1 files changed, 107 insertions, 0 deletions
diff --git a/src/erasure-code/jerasure/gf-complete/examples/gf_example_2.c b/src/erasure-code/jerasure/gf-complete/examples/gf_example_2.c
new file mode 100644
index 000000000..576d9a534
--- /dev/null
+++ b/src/erasure-code/jerasure/gf-complete/examples/gf_example_2.c
@@ -0,0 +1,107 @@
+/*
+ * GF-Complete: A Comprehensive Open Source Library for Galois Field Arithmetic
+ * James S. Plank, Ethan L. Miller, Kevin M. Greenan,
+ * Benjamin A. Arnold, John A. Burnum, Adam W. Disney, Allen C. McBride.
+ *
+ * gf_example_2.c
+ *
+ * Demonstrates using the procedures for examples in GF(2^w) for w <= 32.
+ */
+
+#include <stdio.h>
+#include <getopt.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdlib.h>
+#include <time.h>
+
+#include "gf_complete.h"
+#include "gf_rand.h"
+
+void usage(char *s)
+{
+  fprintf(stderr, "usage: gf_example_2 w - w must be between 1 and 32\n");
+  exit(1);
+}
+
+int main(int argc, char **argv)
+{
+  uint32_t a, b, c;
+  uint8_t *r1, *r2;
+  uint16_t *r16 = NULL;
+  uint32_t *r32 = NULL;
+  int w, i;
+  gf_t gf;
+
+  if (argc != 2) usage(NULL);
+  w = atoi(argv[1]);
+  if (w <= 0 || w > 32) usage("Bad w");
+
+  /* Get two random numbers in a and b */
+
+  MOA_Seed(time(0));
+  a = MOA_Random_W(w, 0);
+  b = MOA_Random_W(w, 0);
+
+  /* Create the proper instance of the gf_t object using defaults: */
+
+  gf_init_easy(&gf, w);
+
+  /* And multiply a and b using the galois field: */
+
+  c = gf.multiply.w32(&gf, a, b);
+  printf("%u * %u = %u\n", a, b, c);
+
+  /* Divide the product by a and b */
+
+  printf("%u / %u = %u\n", c, a, gf.divide.w32(&gf, c, a));
+  printf("%u / %u = %u\n", c, b, gf.divide.w32(&gf, c, b));
+
+  /* If w is 4, 8, 16 or 32, do a very small region operation */
+
+  if (w == 4 || w == 8 || w == 16 || w == 32) {
+    r1 = (uint8_t *) malloc(16);
+    r2 = (uint8_t *) malloc(16);
+
+    if (w == 4 || w == 8) {
+      r1[0] = b;
+      for (i = 1; i < 16; i++) r1[i] = MOA_Random_W(8, 1);
+    } else if (w == 16) {
+      r16 = (uint16_t *) r1;
+      r16[0] = b;
+      for (i = 1; i < 8; i++) r16[i] = MOA_Random_W(16, 1);
+    } else {
+      r32 = (uint32_t *) r1;
+      r32[0] = b;
+      for (i = 1; i < 4; i++) r32[i] = MOA_Random_W(32, 1);
+    }
+
+    gf.multiply_region.w32(&gf, r1, r2, a, 16, 0);
+  
+    printf("\nmultiply_region by 0x%x (%u)\n\n", a, a);
+    printf("R1 (the source):  ");
+    if (w == 4) {
+      for (i = 0; i < 16; i++) printf(" %x %x", r1[i] >> 4, r1[i] & 0xf);
+    } else if (w == 8) {
+      for (i = 0; i < 16; i++) printf(" %02x", r1[i]);
+    } else if (w == 16) {
+      for (i = 0; i < 8; i++) printf(" %04x", r16[i]);
+    } else if (w == 32) {
+      for (i = 0; i < 4; i++) printf(" %08x", r32[i]);
+    }
+    printf("\nR2 (the product): ");
+    if (w == 4) {
+      for (i = 0; i < 16; i++) printf(" %x %x", r2[i] >> 4, r2[i] & 0xf);
+    } else if (w == 8) {
+      for (i = 0; i < 16; i++) printf(" %02x", r2[i]);
+    } else if (w == 16) {
+      r16 = (uint16_t *) r2;
+      for (i = 0; i < 8; i++) printf(" %04x", r16[i]);
+    } else if (w == 32) {
+      r32 = (uint32_t *) r2;
+      for (i = 0; i < 4; i++) printf(" %08x", r32[i]);
+    }
+    printf("\n");
+  }
+  exit(0);
+}