125 lines
3.5 KiB
C
125 lines
3.5 KiB
C
//
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// fcvt.c
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//
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// Floating point to string conversion routines
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//
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// Copyright (C) 2002 Michael Ringgaard. All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions
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// are met:
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//
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// 1. Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// 2. Redistributions in binary form must reproduce the above copyright
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// notice, this list of conditions and the following disclaimer in the
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// documentation and/or other materials provided with the distribution.
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// 3. Neither the name of the project nor the names of its contributors
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// may be used to endorse or promote products derived from this software
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// without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
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// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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// SUCH DAMAGE.
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//
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#include <math.h>
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#define CVTBUFSIZE 64
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//
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// cvt.c - IEEE floating point formatting routines for FreeBSD
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// from GNU libc-4.6.27
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//
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static char *cvt(double arg, int ndigits, int *decpt, int *sign, char *buf, int eflag) {
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int r2;
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double fi, fj;
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char *p, *p1;
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if (ndigits < 0) ndigits = 0;
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if (ndigits >= CVTBUFSIZE - 1) ndigits = CVTBUFSIZE - 2;
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r2 = 0;
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*sign = 0;
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p = &buf[0];
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if (arg < 0) {
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*sign = 1;
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arg = -arg;
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}
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arg = modf(arg, &fi);
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p1 = &buf[CVTBUFSIZE];
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if (fi != 0) {
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p1 = &buf[CVTBUFSIZE];
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while (fi != 0) {
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fj = modf(fi / 10, &fi);
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*--p1 = (int)((fj + .03) * 10) + '0';
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r2++;
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}
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while (p1 < &buf[CVTBUFSIZE]) *p++ = *p1++;
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} else if (arg > 0) {
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while ((fj = arg * 10) < 1) {
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arg = fj;
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r2--;
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}
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}
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p1 = &buf[ndigits];
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if (eflag == 0) p1 += r2;
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*decpt = r2;
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if (p1 < &buf[0]) {
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buf[0] = '\0';
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return buf;
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}
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while (p <= p1 && p < &buf[CVTBUFSIZE]) {
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arg *= 10;
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arg = modf(arg, &fj);
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*p++ = (int) fj + '0';
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}
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if (p1 >= &buf[CVTBUFSIZE]) {
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buf[CVTBUFSIZE - 1] = '\0';
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return buf;
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}
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p = p1;
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*p1 += 5;
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while (*p1 > '9') {
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*p1 = '0';
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if (p1 > buf) {
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++*--p1;
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} else {
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*p1 = '1';
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(*decpt)++;
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if (eflag == 0) {
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if (p > buf) *p = '0';
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p++;
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}
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}
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}
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*p = '\0';
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return buf;
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}
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inline char *ecvt(double arg, int ndigits, int *decpt, int *sign) {
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char cvtbuf[CVTBUFSIZE];
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return cvt(arg, ndigits, decpt, sign, cvtbuf, 1);
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}
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inline char *ecvtbuf(double arg, int ndigits, int *decpt, int *sign, char *buf) {
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return cvt(arg, ndigits, decpt, sign, buf, 1);
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}
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inline char *fcvt(double arg, int ndigits, int *decpt, int *sign) {
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char cvtbuf[CVTBUFSIZE];
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return cvt(arg, ndigits, decpt, sign, cvtbuf, 0);
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}
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inline char *fcvtbuf(double arg, int ndigits, int *decpt, int *sign, char *buf) {
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return cvt(arg, ndigits, decpt, sign, buf, 0);
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}
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