ref: 75c92428225428c8fde2d015f010e608a0b12f1d
dir: /libmath/gfltconv.c/
#include "lib9.h" #include "mathi.h" extern char *dtoa(double, int, int, int *, int *, char **); extern void freedtoa(char*); extern int _fmtcpy(Fmt*, void*, int, int); enum { NONE = -1000, FDIGIT = 20, FDEFLT = 6, NSIGNIF = 17 }; int gfltconv(Fmt *f) { int flags = f->flags; int precision; int fmt = f->r; double d; int echr, exponent, sign, ndig, nout, i; char *digits, *edigits, ebuf[32], *eptr; char out[64], *pout; d = va_arg(f->args, double); echr = 'e'; precision = FDEFLT; if(f->flags & FmtPrec) precision = f->prec; if(precision > FDIGIT) precision = FDIGIT; switch(fmt){ case 'f': digits = dtoa(d, 3, precision, &exponent, &sign, &edigits); break; case 0x00c9: /* L'É' */ case 'E': echr = 'E'; fmt = 'e'; /* fall through */ case 'e': digits = dtoa(d, 2, 1+precision, &exponent, &sign, &edigits); break; case 'G': echr = 'E'; /* fall through */ default: case 'g': if((flags&(FmtWidth|FmtPrec)) == 0){ g_fmt(out, d, echr); f->flags &= FmtWidth|FmtLeft; return _fmtcpy(f, out, strlen(out), strlen(out)); } if (precision > 0) digits = dtoa(d, 2, precision, &exponent, &sign, &edigits); else { digits = dtoa(d, 0, precision, &exponent, &sign, &edigits); precision = edigits - digits; if (exponent > precision && exponent <= precision + 4) precision = exponent; } if(exponent >= -3 && exponent <= precision){ fmt = 'f'; precision -= exponent; }else{ fmt = 'e'; --precision; } break; } if (exponent == 9999) { /* Infinity or Nan */ precision = 0; exponent = edigits - digits; fmt = 'f'; } ndig = edigits-digits; if((f->r=='g' || f->r=='G') && !(flags&FmtSharp)){ /* knock off trailing zeros */ if(fmt == 'f'){ if(precision+exponent > ndig) { precision = ndig - exponent; if(precision < 0) precision = 0; } } else{ if(precision > ndig-1) precision = ndig-1; } } eptr = ebuf; if(fmt != 'f'){ /* exponent */ for(i=exponent<=0?1-exponent:exponent-1; i; i/=10) *eptr++ = '0' + i%10; while(eptr<ebuf+2) *eptr++ = '0'; } pout = out; if(sign) *pout++ = '-'; else if(flags&FmtSign) *pout++ = '+'; else if(flags&FmtSpace) *pout++ = ' '; if(fmt == 'f'){ for(i=0; i<exponent; i++) *pout++ = i<ndig?digits[i]:'0'; if(i == 0) *pout++ = '0'; if(precision>0 || flags&FmtSharp) *pout++ = '.'; for(i=0; i!=precision; i++) *pout++ = 0<=i+exponent && i+exponent<ndig?digits[i+exponent]:'0'; } else{ *pout++ = digits[0]; if(precision>0 || flags&FmtSharp) *pout++ = '.'; for(i=0; i!=precision; i++) *pout++ = i<ndig-1?digits[i+1]:'0'; } if(fmt != 'f'){ *pout++ = echr; *pout++ = exponent<=0?'-':'+'; while(eptr>ebuf) *pout++ = *--eptr; } *pout = 0; freedtoa(digits); f->flags &= FmtWidth|FmtLeft; nout = pout-out; return _fmtcpy(f, out, nout, nout); }