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Diffstat (limited to 'src/lib9/fmt/fltfmt.c')
-rw-r--r-- | src/lib9/fmt/fltfmt.c | 610 |
1 files changed, 610 insertions, 0 deletions
diff --git a/src/lib9/fmt/fltfmt.c b/src/lib9/fmt/fltfmt.c new file mode 100644 index 00000000..234f03d9 --- /dev/null +++ b/src/lib9/fmt/fltfmt.c @@ -0,0 +1,610 @@ +/* + * The authors of this software are Rob Pike and Ken Thompson. + * Copyright (c) 2002 by Lucent Technologies. + * Permission to use, copy, modify, and distribute this software for any + * purpose without fee is hereby granted, provided that this entire notice + * is included in all copies of any software which is or includes a copy + * or modification of this software and in all copies of the supporting + * documentation for such software. + * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED + * WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY + * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY + * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE. + */ +#include <stdio.h> +#include <math.h> +#include <float.h> +#include <string.h> +#include <stdlib.h> +#include <errno.h> +#include <stdarg.h> +#include "fmt.h" +#include "fmtdef.h" +#include "nan.h" + +enum +{ + FDEFLT = 6, + NSIGNIF = 17 +}; + +/* + * first few powers of 10, enough for about 1/2 of the + * total space for doubles. + */ +static double pows10[] = +{ + 1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, + 1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19, + 1e20, 1e21, 1e22, 1e23, 1e24, 1e25, 1e26, 1e27, 1e28, 1e29, + 1e30, 1e31, 1e32, 1e33, 1e34, 1e35, 1e36, 1e37, 1e38, 1e39, + 1e40, 1e41, 1e42, 1e43, 1e44, 1e45, 1e46, 1e47, 1e48, 1e49, + 1e50, 1e51, 1e52, 1e53, 1e54, 1e55, 1e56, 1e57, 1e58, 1e59, + 1e60, 1e61, 1e62, 1e63, 1e64, 1e65, 1e66, 1e67, 1e68, 1e69, + 1e70, 1e71, 1e72, 1e73, 1e74, 1e75, 1e76, 1e77, 1e78, 1e79, + 1e80, 1e81, 1e82, 1e83, 1e84, 1e85, 1e86, 1e87, 1e88, 1e89, + 1e90, 1e91, 1e92, 1e93, 1e94, 1e95, 1e96, 1e97, 1e98, 1e99, + 1e100, 1e101, 1e102, 1e103, 1e104, 1e105, 1e106, 1e107, 1e108, 1e109, + 1e110, 1e111, 1e112, 1e113, 1e114, 1e115, 1e116, 1e117, 1e118, 1e119, + 1e120, 1e121, 1e122, 1e123, 1e124, 1e125, 1e126, 1e127, 1e128, 1e129, + 1e130, 1e131, 1e132, 1e133, 1e134, 1e135, 1e136, 1e137, 1e138, 1e139, + 1e140, 1e141, 1e142, 1e143, 1e144, 1e145, 1e146, 1e147, 1e148, 1e149, + 1e150, 1e151, 1e152, 1e153, 1e154, 1e155, 1e156, 1e157, 1e158, 1e159, +}; + +static double +pow10(int n) +{ + double d; + int neg; + + neg = 0; + if(n < 0){ + if(n < DBL_MIN_10_EXP){ + return 0.; + } + neg = 1; + n = -n; + }else if(n > DBL_MAX_10_EXP){ + return HUGE_VAL; + } + if(n < (int)(sizeof(pows10)/sizeof(pows10[0]))) + d = pows10[n]; + else{ + d = pows10[sizeof(pows10)/sizeof(pows10[0]) - 1]; + for(;;){ + n -= sizeof(pows10)/sizeof(pows10[0]) - 1; + if(n < (int)(sizeof(pows10)/sizeof(pows10[0]))){ + d *= pows10[n]; + break; + } + d *= pows10[sizeof(pows10)/sizeof(pows10[0]) - 1]; + } + } + if(neg){ + return 1./d; + } + return d; +} + +static int +xadd(char *a, int n, int v) +{ + char *b; + int c; + + if(n < 0 || n >= NSIGNIF) + return 0; + for(b = a+n; b >= a; b--) { + c = *b + v; + if(c <= '9') { + *b = c; + return 0; + } + *b = '0'; + v = 1; + } + *a = '1'; /* overflow adding */ + return 1; +} + +static int +xsub(char *a, int n, int v) +{ + char *b; + int c; + + for(b = a+n; b >= a; b--) { + c = *b - v; + if(c >= '0') { + *b = c; + return 0; + } + *b = '9'; + v = 1; + } + *a = '9'; /* underflow subtracting */ + return 1; +} + +static void +xaddexp(char *p, int e) +{ + char se[9]; + int i; + + *p++ = 'e'; + if(e < 0) { + *p++ = '-'; + e = -e; + } + i = 0; + while(e) { + se[i++] = e % 10 + '0'; + e /= 10; + } + if(i == 0) { + *p++ = '0'; + } else { + while(i > 0) + *p++ = se[--i]; + } + *p++ = '\0'; +} + +static char* +xdodtoa(char *s1, double f, int chr, int prec, int *decpt, int *rsign) +{ + char s2[NSIGNIF+10]; + double g, h; + int e, d, i; + int c2, sign, oerr; + + if(chr == 'F') + chr = 'f'; + if(prec > NSIGNIF) + prec = NSIGNIF; + if(prec < 0) + prec = 0; + if(__isNaN(f)) { + *decpt = 9999; + *rsign = 0; + strcpy(s1, "nan"); + return &s1[3]; + } + sign = 0; + if(f < 0) { + f = -f; + sign++; + } + *rsign = sign; + if(__isInf(f, 1) || __isInf(f, -1)) { + *decpt = 9999; + strcpy(s1, "inf"); + return &s1[3]; + } + + e = 0; + g = f; + if(g != 0) { + frexp(f, &e); + e = (int)(e * .301029995664); + if(e >= -150 && e <= +150) { + d = 0; + h = f; + } else { + d = e/2; + h = f * pow10(-d); + } + g = h * pow10(d-e); + while(g < 1) { + e--; + g = h * pow10(d-e); + } + while(g >= 10) { + e++; + g = h * pow10(d-e); + } + } + + /* + * convert NSIGNIF digits and convert + * back to get accuracy. + */ + for(i=0; i<NSIGNIF; i++) { + d = (int)g; + s1[i] = d + '0'; + g = (g - d) * 10; + } + s1[i] = 0; + + /* + * try decimal rounding to eliminate 9s + */ + c2 = prec + 1; + if(chr == 'f') + c2 += e; + oerr = errno; + if(c2 >= NSIGNIF-2) { + strcpy(s2, s1); + d = e; + s1[NSIGNIF-2] = '0'; + s1[NSIGNIF-1] = '0'; + xaddexp(s1+NSIGNIF, e-NSIGNIF+1); + g = fmtstrtod(s1, nil); + if(g == f) + goto found; + if(xadd(s1, NSIGNIF-3, 1)) { + e++; + xaddexp(s1+NSIGNIF, e-NSIGNIF+1); + } + g = fmtstrtod(s1, nil); + if(g == f) + goto found; + strcpy(s1, s2); + e = d; + } + + /* + * convert back so s1 gets exact answer + */ + for(d = 0; d < 10; d++) { + xaddexp(s1+NSIGNIF, e-NSIGNIF+1); + g = fmtstrtod(s1, nil); + if(f > g) { + if(xadd(s1, NSIGNIF-1, 1)) + e--; + continue; + } + if(f < g) { + if(xsub(s1, NSIGNIF-1, 1)) + e++; + continue; + } + break; + } + +found: + errno = oerr; + + /* + * sign + */ + d = 0; + i = 0; + + /* + * round & adjust 'f' digits + */ + c2 = prec + 1; + if(chr == 'f'){ + if(xadd(s1, c2+e, 5)) + e++; + c2 += e; + if(c2 < 0){ + c2 = 0; + e = -prec - 1; + } + }else{ + if(xadd(s1, c2, 5)) + e++; + } + if(c2 > NSIGNIF){ + c2 = NSIGNIF; + } + + *decpt = e + 1; + + /* + * terminate the converted digits + */ + s1[c2] = '\0'; + return &s1[c2]; +} + +/* + * this function works like the standard dtoa, if you want it. + */ +#if 0 +static char* +__dtoa(double f, int mode, int ndigits, int *decpt, int *rsign, char **rve) +{ + static char s2[NSIGNIF + 10]; + char *es; + int chr, prec; + + switch(mode) { + /* like 'e' */ + case 2: + case 4: + case 6: + case 8: + chr = 'e'; + break; + /* like 'g' */ + case 0: + case 1: + default: + chr = 'g'; + break; + /* like 'f' */ + case 3: + case 5: + case 7: + case 9: + chr = 'f'; + break; + } + + if(chr != 'f' && ndigits){ + ndigits--; + } + prec = ndigits; + if(prec > NSIGNIF) + prec = NSIGNIF; + if(ndigits == 0) + prec = NSIGNIF; + es = xdodtoa(s2, f, chr, prec, decpt, rsign); + + /* + * strip trailing 0 + */ + for(; es > s2 + 1; es--){ + if(es[-1] != '0'){ + break; + } + } + *es = '\0'; + if(rve != NULL) + *rve = es; + return s2; +} +#endif + +static int +fmtzdotpad(Fmt *f, int n, int pt) +{ + char *t, *s; + int i; + Rune *rt, *rs; + + if(f->runes){ + rt = (Rune*)f->to; + rs = (Rune*)f->stop; + for(i = 0; i < n; i++){ + if(i == pt){ + FMTRCHAR(f, rt, rs, '.'); + } + FMTRCHAR(f, rt, rs, '0'); + } + f->nfmt += rt - (Rune*)f->to; + f->to = rt; + }else{ + t = (char*)f->to; + s = (char*)f->stop; + for(i = 0; i < n; i++){ + if(i == pt){ + FMTCHAR(f, t, s, '.'); + } + FMTCHAR(f, t, s, '0'); + } + f->nfmt += t - (char *)f->to; + f->to = t; + } + return 0; +} + +int +__efgfmt(Fmt *fmt) +{ + double f; + char s1[NSIGNIF+10]; + int e, d, n; + int c1, c2, c3, c4, ucase, sign, chr, prec, fl; + + f = va_arg(fmt->args, double); + prec = FDEFLT; + fl = fmt->flags; + fmt->flags = 0; + if(fl & FmtPrec) + prec = fmt->prec; + chr = fmt->r; + ucase = 0; + if(chr == 'E'){ + chr = 'e'; + ucase = 1; + }else if(chr == 'F'){ + chr = 'f'; + ucase = 1; + }else if(chr == 'G'){ + chr = 'g'; + ucase = 1; + } + if(prec > 0 && chr == 'g') + prec--; + if(prec < 0) + prec = 0; + + xdodtoa(s1, f, chr, prec, &e, &sign); + e--; + if(*s1 == 'i' || *s1 == 'n'){ + if(ucase){ + if(*s1 == 'i'){ + strcpy(s1, "INF"); + }else{ + strcpy(s1, "NAN"); + } + } + fmt->flags = fl & (FmtWidth|FmtLeft); + return __fmtcpy(fmt, (const void*)s1, 3, 3); + } + + /* + * copy into final place + * c1 digits of leading '0' + * c2 digits from conversion + * c3 digits of trailing '0' + * c4 digits after '.' + */ + c1 = 0; + c2 = prec + 1; + c3 = 0; + c4 = prec; + switch(chr) { + default: + chr = 'e'; + break; + case 'g': + /* + * decide on 'e' of 'f' style convers + */ + if(e >= -4 && e <= prec) { + c1 = -e; + c4 = prec - e; + chr = 'h'; /* flag for 'f' style */ + } + break; + case 'f': + c1 = -e; + if(c1 > prec) + c1 = prec + 1; + c2 += e; + break; + } + + /* + * clean up c1 c2 and c3 + */ + if(c1 < 0) + c1 = 0; + if(c2 < 0) + c2 = 0; + if(c2 > NSIGNIF) { + c3 = c2-NSIGNIF; + c2 = NSIGNIF; + } + + /* + * trim trailing zeros for %g + */ + if(!(fl & FmtSharp) + && (chr == 'g' || chr == 'h')){ + if(c4 >= c3){ + c4 -= c3; + c3 = 0; + }else{ + c3 -= c4; + c4 = 0; + } + while(c4 && c2 > 1 && s1[c2 - 1] == '0'){ + c4--; + c2--; + } + } + + /* + * calculate the total length + */ + n = c1 + c2 + c3; + if(sign || (fl & (FmtSign|FmtSpace))) + n++; + if(c4 || (fl & FmtSharp)){ + n++; + } + if(chr == 'e' || chr == 'g'){ + n += 4; + if(e >= 100) + n++; + } + + /* + * pad to width if right justified + */ + if((fl & (FmtWidth|FmtLeft)) == FmtWidth && n < fmt->width){ + if(fl & FmtZero){ + c1 += fmt->width - n; + }else{ + if(__fmtpad(fmt, fmt->width - n) < 0){ + return -1; + } + } + } + + /* + * sign + */ + d = 0; + if(sign) + d = '-'; + else if(fl & FmtSign) + d = '+'; + else if(fl & FmtSpace) + d = ' '; + if(d && fmtrune(fmt, d) < 0){ + return -1; + } + + /* + * copy digits + */ + c4 = c1 + c2 + c3 - c4; + if(c1 > 0){ + if(fmtzdotpad(fmt, c1, c4) < 0){ + return -1; + } + c4 -= c1; + } + d = 0; + if(c4 >= 0 && c4 < c2){ + if(__fmtcpy(fmt, s1, c4, c4) < 0 || fmtrune(fmt, '.') < 0) + return -1; + d = c4; + c2 -= c4; + c4 = -1; + } + if(__fmtcpy(fmt, (const void*)(s1 + d), c2, c2) < 0){ + return -1; + } + c4 -= c2; + if(c3 > 0){ + if(fmtzdotpad(fmt, c3, c4) < 0){ + return -1; + } + c4 -= c3; + } + + /* + * strip trailing '0' on g conv + */ + if((fl & FmtSharp) && c4 == 0 && fmtrune(fmt, '.') < 0){ + return -1; + } + if(chr == 'e' || chr == 'g') { + d = 0; + if(ucase) + s1[d++] = 'E'; + else + s1[d++] = 'e'; + c1 = e; + if(c1 < 0) { + s1[d++] = '-'; + c1 = -c1; + } else + s1[d++] = '+'; + if(c1 >= 100) { + s1[d++] = c1/100 + '0'; + c1 = c1%100; + } + s1[d++] = c1/10 + '0'; + s1[d++] = c1%10 + '0'; + if(__fmtcpy(fmt, s1, d, d) < 0){ + return -1; + } + } + if((fl & (FmtWidth|FmtLeft)) == (FmtWidth|FmtLeft) && n < fmt->width){ + if(__fmtpad(fmt, fmt->width - n) < 0){ + return -1; + } + } + return 0; +} |