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 //config:config EXPAND
  24 //config:       bool "expand (5.8 kb)"
  25 //config:       default y
  26 //config:       help
  27 //config:         By default, convert all tabs to spaces.
  28 //config:
  29 //config:config FEATURE_EXPAND_LONG_OPTIONS
  30 //config:       bool "Enable long options"
  31 //config:       default y
  32 //config:       depends on EXPAND && LONG_OPTS
  33 //config:
  34 //config:config UNEXPAND
  35 //config:       bool "unexpand (6 kb)"
  36 //config:       default y
  37 //config:       help
  38 //config:         By default, convert only leading sequences of blanks to tabs.
  39 //config:
  40 //config:config FEATURE_UNEXPAND_LONG_OPTIONS
  41 //config:       bool "Enable long options"
  42 //config:       default y
  43 //config:       depends on UNEXPAND && LONG_OPTS
  44
  45 //applet:IF_EXPAND(APPLET(expand, BB_DIR_USR_BIN, BB_SUID_DROP))
  46 //                   APPLET_ODDNAME:name      main    location        suid_type     help
  47 //applet:IF_UNEXPAND(APPLET_ODDNAME(unexpand, expand, BB_DIR_USR_BIN, BB_SUID_DROP, unexpand))
  48
  49 //kbuild:lib-$(CONFIG_EXPAND) += expand.o
  50 //kbuild:lib-$(CONFIG_UNEXPAND) += expand.o
  51
  52 //usage:#define expand_trivial_usage
  53 //usage:       "[-i] [-t N] [FILE]..."
  54 //usage:#define expand_full_usage "\n\n"
  55 //usage:       "Convert tabs to spaces, writing to stdout\n"
  56 //usage:        IF_FEATURE_EXPAND_LONG_OPTIONS(
  57 //usage:     "\n        -i,--initial    Don't convert tabs after non blanks"
  58 //usage:     "\n        -t,--tabs N     Tabstops every N chars"
  59 //usage:        )
  60 //usage:        IF_NOT_FEATURE_EXPAND_LONG_OPTIONS(
  61 //usage:     "\n        -i      Don't convert tabs after non blanks"
  62 //usage:     "\n        -t      Tabstops every N chars"
  63 //usage:        )
  64
  65 //usage:#define unexpand_trivial_usage
  66 //usage:       "[-fa][-t N] [FILE]..."
  67 //usage:#define unexpand_full_usage "\n\n"
  68 //usage:       "Convert spaces to tabs, writing to stdout\n"
  69 //usage:        IF_FEATURE_UNEXPAND_LONG_OPTIONS(
  70 //usage:     "\n        -a,--all        Convert all blanks"
  71 //usage:     "\n        -f,--first-only Convert only leading blanks"
  72 //usage:     "\n        -t,--tabs N     Tabstops every N chars"
  73 //usage:        )
  74 //usage:        IF_NOT_FEATURE_UNEXPAND_LONG_OPTIONS(
  75 //usage:     "\n        -a      Convert all blanks"
  76 //usage:     "\n        -f      Convert only leading blanks"
  77 //usage:     "\n        -t N    Tabstops every N chars"
  78 //usage:        )
  79
  80 #include "libbb.h"
  81 #include "unicode.h"
  82
  83 enum {
  84         OPT_INITIAL     = 1 << 0,
  85         OPT_TABS        = 1 << 1,
  86         OPT_ALL         = 1 << 2,
  87 };
  88
  89 #if ENABLE_EXPAND
  90 static void expand(FILE *file, unsigned tab_size, unsigned opt)
  91 {
  92         char *line;
  93
  94         while ((line = xmalloc_fgets(file)) != NULL) {
  95                 unsigned char c;
  96                 char *ptr;
  97                 char *ptr_strbeg;
  98
  99                 ptr = ptr_strbeg = line;
 100                 while ((c = *ptr) != '\0') {
 101                         if ((opt & OPT_INITIAL) && !isblank(c)) {
 102                                 /* not space or tab */
 103                                 break;
 104                         }
 105                         if (c == '\t') {
 106                                 unsigned len;
 107                                 *ptr = '\0';
 108 # if ENABLE_UNICODE_SUPPORT
 109                                 len = unicode_strwidth(ptr_strbeg);
 110 # else
 111                                 len = ptr - ptr_strbeg;
 112 # endif
 113                                 len = tab_size - (len % tab_size);
 114                                 /*while (ptr[1] == '\t') { ptr++; len += tab_size; } - can handle many tabs at once */
 115                                 printf("%s%*s", ptr_strbeg, len, "");
 116                                 ptr_strbeg = ptr + 1;
 117                         }
 118                         ptr++;
 119                 }
 120                 fputs(ptr_strbeg, stdout);
 121                 free(line);
 122         }
 123 }
 124 #endif
 125
 126 #if ENABLE_UNEXPAND
 127 static void unexpand(FILE *file, unsigned tab_size, unsigned opt)
 128 {
 129         char *line;
 130
 131         while ((line = xmalloc_fgets(file)) != NULL) {
 132                 char *ptr = line;
 133                 unsigned column = 0;
 134
 135                 while (*ptr) {
 136                         unsigned n;
 137                         unsigned len = 0;
 138
 139                         while (*ptr == ' ') {
 140                                 ptr++;
 141                                 len++;
 142                         }
 143                         column += len;
 144                         if (*ptr == '\t') {
 145                                 column += tab_size - (column % tab_size);
 146                                 ptr++;
 147                                 continue;
 148                         }
 149
 150                         n = column / tab_size;
 151                         if (n) {
 152                                 len = column = column % tab_size;
 153                                 while (n--)
 154                                         putchar('\t');
 155                         }
 156
 157                         if ((opt & OPT_INITIAL) && ptr != line) {
 158                                 printf("%*s%s", len, "", ptr);
 159                                 break;
 160                         }
 161                         n = strcspn(ptr, "\t ");
 162                         printf("%*s%.*s", len, "", n, ptr);
 163 # if ENABLE_UNICODE_SUPPORT
 164                         {
 165                                 char c = ptr[n];
 166                                 ptr[n] = '\0';
 167                                 len = unicode_strwidth(ptr);
 168                                 ptr[n] = c;
 169                         }
 170 # else
 171                         len = n;
 172 # endif
 173                         ptr += n;
 174                         column = (column + len) % tab_size;
 175                 }
 176                 free(line);
 177         }
 178 }
 179 #endif
 180
 181 int expand_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 182 int expand_main(int argc UNUSED_PARAM, char **argv)
 183 {
 184         /* Default 8 spaces for 1 tab */
 185         const char *opt_t = "8";
 186         FILE *file;
 187         unsigned tab_size;
 188         unsigned opt;
 189         int exit_status = EXIT_SUCCESS;
 190
 191 #if ENABLE_FEATURE_EXPAND_LONG_OPTIONS
 192         static const char expand_longopts[] ALIGN1 =
 193                 /* name, has_arg, val */
 194                 "initial\0"          No_argument       "i"
 195                 "tabs\0"             Required_argument "t"
 196         ;
 197 #endif
 198 #if ENABLE_FEATURE_UNEXPAND_LONG_OPTIONS
 199         static const char unexpand_longopts[] ALIGN1 =
 200                 /* name, has_arg, val */
 201                 "first-only\0"       No_argument       "i"
 202                 "tabs\0"             Required_argument "t"
 203                 "all\0"              No_argument       "a"
 204         ;
 205 #endif
 206         init_unicode();
 207
 208         if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e')) {
 209                 IF_FEATURE_EXPAND_LONG_OPTIONS(applet_long_options = expand_longopts);
 210                 opt = getopt32(argv, "it:", &opt_t);
 211         } else {
 212                 IF_FEATURE_UNEXPAND_LONG_OPTIONS(applet_long_options = unexpand_longopts);
 213                 /* -t NUM sets also -a */
 214                 opt_complementary = "ta";
 215                 opt = getopt32(argv, "ft:a", &opt_t);
 216                 /* -f --first-only is the default */
 217                 if (!(opt & OPT_ALL)) opt |= OPT_INITIAL;
 218         }
 219         tab_size = xatou_range(opt_t, 1, UINT_MAX);
 220
 221         argv += optind;
 222
 223         if (!*argv) {
 224                 *--argv = (char*)bb_msg_standard_input;
 225         }
 226         do {
 227                 file = fopen_or_warn_stdin(*argv);
 228                 if (!file) {
 229                         exit_status = EXIT_FAILURE;
 230                         continue;
 231                 }
 232
 233                 if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e'))
 234                         IF_EXPAND(expand(file, tab_size, opt));
 235                 else
 236                         IF_UNEXPAND(unexpand(file, tab_size, opt));
 237
 238                 /* Check and close the file */
 239                 if (fclose_if_not_stdin(file)) {
 240                         bb_simple_perror_msg(*argv);
 241                         exit_status = EXIT_FAILURE;
 242                 }
 243                 /* If stdin also clear EOF */
 244                 if (file == stdin)
 245                         clearerr(file);
 246         } while (*++argv);
 247
 248         /* Now close stdin also */
 249         /* (if we didn't read from it, it's a no-op) */
 250         if (fclose(stdin))
 251                 bb_perror_msg_and_die(bb_msg_standard_input);
 252
 253         fflush_stdout_and_exit(exit_status);
 254 }