1 91c13e54 2004-02-29 devnull /*
 2 91c13e54 2004-02-29 devnull  * The authors of this software are Rob Pike and Ken Thompson.
 3 91c13e54 2004-02-29 devnull  *              Copyright (c) 2002 by Lucent Technologies.
 4 91c13e54 2004-02-29 devnull  * Permission to use, copy, modify, and distribute this software for any
 5 91c13e54 2004-02-29 devnull  * purpose without fee is hereby granted, provided that this entire notice
 6 91c13e54 2004-02-29 devnull  * is included in all copies of any software which is or includes a copy
 7 91c13e54 2004-02-29 devnull  * or modification of this software and in all copies of the supporting
 8 91c13e54 2004-02-29 devnull  * documentation for such software.
 9 91c13e54 2004-02-29 devnull  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
10 c90dd38f 2004-12-29 devnull  * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE
11 c90dd38f 2004-12-29 devnull  * ANY REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
12 91c13e54 2004-02-29 devnull  * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
13 91c13e54 2004-02-29 devnull  */
14 91c13e54 2004-02-29 devnull #include <stdarg.h>
15 91c13e54 2004-02-29 devnull #include <string.h>
16 e5aa96ac 2004-12-26 devnull #include "plan9.h"
17 91c13e54 2004-02-29 devnull #include "fmt.h"
18 91c13e54 2004-02-29 devnull #include "fmtdef.h"
19 91c13e54 2004-02-29 devnull 
20 91c13e54 2004-02-29 devnull /*
21 91c13e54 2004-02-29 devnull  * Reads a floating-point number by interpreting successive characters
22 91c13e54 2004-02-29 devnull  * returned by (*f)(vp).  The last call it makes to f terminates the
23 91c13e54 2004-02-29 devnull  * scan, so is not a character in the number.  It may therefore be
24 91c13e54 2004-02-29 devnull  * necessary to back up the input stream up one byte after calling charstod.
25 91c13e54 2004-02-29 devnull  */
26 91c13e54 2004-02-29 devnull 
27 91c13e54 2004-02-29 devnull double
28 91c13e54 2004-02-29 devnull fmtcharstod(int(*f)(void*), void *vp)
29 91c13e54 2004-02-29 devnull {
30 91c13e54 2004-02-29 devnull 	double num, dem;
31 91c13e54 2004-02-29 devnull 	int neg, eneg, dig, exp, c;
32 91c13e54 2004-02-29 devnull 
33 91c13e54 2004-02-29 devnull 	num = 0;
34 91c13e54 2004-02-29 devnull 	neg = 0;
35 91c13e54 2004-02-29 devnull 	dig = 0;
36 91c13e54 2004-02-29 devnull 	exp = 0;
37 91c13e54 2004-02-29 devnull 	eneg = 0;
38 91c13e54 2004-02-29 devnull 
39 91c13e54 2004-02-29 devnull 	c = (*f)(vp);
40 91c13e54 2004-02-29 devnull 	while(c == ' ' || c == '\t')
41 91c13e54 2004-02-29 devnull 		c = (*f)(vp);
42 91c13e54 2004-02-29 devnull 	if(c == '-' || c == '+'){
43 91c13e54 2004-02-29 devnull 		if(c == '-')
44 91c13e54 2004-02-29 devnull 			neg = 1;
45 91c13e54 2004-02-29 devnull 		c = (*f)(vp);
46 91c13e54 2004-02-29 devnull 	}
47 91c13e54 2004-02-29 devnull 	while(c >= '0' && c <= '9'){
48 91c13e54 2004-02-29 devnull 		num = num*10 + c-'0';
49 91c13e54 2004-02-29 devnull 		c = (*f)(vp);
50 91c13e54 2004-02-29 devnull 	}
51 91c13e54 2004-02-29 devnull 	if(c == '.')
52 91c13e54 2004-02-29 devnull 		c = (*f)(vp);
53 91c13e54 2004-02-29 devnull 	while(c >= '0' && c <= '9'){
54 91c13e54 2004-02-29 devnull 		num = num*10 + c-'0';
55 91c13e54 2004-02-29 devnull 		dig++;
56 91c13e54 2004-02-29 devnull 		c = (*f)(vp);
57 91c13e54 2004-02-29 devnull 	}
58 91c13e54 2004-02-29 devnull 	if(c == 'e' || c == 'E'){
59 91c13e54 2004-02-29 devnull 		c = (*f)(vp);
60 91c13e54 2004-02-29 devnull 		if(c == '-' || c == '+'){
61 91c13e54 2004-02-29 devnull 			if(c == '-'){
62 91c13e54 2004-02-29 devnull 				dig = -dig;
63 91c13e54 2004-02-29 devnull 				eneg = 1;
64 91c13e54 2004-02-29 devnull 			}
65 91c13e54 2004-02-29 devnull 			c = (*f)(vp);
66 91c13e54 2004-02-29 devnull 		}
67 91c13e54 2004-02-29 devnull 		while(c >= '0' && c <= '9'){
68 91c13e54 2004-02-29 devnull 			exp = exp*10 + c-'0';
69 91c13e54 2004-02-29 devnull 			c = (*f)(vp);
70 91c13e54 2004-02-29 devnull 		}
71 91c13e54 2004-02-29 devnull 	}
72 91c13e54 2004-02-29 devnull 	exp -= dig;
73 91c13e54 2004-02-29 devnull 	if(exp < 0){
74 91c13e54 2004-02-29 devnull 		exp = -exp;
75 91c13e54 2004-02-29 devnull 		eneg = !eneg;
76 91c13e54 2004-02-29 devnull 	}
77 91c13e54 2004-02-29 devnull 	dem = __fmtpow10(exp);
78 91c13e54 2004-02-29 devnull 	if(eneg)
79 91c13e54 2004-02-29 devnull 		num /= dem;
80 91c13e54 2004-02-29 devnull 	else
81 91c13e54 2004-02-29 devnull 		num *= dem;
82 91c13e54 2004-02-29 devnull 	if(neg)
83 91c13e54 2004-02-29 devnull 		return -num;
84 91c13e54 2004-02-29 devnull 	return num;
85 91c13e54 2004-02-29 devnull }