src/paste.c

   1 /* paste - merge lines of files
   2    Copyright (C) 1997-2012 Free Software Foundation, Inc.
   3    Copyright (C) 1984 David M. Ihnat
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation, either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 /* Written by David Ihnat.  */
  19
  20 /* The list of valid escape sequences has been expanded over the Unix
  21    version, to include \b, \f, \r, and \v.
  22
  23    POSIX changes, bug fixes, long-named options, and cleanup
  24    by David MacKenzie <djm@gnu.ai.mit.edu>.
  25
  26    Options:
  27    --serial
  28    -s                           Paste one file at a time rather than
  29                                 one line from each file.
  30    --delimiters=delim-list
  31    -d delim-list                Consecutively use the characters in
  32                                 DELIM-LIST instead of tab to separate
  33                                 merged lines.  When DELIM-LIST is exhausted,
  34                                 start again at its beginning.
  35    A FILE of '-' means standard input.
  36    If no FILEs are given, standard input is used. */
  37
  38 #include <config.h>
  39
  40 #include <stdio.h>
  41 #include <getopt.h>
  42 #include <sys/types.h>
  43 #include "system.h"
  44 #include "error.h"
  45 #include "fadvise.h"
  46 #include "quotearg.h"
  47
  48 /* The official name of this program (e.g., no 'g' prefix).  */
  49 #define PROGRAM_NAME "paste"
  50
  51 #define AUTHORS \
  52   proper_name ("David M. Ihnat"), \
  53   proper_name ("David MacKenzie")
  54
  55 /* Indicates that no delimiter should be added in the current position. */
  56 #define EMPTY_DELIM '\0'
  57
  58 /* If nonzero, we have read standard input at some point. */
  59 static bool have_read_stdin;
  60
  61 /* If nonzero, merge subsequent lines of each file rather than
  62    corresponding lines from each file in parallel. */
  63 static bool serial_merge;
  64
  65 /* The delimeters between lines of input files (used cyclically). */
  66 static char *delims;
  67
  68 /* A pointer to the character after the end of 'delims'. */
  69 static char const *delim_end;
  70
  71 static struct option const longopts[] =
  72 {
  73   {"serial", no_argument, NULL, 's'},
  74   {"delimiters", required_argument, NULL, 'd'},
  75   {GETOPT_HELP_OPTION_DECL},
  76   {GETOPT_VERSION_OPTION_DECL},
  77   {NULL, 0, NULL, 0}
  78 };
  79
  80 /* Set globals delims and delim_end.  Copy STRPTR to DELIMS, converting
  81    backslash representations of special characters in STRPTR to their actual
  82    values. The set of possible backslash characters has been expanded beyond
  83    that recognized by the Unix version.
  84    Return 0 upon success.
  85    If the string ends in an odd number of backslashes, ignore the
  86    final backslash and return nonzero.  */
  87
  88 static int
  89 collapse_escapes (char const *strptr)
  90 {
  91   char *strout = xstrdup (strptr);
  92   bool backslash_at_end = false;
  93
  94   delims = strout;
  95
  96   while (*strptr)
  97     {
  98       if (*strptr != '\\')      /* Is it an escape character? */
  99         *strout++ = *strptr++;  /* No, just transfer it. */
 100       else
 101         {
 102           switch (*++strptr)
 103             {
 104             case '0':
 105               *strout++ = EMPTY_DELIM;
 106               break;
 107
 108             case 'b':
 109               *strout++ = '\b';
 110               break;
 111
 112             case 'f':
 113               *strout++ = '\f';
 114               break;
 115
 116             case 'n':
 117               *strout++ = '\n';
 118               break;
 119
 120             case 'r':
 121               *strout++ = '\r';
 122               break;
 123
 124             case 't':
 125               *strout++ = '\t';
 126               break;
 127
 128             case 'v':
 129               *strout++ = '\v';
 130               break;
 131
 132             case '\\':
 133               *strout++ = '\\';
 134               break;
 135
 136             case '\0':
 137               backslash_at_end = true;
 138               goto done;
 139
 140             default:
 141               *strout++ = *strptr;
 142               break;
 143             }
 144           strptr++;
 145         }
 146     }
 147
 148  done:
 149
 150   delim_end = strout;
 151   return backslash_at_end ? 1 : 0;
 152 }
 153
 154 /* Report a write error and exit.  */
 155
 156 static void write_error (void) ATTRIBUTE_NORETURN;
 157 static void
 158 write_error (void)
 159 {
 160   error (EXIT_FAILURE, errno, _("write error"));
 161   abort ();
 162 }
 163
 164 /* Output a single byte, reporting any write errors.  */
 165
 166 static inline void
 167 xputchar (char c)
 168 {
 169   if (putchar (c) < 0)
 170     write_error ();
 171 }
 172
 173 /* Perform column paste on the NFILES files named in FNAMPTR.
 174    Return true if successful, false if one or more files could not be
 175    opened or read. */
 176
 177 static bool
 178 paste_parallel (size_t nfiles, char **fnamptr)
 179 {
 180   bool ok = true;
 181   /* If all files are just ready to be closed, or will be on this
 182      round, the string of delimiters must be preserved.
 183      delbuf[0] through delbuf[nfiles]
 184      store the delimiters for closed files. */
 185   char *delbuf = xmalloc (nfiles + 2);
 186
 187   /* Streams open to the files to process; NULL if the corresponding
 188      stream is closed.  */
 189   FILE **fileptr = xnmalloc (nfiles + 1, sizeof *fileptr);
 190
 191   /* Number of files still open to process.  */
 192   size_t files_open;
 193
 194   /* True if any fopen got fd == STDIN_FILENO.  */
 195   bool opened_stdin = false;
 196
 197   /* Attempt to open all files.  This could be expanded to an infinite
 198      number of files, but at the (considerable) expense of remembering
 199      each file and its current offset, then opening/reading/closing.  */
 200
 201   for (files_open = 0; files_open < nfiles; ++files_open)
 202     {
 203       if (STREQ (fnamptr[files_open], "-"))
 204         {
 205           have_read_stdin = true;
 206           fileptr[files_open] = stdin;
 207         }
 208       else
 209         {
 210           fileptr[files_open] = fopen (fnamptr[files_open], "r");
 211           if (fileptr[files_open] == NULL)
 212             error (EXIT_FAILURE, errno, "%s", fnamptr[files_open]);
 213           else if (fileno (fileptr[files_open]) == STDIN_FILENO)
 214             opened_stdin = true;
 215           fadvise (fileptr[files_open], FADVISE_SEQUENTIAL);
 216         }
 217     }
 218
 219   if (opened_stdin && have_read_stdin)
 220     error (EXIT_FAILURE, 0, _("standard input is closed"));
 221
 222   /* Read a line from each file and output it to stdout separated by a
 223      delimiter, until we go through the loop without successfully
 224      reading from any of the files. */
 225
 226   while (files_open)
 227     {
 228       /* Set up for the next line. */
 229       bool somedone = false;
 230       char const *delimptr = delims;
 231       size_t delims_saved = 0;  /* Number of delims saved in 'delbuf'. */
 232       size_t i;
 233
 234       for (i = 0; i < nfiles && files_open; i++)
 235         {
 236           int chr IF_LINT ( = 0);       /* Input character. */
 237           int err IF_LINT ( = 0);       /* Input errno value.  */
 238           size_t line_length = 0;       /* Number of chars in line. */
 239
 240           if (fileptr[i])
 241             {
 242               chr = getc (fileptr[i]);
 243               err = errno;
 244               if (chr != EOF && delims_saved)
 245                 {
 246                   if (fwrite (delbuf, 1, delims_saved, stdout) != delims_saved)
 247                     write_error ();
 248                   delims_saved = 0;
 249                 }
 250
 251               while (chr != EOF)
 252                 {
 253                   line_length++;
 254                   if (chr == '\n')
 255                     break;
 256                   xputchar (chr);
 257                   chr = getc (fileptr[i]);
 258                   err = errno;
 259                 }
 260             }
 261
 262           if (line_length == 0)
 263             {
 264               /* EOF, read error, or closed file.
 265                  If an EOF or error, close the file.  */
 266               if (fileptr[i])
 267                 {
 268                   if (ferror (fileptr[i]))
 269                     {
 270                       error (0, err, "%s", fnamptr[i]);
 271                       ok = false;
 272                     }
 273                   if (fileptr[i] == stdin)
 274                     clearerr (fileptr[i]); /* Also clear EOF. */
 275                   else if (fclose (fileptr[i]) == EOF)
 276                     {
 277                       error (0, errno, "%s", fnamptr[i]);
 278                       ok = false;
 279                     }
 280
 281                   fileptr[i] = NULL;
 282                   files_open--;
 283                 }
 284
 285               if (i + 1 == nfiles)
 286                 {
 287                   /* End of this output line.
 288                      Is this the end of the whole thing? */
 289                   if (somedone)
 290                     {
 291                       /* No.  Some files were not closed for this line. */
 292                       if (delims_saved)
 293                         {
 294                           if (fwrite (delbuf, 1, delims_saved, stdout)
 295                               != delims_saved)
 296                             write_error ();
 297                           delims_saved = 0;
 298                         }
 299                       xputchar ('\n');
 300                     }
 301                   continue;     /* Next read of files, or exit. */
 302                 }
 303               else
 304                 {
 305                   /* Closed file; add delimiter to 'delbuf'. */
 306                   if (*delimptr != EMPTY_DELIM)
 307                     delbuf[delims_saved++] = *delimptr;
 308                   if (++delimptr == delim_end)
 309                     delimptr = delims;
 310                 }
 311             }
 312           else
 313             {
 314               /* Some data read. */
 315               somedone = true;
 316
 317               /* Except for last file, replace last newline with delim. */
 318               if (i + 1 != nfiles)
 319                 {
 320                   if (chr != '\n' && chr != EOF)
 321                     xputchar (chr);
 322                   if (*delimptr != EMPTY_DELIM)
 323                     xputchar (*delimptr);
 324                   if (++delimptr == delim_end)
 325                     delimptr = delims;
 326                 }
 327               else
 328                 {
 329                   /* If the last line of the last file lacks a newline,
 330                      print one anyhow.  POSIX requires this.  */
 331                   char c = (chr == EOF ? '\n' : chr);
 332                   xputchar (c);
 333                 }
 334             }
 335         }
 336     }
 337   free (fileptr);
 338   free (delbuf);
 339   return ok;
 340 }
 341
 342 /* Perform serial paste on the NFILES files named in FNAMPTR.
 343    Return true if no errors, false if one or more files could not be
 344    opened or read. */
 345
 346 static bool
 347 paste_serial (size_t nfiles, char **fnamptr)
 348 {
 349   bool ok = true;       /* false if open or read errors occur. */
 350   int charnew, charold; /* Current and previous char read. */
 351   char const *delimptr; /* Current delimiter char. */
 352   FILE *fileptr;        /* Open for reading current file. */
 353
 354   for (; nfiles; nfiles--, fnamptr++)
 355     {
 356       int saved_errno;
 357       bool is_stdin = STREQ (*fnamptr, "-");
 358       if (is_stdin)
 359         {
 360           have_read_stdin = true;
 361           fileptr = stdin;
 362         }
 363       else
 364         {
 365           fileptr = fopen (*fnamptr, "r");
 366           if (fileptr == NULL)
 367             {
 368               error (0, errno, "%s", *fnamptr);
 369               ok = false;
 370               continue;
 371             }
 372           fadvise (fileptr, FADVISE_SEQUENTIAL);
 373         }
 374
 375       delimptr = delims;        /* Set up for delimiter string. */
 376
 377       charold = getc (fileptr);
 378       saved_errno = errno;
 379       if (charold != EOF)
 380         {
 381           /* 'charold' is set up.  Hit it!
 382              Keep reading characters, stashing them in 'charnew';
 383              output 'charold', converting to the appropriate delimiter
 384              character if needed.  After the EOF, output 'charold'
 385              if it's a newline; otherwise, output it and then a newline. */
 386
 387           while ((charnew = getc (fileptr)) != EOF)
 388             {
 389               /* Process the old character. */
 390               if (charold == '\n')
 391                 {
 392                   if (*delimptr != EMPTY_DELIM)
 393                     xputchar (*delimptr);
 394
 395                   if (++delimptr == delim_end)
 396                     delimptr = delims;
 397                 }
 398               else
 399                 xputchar (charold);
 400
 401               charold = charnew;
 402             }
 403           saved_errno = errno;
 404
 405           /* Hit EOF.  Process that last character. */
 406           xputchar (charold);
 407         }
 408
 409       if (charold != '\n')
 410         xputchar ('\n');
 411
 412       if (ferror (fileptr))
 413         {
 414           error (0, saved_errno, "%s", *fnamptr);
 415           ok = false;
 416         }
 417       if (is_stdin)
 418         clearerr (fileptr);     /* Also clear EOF. */
 419       else if (fclose (fileptr) == EOF)
 420         {
 421           error (0, errno, "%s", *fnamptr);
 422           ok = false;
 423         }
 424     }
 425   return ok;
 426 }
 427
 428 void
 429 usage (int status)
 430 {
 431   if (status != EXIT_SUCCESS)
 432     emit_try_help ();
 433   else
 434     {
 435       printf (_("\
 436 Usage: %s [OPTION]... [FILE]...\n\
 437 "),
 438               program_name);
 439       fputs (_("\
 440 Write lines consisting of the sequentially corresponding lines from\n\
 441 each FILE, separated by TABs, to standard output.\n\
 442 With no FILE, or when FILE is -, read standard input.\n\
 443 \n\
 444 "), stdout);
 445       fputs (_("\
 446 Mandatory arguments to long options are mandatory for short options too.\n\
 447 "), stdout);
 448       fputs (_("\
 449   -d, --delimiters=LIST   reuse characters from LIST instead of TABs\n\
 450   -s, --serial            paste one file at a time instead of in parallel\n\
 451 "), stdout);
 452       fputs (HELP_OPTION_DESCRIPTION, stdout);
 453       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 454       /* FIXME: add a couple of examples.  */
 455       emit_ancillary_info ();
 456     }
 457   exit (status);
 458 }
 459
 460 int
 461 main (int argc, char **argv)
 462 {
 463   int optc;
 464   bool ok;
 465   char const *delim_arg = "\t";
 466
 467   initialize_main (&argc, &argv);
 468   set_program_name (argv[0]);
 469   setlocale (LC_ALL, "");
 470   bindtextdomain (PACKAGE, LOCALEDIR);
 471   textdomain (PACKAGE);
 472
 473   atexit (close_stdout);
 474
 475   have_read_stdin = false;
 476   serial_merge = false;
 477
 478   while ((optc = getopt_long (argc, argv, "d:s", longopts, NULL)) != -1)
 479     {
 480       switch (optc)
 481         {
 482         case 'd':
 483           /* Delimiter character(s). */
 484           delim_arg = (optarg[0] == '\0' ? "\\0" : optarg);
 485           break;
 486
 487         case 's':
 488           serial_merge = true;
 489           break;
 490
 491         case_GETOPT_HELP_CHAR;
 492
 493         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 494
 495         default:
 496           usage (EXIT_FAILURE);
 497         }
 498     }
 499
 500   if (optind == argc)
 501     argv[argc++] = bad_cast ("-");
 502
 503   if (collapse_escapes (delim_arg))
 504     {
 505       /* Don't use the default quoting style, because that would double the
 506          number of displayed backslashes, making the diagnostic look bogus.  */
 507       set_quoting_style (NULL, escape_quoting_style);
 508       error (EXIT_FAILURE, 0,
 509              _("delimiter list ends with an unescaped backslash: %s"),
 510              quotearg_colon (delim_arg));
 511     }
 512
 513   if (!serial_merge)
 514     ok = paste_parallel (argc - optind, &argv[optind]);
 515   else
 516     ok = paste_serial (argc - optind, &argv[optind]);
 517
 518   free (delims);
 519
 520   if (have_read_stdin && fclose (stdin) == EOF)
 521     error (EXIT_FAILURE, errno, "-");
 522   exit (ok ? EXIT_SUCCESS : EXIT_FAILURE);
 523 }