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                                 len = unicode_strwidth(ptr_strbeg);
  82 # else
  83                                 len = ptr - ptr_strbeg;
  84 # endif
  85                                 len = tab_size - (len % tab_size);
  86                                 /*while (ptr[1] == '\t') { ptr++; len += tab_size; } - can handle many tabs at once */
  87                                 printf("%s%*s", ptr_strbeg, len, "");
  88                                 ptr_strbeg = ptr + 1;
  89                         }
  90                         ptr++;
  91                 }
  92                 fputs(ptr_strbeg, stdout);
  93                 free(line);
  94         }
  95 }
  96 #endif
  97
  98 #if ENABLE_UNEXPAND
  99 static void unexpand(FILE *file, unsigned tab_size, unsigned opt)
 100 {
 101         char *line;
 102
 103         while ((line = xmalloc_fgets(file)) != NULL) {
 104                 char *ptr = line;
 105                 unsigned column = 0;
 106
 107                 while (*ptr) {
 108                         unsigned n;
 109                         unsigned len = 0;
 110
 111                         while (*ptr == ' ') {
 112                                 ptr++;
 113                                 len++;
 114                         }
 115                         column += len;
 116                         if (*ptr == '\t') {
 117                                 column += tab_size - (column % tab_size);
 118                                 ptr++;
 119                                 continue;
 120                         }
 121
 122                         n = column / tab_size;
 123                         if (n) {
 124                                 len = column = column % tab_size;
 125                                 while (n--)
 126                                         putchar('\t');
 127                         }
 128
 129                         if ((opt & OPT_INITIAL) && ptr != line) {
 130                                 printf("%*s%s", len, "", ptr);
 131                                 break;
 132                         }
 133                         n = strcspn(ptr, "\t ");
 134                         printf("%*s%.*s", len, "", n, ptr);
 135 # if ENABLE_UNICODE_SUPPORT
 136                         {
 137                                 char c = ptr[n];
 138                                 ptr[n] = '\0';
 139                                 len = unicode_strwidth(ptr);
 140                                 ptr[n] = c;
 141                         }
 142 # else
 143                         len = n;
 144 # endif
 145                         ptr += n;
 146                         column = (column + len) % tab_size;
 147                 }
 148                 free(line);
 149         }
 150 }
 151 #endif
 152
 153 int expand_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 154 int expand_main(int argc UNUSED_PARAM, char **argv)
 155 {
 156         /* Default 8 spaces for 1 tab */
 157         const char *opt_t = "8";
 158         FILE *file;
 159         unsigned tab_size;
 160         unsigned opt;
 161         int exit_status = EXIT_SUCCESS;
 162
 163 #if ENABLE_FEATURE_EXPAND_LONG_OPTIONS
 164         static const char expand_longopts[] ALIGN1 =
 165                 /* name, has_arg, val */
 166                 "initial\0"          No_argument       "i"
 167                 "tabs\0"             Required_argument "t"
 168         ;
 169 #endif
 170 #if ENABLE_FEATURE_UNEXPAND_LONG_OPTIONS
 171         static const char unexpand_longopts[] ALIGN1 =
 172                 /* name, has_arg, val */
 173                 "first-only\0"       No_argument       "i"
 174                 "tabs\0"             Required_argument "t"
 175                 "all\0"              No_argument       "a"
 176         ;
 177 #endif
 178         init_unicode();
 179
 180         if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e')) {
 181                 IF_FEATURE_EXPAND_LONG_OPTIONS(applet_long_options = expand_longopts);
 182                 opt = getopt32(argv, "it:", &opt_t);
 183         } else {
 184                 IF_FEATURE_UNEXPAND_LONG_OPTIONS(applet_long_options = unexpand_longopts);
 185                 /* -t NUM sets also -a */
 186                 opt_complementary = "ta";
 187                 opt = getopt32(argv, "ft:a", &opt_t);
 188                 /* -f --first-only is the default */
 189                 if (!(opt & OPT_ALL)) opt |= OPT_INITIAL;
 190         }
 191         tab_size = xatou_range(opt_t, 1, UINT_MAX);
 192
 193         argv += optind;
 194
 195         if (!*argv) {
 196                 *--argv = (char*)bb_msg_standard_input;
 197         }
 198         do {
 199                 file = fopen_or_warn_stdin(*argv);
 200                 if (!file) {
 201                         exit_status = EXIT_FAILURE;
 202                         continue;
 203                 }
 204
 205                 if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e'))
 206                         IF_EXPAND(expand(file, tab_size, opt));
 207                 else
 208                         IF_UNEXPAND(unexpand(file, tab_size, opt));
 209
 210                 /* Check and close the file */
 211                 if (fclose_if_not_stdin(file)) {
 212                         bb_simple_perror_msg(*argv);
 213                         exit_status = EXIT_FAILURE;
 214                 }
 215                 /* If stdin also clear EOF */
 216                 if (file == stdin)
 217                         clearerr(file);
 218         } while (*++argv);
 219
 220         /* Now close stdin also */
 221         /* (if we didn't read from it, it's a no-op) */
 222         if (fclose(stdin))
 223                 bb_perror_msg_and_die(bb_msg_standard_input);
 224
 225         fflush_stdout_and_exit(exit_status);
 226 }