs at a time. Does five
 * GF(2^8) dot products across each byte of the input array and five constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 5*32*vlen byte constant array based on the five sets of input coefficients.
 *
 * @requires SSE4.1
 * @param len    Length of each vector in bytes. Must >= 16.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 5*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_5vect_dot_prod_sse(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product with five outputs.
 *
 * Vector dot product optimized to calculate five ouputs at a time. Does five
 * GF(2^8) dot products across each byte of the input array and five constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 5*32*vlen byte constant array based on the five sets of input coefficients.
 *
 * @requires AVX
 * @param len    Length of each vector in bytes. Must >= 16.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 5*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_5vect_dot_prod_avx(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product with five outputs.
 *
 * Vector dot product optimized to calculate five ouputs at a time. Does five
 * GF(2^8) dot products across each byte of the input array and five constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 5*32*vlen byte constant array based on the five sets of input coefficients.
 *
 * @requires AVX2
 * @param len    Length of each vector in bytes. Must >= 32.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 5*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_5vect_dot_prod_avx2(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product with six outputs.
 *
 * Vector dot product optimized to calculate six ouputs at a time. Does six
 * GF(2^8) dot products across each byte of the input array and six constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 6*32*vlen byte constant array based on the six sets of input coefficients.
 *
 * @requires SSE4.1
 * @param len    Length of each vector in bytes. Must be >= 16.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 6*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_6vect_dot_prod_sse(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product with six outputs.
 *
 * Vector dot product optimized to calculate six ouputs at a time. Does six
 * GF(2^8) dot products across each byte of the input array and six constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 6*32*vlen byte constant array based on the six sets of input coefficients.
 *
 * @requires AVX
 * @param len    Length of each vector in bytes. Must be >= 16.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 6*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_6vect_dot_prod_avx(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product with six outputs.
 *
 * Vector dot product optimized to calculate six ouputs at a time. Does six
 * GF(2^8) dot products across each byte of the input array and six constant
 * sets of coefficients to produce each byte of the outputs. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 6*32*vlen byte constant array based on the six sets of input coefficients.
 *
 * @requires AVX2
 * @param len    Length of each vector in bytes. Must be >= 32.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 6*32*vlen byte array of pre-calculated constants
 *               based on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Array of pointers to destination data buffers.
 * @returns none
 */

void gf_6vect_dot_prod_avx2(int len, int vlen, uint8_t *gftbls,
			uint8_t **src, uint8_t **dest);

/**
 * @brief GF(2^8) vector dot product, runs baseline version.
 *
 * Does a GF(2^8) dot product across each byte of the input array and a constant
 * set of coefficients to produce each byte of the output. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 32*vlen byte constant array based on the input coefficients.
 *
 * @param len    Length of each vector in bytes. Must be >= 16.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 32*vlen byte array of pre-calculated constants based
 *               on the array of input coefficients. Only elements 32*CONST*j + 1
 *               of this array are used, where j = (0, 1, 2...) and CONST is the
 *               number of elements in the array of input coefficients. The
 *               elements used correspond to the original input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Pointer to destination data array.
 * @returns none
 */

void gf_vect_dot_prod_base(int len, int vlen, uint8_t *gftbls,
                        uint8_t **src, uint8_t *dest);

/**
 * @brief GF(2^8) vector dot product, runs appropriate version.
 *
 * Does a GF(2^8) dot product across each byte of the input array and a constant
 * set of coefficients to produce each byte of the output. Can be used for
 * erasure coding encode and decode. Function requires pre-calculation of a
 * 32*vlen byte constant array based on the input coefficients.
 *
 * This function determines what instruction sets are enabled and
 * selects the appropriate version at runtime.
 *
 * @param len    Length of each vector in bytes. Must be >= 32.
 * @param vlen   Number of vector sources.
 * @param gftbls Pointer to 32*vlen byte array of pre-calculated constants based
 *               on the array of input coefficients.
 * @param src    Array of pointers to source inputs.
 * @param dest   Pointer to destination data array.
 * @returns none
 */

void gf_vect_dot_prod(int len, int vlen, uint8_t *gftbls,
                        uint8_t **src, uint8_t *dest);

/**********************************************************************
 * The remaining are lib support functions used in GF(2^8) operations.
 */

/**
 * @brief Single element GF(2^8) multiply.
 *
 * @param a  Multiplicand a
 * @param b  Multiplicand b
 * @returns  Product of a and b in GF(2^8)
 */

uint8_t gf_mul(uint8_t a, uint8_t b);

/**
 * @brief Single element GF(2^8) inverse.
 *
 * @param a  Input element
 * @returns  Field element b such that a x b = {1}
 */

uint8_t gf_inv(uint8_t a);

/**
 * @brief Generate a matrix of coefficients to be used for encoding.
 *
 * Vandermonde matrix example of encoding coefficients where high portion of
 * matrix is identity matrix I and lower portion is constructed as 2^{i*(j-k+1)}
 * i:{0,k-1} j:{k,m-1}. Commonly used method for choosing coefficients in
 * erasure encoding but does not guarantee invertable for every sub matrix.  For
 * large k it is possible to find cases where the decode matrix chosen from
 * sources and parity not in erasure are not invertable. Users may want to
 * adjust for k > 5.
 *
 * @param a  [mxk] 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_rs_matrix(uint8_t *a, int m, int k);

/**
 * @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  [mxk] 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(uint8_t *a, int m, int k);

/**
 * @brief Invert a matrix in GF(2^8)
 *
 * @param in  input matrix
 * @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(uint8_t *in, uint8_t *out, const int n);

/*************************************************************/

#ifdef __cplusplus
}
#endif

#endif //_ERASURE_CODE_H_