Rearrange the file tree.

[u/mdw/catacomb] / misc / gfshare-mktab.c

diff --git a/misc/gfshare-mktab.c b/misc/gfshare-mktab.c
new file mode 100644 (file)
index 0000000..9fc073f
--- /dev/null
+++ b/misc/gfshare-mktab.c
@@ -0,0 +1,106 @@
+/* -*-c-*-
+ *
+ * Generate tables for %$\gf{2^8}$% multiplication
+ *
+ * (c) 2000 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of Catacomb.
+ *
+ * Catacomb is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * Catacomb is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with Catacomb; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <mLib/bits.h>
+
+/*----- Magic numbers -----------------------------------------------------*/
+
+#define MOD 0x11d
+
+/*----- Main code ---------------------------------------------------------*/
+
+int main(int argc, char *argv[])
+{
+  octet log[256], alog[256];
+  unsigned x;
+  unsigned i;
+
+  x = 1;
+  for (i = 0; i < 255; i++) {
+    alog[i] = x;
+    log[x] = i;
+    x <<= 1;
+    if (x & 0x100)
+      x ^= MOD;
+  }
+  log[0] = 0;
+  alog[255] = 1;
+
+  fputs("\
+/* -*-c-*-\n\
+ *\n\
+ * Log tables for secret sharing in %$\\gf{2^8}$% [generated]\n\
+ */\n\
+\n\
+#ifndef GFSHARE_TAB_H\n\
+#define GFSHARE_TAB_H\n\
+\n\
+#define GFSHARE_LOG {                                                  \\\n\
+  ", stdout);
+
+  for (i = 0; i < 256; i++) {
+    printf("0x%02x", log[i]);
+    if (i == 255)
+      puts("                   \\\n}\n");
+    else if (i % 8 == 7)
+      fputs(",                 \\\n  ", stdout);
+    else
+      fputs(", ", stdout);
+  }
+
+  fputs("\
+#define GFSHARE_EXP {                                                  \\\n\
+  ", stdout);
+
+  for (i = 0; i < 510; i++) {
+    printf("0x%02x", alog[i % 255]);
+    if (i == 509)
+      puts("                                   \\\n}\n");
+    else if (i % 8 == 7)
+      fputs(",                 \\\n  ", stdout);
+    else
+      fputs(", ", stdout);
+  }
+
+  /* --- Done --- */
+
+  fputs("#endif\n", stdout);
+
+  if (fclose(stdout)) {
+    fprintf(stderr, "error writing data\n");
+    exit(EXIT_FAILURE);
+  }
+
+  return (0);
+}
+
+/*----- That's all, folks -------------------------------------------------*/