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-rw-r--r--src/lib9/fmt/fltfmt.c679
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diff --git a/src/lib9/fmt/fltfmt.c b/src/lib9/fmt/fltfmt.c
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index 000000000..9f3f3edab
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+++ b/src/lib9/fmt/fltfmt.c
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+/*
+ * The authors of this software are Rob Pike and Ken Thompson,
+ * with contributions from Mike Burrows and Sean Dorward.
+ *
+ * Copyright (c) 2002-2006 by Lucent Technologies.
+ * Portions Copyright (c) 2004 Google Inc.
+ *
+ * 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
+ * NOR GOOGLE INC MAKE ANY REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING
+ * THE MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
+ */
+
+/* Copyright (c) 2002-2006 Lucent Technologies; see LICENSE */
+#include <u.h>
+#include <errno.h>
+#include <libc.h>
+#include "fmtdef.h"
+
+enum
+{
+ FDIGIT = 30,
+ 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,
+};
+
+#undef pow10
+#define npows10 ((int)(sizeof(pows10)/sizeof(pows10[0])))
+#define pow10(x) fmtpow10(x)
+
+static double
+pow10(int n)
+{
+ double d;
+ int neg;
+
+ neg = 0;
+ if(n < 0){
+ neg = 1;
+ n = -n;
+ }
+
+ if(n < npows10)
+ d = pows10[n];
+ else{
+ d = pows10[npows10-1];
+ for(;;){
+ n -= npows10 - 1;
+ if(n < npows10){
+ d *= pows10[n];
+ break;
+ }
+ d *= pows10[npows10 - 1];
+ }
+ }
+ if(neg)
+ return 1./d;
+ return d;
+}
+
+/*
+ * add 1 to the decimal integer string a of length n.
+ * if 99999 overflows into 10000, return 1 to tell caller
+ * to move the virtual decimal point.
+ */
+static int
+xadd1(char *a, int n)
+{
+ char *b;
+ int c;
+
+ if(n < 0 || n > NSIGNIF)
+ return 0;
+ for(b = a+n-1; b >= a; b--) {
+ c = *b + 1;
+ if(c <= '9') {
+ *b = c;
+ return 0;
+ }
+ *b = '0';
+ }
+ /*
+ * need to overflow adding digit.
+ * shift number down and insert 1 at beginning.
+ * decimal is known to be 0s or we wouldn't
+ * have gotten this far. (e.g., 99999+1 => 00000)
+ */
+ a[0] = '1';
+ return 1;
+}
+
+/*
+ * subtract 1 from the decimal integer string a.
+ * if 10000 underflows into 09999, make it 99999
+ * and return 1 to tell caller to move the virtual
+ * decimal point. this way, xsub1 is inverse of xadd1.
+ */
+static int
+xsub1(char *a, int n)
+{
+ char *b;
+ int c;
+
+ if(n < 0 || n > NSIGNIF)
+ return 0;
+ for(b = a+n-1; b >= a; b--) {
+ c = *b - 1;
+ if(c >= '0') {
+ if(c == '0' && b == a) {
+ /*
+ * just zeroed the top digit; shift everyone up.
+ * decimal is known to be 9s or we wouldn't
+ * have gotten this far. (e.g., 10000-1 => 09999)
+ */
+ *b = '9';
+ return 1;
+ }
+ *b = c;
+ return 0;
+ }
+ *b = '9';
+ }
+ /*
+ * can't get here. the number a is always normalized
+ * so that it has a nonzero first digit.
+ */
+ abort();
+}
+
+/*
+ * format exponent like sprintf(p, "e%+02d", e)
+ */
+static void
+xfmtexp(char *p, int e, int ucase)
+{
+ char se[9];
+ int i;
+
+ *p++ = ucase ? 'E' : 'e';
+ if(e < 0) {
+ *p++ = '-';
+ e = -e;
+ } else
+ *p++ = '+';
+ i = 0;
+ while(e) {
+ se[i++] = e % 10 + '0';
+ e /= 10;
+ }
+ while(i < 2)
+ se[i++] = '0';
+ while(i > 0)
+ *p++ = se[--i];
+ *p++ = '\0';
+}
+
+/*
+ * compute decimal integer m, exp such that:
+ * f = m*10^exp
+ * m is as short as possible with losing exactness
+ * assumes special cases (NaN, +Inf, -Inf) have been handled.
+ */
+static void
+xdtoa(double f, char *s, int *exp, int *neg, int *ns)
+{
+ int c, d, e2, e, ee, i, ndigit, oerrno;
+ char tmp[NSIGNIF+10];
+ double g;
+
+ oerrno = errno; /* in case strtod smashes errno */
+
+ /*
+ * make f non-negative.
+ */
+ *neg = 0;
+ if(f < 0) {
+ f = -f;
+ *neg = 1;
+ }
+
+ /*
+ * must handle zero specially.
+ */
+ if(f == 0){
+ *exp = 0;
+ s[0] = '0';
+ s[1] = '\0';
+ *ns = 1;
+ return;
+ }
+
+ /*
+ * find g,e such that f = g*10^e.
+ * guess 10-exponent using 2-exponent, then fine tune.
+ */
+ frexp(f, &e2);
+ e = (int)(e2 * .301029995664);
+ g = f * pow10(-e);
+ while(g < 1) {
+ e--;
+ g = f * pow10(-e);
+ }
+ while(g >= 10) {
+ e++;
+ g = f * pow10(-e);
+ }
+
+ /*
+ * convert NSIGNIF digits as a first approximation.
+ */
+ for(i=0; i<NSIGNIF; i++) {
+ d = (int)g;
+ s[i] = d+'0';
+ g = (g-d) * 10;
+ }
+ s[i] = 0;
+
+ /*
+ * adjust e because s is 314159... not 3.14159...
+ */
+ e -= NSIGNIF-1;
+ xfmtexp(s+NSIGNIF, e, 0);
+
+ /*
+ * adjust conversion until strtod(s) == f exactly.
+ */
+ for(i=0; i<10; i++) {
+ g = strtod(s, nil);
+ if(f > g) {
+ if(xadd1(s, NSIGNIF)) {
+ /* gained a digit */
+ e--;
+ xfmtexp(s+NSIGNIF, e, 0);
+ }
+ continue;
+ }
+ if(f < g) {
+ if(xsub1(s, NSIGNIF)) {
+ /* lost a digit */
+ e++;
+ xfmtexp(s+NSIGNIF, e, 0);
+ }
+ continue;
+ }
+ break;
+ }
+
+ /*
+ * play with the decimal to try to simplify.
+ */
+
+ /*
+ * bump last few digits up to 9 if we can
+ */
+ for(i=NSIGNIF-1; i>=NSIGNIF-3; i--) {
+ c = s[i];
+ if(c != '9') {
+ s[i] = '9';
+ g = strtod(s, nil);
+ if(g != f) {
+ s[i] = c;
+ break;
+ }
+ }
+ }
+
+ /*
+ * add 1 in hopes of turning 9s to 0s
+ */
+ if(s[NSIGNIF-1] == '9') {
+ strcpy(tmp, s);
+ ee = e;
+ if(xadd1(tmp, NSIGNIF)) {
+ ee--;
+ xfmtexp(tmp+NSIGNIF, ee, 0);
+ }
+ g = strtod(tmp, nil);
+ if(g == f) {
+ strcpy(s, tmp);
+ e = ee;
+ }
+ }
+
+ /*
+ * bump last few digits down to 0 as we can.
+ */
+ for(i=NSIGNIF-1; i>=NSIGNIF-3; i--) {
+ c = s[i];
+ if(c != '0') {
+ s[i] = '0';
+ g = strtod(s, nil);
+ if(g != f) {
+ s[i] = c;
+ break;
+ }
+ }
+ }
+
+ /*
+ * remove trailing zeros.
+ */
+ ndigit = NSIGNIF;
+ while(ndigit > 1 && s[ndigit-1] == '0'){
+ e++;
+ --ndigit;
+ }
+ s[ndigit] = 0;
+ *exp = e;
+ *ns = ndigit;
+ errno = oerrno;
+}
+
+#ifdef PLAN9PORT
+static char *special[] = { "NaN", "NaN", "+Inf", "+Inf", "-Inf", "-Inf" };
+#else
+static char *special[] = { "nan", "NAN", "inf", "INF", "-inf", "-INF" };
+#endif
+
+int
+__efgfmt(Fmt *fmt)
+{
+ char buf[NSIGNIF+10], *dot, *digits, *p, *s, suf[10], *t;
+ double f;
+ int c, chr, dotwid, e, exp, fl, ndigits, neg, newndigits;
+ int pad, point, prec, realchr, sign, sufwid, ucase, wid, z1, z2;
+ Rune r, *rs, *rt;
+
+ if(fmt->flags&FmtLong)
+ f = va_arg(fmt->args, long double);
+ else
+ f = va_arg(fmt->args, double);
+
+ /*
+ * extract formatting flags
+ */
+ fl = fmt->flags;
+ fmt->flags = 0;
+ prec = FDEFLT;
+ if(fl & FmtPrec)
+ prec = fmt->prec;
+ chr = fmt->r;
+ ucase = 0;
+ switch(chr) {
+ case 'A':
+ case 'E':
+ case 'F':
+ case 'G':
+ chr += 'a'-'A';
+ ucase = 1;
+ break;
+ }
+
+ /*
+ * pick off special numbers.
+ */
+ if(__isNaN(f)) {
+ s = special[0+ucase];
+ special:
+ fmt->flags = fl & (FmtWidth|FmtLeft);
+ return __fmtcpy(fmt, s, strlen(s), strlen(s));
+ }
+ if(__isInf(f, 1)) {
+ s = special[2+ucase];
+ goto special;
+ }
+ if(__isInf(f, -1)) {
+ s = special[4+ucase];
+ goto special;
+ }
+
+ /*
+ * get exact representation.
+ */
+ digits = buf;
+ xdtoa(f, digits, &exp, &neg, &ndigits);
+
+ /*
+ * get locale's decimal point.
+ */
+ dot = fmt->decimal;
+ if(dot == nil)
+ dot = ".";
+ dotwid = utflen(dot);
+
+ /*
+ * now the formatting fun begins.
+ * compute parameters for actual fmt:
+ *
+ * pad: number of spaces to insert before/after field.
+ * z1: number of zeros to insert before digits
+ * z2: number of zeros to insert after digits
+ * point: number of digits to print before decimal point
+ * ndigits: number of digits to use from digits[]
+ * suf: trailing suffix, like "e-5"
+ */
+ realchr = chr;
+ switch(chr){
+ case 'g':
+ /*
+ * convert to at most prec significant digits. (prec=0 means 1)
+ */
+ if(prec == 0)
+ prec = 1;
+ if(ndigits > prec) {
+ if(digits[prec] >= '5' && xadd1(digits, prec))
+ exp++;
+ exp += ndigits-prec;
+ ndigits = prec;
+ }
+
+ /*
+ * extra rules for %g (implemented below):
+ * trailing zeros removed after decimal unless FmtSharp.
+ * decimal point only if digit follows.
+ */
+
+ /* fall through to %e */
+ default:
+ case 'e':
+ /*
+ * one significant digit before decimal, no leading zeros.
+ */
+ point = 1;
+ z1 = 0;
+
+ /*
+ * decimal point is after ndigits digits right now.
+ * slide to be after first.
+ */
+ e = exp + (ndigits-1);
+
+ /*
+ * if this is %g, check exponent and convert prec
+ */
+ if(realchr == 'g') {
+ if(-4 <= e && e < prec)
+ goto casef;
+ prec--; /* one digit before decimal; rest after */
+ }
+
+ /*
+ * compute trailing zero padding or truncate digits.
+ */
+ if(1+prec >= ndigits)
+ z2 = 1+prec - ndigits;
+ else {
+ /*
+ * truncate digits
+ */
+ assert(realchr != 'g');
+ newndigits = 1+prec;
+ if(digits[newndigits] >= '5' && xadd1(digits, newndigits)) {
+ /*
+ * had 999e4, now have 100e5
+ */
+ e++;
+ }
+ ndigits = newndigits;
+ z2 = 0;
+ }
+ xfmtexp(suf, e, ucase);
+ sufwid = strlen(suf);
+ break;
+
+ casef:
+ case 'f':
+ /*
+ * determine where digits go with respect to decimal point
+ */
+ if(ndigits+exp > 0) {
+ point = ndigits+exp;
+ z1 = 0;
+ } else {
+ point = 1;
+ z1 = 1 + -(ndigits+exp);
+ }
+
+ /*
+ * %g specifies prec = number of significant digits
+ * convert to number of digits after decimal point
+ */
+ if(realchr == 'g')
+ prec += z1 - point;
+
+ /*
+ * compute trailing zero padding or truncate digits.
+ */
+ if(point+prec >= z1+ndigits)
+ z2 = point+prec - (z1+ndigits);
+ else {
+ /*
+ * truncate digits
+ */
+ assert(realchr != 'g');
+ newndigits = point+prec - z1;
+ if(newndigits < 0) {
+ z1 += newndigits;
+ newndigits = 0;
+ } else if(newndigits == 0) {
+ /* perhaps round up */
+ if(digits[0] >= '5'){
+ digits[0] = '1';
+ newndigits = 1;
+ goto newdigit;
+ }
+ } else if(digits[newndigits] >= '5' && xadd1(digits, newndigits)) {
+ /*
+ * digits was 999, is now 100; make it 1000
+ */
+ digits[newndigits++] = '0';
+ newdigit:
+ /*
+ * account for new digit
+ */
+ if(z1) /* 0.099 => 0.100 or 0.99 => 1.00*/
+ z1--;
+ else /* 9.99 => 10.00 */
+ point++;
+ }
+ z2 = 0;
+ ndigits = newndigits;
+ }
+ sufwid = 0;
+ break;
+ }
+
+ /*
+ * if %g is given without FmtSharp, remove trailing zeros.
+ * must do after truncation, so that e.g. print %.3g 1.001
+ * produces 1, not 1.00. sorry, but them's the rules.
+ */
+ if(realchr == 'g' && !(fl & FmtSharp)) {
+ if(z1+ndigits+z2 >= point) {
+ if(z1+ndigits < point)
+ z2 = point - (z1+ndigits);
+ else{
+ z2 = 0;
+ while(z1+ndigits > point && digits[ndigits-1] == '0')
+ ndigits--;
+ }
+ }
+ }
+
+ /*
+ * compute width of all digits and decimal point and suffix if any
+ */
+ wid = z1+ndigits+z2;
+ if(wid > point)
+ wid += dotwid;
+ else if(wid == point){
+ if(fl & FmtSharp)
+ wid += dotwid;
+ else
+ point++; /* do not print any decimal point */
+ }
+ wid += sufwid;
+
+ /*
+ * determine sign
+ */
+ sign = 0;
+ if(neg)
+ sign = '-';
+ else if(fl & FmtSign)
+ sign = '+';
+ else if(fl & FmtSpace)
+ sign = ' ';
+ if(sign)
+ wid++;
+
+ /*
+ * compute padding
+ */
+ pad = 0;
+ if((fl & FmtWidth) && fmt->width > wid)
+ pad = fmt->width - wid;
+ if(pad && !(fl & FmtLeft) && (fl & FmtZero)){
+ z1 += pad;
+ point += pad;
+ pad = 0;
+ }
+
+ /*
+ * format the actual field. too bad about doing this twice.
+ */
+ if(fmt->runes){
+ if(pad && !(fl & FmtLeft) && __rfmtpad(fmt, pad) < 0)
+ return -1;
+ rt = (Rune*)fmt->to;
+ rs = (Rune*)fmt->stop;
+ if(sign)
+ FMTRCHAR(fmt, rt, rs, sign);
+ while(z1>0 || ndigits>0 || z2>0) {
+ if(z1 > 0){
+ z1--;
+ c = '0';
+ }else if(ndigits > 0){
+ ndigits--;
+ c = *digits++;
+ }else{
+ z2--;
+ c = '0';
+ }
+ FMTRCHAR(fmt, rt, rs, c);
+ if(--point == 0) {
+ for(p = dot; *p; ){
+ p += chartorune(&r, p);
+ FMTRCHAR(fmt, rt, rs, r);
+ }
+ }
+ }
+ fmt->nfmt += rt - (Rune*)fmt->to;
+ fmt->to = rt;
+ if(sufwid && __fmtcpy(fmt, suf, sufwid, sufwid) < 0)
+ return -1;
+ if(pad && (fl & FmtLeft) && __rfmtpad(fmt, pad) < 0)
+ return -1;
+ }else{
+ if(pad && !(fl & FmtLeft) && __fmtpad(fmt, pad) < 0)
+ return -1;
+ t = (char*)fmt->to;
+ s = (char*)fmt->stop;
+ if(sign)
+ FMTCHAR(fmt, t, s, sign);
+ while(z1>0 || ndigits>0 || z2>0) {
+ if(z1 > 0){
+ z1--;
+ c = '0';
+ }else if(ndigits > 0){
+ ndigits--;
+ c = *digits++;
+ }else{
+ z2--;
+ c = '0';
+ }
+ FMTCHAR(fmt, t, s, c);
+ if(--point == 0)
+ for(p=dot; *p; p++)
+ FMTCHAR(fmt, t, s, *p);
+ }
+ fmt->nfmt += t - (char*)fmt->to;
+ fmt->to = t;
+ if(sufwid && __fmtcpy(fmt, suf, sufwid, sufwid) < 0)
+ return -1;
+ if(pad && (fl & FmtLeft) && __fmtpad(fmt, pad) < 0)
+ return -1;
+ }
+ return 0;
+}
+
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-25 16:43:59 +0000