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