xref: /freebsd/lib/libc/stdio/printfcommon.h (revision d9dc1603)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Chris Torek.
9  *
10  * Copyright (c) 2011 The FreeBSD Foundation
11  *
12  * Portions of this software were developed by David Chisnall
13  * under sponsorship from the FreeBSD Foundation.
14  *
15  * Redistribution and use in source and binary forms, with or without
16  * modification, are permitted provided that the following conditions
17  * are met:
18  * 1. Redistributions of source code must retain the above copyright
19  *    notice, this list of conditions and the following disclaimer.
20  * 2. Redistributions in binary form must reproduce the above copyright
21  *    notice, this list of conditions and the following disclaimer in the
22  *    documentation and/or other materials provided with the distribution.
23  * 3. Neither the name of the University nor the names of its contributors
24  *    may be used to endorse or promote products derived from this software
25  *    without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  */
39 
40 /*
41  * This file defines common routines used by both printf and wprintf.
42  * You must define CHAR to either char or wchar_t prior to including this.
43  */
44 
45 
46 #ifndef NO_FLOATING_POINT
47 
48 #define	dtoa		__dtoa
49 #define	freedtoa	__freedtoa
50 
51 #include <float.h>
52 #include <math.h>
53 #include "floatio.h"
54 #include "gdtoa.h"
55 
56 #define	DEFPREC		6
57 
58 static int exponent(CHAR *, int, CHAR);
59 
60 #endif /* !NO_FLOATING_POINT */
61 
62 static CHAR	*__ujtoa(uintmax_t, CHAR *, int, int, const char *);
63 static CHAR	*__ultoa(u_long, CHAR *, int, int, const char *);
64 
65 #define NIOV 8
66 struct io_state {
67 	FILE *fp;
68 	struct __suio uio;	/* output information: summary */
69 	struct __siov iov[NIOV];/* ... and individual io vectors */
70 };
71 
72 static inline void
io_init(struct io_state * iop,FILE * fp)73 io_init(struct io_state *iop, FILE *fp)
74 {
75 
76 	iop->uio.uio_iov = iop->iov;
77 	iop->uio.uio_resid = 0;
78 	iop->uio.uio_iovcnt = 0;
79 	iop->fp = fp;
80 }
81 
82 /*
83  * WARNING: The buffer passed to io_print() is not copied immediately; it must
84  * remain valid until io_flush() is called.
85  */
86 static inline int
io_print(struct io_state * iop,const CHAR * __restrict ptr,int len,locale_t locale)87 io_print(struct io_state *iop, const CHAR * __restrict ptr, int len, locale_t locale)
88 {
89 
90 	iop->iov[iop->uio.uio_iovcnt].iov_base = (char *)ptr;
91 	iop->iov[iop->uio.uio_iovcnt].iov_len = len;
92 	iop->uio.uio_resid += len;
93 	if (++iop->uio.uio_iovcnt >= NIOV)
94 		return (__sprint(iop->fp, &iop->uio, locale));
95 	else
96 		return (0);
97 }
98 
99 /*
100  * Choose PADSIZE to trade efficiency vs. size.  If larger printf
101  * fields occur frequently, increase PADSIZE and make the initialisers
102  * below longer.
103  */
104 #define	PADSIZE	16		/* pad chunk size */
105 static const CHAR blanks[PADSIZE] =
106 {' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' '};
107 static const CHAR zeroes[PADSIZE] =
108 {'0','0','0','0','0','0','0','0','0','0','0','0','0','0','0','0'};
109 
110 /*
111  * Pad with blanks or zeroes. 'with' should point to either the blanks array
112  * or the zeroes array.
113  */
114 static inline int
io_pad(struct io_state * iop,int howmany,const CHAR * __restrict with,locale_t locale)115 io_pad(struct io_state *iop, int howmany, const CHAR * __restrict with,
116 		locale_t locale)
117 {
118 	int n;
119 
120 	while (howmany > 0) {
121 		n = (howmany >= PADSIZE) ? PADSIZE : howmany;
122 		if (io_print(iop, with, n, locale))
123 			return (-1);
124 		howmany -= n;
125 	}
126 	return (0);
127 }
128 
129 /*
130  * Print exactly len characters of the string spanning p to ep, truncating
131  * or padding with 'with' as necessary.
132  */
133 static inline int
io_printandpad(struct io_state * iop,const CHAR * p,const CHAR * ep,int len,const CHAR * __restrict with,locale_t locale)134 io_printandpad(struct io_state *iop, const CHAR *p, const CHAR *ep,
135 	       int len, const CHAR * __restrict with, locale_t locale)
136 {
137 	int p_len;
138 
139 	p_len = ep - p;
140 	if (p_len > len)
141 		p_len = len;
142 	if (p_len > 0) {
143 		if (io_print(iop, p, p_len, locale))
144 			return (-1);
145 	} else {
146 		p_len = 0;
147 	}
148 	return (io_pad(iop, len - p_len, with, locale));
149 }
150 
151 static inline int
io_flush(struct io_state * iop,locale_t locale)152 io_flush(struct io_state *iop, locale_t locale)
153 {
154 
155 	return (__sprint(iop->fp, &iop->uio, locale));
156 }
157 
158 /*
159  * Convert an unsigned long to ASCII for printf purposes, returning
160  * a pointer to the first character of the string representation.
161  * Octal numbers can be forced to have a leading zero; hex numbers
162  * use the given digits.
163  */
164 static CHAR *
__ultoa(u_long val,CHAR * endp,int base,int octzero,const char * xdigs)165 __ultoa(u_long val, CHAR *endp, int base, int octzero, const char *xdigs)
166 {
167 	CHAR *cp = endp;
168 	long sval;
169 
170 	/*
171 	 * Handle the three cases separately, in the hope of getting
172 	 * better/faster code.
173 	 */
174 	switch (base) {
175 	case 10:
176 		if (val < 10) {	/* many numbers are 1 digit */
177 			*--cp = to_char(val);
178 			return (cp);
179 		}
180 		/*
181 		 * On many machines, unsigned arithmetic is harder than
182 		 * signed arithmetic, so we do at most one unsigned mod and
183 		 * divide; this is sufficient to reduce the range of
184 		 * the incoming value to where signed arithmetic works.
185 		 */
186 		if (val > LONG_MAX) {
187 			*--cp = to_char(val % 10);
188 			sval = val / 10;
189 		} else
190 			sval = val;
191 		do {
192 			*--cp = to_char(sval % 10);
193 			sval /= 10;
194 		} while (sval != 0);
195 		break;
196 
197 	case 2:
198 		do {
199 			*--cp = to_char(val & 1);
200 			val >>= 1;
201 		} while (val);
202 		break;
203 
204 	case 8:
205 		do {
206 			*--cp = to_char(val & 7);
207 			val >>= 3;
208 		} while (val);
209 		if (octzero && *cp != '0')
210 			*--cp = '0';
211 		break;
212 
213 	case 16:
214 		do {
215 			*--cp = xdigs[val & 15];
216 			val >>= 4;
217 		} while (val);
218 		break;
219 
220 	default:			/* oops */
221 		abort();
222 	}
223 	return (cp);
224 }
225 
226 /* Identical to __ultoa, but for intmax_t. */
227 static CHAR *
__ujtoa(uintmax_t val,CHAR * endp,int base,int octzero,const char * xdigs)228 __ujtoa(uintmax_t val, CHAR *endp, int base, int octzero, const char *xdigs)
229 {
230 	CHAR *cp = endp;
231 	intmax_t sval;
232 
233 	/* quick test for small values; __ultoa is typically much faster */
234 	/* (perhaps instead we should run until small, then call __ultoa?) */
235 	if (val <= ULONG_MAX)
236 		return (__ultoa((u_long)val, endp, base, octzero, xdigs));
237 	switch (base) {
238 	case 10:
239 		if (val < 10) {
240 			*--cp = to_char(val % 10);
241 			return (cp);
242 		}
243 		if (val > INTMAX_MAX) {
244 			*--cp = to_char(val % 10);
245 			sval = val / 10;
246 		} else
247 			sval = val;
248 		do {
249 			*--cp = to_char(sval % 10);
250 			sval /= 10;
251 		} while (sval != 0);
252 		break;
253 
254 	case 2:
255 		do {
256 			*--cp = to_char(val & 1);
257 			val >>= 1;
258 		} while (val);
259 		break;
260 
261 	case 8:
262 		do {
263 			*--cp = to_char(val & 7);
264 			val >>= 3;
265 		} while (val);
266 		if (octzero && *cp != '0')
267 			*--cp = '0';
268 		break;
269 
270 	case 16:
271 		do {
272 			*--cp = xdigs[val & 15];
273 			val >>= 4;
274 		} while (val);
275 		break;
276 
277 	default:
278 		abort();
279 	}
280 	return (cp);
281 }
282 
283 #ifndef NO_FLOATING_POINT
284 
285 static int
exponent(CHAR * p0,int exp,CHAR fmtch)286 exponent(CHAR *p0, int exp, CHAR fmtch)
287 {
288 	CHAR *p, *t;
289 	CHAR expbuf[MAXEXPDIG];
290 
291 	p = p0;
292 	*p++ = fmtch;
293 	if (exp < 0) {
294 		exp = -exp;
295 		*p++ = '-';
296 	}
297 	else
298 		*p++ = '+';
299 	t = expbuf + MAXEXPDIG;
300 	if (exp > 9) {
301 		do {
302 			*--t = to_char(exp % 10);
303 		} while ((exp /= 10) > 9);
304 		*--t = to_char(exp);
305 		for (; t < expbuf + MAXEXPDIG; *p++ = *t++);
306 	}
307 	else {
308 		/*
309 		 * Exponents for decimal floating point conversions
310 		 * (%[eEgG]) must be at least two characters long,
311 		 * whereas exponents for hexadecimal conversions can
312 		 * be only one character long.
313 		 */
314 		if (fmtch == 'e' || fmtch == 'E')
315 			*p++ = '0';
316 		*p++ = to_char(exp);
317 	}
318 	return (p - p0);
319 }
320 
321 #endif /* !NO_FLOATING_POINT */
322