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| 1 : | anton | 1.3 | /* cheap ecvt replacement |
| 2 : | |||
| 3 : | anton | 1.6 | Copyright (C) 1998,2000 Free Software Foundation, Inc. |
| 4 : | anton | 1.3 | |
| 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 : | anton | 1.7 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. |
| 20 : | anton | 1.3 | */ |
| 21 : | anton | 1.1 | |
| 22 : | pazsan | 1.2 | #include <stdio.h> |
| 23 : | anton | 1.1 | #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 : | anton | 1.8 | 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 : | anton | 1.1 | 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 : | pazsan | 1.5 | if(z<0) z = 0; |
| 74 : | anton | 1.1 | 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 : | pazsan | 1.2 | if(j<0) |
| 92 : | anton | 1.1 | { |
| 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 : | pazsan | 1.2 | char * conv=ecvt(9e0,20,&a,&b); |
| 108 : | anton | 1.1 | |
| 109 : | pazsan | 1.2 | printf("ecvt Test: %f -> %s, %d, %d\n",9e0,conv,a,b); |
| 110 : | anton | 1.1 | } |
| 111 : | #endif | ||
| 112 : | pazsan | 1.5 |
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