1: /* cheap ecvt replacement
2:
3: Copyright (C) 1998,2000,2007 Free Software Foundation, Inc.
4:
5: This file is part of Gforth.
6:
7: Gforth is free software; you can redistribute it and/or
8: modify it under the terms of the GNU General Public License
9: as published by the Free Software Foundation; either version 2
10: of the License, or (at your option) any later version.
11:
12: This program is distributed in the hope that it will be useful,
13: but WITHOUT ANY WARRANTY; without even the implied warranty of
14: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15: GNU General Public License for more details.
16:
17: You should have received a copy of the GNU General Public License
18: along with this program; if not, write to the Free Software
19: Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
20: */
21:
22: #include <stdio.h>
23: #include "config.h"
24: #include <math.h>
25: extern double floor(double);
26: extern double pow10(double);
27:
28: #define MAXCONV 0x40
29: char scratch[MAXCONV];
30:
31: char* ecvt(double x, int len, int* exp, int* sign)
32: {
33: int i, j;
34: double z;
35:
36: if (isnan(x)) {
37: *sign=0;
38: *exp=0;
39: return "nan";
40: }
41: if (isinf(x)) {
42: *sign=0; /* this mimics the glibc ecvt */
43: *exp=0;
44: if (x<0)
45: return "-inf";
46: else
47: return "inf";
48: }
49:
50: if(len > (MAXCONV-1)) len = MAXCONV-1;
51:
52: if(x<0)
53: {
54: *sign = 1;
55: x = -x;
56: }
57: else
58: {
59: *sign = 0;
60: }
61:
62: if(x==0)
63: *exp=-1;
64: else
65: *exp=(int)floor(log10(x));
66: x = x / pow10((double)*exp);
67:
68: *exp += 1;
69:
70: for(i=0; i < len; i++)
71: {
72: z=floor(x);
73: if(z<0) z = 0;
74: scratch[i]='0'+(char)((int)z);
75: x = (x-z)*10;
76: }
77:
78: if((x >= 5) && i)
79: {
80: for(j=i-1; j>=0; j--)
81: {
82: if(scratch[j]!='9')
83: {
84: scratch[j]+=1; break;
85: }
86: else
87: {
88: scratch[j]='0';
89: }
90: }
91: if(j<0)
92: {
93: scratch[0]='1';
94: *exp += 1;
95: }
96: }
97:
98: scratch[i]='\0';
99:
100: return scratch;
101: }
102:
103: #ifdef TEST
104: int main(int argc, char ** argv)
105: {
106: int a, b;
107: char * conv=ecvt(9e0,20,&a,&b);
108:
109: printf("ecvt Test: %f -> %s, %d, %d\n",9e0,conv,a,b);
110: }
111: #endif
112:
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