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