coreutils/tr.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini tr implementation for busybox
   4  *
   5  ** Copyright (c) 1987,1997, Prentice Hall   All rights reserved.
   6  *
   7  * The name of Prentice Hall may not be used to endorse or promote
   8  * products derived from this software without specific prior
   9  * written permission.
  10  *
  11  * Copyright (c) Michiel Huisjes
  12  *
  13  * This version of tr is adapted from Minix tr and was modified
  14  * by Erik Andersen <andersen@codepoet.org> to be used in busybox.
  15  *
  16  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  17  */
  18 /* http://www.opengroup.org/onlinepubs/009695399/utilities/tr.html
  19  * TODO: graph, print
  20  */
  21
  22 //kbuild:lib-$(CONFIG_TR) += tr.o
  23
  24 //config:config TR
  25 //config:       bool "tr"
  26 //config:       default y
  27 //config:       help
  28 //config:         tr is used to squeeze, and/or delete characters from standard
  29 //config:         input, writing to standard output.
  30 //config:
  31 //config:config FEATURE_TR_CLASSES
  32 //config:       bool "Enable character classes (such as [:upper:])"
  33 //config:       default y
  34 //config:       depends on TR
  35 //config:       help
  36 //config:         Enable character classes, enabling commands such as:
  37 //config:         tr [:upper:] [:lower:] to convert input into lowercase.
  38 //config:
  39 //config:config FEATURE_TR_EQUIV
  40 //config:       bool "Enable equivalence classes"
  41 //config:       default y
  42 //config:       depends on TR
  43 //config:       help
  44 //config:         Enable equivalence classes, which essentially add the enclosed
  45 //config:         character to the current set. For instance, tr [=a=] xyz would
  46 //config:         replace all instances of 'a' with 'xyz'. This option is mainly
  47 //config:         useful for cases when no other way of expressing a character
  48 //config:         is possible.
  49
  50 //usage:#define tr_trivial_usage
  51 //usage:       "[-cds] STRING1 [STRING2]"
  52 //usage:#define tr_full_usage "\n\n"
  53 //usage:       "Translate, squeeze, or delete characters from stdin, writing to stdout\n"
  54 //usage:     "\n        -c      Take complement of STRING1"
  55 //usage:     "\n        -d      Delete input characters coded STRING1"
  56 //usage:     "\n        -s      Squeeze multiple output characters of STRING2 into one character"
  57 //usage:
  58 //usage:#define tr_example_usage
  59 //usage:       "$ echo \"gdkkn vnqkc\" | tr [a-y] [b-z]\n"
  60 //usage:       "hello world\n"
  61
  62 #include "libbb.h"
  63
  64 enum {
  65         ASCII = 256,
  66         /* string buffer needs to be at least as big as the whole "alphabet".
  67          * BUFSIZ == ASCII is ok, but we will realloc in expand
  68          * even for smallest patterns, let's avoid that by using *2:
  69          */
  70         TR_BUFSIZ = (BUFSIZ > ASCII*2) ? BUFSIZ : ASCII*2,
  71 };
  72
  73 static void map(char *pvector,
  74                 char *string1, unsigned string1_len,
  75                 char *string2, unsigned string2_len)
  76 {
  77         char last = '0';
  78         unsigned i, j;
  79
  80         for (j = 0, i = 0; i < string1_len; i++) {
  81                 if (string2_len <= j)
  82                         pvector[(unsigned char)(string1[i])] = last;
  83                 else
  84                         pvector[(unsigned char)(string1[i])] = last = string2[j++];
  85         }
  86 }
  87
  88 /* supported constructs:
  89  *   Ranges,  e.g.,  0-9   ==>  0123456789
  90  *   Escapes, e.g.,  \a    ==>  Control-G
  91  *   Character classes, e.g. [:upper:] ==> A...Z
  92  *   Equiv classess, e.g. [=A=] ==> A   (hmmmmmmm?)
  93  * not supported:
  94  *   [x*N] - repeat char x N times
  95  *   [x*] - repeat char x until it fills STRING2:
  96  * # echo qwe123 | /usr/bin/tr 123456789 '[d]'
  97  * qwe[d]
  98  * # echo qwe123 | /usr/bin/tr 123456789 '[d*]'
  99  * qweddd
 100  */
 101 static unsigned expand(char *arg, char **buffer_p)
 102 {
 103         char *buffer = *buffer_p;
 104         unsigned pos = 0;
 105         unsigned size = TR_BUFSIZ;
 106         unsigned i; /* can't be unsigned char: must be able to hold 256 */
 107         unsigned char ac;
 108
 109         while (*arg) {
 110                 if (pos + ASCII > size) {
 111                         size += ASCII;
 112                         *buffer_p = buffer = xrealloc(buffer, size);
 113                 }
 114                 if (*arg == '\\') {
 115                         const char *z;
 116                         arg++;
 117                         z = arg;
 118                         ac = bb_process_escape_sequence(&z);
 119                         arg = (char *)z;
 120                         arg--;
 121                         *arg = ac;
 122                         /*
 123                          * fall through, there may be a range.
 124                          * If not, current char will be treated anyway.
 125                          */
 126                 }
 127                 if (arg[1] == '-') { /* "0-9..." */
 128                         ac = arg[2];
 129                         if (ac == '\0') { /* "0-": copy verbatim */
 130                                 buffer[pos++] = *arg++; /* copy '0' */
 131                                 continue; /* next iter will copy '-' and stop */
 132                         }
 133                         i = (unsigned char) *arg;
 134                         arg += 3; /* skip 0-9 or 0-\ */
 135                         if (ac == '\\') {
 136                                 const char *z;
 137                                 z = arg;
 138                                 ac = bb_process_escape_sequence(&z);
 139                                 arg = (char *)z;
 140                         }
 141                         while (i <= ac) /* ok: i is unsigned _int_ */
 142                                 buffer[pos++] = i++;
 143                         continue;
 144                 }
 145                 if ((ENABLE_FEATURE_TR_CLASSES || ENABLE_FEATURE_TR_EQUIV)
 146                  && *arg == '['
 147                 ) {
 148                         arg++;
 149                         i = (unsigned char) *arg++;
 150                         /* "[xyz...". i=x, arg points to y */
 151                         if (ENABLE_FEATURE_TR_CLASSES && i == ':') { /* [:class:] */
 152 #define CLO ":]\0"
 153                                 static const char classes[] ALIGN1 =
 154                                         "alpha"CLO "alnum"CLO "digit"CLO
 155                                         "lower"CLO "upper"CLO "space"CLO
 156                                         "blank"CLO "punct"CLO "cntrl"CLO
 157                                         "xdigit"CLO;
 158                                 enum {
 159                                         CLASS_invalid = 0, /* we increment the retval */
 160                                         CLASS_alpha = 1,
 161                                         CLASS_alnum = 2,
 162                                         CLASS_digit = 3,
 163                                         CLASS_lower = 4,
 164                                         CLASS_upper = 5,
 165                                         CLASS_space = 6,
 166                                         CLASS_blank = 7,
 167                                         CLASS_punct = 8,
 168                                         CLASS_cntrl = 9,
 169                                         CLASS_xdigit = 10,
 170                                         //CLASS_graph = 11,
 171                                         //CLASS_print = 12,
 172                                 };
 173                                 smalluint j;
 174                                 char *tmp;
 175
 176                                 /* xdigit needs 8, not 7 */
 177                                 i = 7 + (arg[0] == 'x');
 178                                 tmp = xstrndup(arg, i);
 179                                 j = index_in_strings(classes, tmp) + 1;
 180                                 free(tmp);
 181
 182                                 if (j == CLASS_invalid)
 183                                         goto skip_bracket;
 184
 185                                 arg += i;
 186                                 if (j == CLASS_alnum || j == CLASS_digit || j == CLASS_xdigit) {
 187                                         for (i = '0'; i <= '9'; i++)
 188                                                 buffer[pos++] = i;
 189                                 }
 190                                 if (j == CLASS_alpha || j == CLASS_alnum || j == CLASS_upper) {
 191                                         for (i = 'A'; i <= 'Z'; i++)
 192                                                 buffer[pos++] = i;
 193                                 }
 194                                 if (j == CLASS_alpha || j == CLASS_alnum || j == CLASS_lower) {
 195                                         for (i = 'a'; i <= 'z'; i++)
 196                                                 buffer[pos++] = i;
 197                                 }
 198                                 if (j == CLASS_space || j == CLASS_blank) {
 199                                         buffer[pos++] = '\t';
 200                                         if (j == CLASS_space) {
 201                                                 buffer[pos++] = '\n';
 202                                                 buffer[pos++] = '\v';
 203                                                 buffer[pos++] = '\f';
 204                                                 buffer[pos++] = '\r';
 205                                         }
 206                                         buffer[pos++] = ' ';
 207                                 }
 208                                 if (j == CLASS_punct || j == CLASS_cntrl) {
 209                                         for (i = '\0'; i < ASCII; i++) {
 210                                                 if ((j == CLASS_punct && isprint_asciionly(i) && !isalnum(i) && !isspace(i))
 211                                                  || (j == CLASS_cntrl && iscntrl(i))
 212                                                 ) {
 213                                                         buffer[pos++] = i;
 214                                                 }
 215                                         }
 216                                 }
 217                                 if (j == CLASS_xdigit) {
 218                                         for (i = 'A'; i <= 'F'; i++) {
 219                                                 buffer[pos + 6] = i | 0x20;
 220                                                 buffer[pos++] = i;
 221                                         }
 222                                         pos += 6;
 223                                 }
 224                                 continue;
 225                         }
 226                         /* "[xyz...", i=x, arg points to y */
 227                         if (ENABLE_FEATURE_TR_EQUIV && i == '=') { /* [=CHAR=] */
 228                                 buffer[pos++] = *arg; /* copy CHAR */
 229                                 if (!arg[0] || arg[1] != '=' || arg[2] != ']')
 230                                         bb_show_usage();
 231                                 arg += 3;  /* skip CHAR=] */
 232                                 continue;
 233                         }
 234                         /* The rest of "[xyz..." cases is treated as normal
 235                          * string, "[" has no special meaning here:
 236                          * tr "[a-z]" "[A-Z]" can be written as tr "a-z" "A-Z",
 237                          * also try tr "[a-z]" "_A-Z+" and you'll see that
 238                          * [] is not special here.
 239                          */
 240  skip_bracket:
 241                         arg -= 2; /* points to "[" in "[xyz..." */
 242                 }
 243                 buffer[pos++] = *arg++;
 244         }
 245         return pos;
 246 }
 247
 248 /* NB: buffer is guaranteed to be at least TR_BUFSIZE
 249  * (which is >= ASCII) big.
 250  */
 251 static int complement(char *buffer, int buffer_len)
 252 {
 253         int len;
 254         char conv[ASCII];
 255         unsigned char ch;
 256
 257         len = 0;
 258         ch = '\0';
 259         while (1) {
 260                 if (memchr(buffer, ch, buffer_len) == NULL)
 261                         conv[len++] = ch;
 262                 if (++ch == '\0')
 263                         break;
 264         }
 265         memcpy(buffer, conv, len);
 266         return len;
 267 }
 268
 269 int tr_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 270 int tr_main(int argc UNUSED_PARAM, char **argv)
 271 {
 272         int i;
 273         smalluint opts;
 274         ssize_t read_chars;
 275         size_t in_index, out_index;
 276         unsigned last = UCHAR_MAX + 1; /* not equal to any char */
 277         unsigned char coded, c;
 278         char *str1 = xmalloc(TR_BUFSIZ);
 279         char *str2 = xmalloc(TR_BUFSIZ);
 280         int str2_length;
 281         int str1_length;
 282         char *vector = xzalloc(ASCII * 3);
 283         char *invec  = vector + ASCII;
 284         char *outvec = vector + ASCII * 2;
 285
 286 #define TR_OPT_complement   (3 << 0)
 287 #define TR_OPT_delete       (1 << 2)
 288 #define TR_OPT_squeeze_reps (1 << 3)
 289
 290         for (i = 0; i < ASCII; i++) {
 291                 vector[i] = i;
 292                 /*invec[i] = outvec[i] = FALSE; - done by xzalloc */
 293         }
 294
 295         /* -C/-c difference is that -C complements "characters",
 296          * and -c complements "values" (binary bytes I guess).
 297          * In POSIX locale, these are the same.
 298          */
 299
 300         opt_complementary = "-1";
 301         opts = getopt32(argv, "+Ccds"); /* '+': stop at first non-option */
 302         argv += optind;
 303
 304         str1_length = expand(*argv++, &str1);
 305         str2_length = 0;
 306         if (opts & TR_OPT_complement)
 307                 str1_length = complement(str1, str1_length);
 308         if (*argv) {
 309                 if (argv[0][0] == '\0')
 310                         bb_error_msg_and_die("STRING2 cannot be empty");
 311                 str2_length = expand(*argv, &str2);
 312                 map(vector, str1, str1_length,
 313                                 str2, str2_length);
 314         }
 315         for (i = 0; i < str1_length; i++)
 316                 invec[(unsigned char)(str1[i])] = TRUE;
 317         for (i = 0; i < str2_length; i++)
 318                 outvec[(unsigned char)(str2[i])] = TRUE;
 319
 320         goto start_from;
 321
 322         /* In this loop, str1 space is reused as input buffer,
 323          * str2 - as output one. */
 324         for (;;) {
 325                 /* If we're out of input, flush output and read more input. */
 326                 if ((ssize_t)in_index == read_chars) {
 327                         if (out_index) {
 328                                 xwrite(STDOUT_FILENO, str2, out_index);
 329  start_from:
 330                                 out_index = 0;
 331                         }
 332                         read_chars = safe_read(STDIN_FILENO, str1, TR_BUFSIZ);
 333                         if (read_chars <= 0) {
 334                                 if (read_chars < 0)
 335                                         bb_perror_msg_and_die(bb_msg_read_error);
 336                                 break;
 337                         }
 338                         in_index = 0;
 339                 }
 340                 c = str1[in_index++];
 341                 if ((opts & TR_OPT_delete) && invec[c])
 342                         continue;
 343                 coded = vector[c];
 344                 if ((opts & TR_OPT_squeeze_reps) && last == coded
 345                  && (invec[c] || outvec[coded])
 346                 ) {
 347                         continue;
 348                 }
 349                 str2[out_index++] = last = coded;
 350         }
 351
 352         if (ENABLE_FEATURE_CLEAN_UP) {
 353                 free(vector);
 354                 free(str2);
 355                 free(str1);
 356         }
 357
 358         return EXIT_SUCCESS;
 359 }