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Added tests for the GF init helper functions in galois.c 

Updated the README to explain the GF change procedure.
master
Kevin Greenan 2013-11-24 13:20:21 -08:00
parent e5170f7072
commit d8c84dcbb9
8 changed files with 729 additions and 65 deletions
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13
Examples/makefile
View File

@ -63,6 +63,7 @@ ALL = jerasure_01 \
reed_sol_04 \
reed_sol_test_gf \
reed_sol_time_gf \
reed_sol_hard_time_gf \
cauchy_01 \
cauchy_02 \
cauchy_03 \
@ -190,9 +191,13 @@ decoder: decoder.o galois.o jerasure.o liberation.o reed_sol.o cauchy.o
$(CC) $(CFLAGS) -o decoder decoder.o liberation.o jerasure.o galois.o reed_sol.o cauchy.o -lgf_complete
reed_sol_test_gf.o: galois.h reed_sol.h jerasure.h
reed_sol_test_gf: reed_sol_test_gf.o galois.o ${LIBDIR}/gf_complete.a jerasure.o reed_sol.o
$(CC) $(CFLAGS) -o reed_sol_test_gf reed_sol_test_gf.o reed_sol.o jerasure.o galois.o ${LIBDIR}/gf_complete.a
reed_sol_test_gf: reed_sol_test_gf.o galois.o jerasure.o reed_sol.o
$(CC) $(CFLAGS) -o reed_sol_test_gf reed_sol_test_gf.o reed_sol.o jerasure.o galois.o -lgf_complete
reed_sol_time_gf.o: galois.h reed_sol.h jerasure.h
reed_sol_time_gf: reed_sol_time_gf.o galois.o ${LIBDIR}/gf_complete.a jerasure.o reed_sol.o
$(CC) $(CFLAGS) -o reed_sol_time_gf reed_sol_time_gf.o reed_sol.o jerasure.o galois.o ${LIBDIR}/gf_complete.a
reed_sol_time_gf: reed_sol_time_gf.o galois.o jerasure.o reed_sol.o
$(CC) $(CFLAGS) -o reed_sol_time_gf reed_sol_time_gf.o reed_sol.o jerasure.o galois.o -lgf_complete
reed_sol_hard_time_gf.o: galois.h reed_sol.h jerasure.h
reed_sol_hard_time_gf: reed_sol_hard_time_gf.o galois.o jerasure.o reed_sol.o
$(CC) $(CFLAGS) -o reed_sol_hard_time_gf reed_sol_hard_time_gf.o reed_sol.o jerasure.o galois.o -lgf_complete

361
Examples/reed_sol_hard_time_gf.c Normal file
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@ -0,0 +1,361 @@
/* *
* Copyright (c) 2013, James S. Plank and Kevin Greenan
* All rights reserved.
*
* Jerasure - A C/C++ Library for a Variety of Reed-Solomon and RAID-6 Erasure
* Coding Techniques
*
* Revision 2.0: Galois Field backend now links to GF-Complete
*
* 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 the University of Tennessee 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
* HOLDER 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <gf_complete.h>
#include "jerasure.h"
#include "reed_sol.h"
#define BUFSIZE 4096
int get_gfp_from_argv(gf_t **gfp, int w, int argc, char **argv, int starting)
{
int mult_type, divide_type, region_type;
int arg1, arg2, subrg_size, degree;
uint64_t prim_poly;
gf_t *base;
char *crt, *x, *y;
mult_type = GF_MULT_DEFAULT;
region_type = GF_REGION_DEFAULT;
divide_type = GF_DIVIDE_DEFAULT;
prim_poly = 0;
base = NULL;
arg1 = 0;
arg2 = 0;
degree = 0;
while (1) {
if (argc > starting) {
if (strcmp(argv[starting], "-m") == 0) {
starting++;
if (mult_type != GF_MULT_DEFAULT) {
if (base != NULL) gf_free(base, 1);
return 0;
}
if (strcmp(argv[starting], "SHIFT") == 0) {
mult_type = GF_MULT_SHIFT;
starting++;
} else if (strcmp(argv[starting], "CARRY_FREE") == 0) {
mult_type = GF_MULT_CARRY_FREE;
starting++;
} else if (strcmp(argv[starting], "GROUP") == 0) {
mult_type = GF_MULT_GROUP;
if (argc < starting + 3) {
return 0;
}
if (sscanf(argv[starting+1], "%d", &arg1) == 0 ||
sscanf(argv[starting+2], "%d", &arg2) == 0) {
return 0;
}
starting += 3;
} else if (strcmp(argv[starting], "BYTWO_p") == 0) {
mult_type = GF_MULT_BYTWO_p;
starting++;
} else if (strcmp(argv[starting], "BYTWO_b") == 0) {
mult_type = GF_MULT_BYTWO_b;
starting++;
} else if (strcmp(argv[starting], "TABLE") == 0) {
mult_type = GF_MULT_TABLE;
starting++;
} else if (strcmp(argv[starting], "LOG") == 0) {
mult_type = GF_MULT_LOG_TABLE;
starting++;
} else if (strcmp(argv[starting], "LOG_ZERO") == 0) {
mult_type = GF_MULT_LOG_ZERO;
starting++;
} else if (strcmp(argv[starting], "LOG_ZERO_EXT") == 0) {
mult_type = GF_MULT_LOG_ZERO_EXT;
starting++;
} else if (strcmp(argv[starting], "SPLIT") == 0) {
mult_type = GF_MULT_SPLIT_TABLE;
if (argc < starting + 3) {
return 0;
}
if (sscanf(argv[starting+1], "%d", &arg1) == 0 ||
sscanf(argv[starting+2], "%d", &arg2) == 0) {
return 0;
}
starting += 3;
} else if (strcmp(argv[starting], "COMPOSITE") == 0) {
mult_type = GF_MULT_COMPOSITE;
if (argc < starting + 2) { return 0; }
if (sscanf(argv[starting+1], "%d", &arg1) == 0) {
return 0;
}
starting += 2;
degree = arg1;
starting = get_gfp_from_argv(&base, w/degree, argc, argv, starting);
if (starting == 0) {
free(base);
return 0;
}
} else {
if (base != NULL) gf_free(base, 1);
return 0;
}
} else if (strcmp(argv[starting], "-r") == 0) {
starting++;
if (strcmp(argv[starting], "DOUBLE") == 0) {
region_type |= GF_REGION_DOUBLE_TABLE;
starting++;
} else if (strcmp(argv[starting], "QUAD") == 0) {
region_type |= GF_REGION_QUAD_TABLE;
starting++;
} else if (strcmp(argv[starting], "LAZY") == 0) {
region_type |= GF_REGION_LAZY;
starting++;
} else if (strcmp(argv[starting], "SSE") == 0) {
region_type |= GF_REGION_SSE;
starting++;
} else if (strcmp(argv[starting], "NOSSE") == 0) {
region_type |= GF_REGION_NOSSE;
starting++;
} else if (strcmp(argv[starting], "CAUCHY") == 0) {
region_type |= GF_REGION_CAUCHY;
starting++;
} else if (strcmp(argv[starting], "ALTMAP") == 0) {
region_type |= GF_REGION_ALTMAP;
starting++;
} else {
if (base != NULL) gf_free(base, 1);
return 0;
}
} else if (strcmp(argv[starting], "-p") == 0) {
starting++;
if (sscanf(argv[starting], "%llx", (long long unsigned int *)(&prim_poly)) == 0) {
if (base != NULL) gf_free(base, 1);
return 0;
}
starting++;
} else if (strcmp(argv[starting], "-d") == 0) {
starting++;
if (divide_type != GF_DIVIDE_DEFAULT) {
if (base != NULL) gf_free(base, 1);
return 0;
} else if (strcmp(argv[starting], "EUCLID") == 0) {
divide_type = GF_DIVIDE_EUCLID;
starting++;
} else if (strcmp(argv[starting], "MATRIX") == 0) {
divide_type = GF_DIVIDE_MATRIX;
starting++;
} else {
return 0;
}
} else if (strcmp(argv[starting], "-") == 0) {
if (mult_type == GF_MULT_COMPOSITE) {
*gfp = galois_init_composite_field(w, region_type, divide_type, degree, base);
} else {
*gfp = galois_init_field(w, mult_type, region_type, divide_type, prim_poly, arg1, arg2);
}
starting++;
break;
} else {
if (base != NULL) gf_free(base, 1);
return 0;
}
}
}
return starting;
}
static void *malloc16(int size) {
void *mem = malloc(size+16+sizeof(void*));
void **ptr = (void**)((long)(mem+16+sizeof(void*)) & ~(15));
ptr[-1] = mem;
return ptr;
}
static void free16(void *ptr) {
free(((void**)ptr)[-1]);
}
#define talloc(type, num) (type *) malloc16(sizeof(type)*(num))
void
timer_start (double *t)
{
struct timeval tv;
gettimeofday (&tv, NULL);
*t = (double)tv.tv_sec + (double)tv.tv_usec * 1e-6;
}
double
timer_split (const double *t)
{
struct timeval tv;
double cur_t;
gettimeofday (&tv, NULL);
cur_t = (double)tv.tv_sec + (double)tv.tv_usec * 1e-6;
return (cur_t - *t);
}
usage(char *s)
{
fprintf(stderr, "usage: reed_sol_hard_test_gf k m w [additional GF args]- Test and time Reed-Solomon in a particular GF(2^w).\n");
fprintf(stderr, " \n");
fprintf(stderr, " w must be 8, 16 or 32. k+m must be <= 2^w.\n");
fprintf(stderr, " See the README for information on the additional GF args.\n");
fprintf(stderr, " Set up a Vandermonde-based distribution matrix and encodes k devices of\n");
fprintf(stderr, " %d bytes each with it. Then it decodes.\n", BUFSIZE);
fprintf(stderr, " \n");
fprintf(stderr, "This tests: jerasure_matrix_encode()\n");
fprintf(stderr, " jerasure_matrix_decode()\n");
fprintf(stderr, " jerasure_print_matrix()\n");
fprintf(stderr, " galois_init_composite_field()\n");
fprintf(stderr, " galois_init_field()\n");
fprintf(stderr, " galois_change_technique()\n");
fprintf(stderr, " reed_sol_vandermonde_coding_matrix()\n");
if (s != NULL) fprintf(stderr, "%s\n", s);
exit(1);
}
static void fill_buffer(unsigned char *buf, int size)
{
int i;
buf[0] = (char)(lrand48() % 256);
for (i=1; i < size; i++) {
buf[i] = ((buf[i-1] + i) % 256);
}
}
int main(int argc, char **argv)
{
long l;
int k, w, i, j, m, iterations, bufsize;
int *matrix;
char **data, **coding, **old_values;
int *erasures, *erased;
int *decoding_matrix, *dm_ids;
double t = 0, total_time = 0;
gf_t *gf = NULL;
int ret = 0;
if (argc < 6) usage(NULL);
if (sscanf(argv[1], "%d", &k) == 0 || k <= 0) usage("Bad k");
if (sscanf(argv[2], "%d", &m) == 0 || m <= 0) usage("Bad m");
if (sscanf(argv[3], "%d", &w) == 0 || (w != 8 && w != 16 && w != 32)) usage("Bad w");
if (sscanf(argv[4], "%d", &iterations) == 0) usage("Bad iterations");
if (sscanf(argv[5], "%d", &bufsize) == 0) usage("Bad bufsize");
if (w <= 16 && k + m > (1 << w)) usage("k + m is too big");
srand48(time(0));
ret = get_gfp_from_argv(&gf, w, argc, argv, 6);
if (ret == 0 || gf == NULL) {
usage("Invalid arguments given for GF!\n");
}
galois_change_technique(gf, w);
matrix = reed_sol_vandermonde_coding_matrix(k, m, w);
printf("Last m rows of the Distribution Matrix:\n\n");
jerasure_print_matrix(matrix, m, k, w);
printf("\n");
data = talloc(char *, k);
for (i = 0; i < k; i++) {
data[i] = talloc(char, bufsize);
fill_buffer(data[i], bufsize);
}
coding = talloc(char *, m);
old_values = talloc(char *, m);
for (i = 0; i < m; i++) {
coding[i] = talloc(char, bufsize);
old_values[i] = talloc(char, bufsize);
}
for (i = 0; i < iterations; i++) {
timer_start(&t);
jerasure_matrix_encode(k, m, w, matrix, data, coding, bufsize);
total_time += timer_split(&t);
}
fprintf(stderr, "Encode thput for %d iterations: %.2f MB/s (%.2f sec)\n", iterations, (double)(k*iterations*bufsize/1024/1024) / total_time, total_time);
erasures = talloc(int, (m+1));
erased = talloc(int, (k+m));
for (i = 0; i < m+k; i++) erased[i] = 0;
l = 0;
for (i = 0; i < m; ) {
erasures[i] = ((unsigned int)lrand48())%(k+m);
if (erased[erasures[i]] == 0) {
erased[erasures[i]] = 1;
memcpy(old_values[i], (erasures[i] < k) ? data[erasures[i]] : coding[erasures[i]-k], bufsize);
bzero((erasures[i] < k) ? data[erasures[i]] : coding[erasures[i]-k], bufsize);
i++;
}
}
erasures[i] = -1;
for (i = 0; i < iterations; i++) {
timer_start(&t);
jerasure_matrix_decode(k, m, w, matrix, 1, erasures, data, coding, bufsize);
total_time += timer_split(&t);
}
fprintf(stderr, "Decode thput for %d iterations: %.2f MB/s (%.2f sec)\n", iterations, (double)(m*iterations*bufsize/1024/1024) / total_time, total_time);
for (i = 0; i < m; i++) {
if (erasures[i] < k) {
if (memcmp(data[erasures[i]], old_values[i], bufsize)) {
fprintf(stderr, "Decoding failed for %d!\n", erasures[i]);
exit(1);
}
} else {
if (memcmp(coding[erasures[i]-k], old_values[i], bufsize)) {
fprintf(stderr, "Decoding failed for %d!\n", erasures[i]);
exit(1);
}
}
}
return 0;
}

0
Examples/time_all_gfs.sh → Examples/time_all_gfs_argv_init.sh
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92
Examples/time_all_gfs_hard_init.sh Executable file
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@ -0,0 +1,92 @@
#
#
# Copyright (c) 2013, James S. Plank and Kevin Greenan
# All rights reserved.
#
# Jerasure - A C/C++ Library for a Variety of Reed-Solomon and RAID-6 Erasure
# Coding Techniques
#
# Revision 2.0: Galois Field backend now links to GF-Complete
#
# 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 the University of Tennessee 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
# HOLDER 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.
#
GF_COMPLETE_DIR=/usr/local/bin
GF_METHODS=${GF_COMPLETE_DIR}/gf_methods
ITERATIONS=128
BUFSIZE=65536
k=12
m=3
# Test all w=8
${GF_METHODS} | awk -F: '{ if ($1 == "w=8") print $2; }' |
while read method; do
echo "Testing ${k} ${m} 8 ${ITERATIONS} ${BUFSIZE} ${method}"
./reed_sol_hard_time_gf ${k} ${m} 8 ${ITERATIONS} ${BUFSIZE} ${method}
if [[ $? != "0" ]]; then
echo "Failed test for ${k} ${m} 8 ${ITERATIONS} ${BUFSIZE} ${method}"
exit 1
fi
done
if [[ $? == "1" ]]; then
exit 1
fi
# Test all w=16
${GF_METHODS} | grep -v 'TABLE' | awk -F: '{ if ($1 == "w=16") print $2; }' |
while read method; do
echo "Testing ${k} ${m} 16 ${ITERATIONS} ${BUFSIZE} ${method}"
./reed_sol_hard_time_gf ${k} ${m} 16 ${ITERATIONS} ${BUFSIZE} ${method}
if [[ $? != "0" ]]; then
echo "Failed test for ${k} ${m} 16 ${ITERATIONS} ${BUFSIZE} ${method}"
exit 1
fi
done
if [[ $? == "1" ]]; then
exit 1
fi
# Test all w=32
${GF_METHODS} | awk -F: '{ if ($1 == "w=32") print $2; }' |
while read method; do
echo "Testing ${k} ${m} 32 ${ITERATIONS} ${BUFSIZE} ${method}"
./reed_sol_hard_time_gf ${k} ${m} 32 ${ITERATIONS} ${BUFSIZE} ${method}
if [[ $? != "0" ]]; then
echo "Failed test for ${k} ${m} 32 ${ITERATIONS} ${BUFSIZE} ${method}"
exit 1
fi
done
if [[ $? == "1" ]]; then
exit 1
fi
echo "Passed all tests!"

110
README.nd
View File

@ -29,4 +29,112 @@ determine the default field to use, if one is not specified.
If you would like to explore a using a different Galois Field implementation,
you can dynamically set the backend GF for a given word-size (w).
<TBD - Add instructions>
The new galois.[ch] exports the following functions to be used by applications
for dynamically setting the backend GF:
1.) galois_change_technique
Function signature:
void galois_change_technique(gf_t *gf, int w);
This function will take a pointer to a Galois field structure and set it as the
current backend for all operations in GF(2^w). Note that you must specify 'w'
here, since the internal GF structure is mostly opaque to Jerasure. Be sure to
change the technique with the correct structure and word-size.
There are a few ways to get a pointer to a gf_t structure: via GF-Complete or
using the helper functions provided by Jerasure: galois_init_field and
galois_init_composite_field.
GF-Complete exposes create_gf_from_argv, gf_init_easy and gf_init_hard. See
the GF-Complete documentation for more detail on how to use those functions.
You can definitely create more complicated fields with the GF-Complete
initialization functions, but the two helper functions provided by Jerasure
(galois_init_field and galois_init_composite_field) can be used to create most
of the supported Galois Fields.
2.) galois_init_field
Function signature:
gf_t* galois_init_field(int w,
int mult_type,
int region_type,
int divide_type,
uint64_t prim_poly,
int arg1,
int arg2);
This is a helper function that will initialize a Galois field. See the GF-Complete
documentation for more info on what the arguments mean. Here is a brief description
of the arguments:
mult_type can be any *one* of the following:
GF_MULT_DEFAULT
GF_MULT_SHIFT
GF_MULT_CARRY_FREE
GF_MULT_GROUP
GF_MULT_BYTWO_p
GF_MULT_BYTWO_b
GF_MULT_TABLE
GF_MULT_LOG_TABLE
GF_MULT_LOG_ZERO
GF_MULT_LOG_ZERO_EXT
GF_MULT_SPLIT_TABLE
region_type can be a combination of the following (some combinations will not
be valid):
GF_REGION_DEFAULT
GF_REGION_DOUBLE_TABLE
GF_REGION_QUAD_TABLE
GF_REGION_LAZY
GF_REGION_SSE
GF_REGION_NOSSE
GF_REGION_ALTMAP
GF_REGION_CAUCHY
divide_type can be one of the following:
GF_DIVIDE_DEFAULT
GF_DIVIDE_MATRIX
GF_DIVIDE_EUCLID
prim_poly is the field-defining primitive polynomial
arg1 and arg2 are special arguments usually used for defining SPLIT and GROUP
operations
3.) galois_init_composite_field
Function signature:
gf_t* galois_init_composite_field(int w,
int region_type,
int divide_type,
int degree,
gf_t* base_gf);
This is a helper function designed to make creating Composite fields easier. All you
need to do is hand it w, region mult type, divide type, degree and a pointer to a base
field. Note that the base_gf must have degree w/degree in order for this to work.
For example, if we create a GF using:
galois_init_composite_field(32, GF_REGION_DEFAULT, GF_DIVIDE_DEFAULT, 2, base_gf);
Then base_gf must have w=16.
For more information on how to change the backing fields for Jerasure, please refer to
1.) Examples/reed_sol_test_gf.c: Runs basic tests for Reed-Solomon given args
for a backing GF (uses create_gf_from_argv to get gf_t pointer)
2.) Examples/reed_sol_time_gf.c: Runs more thorough timing and validation tests
for a backing GF (uses create_gf_from_argv to get gf_t pointer)
3.) Examples/reed_sol_hard_time_gf.c: Runs more thorough timing and validation tests
for a backing GF (uses galois_init_field and galois_init_composite_field to get gf_t
pointer)

110
README.txt
View File

@ -29,4 +29,112 @@ determine the default field to use, if one is not specified.
If you would like to explore a using a different Galois Field implementation,
you can dynamically set the backend GF for a given word-size (w).
<TBD - Add instructions>
The new galois.[ch] exports the following functions to be used by applications
for dynamically setting the backend GF:
1.) galois_change_technique
Function signature:
void galois_change_technique(gf_t *gf, int w);
This function will take a pointer to a Galois field structure and set it as the
current backend for all operations in GF(2^w). Note that you must specify 'w'
here, since the internal GF structure is mostly opaque to Jerasure. Be sure to
change the technique with the correct structure and word-size.
There are a few ways to get a pointer to a gf_t structure: via GF-Complete or
using the helper functions provided by Jerasure: galois_init_field and
galois_init_composite_field.
GF-Complete exposes create_gf_from_argv, gf_init_easy and gf_init_hard. See
the GF-Complete documentation for more detail on how to use those functions.
You can definitely create more complicated fields with the GF-Complete
initialization functions, but the two helper functions provided by Jerasure
(galois_init_field and galois_init_composite_field) can be used to create most
of the supported Galois Fields.
2.) galois_init_field
Function signature:
gf_t* galois_init_field(int w,
int mult_type,
int region_type,
int divide_type,
uint64_t prim_poly,
int arg1,
int arg2);
This is a helper function that will initialize a Galois field. See the GF-Complete
documentation for more info on what the arguments mean. Here is a brief description
of the arguments:
mult_type can be any *one* of the following:
GF_MULT_DEFAULT
GF_MULT_SHIFT
GF_MULT_CARRY_FREE
GF_MULT_GROUP
GF_MULT_BYTWO_p
GF_MULT_BYTWO_b
GF_MULT_TABLE
GF_MULT_LOG_TABLE
GF_MULT_LOG_ZERO
GF_MULT_LOG_ZERO_EXT
GF_MULT_SPLIT_TABLE
region_type can be a combination of the following (some combinations will not
be valid):
GF_REGION_DEFAULT
GF_REGION_DOUBLE_TABLE
GF_REGION_QUAD_TABLE
GF_REGION_LAZY
GF_REGION_SSE
GF_REGION_NOSSE
GF_REGION_ALTMAP
GF_REGION_CAUCHY
divide_type can be one of the following:
GF_DIVIDE_DEFAULT
GF_DIVIDE_MATRIX
GF_DIVIDE_EUCLID
prim_poly is the field-defining primitive polynomial
arg1 and arg2 are special arguments usually used for defining SPLIT and GROUP
operations
3.) galois_init_composite_field
Function signature:
gf_t* galois_init_composite_field(int w,
int region_type,
int divide_type,
int degree,
gf_t* base_gf);
This is a helper function designed to make creating Composite fields easier. All you
need to do is hand it w, region mult type, divide type, degree and a pointer to a base
field. Note that the base_gf must have degree w/degree in order for this to work.
For example, if we create a GF using:
galois_init_composite_field(32, GF_REGION_DEFAULT, GF_DIVIDE_DEFAULT, 2, base_gf);
Then base_gf must have w=16.
For more information on how to change the backing fields for Jerasure, please refer to
1.) Examples/reed_sol_test_gf.c: Runs basic tests for Reed-Solomon given args
for a backing GF (uses create_gf_from_argv to get gf_t pointer)
2.) Examples/reed_sol_time_gf.c: Runs more thorough timing and validation tests
for a backing GF (uses create_gf_from_argv to get gf_t pointer)
3.) Examples/reed_sol_hard_time_gf.c: Runs more thorough timing and validation tests
for a backing GF (uses galois_init_field and galois_init_composite_field to get gf_t
pointer)

88
galois.c
View File

@ -44,8 +44,9 @@
#include "galois.h"
#define MAX_GF_INSTANCES 128
#define MAX_GF_INSTANCES 64
gf_t *gfp_array[MAX_GF_INSTANCES] = { 0 };
int gfp_is_composite[MAX_GF_INSTANCES] = { 0 };
gf_t *galois_get_field_ptr(int w)
{
@ -56,23 +57,29 @@ gf_t *galois_get_field_ptr(int w)
return NULL;
}
int galois_init_base_field(int w,
int mult_type,
int region_type,
int divide_type,
uint64_t prim_poly,
int arg1,
int arg2)
gf_t* galois_init_field(int w,
int mult_type,
int region_type,
int divide_type,
uint64_t prim_poly,
int arg1,
int arg2)
{
int scratch_size;
void *scratch_memory;
int ret;
gf_t *gfp;
if (w <= 0 || w > 32) {
fprintf(stderr, "ERROR -- cannot init default Galois field for w=%d\n", w);
exit(1);
}
gfp = (gf_t *) malloc(sizeof(gf_t));
if (!gfp) {
fprintf(stderr, "ERROR -- cannot allocate memory for Galois field w=%d\n", w);
exit(1);
}
scratch_size = gf_scratch_size(w, mult_type, region_type, divide_type, arg1, arg2);
if (!scratch_size) {
fprintf(stderr, "ERROR -- cannot get scratch size for base field w=%d\n", w);
@ -85,20 +92,7 @@ int galois_init_base_field(int w,
exit(1);
}
/*
* Properly free up the old field
*/
if (gfp_array[w] != NULL) {
gf_free(gfp_array[w], 0);
}
gfp_array[w] = (gf_t*)malloc(sizeof(gf_t));
if (gfp_array[w] == NULL) {
fprintf(stderr, "ERROR -- cannot allocate memory for Galois field w=%d\n", w);
exit(1);
}
if(!gf_init_hard(gfp_array[w],
if(!gf_init_hard(gfp,
w,
mult_type,
region_type,
@ -112,27 +106,33 @@ int galois_init_base_field(int w,
fprintf(stderr, "ERROR -- cannot init default Galois field for w=%d\n", w);
exit(1);
}
return 0;
gfp_is_composite[w] = 0;
return gfp;
}
int galois_init_composite_field(int w,
gf_t* galois_init_composite_field(int w,
int region_type,
int divide_type,
uint64_t prim_poly,
int arg1,
int arg2,
int degree,
gf_t* base_gf)
{
int scratch_size;
void *scratch_memory;
int ret;
gf_t *gfp;
if (w <= 0 || w > 32) {
fprintf(stderr, "ERROR -- cannot init composite field for w=%d\n", w);
exit(1);
}
gfp = (gf_t *) malloc(sizeof(gf_t));
if (!gfp) {
fprintf(stderr, "ERROR -- cannot allocate memory for Galois field w=%d\n", w);
exit(1);
}
scratch_size = gf_scratch_size(w, GF_MULT_COMPOSITE, region_type, divide_type, arg1, arg2);
scratch_size = gf_scratch_size(w, GF_MULT_COMPOSITE, region_type, divide_type, degree, 0);
if (!scratch_size) {
fprintf(stderr, "ERROR -- cannot get scratch size for composite field w=%d\n", w);
exit(1);
@ -144,34 +144,22 @@ int galois_init_composite_field(int w,
exit(1);
}
/*
* Properly free up the old field
*/
if (gfp_array[w] != NULL) {
gf_free(gfp_array[w], 1);
}
gfp_array[w] = (gf_t*)malloc(sizeof(gf_t));
if (gfp_array[w] == NULL) {
fprintf(stderr, "ERROR -- cannot allocate memory for composite field w=%d\n", w);
exit(1);
}
if(!gf_init_hard(gfp_array[w],
if(!gf_init_hard(gfp,
w,
GF_MULT_COMPOSITE,
region_type,
divide_type,
prim_poly,
arg1,
arg2,
0,
degree,
0,
base_gf,
scratch_memory))
{
fprintf(stderr, "ERROR -- cannot init default composite field for w=%d\n", w);
exit(1);
}
return 0;
gfp_is_composite[w] = 1;
return gfp;
}
static void galois_init_default_field(int w)
@ -237,6 +225,10 @@ void galois_change_technique(gf_t *gf, int w)
exit(1);
}
if (gfp_array[w] != NULL) {
gf_free(gfp_array[w], gfp_is_composite[w]);
}
gfp_array[w] = gf;
}

20
galois.h
View File

@ -80,20 +80,18 @@ void galois_w32_region_multiply(char *region, /* Region to multiply */
Otherwise region is overwritten */
int add); /* If (r2 != NULL && add) the produce is XOR'd with r2 */
int galois_init_base_field(int w,
int mult_type,
int region_type,
int divide_type,
uint64_t prim_poly,
int arg1,
int arg2);
gf_t* galois_init_field(int w,
int mult_type,
int region_type,
int divide_type,
uint64_t prim_poly,
int arg1,
int arg2);
int galois_init_composite_field(int w,
gf_t* galois_init_composite_field(int w,
int region_type,
int divide_type,
uint64_t prim_poly,
int arg1,
int arg2,
int degree,
gf_t* base_gf);
gf_t * galois_get_field_ptr(int w);