coreutils/expand.c

   1 /* expand - convert tabs to spaces
   2  * unexpand - convert spaces to tabs
   3  *
   4  * Copyright (C) 89, 91, 1995-2006 Free Software Foundation, Inc.
   5  *
   6  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   7  *
   8  * David MacKenzie <djm@gnu.ai.mit.edu>
   9  *
  10  * Options for expand:
  11  * -t num  --tabs=NUM      Convert tabs to num spaces (default 8 spaces).
  12  * -i      --initial       Only convert initial tabs on each line to spaces.
  13  *
  14  * Options for unexpand:
  15  * -a      --all           Convert all blanks, instead of just initial blanks.
  16  * -f      --first-only    Convert only leading sequences of blanks (default).
  17  * -t num  --tabs=NUM      Have tabs num characters apart instead of 8.
  18  *
  19  *  Busybox version (C) 2007 by Tito Ragusa <farmatito@tiscali.it>
  20  *
  21  *  Caveat: this versions of expand and unexpand don't accept tab lists.
  22  */
  23
  24 #include "libbb.h"
  25
  26 enum {
  27         OPT_INITIAL     = 1 << 0,
  28         OPT_TABS        = 1 << 1,
  29         OPT_ALL         = 1 << 2,
  30 };
  31
  32 #if ENABLE_EXPAND
  33 static void expand(FILE *file, int tab_size, unsigned opt)
  34 {
  35         char *line;
  36
  37         tab_size = -tab_size;
  38
  39         while ((line = xmalloc_fgets(file)) != NULL) {
  40                 int pos;
  41                 unsigned char c;
  42                 char *ptr = line;
  43
  44                 goto start;
  45                 while ((c = *ptr) != '\0') {
  46                         if ((opt & OPT_INITIAL) && !isblank(c)) {
  47                                 fputs(ptr, stdout);
  48                                 break;
  49                         }
  50                         ptr++;
  51                         if (c == '\t') {
  52                                 c = ' ';
  53                                 while (++pos < 0)
  54                                         bb_putchar(c);
  55                         }
  56                         bb_putchar(c);
  57                         if (++pos >= 0) {
  58  start:
  59                                 pos = tab_size;
  60                         }
  61                 }
  62                 free(line);
  63         }
  64 }
  65 #endif
  66
  67 #if ENABLE_UNEXPAND
  68 static void unexpand(FILE *file, unsigned tab_size, unsigned opt)
  69 {
  70         char *line;
  71         char *ptr;
  72         int convert;
  73         int pos;
  74         int i = 0;
  75         unsigned column = 0;
  76
  77         while ((line = xmalloc_fgets(file)) != NULL) {
  78                 convert = 1;
  79                 pos = 0;
  80                 ptr = line;
  81                 while (*line) {
  82                         while ((*line == ' ' || *line == '\t') && convert) {
  83                                 pos += (*line == ' ') ? 1 : tab_size;
  84                                 line++;
  85                                 column++;
  86                                 if ((opt & OPT_ALL) && column == tab_size) {
  87                                         column = 0;
  88                                         goto put_tab;
  89                                 }
  90                         }
  91                         if (pos) {
  92                                 i = pos / tab_size;
  93                                 if (i) {
  94                                         for (; i > 0; i--) {
  95  put_tab:
  96                                                 bb_putchar('\t');
  97                                         }
  98                                 } else {
  99                                         for (i = pos % tab_size; i > 0; i--) {
 100                                                 bb_putchar(' ');
 101                                         }
 102                                 }
 103                                 pos = 0;
 104                         } else {
 105                                 if (opt & OPT_INITIAL) {
 106                                         convert = 0;
 107                                 }
 108                                 if (opt & OPT_ALL) {
 109                                         column++;
 110                                 }
 111                                 bb_putchar(*line);
 112                                 line++;
 113                         }
 114                 }
 115                 free(ptr);
 116         }
 117 }
 118 #endif
 119
 120 int expand_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 121 int expand_main(int argc UNUSED_PARAM, char **argv)
 122 {
 123         /* Default 8 spaces for 1 tab */
 124         const char *opt_t = "8";
 125         FILE *file;
 126         unsigned tab_size;
 127         unsigned opt;
 128         int exit_status = EXIT_SUCCESS;
 129
 130 #if ENABLE_FEATURE_EXPAND_LONG_OPTIONS
 131         static const char expand_longopts[] ALIGN1 =
 132                 /* name, has_arg, val */
 133                 "initial\0"          No_argument       "i"
 134                 "tabs\0"             Required_argument "t"
 135         ;
 136 #endif
 137 #if ENABLE_FEATURE_UNEXPAND_LONG_OPTIONS
 138         static const char unexpand_longopts[] ALIGN1 =
 139                 /* name, has_arg, val */
 140                 "first-only\0"       No_argument       "i"
 141                 "tabs\0"             Required_argument "t"
 142                 "all\0"              No_argument       "a"
 143         ;
 144 #endif
 145
 146         if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e')) {
 147                 USE_FEATURE_EXPAND_LONG_OPTIONS(applet_long_options = expand_longopts);
 148                 opt = getopt32(argv, "it:", &opt_t);
 149         } else {
 150                 USE_FEATURE_UNEXPAND_LONG_OPTIONS(applet_long_options = unexpand_longopts);
 151                 /* -t NUM sets also -a */
 152                 opt_complementary = "ta";
 153                 opt = getopt32(argv, "ft:a", &opt_t);
 154                 /* -f --first-only is the default */
 155                 if (!(opt & OPT_ALL)) opt |= OPT_INITIAL;
 156         }
 157         tab_size = xatou_range(opt_t, 1, UINT_MAX);
 158
 159         argv += optind;
 160
 161         if (!*argv) {
 162                 *--argv = (char*)bb_msg_standard_input;
 163         }
 164         do {
 165                 file = fopen_or_warn_stdin(*argv);
 166                 if (!file) {
 167                         exit_status = EXIT_FAILURE;
 168                         continue;
 169                 }
 170
 171                 if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e'))
 172                         USE_EXPAND(expand(file, tab_size, opt));
 173                 else
 174                         USE_UNEXPAND(unexpand(file, tab_size, opt));
 175
 176                 /* Check and close the file */
 177                 if (fclose_if_not_stdin(file)) {
 178                         bb_simple_perror_msg(*argv);
 179                         exit_status = EXIT_FAILURE;
 180                 }
 181                 /* If stdin also clear EOF */
 182                 if (file == stdin)
 183                         clearerr(file);
 184         } while (*++argv);
 185
 186         /* Now close stdin also */
 187         /* (if we didn't read from it, it's a no-op) */
 188         if (fclose(stdin))
 189                 bb_perror_msg_and_die(bb_msg_standard_input);
 190
 191         fflush_stdout_and_exit(exit_status);
 192 }