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