113 lines
2.1 KiB
C
113 lines
2.1 KiB
C
/* $Header$ */
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#ifndef NOFLOAT
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extern double modf();
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static char *cvt();
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#define NDIGITS 128
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char *
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ecvt(value, ndigit, decpt, sign)
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double value;
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int ndigit, *decpt, *sign;
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{
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return cvt(value, ndigit, decpt, sign, 1);
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}
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char *
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fcvt(value, ndigit, decpt, sign)
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double value;
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int ndigit, *decpt, *sign;
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{
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return cvt(value, ndigit, decpt, sign, 0);
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}
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static char *
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cvt(value, ndigit, decpt, sign, ecvtflag)
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double value;
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int ndigit, *decpt, *sign;
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{
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double intpart, fractpart;
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static char buf[NDIGITS];
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char buf1[NDIGITS];
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register char *pe = buf1;
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register char *pb;
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int pointpos = 0;
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if (ndigit < 0) ndigit = 0;
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if (ndigit >= NDIGITS - 10) ndigit = NDIGITS - 11;
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*sign = 0;
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if (value < 0) {
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*sign = 1;
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value = -value;
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}
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fractpart = modf(value, &intpart);
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if (intpart != 0) {
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do { /* get digits of integer part, low order digit
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first
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*/
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value = modf(intpart/10, &intpart);
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/* compensate for rounding errors, because
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the conversion to "int" truncates
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*/
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if (pe >= &buf1[NDIGITS]) {
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pb = &buf1[10];
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pe = &buf1[0];
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while (pb < &buf1[NDIGITS]) *pe++ = *pb++;
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}
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*pe++ = (int)((value+.05) * 10) + '0';
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pointpos++;
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} while (intpart != 0);
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pb = buf;
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while (pe > buf1) *pb++ = *--pe;
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}
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else {
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pb = &buf[0];
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if (value > 0) {
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fractpart = value;
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while ((value = value*10) < 1) {
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fractpart = value;
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pointpos--;
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}
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}
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}
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pe = &buf[ndigit];
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if (! ecvtflag) {
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/* for fcvt() we need ndigit digits behind the dot */
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pe += pointpos;
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if (pe < buf) {
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/* pointpos was too far left of the beginning */
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buf[0] = 0;
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*decpt = pointpos;
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return buf;
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}
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if (pe > &buf[NDIGITS]) pe = &buf[NDIGITS];
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}
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while (pb <= pe) {
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fractpart = modf(fractpart * 10, &value);
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*pb++ = (int)value + '0';
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}
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pb = pe;
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*pb += 5; /* round of at the end */
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while (*pb > '9') {
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*pb = '0';
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if (pb > buf) ++*--pb;
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else {
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*pb = '1';
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pointpos++;
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if (! ecvtflag) {
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/* maybe add another digit at the end,
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because the point was shifted right
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*/
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if (pe > buf) *pe = '0';
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pe++;
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}
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}
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}
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*decpt = pointpos;
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*pe = '\0';
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return buf;
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}
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#endif
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