Mon Nov 17 23:42:03 1997 Bruno Haible <haible@ilog.fr>
[official-gcc.git] / libio / outfloat.c
blob5cbb6c925982a978baa4975c1fcde2146c281d96
1 /*
2 Copyright (C) 1993 Free Software Foundation
4 This file is part of the GNU IO Library. This library is free
5 software; you can redistribute it and/or modify it under the
6 terms of the GNU General Public License as published by the
7 Free Software Foundation; either version 2, or (at your option)
8 any later version.
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this library; see the file COPYING. If not, write to the Free
17 Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 As a special exception, if you link this library with files
20 compiled with a GNU compiler to produce an executable, this does not cause
21 the resulting executable to be covered by the GNU General Public License.
22 This exception does not however invalidate any other reasons why
23 the executable file might be covered by the GNU General Public License. */
25 #include "libioP.h"
27 #ifdef _IO_USE_DTOA
28 /* Format floating-point number and print them.
29 Return number of chars printed, or EOF on error.
31 sign_mode == '+' : print "-" or "+"
32 sign_mode == ' ' : print "-" or " "
33 sign_mode == '\0' : print "-' or ""
36 int
37 _IO_outfloat (value, sb, type, width, precision, flags, sign_mode, fill)
38 double value;
39 _IO_FILE *sb;
40 int type;
41 int width;
42 int precision;
43 int flags;
44 int sign_mode;
45 int fill;
47 int count = 0;
48 #define PUT(x) do {if (_IO_putc(x, sb) < 0) goto error; count++;} while (0)
49 #define PUTN(p, n) \
50 do {int _n=n; count+=_n; if (_IO_sputn(sb, p,_n) != _n) goto error;} while(0)
51 #define PADN(fill, n) \
52 do {int _n = n; count+=_n; if (_IO_padn(sb, fill, _n) != _n) goto error;} while (0)
53 int pad_kind = flags & (_IO_LEFT|_IO_RIGHT|_IO_INTERNAL);
54 int skip_zeroes = 0;
55 int show_dot = (flags & _IO_SHOWPOINT) != 0;
56 int decpt;
57 int sign;
58 int mode;
59 int exponent_size;
60 int print_sign;
61 int trailing_zeroes, useful_digits;
62 int padding, unpadded_width;
63 char *p;
64 char *exponent_start;
65 register int i;
66 #define EBUF_SIZE 12
67 #define EBUF_END &ebuf[EBUF_SIZE]
68 char ebuf[EBUF_SIZE];
69 char *end;
70 int exp = 0;
71 switch (type)
73 case 'f':
74 mode = 3;
75 break;
76 case 'e':
77 case 'E':
78 exp = type;
79 mode = 2;
80 if (precision != 999)
81 precision++; /* Add one to include digit before decimal point. */
82 break;
83 case 'g':
84 case 'G':
85 exp = type == 'g' ? 'e' : 'E';
86 if (precision == 0) precision = 1;
87 if (!(flags & _IO_SHOWPOINT))
88 skip_zeroes = 1;
89 type = 'g';
90 mode = 2;
91 break;
93 /* Do the actual convension */
94 if (precision == 999 && mode != 3)
95 mode = 0;
96 p = _IO_dtoa(value, mode, precision, &decpt, &sign, &end);
97 useful_digits = end-p;
98 exponent_start = EBUF_END;
99 if (mode == 0)
100 precision = useful_digits;
101 /* Check if we need to emit an exponent. */
102 if (mode != 3 && decpt != 9999)
104 i = decpt - 1;
105 if ((type != 'g' && type != 'F') || i < -4 || i >= precision)
107 /* Print the exponent into ebuf.
108 We write ebuf in reverse order (right-to-left). */
109 char sign;
110 if (i >= 0)
111 sign = '+';
112 else
113 sign = '-', i = -i;
114 /* Note: ANSI requires at least 2 exponent digits. */
115 do {
116 *--exponent_start = (i % 10) + '0';
117 i /= 10;
118 } while (i >= 10);
119 *--exponent_start = i + '0';
120 *--exponent_start = sign;
121 *--exponent_start = exp;
124 exponent_size = EBUF_END - exponent_start;
125 if (mode == 1)
126 precision = 1;
127 /* If we print an exponent, always show just one digit before point. */
128 if (exponent_size)
129 decpt = 1;
130 if (decpt == 9999)
131 { /* Infinity or NaN */
132 decpt = useful_digits;
133 precision = 0;
134 show_dot = 0;
137 /* dtoa truncates trailing zeroes. Set the variable trailing_zeroes to
138 the number of 0's we have to add (after the decimal point). */
139 if (skip_zeroes)
140 trailing_zeroes = 0;
141 else if (type == 'f')
142 trailing_zeroes = useful_digits <= decpt ? precision
143 : precision-(useful_digits-decpt);
144 else if (exponent_size) /* 'e' 'E' or 'g' format using exponential notation*/
145 trailing_zeroes = precision - useful_digits;
146 else /* 'g' format not using exponential notation. */
147 trailing_zeroes = useful_digits <= decpt ? precision - decpt
148 : precision-useful_digits;
149 if (trailing_zeroes < 0) trailing_zeroes = 0;
151 if (trailing_zeroes != 0 || useful_digits > decpt)
152 show_dot = 1;
153 if (sign_mode == 0)
154 print_sign = sign ? '-' : 0;
155 else if (sign_mode == '+')
156 print_sign = sign ? '-' : '+';
157 else /* if (sign_mode == ' ') */
158 print_sign = sign ? '-' : ' ';
160 /* Calculate the width (before padding). */
161 unpadded_width =
162 (print_sign != 0) + trailing_zeroes + exponent_size + show_dot
163 + useful_digits
164 + (decpt > useful_digits ? decpt - useful_digits
165 : decpt > 0 ? 0 : 1 - decpt);
167 padding = width > unpadded_width ? width - unpadded_width : 0;
168 if (padding > 0 && pad_kind != _IO_LEFT && pad_kind != _IO_INTERNAL)
169 PADN(fill, padding); /* Default (right) adjust */
170 if (print_sign)
171 PUT(print_sign);
172 if (pad_kind == _IO_INTERNAL && padding > 0)
173 PADN(fill, padding);
174 if (decpt > 0)
176 if (useful_digits >= decpt)
177 PUTN(p, decpt);
178 else
180 PUTN(p, useful_digits);
181 PADN('0', decpt-useful_digits);
183 if (show_dot)
185 PUT('.');
186 /* Print digits after the decimal point. */
187 if (useful_digits > decpt)
188 PUTN(p + decpt, useful_digits-decpt);
191 else
193 PUT('0');
194 if (show_dot)
196 PUT('.');
197 PADN('0', -decpt);
198 /* Print digits after the decimal point. */
199 PUTN(p, useful_digits);
202 PADN('0', trailing_zeroes);
203 if (exponent_size)
204 PUTN(exponent_start, exponent_size);
205 if (pad_kind == _IO_LEFT && padding > 0) /* Left adjustment*/
206 PADN(fill, padding);
207 return count;
208 error:
209 return EOF;
211 #endif