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, const char *argument);
  46
  47 typedef void (*converter)(const char *arg, void *result);
  48
  49 static void multiconvert(const 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(const char *arg, void *result)
  62 {
  63         *(unsigned long*)result = bb_strtoul(arg, NULL, 10);
  64 }
  65 static void conv_strtol(const char *arg, void *result)
  66 {
  67         *(long*)result = bb_strtol(arg, NULL, 10);
  68 }
  69 static void conv_strtod(const 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(const char *arg)
  79 {
  80         unsigned long result;
  81         multiconvert(arg, &result, conv_strtoul);
  82         return result;
  83 }
  84
  85 static long my_xstrtol(const char *arg)
  86 {
  87         long result;
  88         multiconvert(arg, &result, conv_strtol);
  89         return result;
  90 }
  91
  92 static double my_xstrtod(const 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 int printf_main(int argc, char **argv)
 114 {
 115         char *format;
 116         int args_used;
 117
 118         if (argc <= 1 || argv[1][0] == '-') {
 119                 bb_show_usage();
 120         }
 121
 122         format = argv[1];
 123         argc -= 2;
 124         argv += 2;
 125
 126         do {
 127                 args_used = print_formatted(format, argc, argv);
 128                 argc -= args_used;
 129                 argv += args_used;
 130         }
 131         while (args_used > 0 && argc > 0);
 132
 133 /*      if (argc > 0)
 134                 fprintf(stderr, "excess args ignored");
 135 */
 136
 137         return EXIT_SUCCESS;
 138 }
 139
 140 /* Print the text in FORMAT, using ARGV (with ARGC elements) for
 141    arguments to any '%' directives.
 142    Return the number of elements of ARGV used.  */
 143
 144 static int print_formatted(char *format, int argc, char **argv)
 145 {
 146         int save_argc = argc;           /* Preserve original value.  */
 147         char *f;                                        /* Pointer into 'format'.  */
 148         char *direc_start;                      /* Start of % directive.  */
 149         size_t direc_length;            /* Length of % directive.  */
 150         int field_width;                        /* Arg to first '*', or -1 if none.  */
 151         int precision;                          /* Arg to second '*', or -1 if none.  */
 152
 153         for (f = format; *f; ++f) {
 154                 switch (*f) {
 155                 case '%':
 156                         direc_start = f++;
 157                         direc_length = 1;
 158                         field_width = precision = -1;
 159                         if (*f == '%') {
 160                                 putchar('%');
 161                                 break;
 162                         }
 163                         if (*f == 'b') {
 164                                 if (argc > 0) {
 165                                         print_esc_string(*argv);
 166                                         ++argv;
 167                                         --argc;
 168                                 }
 169                                 break;
 170                         }
 171                         if (strchr("-+ #", *f)) {
 172                                 ++f;
 173                                 ++direc_length;
 174                         }
 175                         if (*f == '*') {
 176                                 ++f;
 177                                 ++direc_length;
 178                                 if (argc > 0) {
 179                                         field_width = my_xstrtoul(*argv);
 180                                         ++argv;
 181                                         --argc;
 182                                 } else
 183                                         field_width = 0;
 184                         } else
 185                                 while (isdigit(*f)) {
 186                                         ++f;
 187                                         ++direc_length;
 188                                 }
 189                         if (*f == '.') {
 190                                 ++f;
 191                                 ++direc_length;
 192                                 if (*f == '*') {
 193                                         ++f;
 194                                         ++direc_length;
 195                                         if (argc > 0) {
 196                                                 precision = my_xstrtoul(*argv);
 197                                                 ++argv;
 198                                                 --argc;
 199                                         } else
 200                                                 precision = 0;
 201                                 } else
 202                                         while (isdigit(*f)) {
 203                                                 ++f;
 204                                                 ++direc_length;
 205                                         }
 206                         }
 207                         if (*f == 'l' || *f == 'L' || *f == 'h') {
 208                                 ++f;
 209                                 ++direc_length;
 210                         }
 211                         /*
 212                         if (!strchr ("diouxXfeEgGcs", *f))
 213                         fprintf(stderr, "%%%c: invalid directive", *f);
 214                         */
 215                         ++direc_length;
 216                         if (argc > 0) {
 217                                 print_direc(direc_start, direc_length, field_width,
 218                                                         precision, *argv);
 219                                 ++argv;
 220                                 --argc;
 221                         } else
 222                                 print_direc(direc_start, direc_length, field_width,
 223                                                         precision, "");
 224                         break;
 225
 226                 case '\\':
 227                         if (*++f == 'c')
 228                                 exit(0);
 229                         putchar(bb_process_escape_sequence((const char **)&f));
 230                         f--;
 231                         break;
 232
 233                 default:
 234                         putchar(*f);
 235                 }
 236         }
 237
 238         return save_argc - argc;
 239 }
 240
 241 static void
 242 print_direc(char *start, size_t length, int field_width, int precision,
 243                 const char *argument)
 244 {
 245         char *p;                /* Null-terminated copy of % directive. */
 246
 247         p = xmalloc((unsigned) (length + 1));
 248         strncpy(p, start, length);
 249         p[length] = 0;
 250
 251         switch (p[length - 1]) {
 252         case 'd':
 253         case 'i':
 254                 if (field_width < 0) {
 255                         if (precision < 0)
 256                                 printf(p, my_xstrtol(argument));
 257                         else
 258                                 printf(p, precision, my_xstrtol(argument));
 259                 } else {
 260                         if (precision < 0)
 261                                 printf(p, field_width, my_xstrtol(argument));
 262                         else
 263                                 printf(p, field_width, precision, my_xstrtol(argument));
 264                 }
 265                 break;
 266
 267         case 'o':
 268         case 'u':
 269         case 'x':
 270         case 'X':
 271                 if (field_width < 0) {
 272                         if (precision < 0)
 273                                 printf(p, my_xstrtoul(argument));
 274                         else
 275                                 printf(p, precision, my_xstrtoul(argument));
 276                 } else {
 277                         if (precision < 0)
 278                                 printf(p, field_width, my_xstrtoul(argument));
 279                         else
 280                                 printf(p, field_width, precision, my_xstrtoul(argument));
 281                 }
 282                 break;
 283
 284         case 'f':
 285         case 'e':
 286         case 'E':
 287         case 'g':
 288         case 'G':
 289                 if (field_width < 0) {
 290                         if (precision < 0)
 291                                 printf(p, my_xstrtod(argument));
 292                         else
 293                                 printf(p, precision, my_xstrtod(argument));
 294                 } else {
 295                         if (precision < 0)
 296                                 printf(p, field_width, my_xstrtod(argument));
 297                         else
 298                                 printf(p, field_width, precision, my_xstrtod(argument));
 299                 }
 300                 break;
 301
 302         case 'c':
 303                 printf(p, *argument);
 304                 break;
 305
 306         case 's':
 307                 if (field_width < 0) {
 308                         if (precision < 0)
 309                                 printf(p, argument);
 310                         else
 311                                 printf(p, precision, argument);
 312                 } else {
 313                         if (precision < 0)
 314                                 printf(p, field_width, argument);
 315                         else
 316                                 printf(p, field_width, precision, argument);
 317                 }
 318                 break;
 319         }
 320
 321         free(p);
 322 }