1: /* cheap ecvt replacement
2:
3: Copyright (C) 1998,2000 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., 675 Mass Ave, Cambridge, MA 02139, 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(len > (MAXCONV-1)) len = MAXCONV-1;
37:
38: if(x<0)
39: {
40: *sign = 1;
41: x = -x;
42: }
43: else
44: {
45: *sign = 0;
46: }
47:
48: if(x==0)
49: *exp=-1;
50: else
51: *exp=(int)floor(log10(x));
52: x = x / pow10((double)*exp);
53:
54: *exp += 1;
55:
56: for(i=0; i < len; i++)
57: {
58: z=floor(x);
59: if(z<0) z = 0;
60: scratch[i]='0'+(char)((int)z);
61: x = (x-z)*10;
62: }
63:
64: if((x >= 5) && i)
65: {
66: for(j=i-1; j>=0; j--)
67: {
68: if(scratch[j]!='9')
69: {
70: scratch[j]+=1; break;
71: }
72: else
73: {
74: scratch[j]='0';
75: }
76: }
77: if(j<0)
78: {
79: scratch[0]='1';
80: *exp += 1;
81: }
82: }
83:
84: scratch[i]='\0';
85:
86: return scratch;
87: }
88:
89: #ifdef TEST
90: int main(int argc, char ** argv)
91: {
92: int a, b;
93: char * conv=ecvt(9e0,20,&a,&b);
94:
95: printf("ecvt Test: %f -> %s, %d, %d\n",9e0,conv,a,b);
96: }
97: #endif
98:
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