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 source tree.
   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 //usage:#define expand_trivial_usage
  25 //usage:       "[-i] [-t N] [FILE]..."
  26 //usage:#define expand_full_usage "\n\n"
  27 //usage:       "Convert tabs to spaces, writing to stdout\n"
  28 //usage:        IF_FEATURE_EXPAND_LONG_OPTIONS(
  29 //usage:     "\n        -i,--initial    Don't convert tabs after non blanks"
  30 //usage:     "\n        -t,--tabs=N     Tabstops every N chars"
  31 //usage:        )
  32 //usage:        IF_NOT_FEATURE_EXPAND_LONG_OPTIONS(
  33 //usage:     "\n        -i      Don't convert tabs after non blanks"
  34 //usage:     "\n        -t      Tabstops every N chars"
  35 //usage:        )
  36
  37 //usage:#define unexpand_trivial_usage
  38 //usage:       "[-fa][-t N] [FILE]..."
  39 //usage:#define unexpand_full_usage "\n\n"
  40 //usage:       "Convert spaces to tabs, writing to stdout\n"
  41 //usage:        IF_FEATURE_UNEXPAND_LONG_OPTIONS(
  42 //usage:     "\n        -a,--all        Convert all blanks"
  43 //usage:     "\n        -f,--first-only Convert only leading blanks"
  44 //usage:     "\n        -t,--tabs=N     Tabstops every N chars"
  45 //usage:        )
  46 //usage:        IF_NOT_FEATURE_UNEXPAND_LONG_OPTIONS(
  47 //usage:     "\n        -a      Convert all blanks"
  48 //usage:     "\n        -f      Convert only leading blanks"
  49 //usage:     "\n        -t N    Tabstops every N chars"
  50 //usage:        )
  51
  52 #include "libbb.h"
  53 #include "unicode.h"
  54
  55 enum {
  56         OPT_INITIAL     = 1 << 0,
  57         OPT_TABS        = 1 << 1,
  58         OPT_ALL         = 1 << 2,
  59 };
  60
  61 #if ENABLE_EXPAND
  62 static void expand(FILE *file, unsigned tab_size, unsigned opt)
  63 {
  64         char *line;
  65
  66         while ((line = xmalloc_fgets(file)) != NULL) {
  67                 unsigned char c;
  68                 char *ptr;
  69                 char *ptr_strbeg;
  70
  71                 ptr = ptr_strbeg = line;
  72                 while ((c = *ptr) != '\0') {
  73                         if ((opt & OPT_INITIAL) && !isblank(c)) {
  74                                 /* not space or tab */
  75                                 break;
  76                         }
  77                         if (c == '\t') {
  78                                 unsigned len;
  79                                 *ptr = '\0';
  80 # if ENABLE_UNICODE_SUPPORT
  81                                 {
  82                                         uni_stat_t uni_stat;
  83                                         printable_string(&uni_stat, ptr_strbeg);
  84                                         len = uni_stat.unicode_width;
  85                                 }
  86 # else
  87                                 len = ptr - ptr_strbeg;
  88 # endif
  89                                 len = tab_size - (len % tab_size);
  90                                 /*while (ptr[1] == '\t') { ptr++; len += tab_size; } - can handle many tabs at once */
  91                                 printf("%s%*s", ptr_strbeg, len, "");
  92                                 ptr_strbeg = ptr + 1;
  93                         }
  94                         ptr++;
  95                 }
  96                 fputs(ptr_strbeg, stdout);
  97                 free(line);
  98         }
  99 }
 100 #endif
 101
 102 #if ENABLE_UNEXPAND
 103 static void unexpand(FILE *file, unsigned tab_size, unsigned opt)
 104 {
 105         char *line;
 106
 107         while ((line = xmalloc_fgets(file)) != NULL) {
 108                 char *ptr = line;
 109                 unsigned column = 0;
 110
 111                 while (*ptr) {
 112                         unsigned n;
 113                         unsigned len = 0;
 114
 115                         while (*ptr == ' ') {
 116                                 ptr++;
 117                                 len++;
 118                         }
 119                         column += len;
 120                         if (*ptr == '\t') {
 121                                 column += tab_size - (column % tab_size);
 122                                 ptr++;
 123                                 continue;
 124                         }
 125
 126                         n = column / tab_size;
 127                         if (n) {
 128                                 len = column = column % tab_size;
 129                                 while (n--)
 130                                         putchar('\t');
 131                         }
 132
 133                         if ((opt & OPT_INITIAL) && ptr != line) {
 134                                 printf("%*s%s", len, "", ptr);
 135                                 break;
 136                         }
 137                         n = strcspn(ptr, "\t ");
 138                         printf("%*s%.*s", len, "", n, ptr);
 139 # if ENABLE_UNICODE_SUPPORT
 140                         {
 141                                 char c;
 142                                 uni_stat_t uni_stat;
 143                                 c = ptr[n];
 144                                 ptr[n] = '\0';
 145                                 printable_string(&uni_stat, ptr);
 146                                 len = uni_stat.unicode_width;
 147                                 ptr[n] = c;
 148                         }
 149 # else
 150                         len = n;
 151 # endif
 152                         ptr += n;
 153                         column = (column + len) % tab_size;
 154                 }
 155                 free(line);
 156         }
 157 }
 158 #endif
 159
 160 int expand_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 161 int expand_main(int argc UNUSED_PARAM, char **argv)
 162 {
 163         /* Default 8 spaces for 1 tab */
 164         const char *opt_t = "8";
 165         FILE *file;
 166         unsigned tab_size;
 167         unsigned opt;
 168         int exit_status = EXIT_SUCCESS;
 169
 170 #if ENABLE_FEATURE_EXPAND_LONG_OPTIONS
 171         static const char expand_longopts[] ALIGN1 =
 172                 /* name, has_arg, val */
 173                 "initial\0"          No_argument       "i"
 174                 "tabs\0"             Required_argument "t"
 175         ;
 176 #endif
 177 #if ENABLE_FEATURE_UNEXPAND_LONG_OPTIONS
 178         static const char unexpand_longopts[] ALIGN1 =
 179                 /* name, has_arg, val */
 180                 "first-only\0"       No_argument       "i"
 181                 "tabs\0"             Required_argument "t"
 182                 "all\0"              No_argument       "a"
 183         ;
 184 #endif
 185         init_unicode();
 186
 187         if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e')) {
 188                 IF_FEATURE_EXPAND_LONG_OPTIONS(applet_long_options = expand_longopts);
 189                 opt = getopt32(argv, "it:", &opt_t);
 190         } else {
 191                 IF_FEATURE_UNEXPAND_LONG_OPTIONS(applet_long_options = unexpand_longopts);
 192                 /* -t NUM sets also -a */
 193                 opt_complementary = "ta";
 194                 opt = getopt32(argv, "ft:a", &opt_t);
 195                 /* -f --first-only is the default */
 196                 if (!(opt & OPT_ALL)) opt |= OPT_INITIAL;
 197         }
 198         tab_size = xatou_range(opt_t, 1, UINT_MAX);
 199
 200         argv += optind;
 201
 202         if (!*argv) {
 203                 *--argv = (char*)bb_msg_standard_input;
 204         }
 205         do {
 206                 file = fopen_or_warn_stdin(*argv);
 207                 if (!file) {
 208                         exit_status = EXIT_FAILURE;
 209                         continue;
 210                 }
 211
 212                 if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e'))
 213                         IF_EXPAND(expand(file, tab_size, opt));
 214                 else
 215                         IF_UNEXPAND(unexpand(file, tab_size, opt));
 216
 217                 /* Check and close the file */
 218                 if (fclose_if_not_stdin(file)) {
 219                         bb_simple_perror_msg(*argv);
 220                         exit_status = EXIT_FAILURE;
 221                 }
 222                 /* If stdin also clear EOF */
 223                 if (file == stdin)
 224                         clearerr(file);
 225         } while (*++argv);
 226
 227         /* Now close stdin also */
 228         /* (if we didn't read from it, it's a no-op) */
 229         if (fclose(stdin))
 230                 bb_perror_msg_and_die(bb_msg_standard_input);
 231
 232         fflush_stdout_and_exit(exit_status);
 233 }