X-Git-Url: https://git.dogcows.com/gitweb?a=blobdiff_plain;f=src%2Farith.h;h=2bc5ced92b02b352f7054506194d195f863dbf24;hb=120e96c480fbfc5fa31fba0f59ba1a45953b838e;hp=e8c2ace395734d76b0a710529d806105b674f385;hpb=271ed97494af6cbc0f6f83ed477afa8154e9ec23;p=chaz%2Ftar

diff --git a/src/arith.h b/src/arith.h
index e8c2ace..2bc5ced 100644
--- a/src/arith.h
+++ b/src/arith.h
@@ -1,5 +1,5 @@
-/* Simple arithmetic for numbers greater than a long int, for GNU tar.
-   Copyright (C) 1996, 1997 Free Software Foundation, Inc.
+/* Long integers, for GNU tar.
+   Copyright 1999 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -13,111 +13,15 @@
 
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software Foundation,
-   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
-
-/* Also, see comments at beginning of arith.c.  */
-
-#define BITS_PER_BYTE 8		/* number of bits in each sizeof unit */
-#define BITS_PER_TARLONG 42	/* wanted number of bits in each tarlong */
-
-/* In all cases, tarlong is the proper type for a big number.
-
-   For simulated arithmetic, SUPERDIGIT is the base, TARLONG_FORMAT is the
-   format to print a single super-digit filled with zeroes to the left, and
-   BITS_PER_SUPERDIGIT is the smallest number of bits required to fully
-   represent each super-digit.  LONGS_PER_TARLONG says how many longs are
-   required for a full tarlong, and SIZEOF_TARLONG is the size of a tarlong
-   in bytes.
-
-   For straight compiler arithmetic, SUPERDIGIT is zero and TARLONG_FORMAT
-   is the format to directly print a tarlong (without zero-filling).
-
-   The values of SIZEOF_LONG_LONG and SIZEOF_UNSIGNED_LONG, below, are
-   obtained through the configuration process.  */
-
-#if BITS_PER_BYTE * SIZEOF_UNSIGNED_LONG >= BITS_PER_TARLONG
-# define SUPERDIGIT 0
-# define TARLONG_FORMAT "%uld"
-typedef unsigned long tarlong;
-#else
-# if BITS_PER_BYTE * SIZEOF_LONG_LONG >= BITS_PER_TARLONG + 1
-#  define SUPERDIGIT 0
-#  define TARLONG_FORMAT "%lld"
-typedef long long tarlong;
-# else
-#  if BITS_PER_BYTE * SIZEOF_UNSIGNED_LONG >= 64
-#   define SUPERDIGIT 1000000000L
-#   define BITS_PER_SUPERDIGIT 29
-#   define TARLONG_FORMAT "%09uld"
-#  else
-#   if BITS_PER_BYTE * SIZEOF_UNSIGNED_LONG >= 32
-#    define SUPERDIGIT 10000L
-#    define BITS_PER_SUPERDIGIT 14
-#    define TARLONG_FORMAT "%04uld"
-#   endif
-#  endif
-# endif
-#endif
-
-#if SUPERDIGIT
-
-# define LONGS_PER_TARLONG \
-    ((BITS_PER_TARLONG + BITS_PER_SUPERDIGIT - 1) / BITS_PER_SUPERDIGIT)
-# define SIZEOF_TARLONG (LONGS_PER_TARLONG * sizeof (unsigned long))
-
-/* The NEC EWS 4.2 C compiler gets confused by a pointer to a typedef that
-   is an array.  So we wrap the array into a struct.  (Pouah!)  */
-
-struct tarlong
-{
-  unsigned long digit[LONGS_PER_TARLONG];
-};
-
-typedef struct tarlong tarlong;
-
-int zerop_tarlong_helper PARAMS ((unsigned long *));
-int lessp_tarlong_helper PARAMS ((unsigned long *, unsigned long *));
-void clear_tarlong_helper PARAMS ((unsigned long *));
-void add_to_tarlong_helper PARAMS ((unsigned long *, int));
-void mult_tarlong_helper PARAMS ((unsigned long *, int));
-void print_tarlong_helper PARAMS ((unsigned long *, FILE *));
-
-# define zerop_tarlong(Accumulator) \
-   zerop_tarlong_helper (&(Accumulator).digit[0])
-
-# define lessp_tarlong(First, Second) \
-   lessp_tarlong_helper (&(First).digit[0], &(Second).digit[0])
-
-# define clear_tarlong(Accumulator) \
-   clear_tarlong_helper (&(Accumulator).digit[0])
-
-# define add_to_tarlong(Accumulator, Value) \
-   add_to_tarlong_helper (&(Accumulator).digit[0], (Value))
-
-# define mult_tarlong(Accumulator, Value) \
-   mult_tarlong_helper (&(Accumulator).digit[0], (Value))
-
-# define print_tarlong(Accumulator, File) \
-   print_tarlong_helper (&(Accumulator).digit[0], (File))
-
-#else /* not SUPERDIGIT */
-
-# define zerop_tarlong(Accumulator) \
-   ((Accumulator) == 0)
-
-# define lessp_tarlong(First, Second) \
-   ((First) < (Second))
-
-# define clear_tarlong(Accumulator) \
-   ((Accumulator) = 0)
-
-# define add_to_tarlong(Accumulator, Value) \
-   ((Accumulator) += (Value))
-
-# define mult_tarlong(Accumulator, Value) \
-   ((Accumulator) *= (Value))
-
-# define print_tarlong(Accumulator, File) \
-   (fprintf ((File), TARLONG_FORMAT, (Accumulator)))
-
-#endif /* not SUPERDIGIT */
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/* Handle large integers for calculating big tape lengths and the
+   like.  In practice, double precision does for now.  On the vast
+   majority of machines, it counts up to 2**52 bytes without any loss
+   of information, and counts up to 2**62 bytes if data are always
+   blocked in 1 kB boundaries.  We'll need arbitrary precision
+   arithmetic anyway once we get into the 2**64 range, so there's no
+   point doing anything fancy before then.  */
+   
+#define TARLONG_FORMAT "%.0f"
+typedef double tarlong;