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 "busybox.h"
  42
  43 static int print_formatted(char *format, int argc, char **argv);
  44 static void print_direc(char *start, size_t length,
  45                         int field_width, int precision, char *argument);
  46
  47 typedef void (*converter)(char *arg, void *result);
  48
  49 static void multiconvert(char *arg, void *result, converter convert)
  50 {
  51         char s[16];
  52         if (*arg == '"' || *arg == '\'') {
  53                 sprintf(s, "%d", (unsigned char)arg[1]);
  54                 arg = s;
  55         }
  56         convert(arg, result);
  57         if (errno) /* Huh, looks strange... bug? */
  58                 fputs(arg, stderr);
  59 }
  60
  61 static void conv_strtoul(char *arg, void *result)
  62 {
  63         *(unsigned long*)result = bb_strtoul(arg, NULL, 10);
  64 }
  65 static void conv_strtol(char *arg, void *result)
  66 {
  67         *(long*)result = bb_strtol(arg, NULL, 10);
  68 }
  69 static void conv_strtod(char *arg, void *result)
  70 {
  71         char *end;
  72         /* Well, this one allows leading whitespace... so what */
  73         /* What I like much less is that "-" is accepted too! :( */
  74         *(double*)result = strtod(arg, &end);
  75         if (end[0]) errno = ERANGE;
  76 }
  77
  78 static unsigned long my_xstrtoul(char *arg)
  79 {
  80         unsigned long result;
  81         multiconvert(arg, &result, conv_strtoul);
  82         return result;
  83 }
  84
  85 static long my_xstrtol(char *arg)
  86 {
  87         long result;
  88         multiconvert(arg, &result, conv_strtol);
  89         return result;
  90 }
  91
  92 static double my_xstrtod(char *arg)
  93 {
  94         double result;
  95         multiconvert(arg, &result, conv_strtod);
  96         return result;
  97 }
  98
  99 static void print_esc_string(char *str)
 100 {
 101         for (; *str; str++) {
 102                 if (*str == '\\') {
 103                         str++;
 104                         putchar(bb_process_escape_sequence((const char **)&str));
 105                 } else {
 106                         putchar(*str);
 107                 }
 108
 109         }
 110 }
 111
 112 int printf_main(int argc, char **argv)
 113 {
 114         char *format;
 115         int args_used;
 116
 117         if (argc <= 1 || argv[1][0] == '-') {
 118                 bb_show_usage();
 119         }
 120
 121         format = argv[1];
 122         argc -= 2;
 123         argv += 2;
 124
 125         do {
 126                 args_used = print_formatted(format, argc, argv);
 127                 argc -= args_used;
 128                 argv += args_used;
 129         }
 130         while (args_used > 0 && argc > 0);
 131
 132 /*      if (argc > 0)
 133                 fprintf(stderr, "excess args ignored");
 134 */
 135
 136         return EXIT_SUCCESS;
 137 }
 138
 139 /* Print the text in FORMAT, using ARGV (with ARGC elements) for
 140    arguments to any '%' directives.
 141    Return the number of elements of ARGV used.  */
 142
 143 static int print_formatted(char *format, int argc, char **argv)
 144 {
 145         int save_argc = argc;           /* Preserve original value.  */
 146         char *f;                                        /* Pointer into 'format'.  */
 147         char *direc_start;                      /* Start of % directive.  */
 148         size_t direc_length;            /* Length of % directive.  */
 149         int field_width;                        /* Arg to first '*', or -1 if none.  */
 150         int precision;                          /* Arg to second '*', or -1 if none.  */
 151
 152         for (f = format; *f; ++f) {
 153                 switch (*f) {
 154                 case '%':
 155                         direc_start = f++;
 156                         direc_length = 1;
 157                         field_width = precision = -1;
 158                         if (*f == '%') {
 159                                 putchar('%');
 160                                 break;
 161                         }
 162                         if (*f == 'b') {
 163                                 if (argc > 0) {
 164                                         print_esc_string(*argv);
 165                                         ++argv;
 166                                         --argc;
 167                                 }
 168                                 break;
 169                         }
 170                         if (strchr("-+ #", *f)) {
 171                                 ++f;
 172                                 ++direc_length;
 173                         }
 174                         if (*f == '*') {
 175                                 ++f;
 176                                 ++direc_length;
 177                                 if (argc > 0) {
 178                                         field_width = my_xstrtoul(*argv);
 179                                         ++argv;
 180                                         --argc;
 181                                 } else
 182                                         field_width = 0;
 183                         } else
 184                                 while (isdigit(*f)) {
 185                                         ++f;
 186                                         ++direc_length;
 187                                 }
 188                         if (*f == '.') {
 189                                 ++f;
 190                                 ++direc_length;
 191                                 if (*f == '*') {
 192                                         ++f;
 193                                         ++direc_length;
 194                                         if (argc > 0) {
 195                                                 precision = my_xstrtoul(*argv);
 196                                                 ++argv;
 197                                                 --argc;
 198                                         } else
 199                                                 precision = 0;
 200                                 } else
 201                                         while (isdigit(*f)) {
 202                                                 ++f;
 203                                                 ++direc_length;
 204                                         }
 205                         }
 206                         if (*f == 'l' || *f == 'L' || *f == 'h') {
 207                                 ++f;
 208                                 ++direc_length;
 209                         }
 210                         /*
 211                         if (!strchr ("diouxXfeEgGcs", *f))
 212                         fprintf(stderr, "%%%c: invalid directive", *f);
 213                         */
 214                         ++direc_length;
 215                         if (argc > 0) {
 216                                 print_direc(direc_start, direc_length, field_width,
 217                                                         precision, *argv);
 218                                 ++argv;
 219                                 --argc;
 220                         } else
 221                                 print_direc(direc_start, direc_length, field_width,
 222                                                         precision, "");
 223                         break;
 224
 225                 case '\\':
 226                         if (*++f == 'c')
 227                                 exit(0);
 228                         putchar(bb_process_escape_sequence((const char **)&f));
 229                         f--;
 230                         break;
 231
 232                 default:
 233                         putchar(*f);
 234                 }
 235         }
 236
 237         return save_argc - argc;
 238 }
 239
 240 static void
 241 print_direc(char *start, size_t length, int field_width, int precision,
 242                         char *argument)
 243 {
 244         char *p;                /* Null-terminated copy of % directive. */
 245
 246         p = xmalloc((unsigned) (length + 1));
 247         strncpy(p, start, length);
 248         p[length] = 0;
 249
 250         switch (p[length - 1]) {
 251         case 'd':
 252         case 'i':
 253                 if (field_width < 0) {
 254                         if (precision < 0)
 255                                 printf(p, my_xstrtol(argument));
 256                         else
 257                                 printf(p, precision, my_xstrtol(argument));
 258                 } else {
 259                         if (precision < 0)
 260                                 printf(p, field_width, my_xstrtol(argument));
 261                         else
 262                                 printf(p, field_width, precision, my_xstrtol(argument));
 263                 }
 264                 break;
 265
 266         case 'o':
 267         case 'u':
 268         case 'x':
 269         case 'X':
 270                 if (field_width < 0) {
 271                         if (precision < 0)
 272                                 printf(p, my_xstrtoul(argument));
 273                         else
 274                                 printf(p, precision, my_xstrtoul(argument));
 275                 } else {
 276                         if (precision < 0)
 277                                 printf(p, field_width, my_xstrtoul(argument));
 278                         else
 279                                 printf(p, field_width, precision, my_xstrtoul(argument));
 280                 }
 281                 break;
 282
 283         case 'f':
 284         case 'e':
 285         case 'E':
 286         case 'g':
 287         case 'G':
 288                 if (field_width < 0) {
 289                         if (precision < 0)
 290                                 printf(p, my_xstrtod(argument));
 291                         else
 292                                 printf(p, precision, my_xstrtod(argument));
 293                 } else {
 294                         if (precision < 0)
 295                                 printf(p, field_width, my_xstrtod(argument));
 296                         else
 297                                 printf(p, field_width, precision, my_xstrtod(argument));
 298                 }
 299                 break;
 300
 301         case 'c':
 302                 printf(p, *argument);
 303                 break;
 304
 305         case 's':
 306                 if (field_width < 0) {
 307                         if (precision < 0)
 308                                 printf(p, argument);
 309                         else
 310                                 printf(p, precision, argument);
 311                 } else {
 312                         if (precision < 0)
 313                                 printf(p, field_width, argument);
 314                         else
 315                                 printf(p, field_width, precision, argument);
 316                 }
 317                 break;
 318         }
 319
 320         free(p);
 321 }