From: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed, 19 Feb 2025 04:09:10 +0000 (-0800)
Subject: cksum: minor crctab generation cleanups
X-Git-Tag: v9.7~38
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6ac924f31910168512dc93eceb55d0e98e1f0a97;p=thirdparty%2Fcoreutils.git

cksum: minor crctab generation cleanups

* src/cksum.c [CRCTAB]: Include only config.h and stdio.h,
to simplify the crctab-generating code.
[!CRCTAB]: Do not include stdint.h or stdio.h, as cksum.h does it now.
(BIT, r, crc_remainder, main) [CRCTAB]: Use unsigned int, not
uint_fast32_t or uint32_t, as this is good enough for GNU where
unsigned int is guaranteed to be at least 32 bits, and this way we
needn’t worry about mismatches between %08x formats and uint_fast32_t.
(main) [CRCTAB]: Prefer more-local decls.  Do not output
unnecessary directives to include stdint.h or stdio.h.
No need for ‘return EXIT_SUCCESS;’ nowadays.
* src/crctab.c: Regenerate.
---

diff --git a/src/cksum.c b/src/cksum.c
index 17999120de..3381125bdb 100644
--- a/src/cksum.c
+++ b/src/cksum.c
@@ -34,20 +34,11 @@
 
 #include <config.h>
 
-#include <stdio.h>
-#include <sys/types.h>
-#include <stdint.h>
-#include <endian.h>
-#include "system.h"
-
-#ifdef USE_VMULL_CRC32
-# include <sys/auxv.h>
-# include <asm/hwcap.h>
-#endif
-
 #ifdef CRCTAB
 
-# define BIT(x)	((uint_fast32_t) 1 << (x))
+# include <stdio.h>
+
+# define BIT(x)	(1u << (x))
 # define SBIT	BIT (31)
 
 /* The generating polynomial is
@@ -61,7 +52,7 @@
                  | BIT (11) | BIT (10) | BIT (8) | BIT (7) | BIT (5) \
                  | BIT (4) | BIT (2) | BIT (1) | BIT (0))
 
-static uint_fast32_t r[8];
+static unsigned int r[8];
 
 static void
 fill_r (void)
@@ -71,10 +62,10 @@ fill_r (void)
     r[i] = (r[i - 1] << 1) ^ ((r[i - 1] & SBIT) ? GEN : 0);
 }
 
-static uint_fast32_t
+static unsigned int
 crc_remainder (int m)
 {
-  uint_fast32_t rem = 0;
+  unsigned int rem = 0;
 
   for (int i = 0; i < 8; i++)
     if (BIT (i) & m)
@@ -86,15 +77,12 @@ crc_remainder (int m)
 int
 main (void)
 {
-  int i;
-  static uint_fast32_t crctab[8][256];
+  static unsigned int crctab[8][256];
 
   fill_r ();
 
-  for (i = 0; i < 256; i++)
-    {
-      crctab[0][i] = crc_remainder (i);
-    }
+  for (int i = 0; i < 256; i++)
+    crctab[0][i] = crc_remainder (i);
 
   /* CRC(0x11 0x22 0x33 0x44)
      is equal to
@@ -103,28 +91,26 @@ main (void)
      We precompute the CRC values for the offset values into
      separate CRC tables. We can then use them to speed up
      CRC calculation by processing multiple bytes at the time. */
-  for (i = 0; i < 256; i++)
+  for (int i = 0; i < 256; i++)
     {
-      uint32_t crc = 0;
+      unsigned int crc = 0;
 
-      crc = (crc << 8) ^ crctab[0][((crc >> 24) ^ (i & 0xFF)) & 0xFF];
-      for (idx_t offset = 1; offset < 8; offset++)
+      crc = (crc << 8) ^ crctab[0][((crc >> 24) ^ i) & 0xFF];
+      for (int offset = 1; offset < 8; offset++)
         {
-          crc = (crc << 8) ^ crctab[0][((crc >> 24) ^ 0x00) & 0xFF];
-          crctab[offset][i] = crc;
+          crc = (crc << 8) ^ crctab[0][((crc >> 24) ^ 0) & 0xFF];
+          crctab[offset][i] = crc & 0xFFFFFFFF;
         }
     }
 
   printf ("#include <config.h>\n");
-  printf ("#include <stdint.h>\n");
-  printf ("#include <stdio.h>\n");
   printf ("#include \"cksum.h\"\n");
   printf ("\n");
   printf ("uint_fast32_t const crctab[8][256] = {\n");
   for (int y = 0; y < 8; y++)
     {
       printf ("{\n  0x%08x", crctab[y][0]);
-      for (i = 0; i < 51; i++)
+      for (int i = 0; i < 51; i++)
         {
           printf (",\n  0x%08x, 0x%08x, 0x%08x, 0x%08x, 0x%08x",
                   crctab[y][i * 5 + 1], crctab[y][i * 5 + 2],
@@ -134,12 +120,20 @@ main (void)
         printf ("\n},\n");
     }
   printf ("};\n");
-  return EXIT_SUCCESS;
 }
 
 #else /* !CRCTAB */
 
 # include "cksum.h"
+# include <sys/types.h>
+# include <endian.h>
+# include "system.h"
+
+# ifdef USE_VMULL_CRC32
+#  include <sys/auxv.h>
+#  include <asm/hwcap.h>
+# endif
+
 # include "crc.h"
 
 /* Number of bytes to read at once.  */
diff --git a/src/crctab.c b/src/crctab.c
index bf5d884bf7..b8a4d88863 100644
--- a/src/crctab.c
+++ b/src/crctab.c
@@ -1,6 +1,4 @@
 #include <config.h>
-#include <stdint.h>
-#include <stdio.h>
 #include "cksum.h"
 
 uint_fast32_t const crctab[8][256] = {