Snippets
Revised by
Takehiko NOZAKI
cbe5884
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* Copyright (c) 2021 Takehiko NOZAKI
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#if defined(HAVE_MATH_H)
#include <math.h>
#endif
#if defined(__NetBSD__)
extern char *__dtoa(double, int, int, int *, int *, char **);
extern void __freedtoa(char *);
#define dtoa __dtoa
#define freedtoa __freedtoa
#include <sys/cdefs.h>
#define arraycount(array) __arraycount(array)
#else
#include "gdtoa.h"
#define arraycount(array) (sizeof(array)/sizeof(array[0]))
#endif
struct dtoatestcase {
double dvalue;
const char *svalue;
};
#define DTOATEST(value) { .dvalue = value, .svalue = #value }
#define debug printf
#define DEFAULTPREC 6
#define MAXEXPSIZ 4
#define NEGATIVE 0x1
#define ALT 0x2
#define SIGN 0x4
#define SPACE 0x8
static inline int
cvt_sign(int flags, FILE *fp)
{
if (flags & NEGATIVE) {
if (putc('-', fp) == EOF)
return 1;
} else if (flags & SIGN) {
if (putc('+', fp) == EOF)
return 1;
} else if (flags & SPACE) {
if (putc(' ', fp) == EOF)
return 1;
}
return 0;
}
static inline int
cvt_inf(int flags, FILE *fp)
{
if (cvt_sign(flags, fp))
return 1;
if (fwrite("inf", 1, 3, fp) != 3)
return 1;
return 0;
}
static inline int
cvt_nan(int flags, FILE *fp)
{
if (fwrite("nan", 1, 3, fp) != 3)
return 1;
return 0;
}
static inline int
fill_zeros(int len, FILE *fp)
{
static const char zeros[10] = "0000000000";
while (len > (int)sizeof(zeros)) {
if (fwrite(zeros, 1, sizeof(zeros), fp) != sizeof(zeros))
return 1;
len -= sizeof(zeros);
}
if (fwrite(zeros, 1, len, fp) != len)
return 1;
return 0;
}
static inline int
to_char(int digit)
{
return '0' + digit;
}
static inline int
cvt_exp(int exp, FILE *fp)
{
char buf[MAXEXPSIZ + 2], *expstr;
int sign;
size_t len;
if (exp >= 0) {
sign = '+';
} else {
sign = '-';
exp = -exp;
}
expstr = &buf[sizeof(buf)];
if (exp > 9) {
do {
*--expstr = to_char(exp % 10);
exp /= 10;
} while (exp > 9);
*--expstr = to_char(exp);
} else {
*--expstr = to_char(exp);
*--expstr = to_char(0);
}
*--expstr = sign;
*--expstr = 'e';
len = &buf[sizeof(buf)] - expstr;
if (fwrite(expstr, 1, len, fp) != len)
return 1;
return 0;
}
static inline int
cvt_efmt(char *head, int len, int prec, int exp, int flags, FILE *fp)
{
if (cvt_sign(flags, fp))
return 1;
if (putc(*head, fp) == EOF)
return 1;
if (((flags & ALT) || prec > 0) && putc('.', fp) == EOF)
return 1;
if (--len > 0 && fwrite(&head[1], 1, len, fp) != len)
return 1;
if (prec > len && fill_zeros(prec - len, fp))
return 1;
if (cvt_exp(exp, fp))
return 1;
return 0;
}
int
ecvt(double dvalue, int prec, FILE *fp)
{
int flags, exp, neg, ret;
char *head, *tail;
if (prec < 0)
prec = DEFAULTPREC;
flags = 0;
head = dtoa(dvalue, 2, prec + 1, &exp, &neg, &tail);
if (head == NULL)
return 1;
if (neg)
flags |= NEGATIVE;
if (exp == 9999) {
switch (*head) {
case 'I':
ret = cvt_inf(flags, fp);
break;
case 'N':
ret = cvt_nan(flags, fp);
break;
default:
ret = 1;
}
} else {
ret = cvt_efmt(head, tail - head, prec, exp - 1, flags, fp);
}
freedtoa(head);
return ret;
}
int
main(int argc, char *argv[])
{
static const struct dtoatestcase t[] = {
#if defined(HAVE_MATH_H) && !defined(__vax__)
DTOATEST(INF),
DTOATEST(NAN),
#else
DTOATEST(1.0/0.0),
DTOATEST(0.0/0.0),
#endif
DTOATEST(0.0),
DTOATEST(1.0),
DTOATEST(10.0),
DTOATEST(100.0),
DTOATEST(1.1),
DTOATEST(1.123456789),
DTOATEST(11.23456789),
DTOATEST(112.3456789),
DTOATEST(1123.456789),
DTOATEST(11234.56789),
DTOATEST(112345.6789),
DTOATEST(1123456.789),
DTOATEST(11234567.89),
DTOATEST(112345678.9),
DTOATEST(1123456789.0),
DTOATEST(11234567890123.0),
};
size_t i, n;
int prec;
FILE *fp;
char *expect, *result;
for (i = 0; i < arraycount(t); ++i) {
for (prec = -1; prec <= 20; ++prec) {
expect = NULL;
if (asprintf(&expect, "%.*e", prec, t[i].dvalue) < 0)
abort();
result = NULL;
fp = open_memstream(&result, &n);
if (fp == NULL)
abort();
if (ecvt(t[i].dvalue, prec, fp))
abort();
fclose(fp);
printf("testcase:[%s], expect:[%s], result[%s]\n",
t[i].svalue, expect, result);
if (strcmp(result, expect))
abort();
free(expect);
free(result);
}
}
}
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