Files
tar/src/arith.h
Paul Eggert cee0eec6d2 GNU tar 1.12
1997-04-16 21:02:57 +00:00

124 lines
4.2 KiB
C

/* Simple arithmetic for numbers greater than a long int, for GNU tar.
Copyright (C) 1996, 1997 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
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program 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 General Public License for more details.
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 */