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