coreutils/printf.c

   1 /* vi: set sw=4 ts=4: */
   2 /* printf - format and print data
   3
   4    Copyright 1999 Dave Cinege
   5    Portions copyright (C) 1990-1996 Free Software Foundation, Inc.
   6
   7    Licensed under GPL v2 or later, see file LICENSE in this tarball for details.
   8 */
   9
  10 /* Usage: printf format [argument...]
  11
  12    A front end to the printf function that lets it be used from the shell.
  13
  14    Backslash escapes:
  15
  16    \" = double quote
  17    \\ = backslash
  18    \a = alert (bell)
  19    \b = backspace
  20    \c = produce no further output
  21    \f = form feed
  22    \n = new line
  23    \r = carriage return
  24    \t = horizontal tab
  25    \v = vertical tab
  26    \0ooo = octal number (ooo is 0 to 3 digits)
  27    \xhhh = hexadecimal number (hhh is 1 to 3 digits)
  28
  29    Additional directive:
  30
  31    %b = print an argument string, interpreting backslash escapes
  32
  33    The `format' argument is re-used as many times as necessary
  34    to convert all of the given arguments.
  35
  36    David MacKenzie <djm@gnu.ai.mit.edu> */
  37
  38
  39 //   19990508 Busy Boxed! Dave Cinege
  40
  41 #include <unistd.h>
  42 #include <stdio.h>
  43 #include <sys/types.h>
  44 #include <string.h>
  45 #include <errno.h>
  46 #include <stdlib.h>
  47 #include <fcntl.h>
  48 #include <ctype.h>
  49 #include <assert.h>
  50 #include "busybox.h"
  51
  52 static int print_formatted (char *format, int argc, char **argv);
  53 static void print_direc (char *start, size_t length,
  54                         int field_width, int precision, char *argument);
  55
  56 typedef int (*converter)(char *arg, void *result);
  57 static void multiconvert(char *arg, void *result, converter convert)
  58 {
  59         char s[16];
  60         if (*arg == '"' || *arg == '\'') {
  61                 sprintf(s,"%d",(unsigned)*(++arg));
  62                 arg=s;
  63         }
  64         if(convert(arg,result)) fprintf(stderr, "%s", arg);
  65 }
  66
  67 static unsigned long xstrtoul(char *arg)
  68 {
  69         unsigned long result;
  70
  71         multiconvert(arg,&result, (converter)safe_strtoul);
  72         return result;
  73 }
  74
  75 static long xstrtol(char *arg)
  76 {
  77         long result;
  78         multiconvert(arg, &result, (converter)safe_strtol);
  79         return result;
  80 }
  81
  82 static double xstrtod(char *arg)
  83 {
  84         double result;
  85         multiconvert(arg, &result, (converter)safe_strtod);
  86         return result;
  87 }
  88
  89 static void print_esc_string(char *str)
  90 {
  91         for (; *str; str++) {
  92                 if (*str == '\\') {
  93                         str++;
  94                         putchar(bb_process_escape_sequence((const char **)&str));
  95                 } else {
  96                         putchar(*str);
  97                 }
  98
  99         }
 100 }
 101
 102 int printf_main(int argc, char **argv)
 103 {
 104         char *format;
 105         int args_used;
 106
 107         if (argc <= 1 || **(argv + 1) == '-') {
 108                 bb_show_usage();
 109         }
 110
 111         format = argv[1];
 112         argc -= 2;
 113         argv += 2;
 114
 115         do {
 116                 args_used = print_formatted(format, argc, argv);
 117                 argc -= args_used;
 118                 argv += args_used;
 119         }
 120         while (args_used > 0 && argc > 0);
 121
 122 /*
 123   if (argc > 0)
 124     fprintf(stderr, "excess args ignored");
 125 */
 126
 127         return EXIT_SUCCESS;
 128 }
 129
 130 /* Print the text in FORMAT, using ARGV (with ARGC elements) for
 131    arguments to any `%' directives.
 132    Return the number of elements of ARGV used.  */
 133
 134 static int print_formatted(char *format, int argc, char **argv)
 135 {
 136         int save_argc = argc;           /* Preserve original value.  */
 137         char *f;                                        /* Pointer into `format'.  */
 138         char *direc_start;                      /* Start of % directive.  */
 139         size_t direc_length;            /* Length of % directive.  */
 140         int field_width;                        /* Arg to first '*', or -1 if none.  */
 141         int precision;                          /* Arg to second '*', or -1 if none.  */
 142
 143         for (f = format; *f; ++f) {
 144                 switch (*f) {
 145                 case '%':
 146                         direc_start = f++;
 147                         direc_length = 1;
 148                         field_width = precision = -1;
 149                         if (*f == '%') {
 150                                 putchar('%');
 151                                 break;
 152                         }
 153                         if (*f == 'b') {
 154                                 if (argc > 0) {
 155                                         print_esc_string(*argv);
 156                                         ++argv;
 157                                         --argc;
 158                                 }
 159                                 break;
 160                         }
 161                         if (strchr("-+ #", *f)) {
 162                                 ++f;
 163                                 ++direc_length;
 164                         }
 165                         if (*f == '*') {
 166                                 ++f;
 167                                 ++direc_length;
 168                                 if (argc > 0) {
 169                                         field_width = xstrtoul(*argv);
 170                                         ++argv;
 171                                         --argc;
 172                                 } else
 173                                         field_width = 0;
 174                         } else
 175                                 while (isdigit(*f)) {
 176                                         ++f;
 177                                         ++direc_length;
 178                                 }
 179                         if (*f == '.') {
 180                                 ++f;
 181                                 ++direc_length;
 182                                 if (*f == '*') {
 183                                         ++f;
 184                                         ++direc_length;
 185                                         if (argc > 0) {
 186                                                 precision = xstrtoul(*argv);
 187                                                 ++argv;
 188                                                 --argc;
 189                                         } else
 190                                                 precision = 0;
 191                                 } else
 192                                         while (isdigit(*f)) {
 193                                                 ++f;
 194                                                 ++direc_length;
 195                                         }
 196                         }
 197                         if (*f == 'l' || *f == 'L' || *f == 'h') {
 198                                 ++f;
 199                                 ++direc_length;
 200                         }
 201                         /*
 202                            if (!strchr ("diouxXfeEgGcs", *f))
 203                            fprintf(stderr, "%%%c: invalid directive", *f);
 204                          */
 205                         ++direc_length;
 206                         if (argc > 0) {
 207                                 print_direc(direc_start, direc_length, field_width,
 208                                                         precision, *argv);
 209                                 ++argv;
 210                                 --argc;
 211                         } else
 212                                 print_direc(direc_start, direc_length, field_width,
 213                                                         precision, "");
 214                         break;
 215
 216                 case '\\':
 217                         if (*++f == 'c')
 218                                 exit(0);
 219                         putchar(bb_process_escape_sequence((const char **)&f));
 220                         f--;
 221                         break;
 222
 223                 default:
 224                         putchar(*f);
 225                 }
 226         }
 227
 228         return save_argc - argc;
 229 }
 230
 231 static void
 232 print_direc(char *start, size_t length, int field_width, int precision,
 233                         char *argument)
 234 {
 235         char *p;                                        /* Null-terminated copy of % directive. */
 236
 237         p = xmalloc((unsigned) (length + 1));
 238         strncpy(p, start, length);
 239         p[length] = 0;
 240
 241         switch (p[length - 1]) {
 242         case 'd':
 243         case 'i':
 244                 if (field_width < 0) {
 245                         if (precision < 0)
 246                                 printf(p, xstrtol(argument));
 247                         else
 248                                 printf(p, precision, xstrtol(argument));
 249                 } else {
 250                         if (precision < 0)
 251                                 printf(p, field_width, xstrtol(argument));
 252                         else
 253                                 printf(p, field_width, precision, xstrtol(argument));
 254                 }
 255                 break;
 256
 257         case 'o':
 258         case 'u':
 259         case 'x':
 260         case 'X':
 261                 if (field_width < 0) {
 262                         if (precision < 0)
 263                                 printf(p, xstrtoul(argument));
 264                         else
 265                                 printf(p, precision, xstrtoul(argument));
 266                 } else {
 267                         if (precision < 0)
 268                                 printf(p, field_width, xstrtoul(argument));
 269                         else
 270                                 printf(p, field_width, precision, xstrtoul(argument));
 271                 }
 272                 break;
 273
 274         case 'f':
 275         case 'e':
 276         case 'E':
 277         case 'g':
 278         case 'G':
 279                 if (field_width < 0) {
 280                         if (precision < 0)
 281                                 printf(p, xstrtod(argument));
 282                         else
 283                                 printf(p, precision, xstrtod(argument));
 284                 } else {
 285                         if (precision < 0)
 286                                 printf(p, field_width, xstrtod(argument));
 287                         else
 288                                 printf(p, field_width, precision, xstrtod(argument));
 289                 }
 290                 break;
 291
 292         case 'c':
 293                 printf(p, *argument);
 294                 break;
 295
 296         case 's':
 297                 if (field_width < 0) {
 298                         if (precision < 0)
 299                                 printf(p, argument);
 300                         else
 301                                 printf(p, precision, argument);
 302                 } else {
 303                         if (precision < 0)
 304                                 printf(p, field_width, argument);
 305                         else
 306                                 printf(p, field_width, precision, argument);
 307                 }
 308                 break;
 309         }
 310
 311         free(p);
 312 }