Home | History | Annotate | Line # | Download | only in printf
printf.c revision 1.1.1.1 
      1 /*
      2  * Copyright (c) 1989 The Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #ifndef lint
     35 char copyright[] =
     36 "@(#) Copyright (c) 1989 The Regents of the University of California.\n\
     37  All rights reserved.\n";
     38 #endif /* not lint */
     39 
     40 #ifndef lint
     41 static char sccsid[] = "@(#)printf.c	5.9 (Berkeley) 6/1/90";
     42 #endif /* not lint */
     43 
     44 #include <sys/types.h>
     45 #include <stdio.h>
     46 
     47 #define PF(f, func) { \
     48 	if (fieldwidth) \
     49 		if (precision) \
     50 			(void)printf(f, fieldwidth, precision, func); \
     51 		else \
     52 			(void)printf(f, fieldwidth, func); \
     53 	else if (precision) \
     54 		(void)printf(f, precision, func); \
     55 	else \
     56 		(void)printf(f, func); \
     57 }
     58 
     59 char **gargv;
     60 
     61 main(argc, argv)
     62 	int argc;
     63 	char **argv;
     64 {
     65 	static char *skip1, *skip2;
     66 	register char *format, *fmt, *start;
     67 	register int end, fieldwidth, precision;
     68 	char convch, nextch, *getstr(), *index(), *mklong();
     69 	double getdouble();
     70 	long getlong();
     71 
     72 	if (argc < 2) {
     73 		fprintf(stderr, "usage: printf format [arg ...]\n");
     74 		exit(1);
     75 	}
     76 
     77 	/*
     78 	 * Basic algorithm is to scan the format string for conversion
     79 	 * specifications -- once one is found, find out if the field
     80 	 * width or precision is a '*'; if it is, gather up value.  Note,
     81 	 * format strings are reused as necessary to use up the provided
     82 	 * arguments, arguments of zero/null string are provided to use
     83 	 * up the format string.
     84 	 */
     85 	skip1 = "#-+ 0";
     86 	skip2 = "*0123456789";
     87 
     88 	escape(fmt = format = *++argv);		/* backslash interpretation */
     89 	gargv = ++argv;
     90 	for (;;) {
     91 		end = 0;
     92 		/* find next format specification */
     93 next:		for (start = fmt;; ++fmt) {
     94 			if (!*fmt) {
     95 				/* avoid infinite loop */
     96 				if (end == 1) {
     97 					fprintf(stderr,
     98 					    "printf: missing format character.\n");
     99 					exit(1);
    100 				}
    101 				end = 1;
    102 				if (fmt > start)
    103 					(void)printf("%s", start);
    104 				if (!*gargv)
    105 					exit(0);
    106 				fmt = format;
    107 				goto next;
    108 			}
    109 			/* %% prints a % */
    110 			if (*fmt == '%') {
    111 				if (*++fmt != '%')
    112 					break;
    113 				*fmt++ = '\0';
    114 				(void)printf("%s", start);
    115 				goto next;
    116 			}
    117 		}
    118 
    119 		/* skip to field width */
    120 		for (; index(skip1, *fmt); ++fmt);
    121 		fieldwidth = *fmt == '*' ? getint() : 0;
    122 
    123 		/* skip to possible '.', get following precision */
    124 		for (; index(skip2, *fmt); ++fmt);
    125 		if (*fmt == '.')
    126 			++fmt;
    127 		precision = *fmt == '*' ? getint() : 0;
    128 
    129 		/* skip to conversion char */
    130 		for (; index(skip2, *fmt); ++fmt);
    131 		if (!*fmt) {
    132 			fprintf(stderr, "printf: missing format character.\n");
    133 			exit(1);
    134 		}
    135 
    136 		convch = *fmt;
    137 		nextch = *++fmt;
    138 		*fmt = '\0';
    139 		switch(convch) {
    140 		case 'c': {
    141 			char p = getchr();
    142 			PF(start, p);
    143 			break;
    144 		}
    145 		case 's': {
    146 			char *p = getstr();
    147 			PF(start, p);
    148 			break;
    149 		}
    150 		case 'd': case 'i': case 'o': case 'u': case 'x': case 'X': {
    151 			char *f = mklong(start, convch);
    152 			long p = getlong();
    153 			PF(f, p);
    154 			break;
    155 		}
    156 		case 'e': case 'E': case 'f': case 'g': case 'G': {
    157 			double p = getdouble();
    158 			PF(start, p);
    159 			break;
    160 		}
    161 		default:
    162 			fprintf(stderr, "printf: illegal format character.\n");
    163 			exit(1);
    164 		}
    165 		*fmt = nextch;
    166 	}
    167 	/* NOTREACHED */
    168 }
    169 
    170 char *
    171 mklong(str, ch)
    172 	char *str, ch;
    173 {
    174 	int len;
    175 	char *copy, *malloc();
    176 
    177 	len = strlen(str) + 2;
    178 	if (!(copy = malloc((u_int)len))) {	/* never freed; XXX */
    179 		fprintf(stderr, "printf: out of memory.\n");
    180 		exit(1);
    181 	}
    182 	bcopy(str, copy, len - 3);
    183 	copy[len - 3] = 'l';
    184 	copy[len - 2] = ch;
    185 	copy[len - 1] = '\0';
    186 	return(copy);
    187 }
    188 
    189 escape(fmt)
    190 	register char *fmt;
    191 {
    192 	register char *store;
    193 	register int value, c;
    194 
    195 	for (store = fmt; c = *fmt; ++fmt, ++store) {
    196 		if (c != '\\') {
    197 			*store = c;
    198 			continue;
    199 		}
    200 		switch (*++fmt) {
    201 		case '\0':		/* EOS, user error */
    202 			*store = '\\';
    203 			*++store = '\0';
    204 			return;
    205 		case '\\':		/* backslash */
    206 		case '\'':		/* single quote */
    207 			*store = *fmt;
    208 			break;
    209 		case 'a':		/* bell/alert */
    210 			*store = '\7';
    211 			break;
    212 		case 'b':		/* backspace */
    213 			*store = '\b';
    214 			break;
    215 		case 'f':		/* form-feed */
    216 			*store = '\f';
    217 			break;
    218 		case 'n':		/* newline */
    219 			*store = '\n';
    220 			break;
    221 		case 'r':		/* carriage-return */
    222 			*store = '\r';
    223 			break;
    224 		case 't':		/* horizontal tab */
    225 			*store = '\t';
    226 			break;
    227 		case 'v':		/* vertical tab */
    228 			*store = '\13';
    229 			break;
    230 					/* octal constant */
    231 		case '0': case '1': case '2': case '3':
    232 		case '4': case '5': case '6': case '7':
    233 			for (c = 3, value = 0;
    234 			    c-- && *fmt >= '0' && *fmt <= '7'; ++fmt) {
    235 				value <<= 3;
    236 				value += *fmt - '0';
    237 			}
    238 			--fmt;
    239 			*store = value;
    240 			break;
    241 		default:
    242 			*store = *fmt;
    243 			break;
    244 		}
    245 	}
    246 	*store = '\0';
    247 }
    248 
    249 getchr()
    250 {
    251 	if (!*gargv)
    252 		return((int)'\0');
    253 	return((int)**gargv++);
    254 }
    255 
    256 char *
    257 getstr()
    258 {
    259 	if (!*gargv)
    260 		return("");
    261 	return(*gargv++);
    262 }
    263 
    264 static char *number = "+-.0123456789";
    265 getint()
    266 {
    267 	if (!*gargv)
    268 		return(0);
    269 	if (index(number, **gargv))
    270 		return(atoi(*gargv++));
    271 	return(asciicode());
    272 }
    273 
    274 long
    275 getlong()
    276 {
    277 	long atol();
    278 
    279 	if (!*gargv)
    280 		return((long)0);
    281 	if (index(number, **gargv))
    282 		return(strtol(*gargv++, (char **)NULL, 0));
    283 	return((long)asciicode());
    284 }
    285 
    286 double
    287 getdouble()
    288 {
    289 	double atof();
    290 
    291 	if (!*gargv)
    292 		return((double)0);
    293 	if (index(number, **gargv))
    294 		return(atof(*gargv++));
    295 	return((double)asciicode());
    296 }
    297 
    298 asciicode()
    299 {
    300 	register char ch;
    301 
    302 	ch = **gargv;
    303 	if (ch == '\'' || ch == '"')
    304 		ch = (*gargv)[1];
    305 	++gargv;
    306 	return(ch);
    307 }
    308