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9bfe9f8b81
mpir/printf/repl-vsnprintf.c
Paweł Bylica 7bac4c1896
Assume ptrdiff_t
2017-09-06 23:13:38 +02:00

389 lines
11 KiB
C
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/* __gmp_replacement_vsnprintf -- for systems which don't have vsnprintf, or
only have a broken one.
THE FUNCTIONS IN THIS FILE ARE FOR INTERNAL USE ONLY. THEY'RE ALMOST
CERTAIN TO BE SUBJECT TO INCOMPATIBLE CHANGES OR DISAPPEAR COMPLETELY IN
FUTURE GNU MP RELEASES.
Copyright 2001, 2002 Free Software Foundation, Inc.
This file is part of the GNU MP Library.
The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version.
The GNU MP Library 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 Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA. */
#include "config.h"
#if ! HAVE_VSNPRINTF /* only need this file if we don't have vsnprintf */
#ifndef _GNU_SOURCE
#define _GNU_SOURCE /* for strnlen prototype */
#endif
#if HAVE_STDARG
#include <stdarg.h>
#else
#include <varargs.h>
#endif
#include <ctype.h> /* for isdigit */
#include <stddef.h> /* for ptrdiff_t */
#include <string.h>
#include <stdio.h> /* for NULL */
#include <stdlib.h>
#if HAVE_FLOAT_H
#include <float.h> /* for DBL_MAX_10_EXP etc */
#endif
#if HAVE_INTTYPES_H
# include <inttypes.h> /* for intmax_t */
#else
# if HAVE_STDINT_H
# include <stdint.h>
# endif
#endif
#if HAVE_SYS_TYPES_H
#include <sys/types.h> /* for quad_t */
#endif
#include "mpir.h"
#include "gmp-impl.h"
/* Autoconf notes that AIX 4.3 has a broken strnlen, but fortunately it
doesn't affect us since __gmp_replacement_vsnprintf is not required on
that system. */
#if ! HAVE_STRNLEN
static size_t
strnlen (const char *s, size_t n)
{
size_t i;
for (i = 0; i < n; i++)
if (s[i] == '\0')
break;
return i;
}
#endif
/* The approach here is to parse the fmt string, and decide how much space
it requires, then use vsprintf into a big enough buffer. The space
calculated isn't an exact amount, but it's certainly no less than
required.
This code was inspired by GNU libiberty/vasprintf.c but we support more
datatypes, when available.
mingw32 - doesn't have vsnprintf, it seems. Because gcc is used a full
set of types are available, but "long double" is just a plain IEEE
64-bit "double" and LDBL_MAX_EXP_10 is correspondingly defined, so we
avoid the big 15-bit exponent estimate. */
int
__gmp_replacement_vsnprintf (char *buf, size_t buf_size,
const char *orig_fmt, va_list orig_ap)
{
va_list ap;
const char *fmt;
size_t total_width, integer_sizeof, floating_sizeof, len;
char fchar, type;
int width, prec, seen_prec, double_digits, long_double_digits;
int *value;
/* preserve orig_ap for use after size estimation */
va_copy (ap, orig_ap);
fmt = orig_fmt;
total_width = strlen (fmt) + 1; /* 1 extra for the '\0' */
integer_sizeof = sizeof (long);
#if HAVE_LONG_LONG
integer_sizeof = MAX (integer_sizeof, sizeof (long long));
#endif
#if HAVE_QUAD_T
integer_sizeof = MAX (integer_sizeof, sizeof (quad_t));
#endif
floating_sizeof = sizeof (double);
#if HAVE_LONG_DOUBLE
floating_sizeof = MAX (floating_sizeof, sizeof (long double));
#endif
/* IEEE double or VAX G floats have an 11 bit exponent, so the default is
a maximum 308 decimal digits. VAX D floats have only an 8 bit
exponent, but we don't bother trying to detect that directly. */
double_digits = 308;
#ifdef DBL_MAX_10_EXP
/* but in any case prefer a value the compiler says */
double_digits = DBL_MAX_10_EXP;
#endif
/* IEEE 128-bit quad, Intel 80-bit temporary, or VAX H floats all have 15
bit exponents, so the default is a maximum 4932 decimal digits. */
long_double_digits = 4932;
/* but if double == long double, then go with that size */
#if HAVE_LONG_DOUBLE
if (sizeof (double) == sizeof (long double))
long_double_digits = double_digits;
#endif
#ifdef LDBL_MAX_10_EXP
/* but in any case prefer a value the compiler says */
long_double_digits = LDBL_MAX_10_EXP;
#endif
for (;;)
{
fmt = strchr (fmt, '%');
if (fmt == NULL)
break;
fmt++;
type = '\0';
width = 0;
prec = 6;
seen_prec = 0;
value = &width;
for (;;)
{
fchar = *fmt++;
switch (fchar) {
case 'c':
/* char, already accounted for by strlen(fmt) */
goto next;
case 'd':
case 'i':
case 'o':
case 'x':
case 'X':
case 'u':
/* at most 3 digits per byte in hex, dec or octal, plus a sign */
total_width += 3 * integer_sizeof + 1;
switch (type) {
case 'j':
/* Let's assume uintmax_t is the same size as intmax_t. */
#if HAVE_INTMAX_T
(void) va_arg (ap, intmax_t);
#else
ASSERT_FAIL (intmax_t not available);
#endif
break;
case 'l':
(void) va_arg (ap, long);
break;
case 'L':
#if HAVE_LONG_LONG
(void) va_arg (ap, long long);
#else
ASSERT_FAIL (long long not available);
#endif
break;
case 'q':
/* quad_t is probably the same as long long, but let's treat
it separately just to be sure. Also let's assume u_quad_t
will be the same size as quad_t. */
#if HAVE_QUAD_T
(void) va_arg (ap, quad_t);
#else
ASSERT_FAIL (quad_t not available);
#endif
break;
case 't':
(void) va_arg (ap, ptrdiff_t);
break;
case 'z':
(void) va_arg (ap, size_t);
break;
default:
/* default is an "int", and this includes h=short and hh=char
since they're promoted to int in a function call */
(void) va_arg (ap, int);
break;
}
goto next;
case 'E':
case 'e':
case 'G':
case 'g':
/* Requested decimals, sign, point and e, plus an overestimate
of exponent digits (the assumption is all the float is
exponent!). */
total_width += prec + 3 + floating_sizeof * 3;
if (type == 'L')
{
#if HAVE_LONG_DOUBLE
(void) va_arg (ap, long double);
#else
ASSERT_FAIL (long double not available);
#endif
}
else
(void) va_arg (ap, double);
break;
case 'f':
/* Requested decimals, sign and point, and a margin for error,
then add the maximum digits that can be in the integer part,
based on the maximum exponent value. */
total_width += prec + 2 + 10;
if (type == 'L')
{
#if HAVE_LONG_DOUBLE
(void) va_arg (ap, long double);
total_width += long_double_digits;
#else
ASSERT_FAIL (long double not available);
#endif
}
else
{
(void) va_arg (ap, double);
total_width += double_digits;
}
break;
case 'h': /* short or char */
case 'j': /* intmax_t */
case 'L': /* long long or long double */
case 'q': /* quad_t */
case 't': /* ptrdiff_t */
set_type:
type = fchar;
break;
case 'l':
/* long or long long */
if (type != 'l')
goto set_type;
type = 'L'; /* "ll" means "L" */
break;
case 'n':
/* bytes written, no output as such */
(void) va_arg (ap, void *);
goto next;
case 's':
/* If no precision was given, then determine the string length
and put it there, to be added to the total under "next". If
a precision was given then that's already the maximum from
this field, but see whether the string is shorter than that,
in case the limit was very big. */
{
const char *s = va_arg (ap, const char *);
prec = (seen_prec ? strnlen (s, prec) : strlen (s));
}
goto next;
case 'p':
/* pointer, let's assume at worst it's octal with some padding */
(void) va_arg (ap, const void *);
total_width += 3 * sizeof (void *) + 16;
goto next;
case '%':
/* literal %, already accounted for by strlen(fmt) */
goto next;
case '#':
/* showbase, at most 2 for "0x" */
total_width += 2;
break;
case '+':
case ' ':
/* sign, already accounted for under numerics */
break;
case '-':
/* left justify, no effect on total width */
break;
case '.':
seen_prec = 1;
value = &prec;
break;
case '*':
{
/* negative width means left justify which can be ignored,
negative prec would be invalid, just use absolute value */
int n = va_arg (ap, int);
*value = ABS (n);
}
break;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
/* process all digits to form a value */
{
int n = 0;
do {
n = n * 10 + (fchar-'0');
fchar = *fmt++;
} while (isascii (fchar) && isdigit (fchar));
fmt--; /* unget the non-digit */
*value = n;
}
break;
default:
/* incomplete or invalid % sequence */
ASSERT (0);
goto next;
}
}
next:
total_width += width;
total_width += prec;
}
if (total_width <= buf_size)
{
vsprintf (buf, orig_fmt, orig_ap);
len = strlen (buf);
}
else
{
char *s;
s = __GMP_ALLOCATE_FUNC_TYPE (total_width, char);
vsprintf (s, orig_fmt, orig_ap);
len = strlen (s);
if (buf_size != 0)
{
size_t copylen = MIN (len, buf_size-1);
memcpy (buf, s, copylen);
buf[copylen] = '\0';
}
(*__gmp_free_func) (s, total_width);
}
/* If total_width was somehow wrong then chances are we've already
clobbered memory, but maybe this check will still work. */
ASSERT_ALWAYS (len < total_width);
return len;
}
#endif /* ! HAVE_VSNPRINTF */
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