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comparison gsm-fw/sprintf/float.c @ 146:4d629b6bbcfd

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gsm-fw/sprintf: %f implemented, debug output looks correct
author Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
date Thu, 14 Nov 2013 19:03:52 +0000
parents
children 4ac657b95f52
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145:7e45ada9c365 146:4d629b6bbcfd
1 /*
2 * Embedded [v]sprintf() implementation by Michael Spacefalcon,
3 * loosely based on the 4.3BSD-Tahoe version.
4 *
5 * This module contains the floating point conversion functions.
6 */
7
8 #include <sys/types.h>
9 #include <ctype.h>
10 #include "defs.h"
11
12 extern double modf();
13
14 extern u_char * _sprintf_field(u_char *op, int width, int flags, int sign,
15 u_char *body, int size, int dprec, int fpprec);
16
17 #define MAX_INT_DIGITS 10 /* 2^32-1 in decimal */
18 #define MAXFRACT 16 /* max sensible for 64-bit double */
19 #define DEFPREC 6
20
21 static char *
22 emit_integer_portion(unsigned number, char *endp)
23 {
24 char *t = endp;
25
26 do {
27 *--t = tochar(number % 10);
28 number /= 10;
29 } while (number);
30 return (t);
31 }
32
33 static int
34 f_round(double fract, char *start, char *end, int sign)
35 {
36 double tmp;
37
38 (void)modf(fract * 10, &tmp);
39 if (tmp > 4)
40 for (;; --end) {
41 if (*end == '.')
42 --end;
43 if (++*end <= '9')
44 break;
45 *end = '0';
46 }
47 /* ``"%.3f", (double)-0.0004'' gives you a negative 0. */
48 else if (sign == '-')
49 for (;; --end) {
50 if (*end == '.')
51 --end;
52 if (*end != '0')
53 break;
54 if (end == start)
55 return(1); /* clear the -ve */
56 }
57 return(0);
58 }
59
60 u_char *
61 _sprintf_percent_f(u_char *op, int width, int flags, int sign,
62 double number, int prec)
63 {
64 char buf[MAX_INT_DIGITS + 1 + MAXFRACT];
65 int extra_prec = 0;
66 int origsign = sign;
67 double fract, tmp;
68 char *start, *t;
69
70 if (number < 0) {
71 sign = '-';
72 number = -number;
73 }
74 fract = modf(number, &tmp);
75 if (tmp > (double) 0xFFFFFFFF)
76 return _sprintf_field(op, width, flags, sign, "Toobig", 6,
77 0, 0);
78 start = emit_integer_portion((unsigned) tmp, buf + MAX_INT_DIGITS);
79 if (prec > MAXFRACT) {
80 extra_prec = prec - MAXFRACT;
81 prec = MAXFRACT;
82 } else if (prec == -1)
83 prec = DEFPREC;
84 t = buf + MAX_INT_DIGITS;
85 /*
86 * if precision required or alternate flag set, add in a
87 * decimal point.
88 */
89 if (prec || flags&ALT)
90 *t++ = '.';
91 /* if requires more precision and some fraction left */
92 if (fract) {
93 if (prec)
94 do {
95 fract = modf(fract * 10, &tmp);
96 *t++ = tochar((int)tmp);
97 } while (--prec && fract);
98 if (fract && f_round(fract, start, t - 1, sign))
99 sign = origsign;
100 }
101 return _sprintf_field(op, width, flags, sign, start, t - start,
102 0, prec + extra_prec);
103 }