cksum.c code cleanup

[Paul Eggert]

I installed this; it doesn't change any behavior but cleans things up
a bit.

2004-09-18  Paul Eggert  <address@hidden>

        * src/cksum.c: Remove obsolete comment about POSIX 1003.2/D11.2.
        The current standard (POSIX 1003.1-2004) is correct.
        (crc_remainder) [defined CRCTAB]: Renamed from "remainder" to avoid
        collision with builtin function.
        (main) [defined CRCTAB]: Output in lowercase hexadecimal, and
        output the first 0 as 8 digits, to make it easier to compare to
        the text of the standard.  Output crctab to be a const array.
        (crctab): Use result of above changes.
        (long_options): Remove; not needed if empty.
        (main): getopt_long can't return 0 here, so simplify the code.

Index: cksum.c
===================================================================
RCS file: /home/eggert/coreutils/cu/src/cksum.c,v
retrieving revision 1.70
retrieving revision 1.71
diff -p -u -r1.70 -r1.71
--- cksum.c     30 Jul 2004 04:12:25 -0000      1.70
+++ cksum.c     19 Sep 2004 00:39:52 -0000      1.71
@@ -23,22 +23,15 @@
   The code segment between "#ifdef CRCTAB" and "#else" is the code
   which calculates the "crctab". It is included for those who want
   verify the correctness of the "crctab". To recreate the "crctab",
-  do following:
+  do something like the following:
 
       cc -DCRCTAB -o crctab cksum.c
       crctab > crctab.h
 
-  As Bruce Evans pointed out to me, the crctab in the sample C code
-  in 4.9.10 Rationale of P1003.2/D11.2 is represented in reversed order.
-  Namely, 0x01 is represented as 0x80, 0x02 is represented as 0x40, etc.
-  The generating polynomial is crctab[0x80]=0xedb88320 instead of
-  crctab[1]=0x04C11DB7.  But the code works only for a non-reverse order
-  crctab.  Therefore, the sample implementation is wrong.
-
   This software is compatible with neither the System V nor the BSD
-  `sum' program.  It is supposed to conform to P1003.2/D11.2,
-  except foreign language interface (4.9.5.3 of P1003.2/D11.2) support.
-  Any inconsistency with the standard except 4.9.5.3 is a bug.  */
+  `sum' program.  It is supposed to conform to POSIX, except perhaps
+  for foreign language support.  Any inconsistency with the standard
+  (other than foreign language support) is a bug.  */
 
 #include <config.h>
 
@@ -84,7 +77,7 @@ fill_r (void)
 }
 
 static uint_fast32_t
-remainder (int m)
+crc_remainder (int m)
 {
   uint_fast32_t rem = 0;
   int i;
@@ -102,13 +95,13 @@ main (void)
   int i;
 
   fill_r ();
-  printf ("static uint_fast32_t crctab[256] =\n{\n  0x0");
+  printf ("static uint_fast32_t const crctab[256] =\n{\n  0x00000000");
   for (i = 0; i < 51; i++)
     {
-      printf (",\n  0x%08X, 0x%08X, 0x%08X, 0x%08X, 0x%08X",
-             remainder (i * 5 + 1), remainder (i * 5 + 2),
-             remainder (i * 5 + 3), remainder (i * 5 + 4),
-             remainder (i * 5 + 5));
+      printf (",\n  0x%08x, 0x%08x, 0x%08x, 0x%08x, 0x%08x",
+             crc_remainder (i * 5 + 1), crc_remainder (i * 5 + 2),
+             crc_remainder (i * 5 + 3), crc_remainder (i * 5 + 4),
+             crc_remainder (i * 5 + 5));
     }
   printf ("\n};\n");
   exit (EXIT_SUCCESS);
@@ -127,65 +120,60 @@ main (void)
 /* The name this program was run with.  */
 char *program_name;
 
-static struct option const long_options[] =
+static uint_fast32_t const crctab[256] =
 {
-  {0, 0, 0, 0}
-};
-
-static uint_fast32_t crctab[256] =
-{
-  0x0,
-  0x04C11DB7, 0x09823B6E, 0x0D4326D9, 0x130476DC, 0x17C56B6B,
-  0x1A864DB2, 0x1E475005, 0x2608EDB8, 0x22C9F00F, 0x2F8AD6D6,
-  0x2B4BCB61, 0x350C9B64, 0x31CD86D3, 0x3C8EA00A, 0x384FBDBD,
-  0x4C11DB70, 0x48D0C6C7, 0x4593E01E, 0x4152FDA9, 0x5F15ADAC,
-  0x5BD4B01B, 0x569796C2, 0x52568B75, 0x6A1936C8, 0x6ED82B7F,
-  0x639B0DA6, 0x675A1011, 0x791D4014, 0x7DDC5DA3, 0x709F7B7A,
-  0x745E66CD, 0x9823B6E0, 0x9CE2AB57, 0x91A18D8E, 0x95609039,
-  0x8B27C03C, 0x8FE6DD8B, 0x82A5FB52, 0x8664E6E5, 0xBE2B5B58,
-  0xBAEA46EF, 0xB7A96036, 0xB3687D81, 0xAD2F2D84, 0xA9EE3033,
-  0xA4AD16EA, 0xA06C0B5D, 0xD4326D90, 0xD0F37027, 0xDDB056FE,
-  0xD9714B49, 0xC7361B4C, 0xC3F706FB, 0xCEB42022, 0xCA753D95,
-  0xF23A8028, 0xF6FB9D9F, 0xFBB8BB46, 0xFF79A6F1, 0xE13EF6F4,
-  0xE5FFEB43, 0xE8BCCD9A, 0xEC7DD02D, 0x34867077, 0x30476DC0,
-  0x3D044B19, 0x39C556AE, 0x278206AB, 0x23431B1C, 0x2E003DC5,
-  0x2AC12072, 0x128E9DCF, 0x164F8078, 0x1B0CA6A1, 0x1FCDBB16,
-  0x018AEB13, 0x054BF6A4, 0x0808D07D, 0x0CC9CDCA, 0x7897AB07,
-  0x7C56B6B0, 0x71159069, 0x75D48DDE, 0x6B93DDDB, 0x6F52C06C,
-  0x6211E6B5, 0x66D0FB02, 0x5E9F46BF, 0x5A5E5B08, 0x571D7DD1,
-  0x53DC6066, 0x4D9B3063, 0x495A2DD4, 0x44190B0D, 0x40D816BA,
-  0xACA5C697, 0xA864DB20, 0xA527FDF9, 0xA1E6E04E, 0xBFA1B04B,
-  0xBB60ADFC, 0xB6238B25, 0xB2E29692, 0x8AAD2B2F, 0x8E6C3698,
-  0x832F1041, 0x87EE0DF6, 0x99A95DF3, 0x9D684044, 0x902B669D,
-  0x94EA7B2A, 0xE0B41DE7, 0xE4750050, 0xE9362689, 0xEDF73B3E,
-  0xF3B06B3B, 0xF771768C, 0xFA325055, 0xFEF34DE2, 0xC6BCF05F,
-  0xC27DEDE8, 0xCF3ECB31, 0xCBFFD686, 0xD5B88683, 0xD1799B34,
-  0xDC3ABDED, 0xD8FBA05A, 0x690CE0EE, 0x6DCDFD59, 0x608EDB80,
-  0x644FC637, 0x7A089632, 0x7EC98B85, 0x738AAD5C, 0x774BB0EB,
-  0x4F040D56, 0x4BC510E1, 0x46863638, 0x42472B8F, 0x5C007B8A,
-  0x58C1663D, 0x558240E4, 0x51435D53, 0x251D3B9E, 0x21DC2629,
-  0x2C9F00F0, 0x285E1D47, 0x36194D42, 0x32D850F5, 0x3F9B762C,
-  0x3B5A6B9B, 0x0315D626, 0x07D4CB91, 0x0A97ED48, 0x0E56F0FF,
-  0x1011A0FA, 0x14D0BD4D, 0x19939B94, 0x1D528623, 0xF12F560E,
-  0xF5EE4BB9, 0xF8AD6D60, 0xFC6C70D7, 0xE22B20D2, 0xE6EA3D65,
-  0xEBA91BBC, 0xEF68060B, 0xD727BBB6, 0xD3E6A601, 0xDEA580D8,
-  0xDA649D6F, 0xC423CD6A, 0xC0E2D0DD, 0xCDA1F604, 0xC960EBB3,
-  0xBD3E8D7E, 0xB9FF90C9, 0xB4BCB610, 0xB07DABA7, 0xAE3AFBA2,
-  0xAAFBE615, 0xA7B8C0CC, 0xA379DD7B, 0x9B3660C6, 0x9FF77D71,
-  0x92B45BA8, 0x9675461F, 0x8832161A, 0x8CF30BAD, 0x81B02D74,
-  0x857130C3, 0x5D8A9099, 0x594B8D2E, 0x5408ABF7, 0x50C9B640,
-  0x4E8EE645, 0x4A4FFBF2, 0x470CDD2B, 0x43CDC09C, 0x7B827D21,
-  0x7F436096, 0x7200464F, 0x76C15BF8, 0x68860BFD, 0x6C47164A,
-  0x61043093, 0x65C52D24, 0x119B4BE9, 0x155A565E, 0x18197087,
-  0x1CD86D30, 0x029F3D35, 0x065E2082, 0x0B1D065B, 0x0FDC1BEC,
-  0x3793A651, 0x3352BBE6, 0x3E119D3F, 0x3AD08088, 0x2497D08D,
-  0x2056CD3A, 0x2D15EBE3, 0x29D4F654, 0xC5A92679, 0xC1683BCE,
-  0xCC2B1D17, 0xC8EA00A0, 0xD6AD50A5, 0xD26C4D12, 0xDF2F6BCB,
-  0xDBEE767C, 0xE3A1CBC1, 0xE760D676, 0xEA23F0AF, 0xEEE2ED18,
-  0xF0A5BD1D, 0xF464A0AA, 0xF9278673, 0xFDE69BC4, 0x89B8FD09,
-  0x8D79E0BE, 0x803AC667, 0x84FBDBD0, 0x9ABC8BD5, 0x9E7D9662,
-  0x933EB0BB, 0x97FFAD0C, 0xAFB010B1, 0xAB710D06, 0xA6322BDF,
-  0xA2F33668, 0xBCB4666D, 0xB8757BDA, 0xB5365D03, 0xB1F740B4
+  0x00000000,
+  0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b,
+  0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6,
+  0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
+  0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac,
+  0x5bd4b01b, 0x569796c2, 0x52568b75, 0x6a1936c8, 0x6ed82b7f,
+  0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a,
+  0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
+  0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58,
+  0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033,
+  0xa4ad16ea, 0xa06c0b5d, 0xd4326d90, 0xd0f37027, 0xddb056fe,
+  0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
+  0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4,
+  0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0,
+  0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5,
+  0x2ac12072, 0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
+  0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, 0x7897ab07,
+  0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c,
+  0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1,
+  0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
+  0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b,
+  0xbb60adfc, 0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698,
+  0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d,
+  0x94ea7b2a, 0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
+  0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, 0xc6bcf05f,
+  0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34,
+  0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80,
+  0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
+  0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a,
+  0x58c1663d, 0x558240e4, 0x51435d53, 0x251d3b9e, 0x21dc2629,
+  0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c,
+  0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
+  0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e,
+  0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65,
+  0xeba91bbc, 0xef68060b, 0xd727bbb6, 0xd3e6a601, 0xdea580d8,
+  0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
+  0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2,
+  0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71,
+  0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74,
+  0x857130c3, 0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
+  0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, 0x7b827d21,
+  0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a,
+  0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e, 0x18197087,
+  0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
+  0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d,
+  0x2056cd3a, 0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce,
+  0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb,
+  0xdbee767c, 0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
+  0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, 0x89b8fd09,
+  0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662,
+  0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf,
+  0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
 };
 
 /* Nonzero if any of the files read were the standard input. */
@@ -297,7 +285,7 @@ Print CRC checksum and byte counts of ea
 int
 main (int argc, char **argv)
 {
-  int i, c;
+  int i;
   bool ok;
 
   initialize_main (&argc, &argv);
@@ -313,17 +301,8 @@ main (int argc, char **argv)
 
   have_read_stdin = false;
 
-  while ((c = getopt_long (argc, argv, "", long_options, NULL)) != -1)
-    {
-      switch (c)
-       {
-       case 0:
-         break;
-
-       default:
-         usage (EXIT_FAILURE);
-       }
-    }
+  if (getopt_long (argc, argv, "", NULL, NULL) != -1)
+    usage (EXIT_FAILURE);
 
   if (optind == argc)
     ok = cksum ("-", false);