exit 0 on success, 1 on failure

[unix-history] / usr / src / usr.bin / printf / printf.c

/*
* Copyright (c) 1989 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley.  The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1989 The Regents of the University of California.\n\
All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)printf.c    5.4 (Berkeley) %G%";
#endif /* not lint */

#include <sys/types.h>
#include <stdio.h>

#define PF(f, func) { \
       if (fieldwidth) \
               if (precision) \
                       (void)printf(f, fieldwidth, precision, func); \
               else \
                       (void)printf(f, fieldwidth, func); \
       else if (precision) \
               (void)printf(f, precision, func); \
       else \
               (void)printf(f, func); \
}

char **gargv;

main(argc, argv)
       int argc;
       char **argv;
{
       static char *skip1, *skip2;
       register char *format, *fmt, *start;
       register int end, fieldwidth, precision;
       char convch, nextch, *getstr(), *index(), *mklong();
       double getdouble();
       long getlong();

       if (argc < 2) {
               fprintf(stderr, "usage: printf format [arg ...]\n");
               exit(1);
       }

       /*
        * Basic algorithm is to scan the format string for conversion
        * specifications -- once one is found, find out if the field
        * width or precision is a '*'; if it is, gather up value.  Note,
        * format strings are reused as necessary to use up the provided
        * arguments, arguments of zero/null string are provided to use
        * up the format string.
        */
       skip1 = "#-+ 0";
       skip2 = "*0123456789";

       escape(fmt = format = *++argv);         /* backslash interpretation */
       gargv = ++argv;
       for (;;) {
               end = 0;
               /* find next format specification */
next:           for (start = fmt;; ++fmt) {
                       if (!*fmt) {
                               /* avoid infinite loop */
                               if (end == 1) {
                                       fprintf(stderr,
                                           "printf: missing format character.\n");
                                       exit(1);
                               }
                               end = 1;
                               if (fmt > start)
                                       (void)printf("%s", start);
                               if (!*gargv)
                                       exit(0);
                               fmt = format;
                               goto next;
                       }
                       /* %% prints a % */
                       if (*fmt == '%' && *++fmt != '%')
                               break;
               }

               /* skip to field width */
               for (; index(skip1, *fmt); ++fmt);
               if (*fmt == '*')
                       fieldwidth = getint();
               /* skip to possible '.' */
               for (; index(skip2, *fmt); ++fmt);
               if (*fmt == '.')
                       ++fmt;
               if (*fmt == '*')
                       precision = getint();
               /* skip to conversion char */
               for (; index(skip2, *fmt); ++fmt);
               if (!*fmt) {
                       fprintf(stderr, "printf: missing format character.\n");
                       exit(1);
               }

               convch = *fmt;
               nextch = *++fmt;
               *fmt = '\0';
               switch(convch) {
               case 'c': {
                       char p = getchr();
                       PF(start, p);
                       break;
               }
               case 's': {
                       char *p = getstr();
                       PF(start, p);
                       break;
               }
               case 'd': case 'i': case 'o': case 'u': case 'x': case 'X': {
                       char *f = mklong(start, convch);
                       long p = getlong();
                       PF(f, p);
                       break;
               }
               case 'e': case 'E': case 'f': case 'g': case 'G': {
                       double p = getdouble();
                       PF(start, p);
                       break;
               }
               default:
                       fprintf(stderr, "printf: illegal format character.\n");
                       exit(1);
               }
               *fmt = nextch;
       }
       /* NOTREACHED */
}

char *
mklong(str, ch)
       char *str, ch;
{
       int len;
       char *copy, *malloc();

       len = strlen(str) + 2;
       if (!(copy = malloc((u_int)len))) {     /* never freed; XXX */
               fprintf(stderr, "printf: out of memory.\n");
               exit(1);
       }
       bcopy(str, copy, len - 3);
       copy[len - 3] = 'l';
       copy[len - 2] = ch;
       copy[len - 1] = '\0';
       return(copy);
}

escape(fmt)
       register char *fmt;
{
       register char *store;
       register int value, c;

       for (store = fmt; c = *fmt; ++fmt, ++store) {
               if (c != '\\') {
                       *store = c;
                       continue;
               }
               switch (*++fmt) {
               case '\0':              /* EOS, user error */
                       *store = '\\';
                       *++store = '\0';
                       return;
               case '\\':              /* backslash */
               case '\'':              /* single quote */
                       *store = *fmt;
                       break;
               case 'a':               /* bell/alert */
                       *store = '\7';
                       break;
               case 'b':               /* backspace */
                       *store = '\b';
                       break;
               case 'f':               /* form-feed */
                       *store = '\f';
                       break;
               case 'n':               /* newline */
                       *store = '\n';
                       break;
               case 'r':               /* carriage-return */
                       *store = '\r';
                       break;
               case 't':               /* horizontal tab */
                       *store = '\t';
                       break;
               case 'v':               /* vertical tab */
                       *store = '\13';
                       break;
                                       /* octal constant */
               case '0': case '1': case '2': case '3':
               case '4': case '5': case '6': case '7':
                       for (c = 3, value = 0;
                           c-- && *fmt >= '0' && *fmt <= '7'; ++fmt) {
                               value <<= 3;
                               value += *fmt - '0';
                       }
                       --fmt;
                       *store = value;
                       break;
               default:
                       *store = *fmt;
                       break;
               }
       }
       *store = '\0';
}

getchr()
{
       if (!*gargv)
               return((int)'\0');
       return((int)**gargv++);
}

char *
getstr()
{
       if (!*gargv)
               return("");
       return(*gargv++);
}

static char *number = "+-0123456789";
getint()
{
       if (!*gargv)
               return(0);
       if (index(number, **gargv))
               return(atoi(*gargv++));
       return(asciicode());
}

long
getlong()
{
       long atol();

       if (!*gargv)
               return((long)0);
       if (index(number, **gargv))
               return(atol(*gargv++));
       return((long)asciicode());
}

double
getdouble()
{
       double atof();

       if (!*gargv)
               return((double)0);
       if (index(number, **gargv))
               return(atof(*gargv++));
       return((double)asciicode());
}

asciicode()
{
       register char ch;

       ch = **gargv;
       if (ch == '\'' || ch == '"')
               ch = (*gargv)[1];
       ++gargv;
       return(ch);
}