coreutils/sort.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * SuS3 compliant sort implementation for busybox
   4  *
   5  * Copyright (C) 2004 by Rob Landley <rob@landley.net>
   6  *
   7  * MAINTAINER: Rob Landley <rob@landley.net>
   8  *
   9  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  10  *
  11  * See SuS3 sort standard at:
  12  * http://www.opengroup.org/onlinepubs/007904975/utilities/sort.html
  13  */
  14 //config:config SORT
  15 //config:       bool "sort (7.4 kb)"
  16 //config:       default y
  17 //config:       help
  18 //config:       sort is used to sort lines of text in specified files.
  19 //config:
  20 //config:config FEATURE_SORT_BIG
  21 //config:       bool "Full SuSv3 compliant sort (support -ktcbdfiogM)"
  22 //config:       default y
  23 //config:       depends on SORT
  24 //config:       help
  25 //config:       Without this, sort only supports -rusz, and an integer version
  26 //config:       of -n. Selecting this adds sort keys, floating point support, and
  27 //config:       more. This adds a little over 3k to a nonstatic build on x86.
  28 //config:
  29 //config:       The SuSv3 sort standard is available at:
  30 //config:       http://www.opengroup.org/onlinepubs/007904975/utilities/sort.html
  31 //config:
  32 //config:config FEATURE_SORT_OPTIMIZE_MEMORY
  33 //config:       bool "Use less memory (but might be slower)"
  34 //config:       default n   # defaults to N since we are size-paranoid tribe
  35 //config:       depends on SORT
  36 //config:       help
  37 //config:       Attempt to use less memory (by storing only one copy
  38 //config:       of duplicated lines, and such). Useful if you work on huge files.
  39
  40 //applet:IF_SORT(APPLET_NOEXEC(sort, sort, BB_DIR_USR_BIN, BB_SUID_DROP, sort))
  41
  42 //kbuild:lib-$(CONFIG_SORT) += sort.o
  43
  44 //usage:#define sort_trivial_usage
  45 //usage:       "[-nru"
  46 //usage:        IF_FEATURE_SORT_BIG("gMcszbdfiokt] [-o FILE] [-k start[.offset][opts][,end[.offset][opts]] [-t CHAR")
  47 //usage:       "] [FILE]..."
  48 //usage:#define sort_full_usage "\n\n"
  49 //usage:       "Sort lines of text\n"
  50 //usage:        IF_FEATURE_SORT_BIG(
  51 //usage:     "\n        -o FILE Output to FILE"
  52 //usage:     "\n        -c      Check whether input is sorted"
  53 //usage:     "\n        -b      Ignore leading blanks"
  54 //usage:     "\n        -f      Ignore case"
  55 //usage:     "\n        -i      Ignore unprintable characters"
  56 //usage:     "\n        -d      Dictionary order (blank or alphanumeric only)"
  57 //usage:        )
  58 //-h, --human-numeric-sort: compare human readable numbers (e.g., 2K 1G)
  59 //usage:     "\n        -n      Sort numbers"
  60 //usage:        IF_FEATURE_SORT_BIG(
  61 //usage:     "\n        -g      General numerical sort"
  62 //usage:     "\n        -M      Sort month"
  63 //usage:     "\n        -t CHAR Field separator"
  64 //usage:     "\n        -k N[,M] Sort by Nth field"
  65 //usage:        )
  66 //usage:     "\n        -r      Reverse sort order"
  67 //usage:     "\n        -s      Stable (don't sort ties alphabetically)"
  68 //usage:     "\n        -u      Suppress duplicate lines"
  69 //usage:     "\n        -z      Lines are terminated by NUL, not newline"
  70 ///////:     "\n        -m      Ignored for GNU compatibility"
  71 ///////:     "\n        -S BUFSZ Ignored for GNU compatibility"
  72 ///////:     "\n        -T TMPDIR Ignored for GNU compatibility"
  73 //usage:
  74 //usage:#define sort_example_usage
  75 //usage:       "$ echo -e \"e\\nf\\nb\\nd\\nc\\na\" | sort\n"
  76 //usage:       "a\n"
  77 //usage:       "b\n"
  78 //usage:       "c\n"
  79 //usage:       "d\n"
  80 //usage:       "e\n"
  81 //usage:       "f\n"
  82 //usage:        IF_FEATURE_SORT_BIG(
  83 //usage:                "$ echo -e \"c 3\\nb 2\\nd 2\" | $SORT -k 2,2n -k 1,1r\n"
  84 //usage:                "d 2\n"
  85 //usage:                "b 2\n"
  86 //usage:                "c 3\n"
  87 //usage:        )
  88 //usage:       ""
  89
  90 #include "libbb.h"
  91
  92 /* These are sort types */
  93 enum {
  94         FLAG_n  = 1,            /* Numeric sort */
  95         FLAG_g  = 2,            /* Sort using strtod() */
  96         FLAG_M  = 4,            /* Sort date */
  97 /* ucsz apply to root level only, not keys.  b at root level implies bb */
  98         FLAG_u  = 8,            /* Unique */
  99         FLAG_c  = 0x10,         /* Check: no output, exit(!ordered) */
 100         FLAG_s  = 0x20,         /* Stable sort, no ascii fallback at end */
 101         FLAG_z  = 0x40,         /* Input and output is NUL terminated, not \n */
 102 /* These can be applied to search keys, the previous four can't */
 103         FLAG_b  = 0x80,         /* Ignore leading blanks */
 104         FLAG_r  = 0x100,        /* Reverse */
 105         FLAG_d  = 0x200,        /* Ignore !(isalnum()|isspace()) */
 106         FLAG_f  = 0x400,        /* Force uppercase */
 107         FLAG_i  = 0x800,        /* Ignore !isprint() */
 108         FLAG_m  = 0x1000,       /* ignored: merge already sorted files; do not sort */
 109         FLAG_S  = 0x2000,       /* ignored: -S, --buffer-size=SIZE */
 110         FLAG_T  = 0x4000,       /* ignored: -T, --temporary-directory=DIR */
 111         FLAG_o  = 0x8000,
 112         FLAG_k  = 0x10000,
 113         FLAG_t  = 0x20000,
 114         FLAG_bb = 0x80000000,   /* Ignore trailing blanks  */
 115         FLAG_no_tie_break = 0x40000000,
 116 };
 117
 118 static const char sort_opt_str[] ALIGN1 = "^"
 119                         "ngMucszbrdfimS:T:o:k:*t:"
 120                         "\0" "o--o:t--t"/*-t, -o: at most one of each*/;
 121 /*
 122  * OPT_STR must not be string literal, needs to have stable address:
 123  * code uses "strchr(OPT_STR,c) - OPT_STR" idiom.
 124  */
 125 #define OPT_STR (sort_opt_str + 1)
 126
 127 #if ENABLE_FEATURE_SORT_BIG
 128 static char key_separator;
 129
 130 static struct sort_key {
 131         struct sort_key *next_key;  /* linked list */
 132         unsigned range[4];          /* start word, start char, end word, end char */
 133         unsigned flags;
 134 } *key_list;
 135
 136
 137 /* This is a NOEXEC applet. Be very careful! */
 138
 139
 140 static char *get_key(char *str, struct sort_key *key, int flags)
 141 {
 142         int start = start; /* for compiler */
 143         int end;
 144         int len, j;
 145         unsigned i;
 146
 147         /* Special case whole string, so we don't have to make a copy */
 148         if (key->range[0] == 1 && !key->range[1] && !key->range[2] && !key->range[3]
 149          && !(flags & (FLAG_b | FLAG_d | FLAG_f | FLAG_i | FLAG_bb))
 150         ) {
 151                 return str;
 152         }
 153
 154         /* Find start of key on first pass, end on second pass */
 155         len = strlen(str);
 156         for (j = 0; j < 2; j++) {
 157                 if (!key->range[2*j])
 158                         end = len;
 159                 /* Loop through fields */
 160                 else {
 161                         unsigned char ch = 0;
 162
 163                         end = 0;
 164                         for (i = 1; i < key->range[2*j] + j; i++) {
 165                                 if (key_separator) {
 166                                         /* Skip body of key and separator */
 167                                         while ((ch = str[end]) != '\0') {
 168                                                         end++;
 169                                                 if (ch == key_separator)
 170                                                         break;
 171                                         }
 172                                 } else {
 173                                         /* Skip leading blanks */
 174                                         while (isspace(str[end]))
 175                                                 end++;
 176                                         /* Skip body of key */
 177                                         while (str[end] != '\0') {
 178                                                 if (isspace(str[end]))
 179                                                         break;
 180                                                 end++;
 181                                         }
 182                                 }
 183                         }
 184                         /* Remove last delim: "abc:def:" => "abc:def" */
 185                         if (j && ch) {
 186                                 //if (str[end-1] != key_separator)
 187                                 //  bb_error_msg(_and_die("BUG! "
 188                                 //  "str[start:%d,end:%d]:'%.*s'",
 189                                 //  start, end, (int)(end-start), &str[start]);
 190                                 end--;
 191                         }
 192                 }
 193                 if (!j) start = end;
 194         }
 195         /* Strip leading whitespace if necessary */
 196         if (flags & FLAG_b)
 197                 /* not using skip_whitespace() for speed */
 198                 while (isspace(str[start])) start++;
 199         /* Strip trailing whitespace if necessary */
 200         if (flags & FLAG_bb)
 201                 while (end > start && isspace(str[end-1])) end--;
 202         /* -kSTART,N.ENDCHAR: honor ENDCHAR (1-based) */
 203         if (key->range[3]) {
 204                 end = key->range[3];
 205                 if (end > len) end = len;
 206         }
 207         /* -kN.STARTCHAR[,...]: honor STARTCHAR (1-based) */
 208         if (key->range[1]) {
 209                 start += key->range[1] - 1;
 210                 if (start > len) start = len;
 211         }
 212         /* Make the copy */
 213         if (end < start)
 214                 end = start;
 215         str = xstrndup(str+start, end-start);
 216         /* Handle -d */
 217         if (flags & FLAG_d) {
 218                 for (start = end = 0; str[end]; end++)
 219                         if (isspace(str[end]) || isalnum(str[end]))
 220                                 str[start++] = str[end];
 221                 str[start] = '\0';
 222         }
 223         /* Handle -i */
 224         if (flags & FLAG_i) {
 225                 for (start = end = 0; str[end]; end++)
 226                         if (isprint_asciionly(str[end]))
 227                                 str[start++] = str[end];
 228                 str[start] = '\0';
 229         }
 230         /* Handle -f */
 231         if (flags & FLAG_f)
 232                 for (i = 0; str[i]; i++)
 233                         str[i] = toupper(str[i]);
 234
 235         return str;
 236 }
 237
 238 static struct sort_key *add_key(void)
 239 {
 240         struct sort_key **pkey = &key_list;
 241         while (*pkey)
 242                 pkey = &((*pkey)->next_key);
 243         return *pkey = xzalloc(sizeof(struct sort_key));
 244 }
 245
 246 #define GET_LINE(fp) \
 247         ((option_mask32 & FLAG_z) \
 248         ? bb_get_chunk_from_file(fp, NULL) \
 249         : xmalloc_fgetline(fp))
 250 #else
 251 #define GET_LINE(fp) xmalloc_fgetline(fp)
 252 #endif
 253
 254 /* Iterate through keys list and perform comparisons */
 255 static int compare_keys(const void *xarg, const void *yarg)
 256 {
 257         int flags = option_mask32, retval = 0;
 258         char *x, *y;
 259
 260 #if ENABLE_FEATURE_SORT_BIG
 261         struct sort_key *key;
 262
 263         for (key = key_list; !retval && key; key = key->next_key) {
 264                 flags = key->flags ? key->flags : option_mask32;
 265                 /* Chop out and modify key chunks, handling -dfib */
 266                 x = get_key(*(char **)xarg, key, flags);
 267                 y = get_key(*(char **)yarg, key, flags);
 268 #else
 269         /* This curly bracket serves no purpose but to match the nesting
 270          * level of the for () loop we're not using */
 271         {
 272                 x = *(char **)xarg;
 273                 y = *(char **)yarg;
 274 #endif
 275                 /* Perform actual comparison */
 276                 switch (flags & (FLAG_n | FLAG_M | FLAG_g)) {
 277                 default:
 278                         bb_error_msg_and_die("unknown sort type");
 279                         break;
 280                 /* Ascii sort */
 281                 case 0:
 282 #if ENABLE_LOCALE_SUPPORT
 283                         retval = strcoll(x, y);
 284 #else
 285                         retval = strcmp(x, y);
 286 #endif
 287                         break;
 288 #if ENABLE_FEATURE_SORT_BIG
 289                 case FLAG_g: {
 290                         char *xx, *yy;
 291                         double dx = strtod(x, &xx);
 292                         double dy = strtod(y, &yy);
 293                         /* not numbers < NaN < -infinity < numbers < +infinity) */
 294                         if (x == xx)
 295                                 retval = (y == yy ? 0 : -1);
 296                         else if (y == yy)
 297                                 retval = 1;
 298                         /* Check for isnan */
 299                         else if (dx != dx)
 300                                 retval = (dy != dy) ? 0 : -1;
 301                         else if (dy != dy)
 302                                 retval = 1;
 303                         /* Check for infinity.  Could underflow, but it avoids libm. */
 304                         else if (1.0 / dx == 0.0) {
 305                                 if (dx < 0)
 306                                         retval = (1.0 / dy == 0.0 && dy < 0) ? 0 : -1;
 307                                 else
 308                                         retval = (1.0 / dy == 0.0 && dy > 0) ? 0 : 1;
 309                         } else if (1.0 / dy == 0.0)
 310                                 retval = (dy < 0) ? 1 : -1;
 311                         else
 312                                 retval = (dx > dy) ? 1 : ((dx < dy) ? -1 : 0);
 313                         break;
 314                 }
 315                 case FLAG_M: {
 316                         struct tm thyme;
 317                         int dx;
 318                         char *xx, *yy;
 319
 320                         xx = strptime(x, "%b", &thyme);
 321                         dx = thyme.tm_mon;
 322                         yy = strptime(y, "%b", &thyme);
 323                         if (!xx)
 324                                 retval = (!yy) ? 0 : -1;
 325                         else if (!yy)
 326                                 retval = 1;
 327                         else
 328                                 retval = dx - thyme.tm_mon;
 329                         break;
 330                 }
 331                 /* Full floating point version of -n */
 332                 case FLAG_n: {
 333                         double dx = atof(x);
 334                         double dy = atof(y);
 335                         retval = (dx > dy) ? 1 : ((dx < dy) ? -1 : 0);
 336                         break;
 337                 }
 338                 } /* switch */
 339                 /* Free key copies. */
 340                 if (x != *(char **)xarg) free(x);
 341                 if (y != *(char **)yarg) free(y);
 342                 /* if (retval) break; - done by for () anyway */
 343 #else
 344                 /* Integer version of -n for tiny systems */
 345                 case FLAG_n:
 346                         retval = atoi(x) - atoi(y);
 347                         break;
 348                 } /* switch */
 349 #endif
 350         } /* for */
 351
 352         if (retval == 0) {
 353                 /* So far lines are "the same" */
 354
 355                 if (option_mask32 & FLAG_s) {
 356                         /* "Stable sort": later line is "greater than",
 357                          * IOW: do not allow qsort() to swap equal lines.
 358                          */
 359                         uint32_t *p32;
 360                         uint32_t x32, y32;
 361                         char *line;
 362                         unsigned len;
 363
 364                         line = *(char**)xarg;
 365                         len = (strlen(line) + 4) & (~3u);
 366                         p32 = (void*)(line + len);
 367                         x32 = *p32;
 368                         line = *(char**)yarg;
 369                         len = (strlen(line) + 4) & (~3u);
 370                         p32 = (void*)(line + len);
 371                         y32 = *p32;
 372
 373                         /* If x > y, 1, else -1 */
 374                         retval = (x32 > y32) * 2 - 1;
 375                 } else
 376                 if (!(option_mask32 & FLAG_no_tie_break)) {
 377                         /* fallback sort */
 378                         flags = option_mask32;
 379                         retval = strcmp(*(char **)xarg, *(char **)yarg);
 380                 }
 381         }
 382
 383         if (flags & FLAG_r)
 384                 return -retval;
 385
 386         return retval;
 387 }
 388
 389 #if ENABLE_FEATURE_SORT_BIG
 390 static unsigned str2u(char **str)
 391 {
 392         unsigned long lu;
 393         if (!isdigit((*str)[0]))
 394                 bb_error_msg_and_die("bad field specification");
 395         lu = strtoul(*str, str, 10);
 396         if ((sizeof(long) > sizeof(int) && lu > INT_MAX) || !lu)
 397                 bb_error_msg_and_die("bad field specification");
 398         return lu;
 399 }
 400 #endif
 401
 402 int sort_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 403 int sort_main(int argc UNUSED_PARAM, char **argv)
 404 {
 405         char **lines;
 406         char *str_ignored, *str_o, *str_t;
 407         llist_t *lst_k = NULL;
 408         int i;
 409         int linecount;
 410         unsigned opts;
 411 #if ENABLE_FEATURE_SORT_OPTIMIZE_MEMORY
 412         bool can_drop_dups;
 413         size_t prev_len = 0;
 414         char *prev_line = (char*) "";
 415         /* Postpone optimizing if the input is small, < 16k lines:
 416          * even just free()ing duplicate lines takes time.
 417          */
 418         size_t count_to_optimize_dups = 0x3fff;
 419 #endif
 420
 421         xfunc_error_retval = 2;
 422
 423         /* Parse command line options */
 424         opts = getopt32(argv,
 425                         sort_opt_str,
 426                         &str_ignored, &str_ignored, &str_o, &lst_k, &str_t
 427         );
 428 #if ENABLE_FEATURE_SORT_OPTIMIZE_MEMORY
 429         /* Can drop dups only if -u but no "complicating" options,
 430          * IOW: if we do a full line compares. Safe options:
 431          * -o FILE Output to FILE
 432          * -z      Lines are terminated by NUL, not newline
 433          * -r      Reverse sort order
 434          * -s      Stable (don't sort ties alphabetically)
 435          * Not sure about these:
 436          * -b      Ignore leading blanks
 437          * -f      Ignore case
 438          * -i      Ignore unprintable characters
 439          * -d      Dictionary order (blank or alphanumeric only)
 440          * -n      Sort numbers
 441          * -g      General numerical sort
 442          * -M      Sort month
 443          */
 444         can_drop_dups = ((opts & ~(FLAG_o|FLAG_z|FLAG_r|FLAG_s)) == FLAG_u);
 445         /* Stable sort needs every line to be uniquely allocated,
 446          * disable optimization to reuse strings:
 447          */
 448         if (opts & FLAG_s)
 449                 count_to_optimize_dups = (size_t)-1L;
 450 #endif
 451         /* global b strips leading and trailing spaces */
 452         if (opts & FLAG_b)
 453                 option_mask32 |= FLAG_bb;
 454 #if ENABLE_FEATURE_SORT_BIG
 455         if (opts & FLAG_t) {
 456                 if (!str_t[0] || str_t[1])
 457                         bb_error_msg_and_die("bad -t parameter");
 458                 key_separator = str_t[0];
 459         }
 460         /* note: below this point we use option_mask32, not opts,
 461          * since that reduces register pressure and makes code smaller */
 462
 463         /* Parse sort key */
 464         while (lst_k) {
 465                 enum {
 466                         FLAG_allowed_for_k =
 467                                 FLAG_n | /* Numeric sort */
 468                                 FLAG_g | /* Sort using strtod() */
 469                                 FLAG_M | /* Sort date */
 470                                 FLAG_b | /* Ignore leading blanks */
 471                                 FLAG_r | /* Reverse */
 472                                 FLAG_d | /* Ignore !(isalnum()|isspace()) */
 473                                 FLAG_f | /* Force uppercase */
 474                                 FLAG_i | /* Ignore !isprint() */
 475                         0
 476                 };
 477                 struct sort_key *key = add_key();
 478                 char *str_k = llist_pop(&lst_k);
 479
 480                 i = 0; /* i==0 before comma, 1 after (-k3,6) */
 481                 while (*str_k) {
 482                         /* Start of range */
 483                         /* Cannot use bb_strtou - suffix can be a letter */
 484                         key->range[2*i] = str2u(&str_k);
 485                         if (*str_k == '.') {
 486                                 str_k++;
 487                                 key->range[2*i+1] = str2u(&str_k);
 488                         }
 489                         while (*str_k) {
 490                                 int flag;
 491                                 const char *idx;
 492
 493                                 if (*str_k == ',' && !i++) {
 494                                         str_k++;
 495                                         break;
 496                                 } /* no else needed: fall through to syntax error
 497                                         because comma isn't in OPT_STR */
 498                                 idx = strchr(OPT_STR, *str_k);
 499                                 if (!idx)
 500                                         bb_error_msg_and_die("unknown key option");
 501                                 flag = 1 << (idx - OPT_STR);
 502                                 if (flag & ~FLAG_allowed_for_k)
 503                                         bb_error_msg_and_die("unknown sort type");
 504                                 /* b after ',' means strip _trailing_ space */
 505                                 if (i && flag == FLAG_b)
 506                                         flag = FLAG_bb;
 507                                 key->flags |= flag;
 508                                 str_k++;
 509                         }
 510                 }
 511         }
 512 #endif
 513
 514         /* Open input files and read data */
 515         argv += optind;
 516         if (!*argv)
 517                 *--argv = (char*)"-";
 518         linecount = 0;
 519         lines = NULL;
 520         do {
 521                 /* coreutils 6.9 compat: abort on first open error,
 522                  * do not continue to next file: */
 523                 FILE *fp = xfopen_stdin(*argv);
 524                 for (;;) {
 525                         char *line = GET_LINE(fp);
 526                         if (!line)
 527                                 break;
 528
 529 #if ENABLE_FEATURE_SORT_OPTIMIZE_MEMORY
 530                         if (count_to_optimize_dups != 0)
 531                                 count_to_optimize_dups--;
 532                         if (count_to_optimize_dups == 0) {
 533                                 size_t len;
 534                                 char *new_line;
 535
 536                                 /* On kernel/linux/arch/ *.[ch] files,
 537                                  * this reduces memory usage by 6%.
 538                                  *  yes | head -99999999 | sort
 539                                  * goes down from 1900Mb to 380 Mb.
 540                                  */
 541                                 len = strlen(line);
 542                                 if (len <= prev_len) {
 543                                         new_line = prev_line + (prev_len - len);
 544                                         if (strcmp(line, new_line) == 0) {
 545                                                 /* it's a tail of the prev line */
 546                                                 if (can_drop_dups && prev_len == len) {
 547                                                         /* it's identical to prev line */
 548                                                         free(line);
 549                                                         continue;
 550                                                 }
 551                                                 free(line);
 552                                                 line = new_line;
 553                                                 /* continue using longer prev_line
 554                                                  * for future tail tests.
 555                                                  */
 556                                                 goto skip;
 557                                         }
 558                                 }
 559                                 prev_len = len;
 560                                 prev_line = line;
 561  skip: ;
 562                         }
 563 #else
 564 //TODO: lighter version which only drops total dups if can_drop_dups == true
 565 #endif
 566                         lines = xrealloc_vector(lines, 6, linecount);
 567                         lines[linecount++] = line;
 568                 }
 569                 fclose_if_not_stdin(fp);
 570         } while (*++argv);
 571
 572 #if ENABLE_FEATURE_SORT_BIG
 573         /* If no key, perform alphabetic sort */
 574         if (!key_list)
 575                 add_key()->range[0] = 1;
 576         /* Handle -c */
 577         if (option_mask32 & FLAG_c) {
 578                 int j = (option_mask32 & FLAG_u) ? -1 : 0;
 579                 for (i = 1; i < linecount; i++) {
 580                         if (compare_keys(&lines[i-1], &lines[i]) > j) {
 581                                 fprintf(stderr, "Check line %u\n", i);
 582                                 return EXIT_FAILURE;
 583                         }
 584                 }
 585                 return EXIT_SUCCESS;
 586         }
 587 #endif
 588
 589         /* For stable sort, store original line position beyond terminating NUL */
 590         if (option_mask32 & FLAG_s) {
 591                 for (i = 0; i < linecount; i++) {
 592                         uint32_t *p32;
 593                         char *line;
 594                         unsigned len;
 595
 596                         line = lines[i];
 597                         len = (strlen(line) + 4) & (~3u);
 598                         lines[i] = line = xrealloc(line, len + 4);
 599                         p32 = (void*)(line + len);
 600                         *p32 = i;
 601                 }
 602                 /*option_mask32 |= FLAG_no_tie_break;*/
 603                 /* ^^^redundant: if FLAG_s, compare_keys() does no tie break */
 604         }
 605
 606         /* Perform the actual sort */
 607         qsort(lines, linecount, sizeof(lines[0]), compare_keys);
 608
 609         /* Handle -u */
 610         if (option_mask32 & FLAG_u) {
 611                 int j = 0;
 612                 /* coreutils 6.3 drop lines for which only key is the same
 613                  * -- disabling last-resort compare, or else compare_keys()
 614                  * will be the same only for completely identical lines.
 615                  */
 616                 option_mask32 |= FLAG_no_tie_break;
 617                 for (i = 1; i < linecount; i++) {
 618                         if (compare_keys(&lines[j], &lines[i]) == 0)
 619                                 free(lines[i]);
 620                         else
 621                                 lines[++j] = lines[i];
 622                 }
 623                 if (linecount)
 624                         linecount = j+1;
 625         }
 626
 627         /* Print it */
 628 #if ENABLE_FEATURE_SORT_BIG
 629         /* Open output file _after_ we read all input ones */
 630         if (option_mask32 & FLAG_o)
 631                 xmove_fd(xopen(str_o, O_WRONLY|O_CREAT|O_TRUNC), STDOUT_FILENO);
 632 #endif
 633         {
 634                 int ch = (option_mask32 & FLAG_z) ? '\0' : '\n';
 635                 for (i = 0; i < linecount; i++)
 636                         printf("%s%c", lines[i], ch);
 637         }
 638
 639         fflush_stdout_and_exit(EXIT_SUCCESS);
 640 }