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 UNEXPAND
  30 //config:       bool "unexpand (6 kb)"
  31 //config:       default y
  32 //config:       help
  33 //config:       By default, convert only leading sequences of blanks to tabs.
  34
  35 //applet:IF_EXPAND(APPLET(expand, BB_DIR_USR_BIN, BB_SUID_DROP))
  36 //                   APPLET_ODDNAME:name      main    location        suid_type     help
  37 //applet:IF_UNEXPAND(APPLET_ODDNAME(unexpand, expand, BB_DIR_USR_BIN, BB_SUID_DROP, unexpand))
  38
  39 //kbuild:lib-$(CONFIG_EXPAND) += expand.o
  40 //kbuild:lib-$(CONFIG_UNEXPAND) += expand.o
  41
  42 //usage:#define expand_trivial_usage
  43 //usage:       "[-i] [-t N] [FILE]..."
  44 //usage:#define expand_full_usage "\n\n"
  45 //usage:       "Convert tabs to spaces, writing to stdout\n"
  46 //usage:     "\n        -i      Don't convert tabs after non blanks"
  47 //usage:     "\n        -t      Tabstops every N chars"
  48
  49 //usage:#define unexpand_trivial_usage
  50 //usage:       "[-fa][-t N] [FILE]..."
  51 //usage:#define unexpand_full_usage "\n\n"
  52 //usage:       "Convert spaces to tabs, writing to stdout\n"
  53 //usage:     "\n        -a      Convert all blanks"
  54 //usage:     "\n        -f      Convert only leading blanks"
  55 //usage:     "\n        -t N    Tabstops every N chars"
  56
  57 #include "libbb.h"
  58 #include "unicode.h"
  59
  60 enum {
  61         OPT_INITIAL     = 1 << 0,
  62         OPT_TABS        = 1 << 1,
  63         OPT_ALL         = 1 << 2,
  64 };
  65
  66 #if ENABLE_EXPAND
  67 static void expand(FILE *file, unsigned tab_size, unsigned opt)
  68 {
  69         char *line;
  70
  71         while ((line = xmalloc_fgets(file)) != NULL) {
  72                 unsigned char c;
  73                 char *ptr;
  74                 char *ptr_strbeg;
  75
  76                 ptr = ptr_strbeg = line;
  77                 while ((c = *ptr) != '\0') {
  78                         if ((opt & OPT_INITIAL) && !isblank(c)) {
  79                                 /* not space or tab */
  80                                 break;
  81                         }
  82                         if (c == '\t') {
  83                                 unsigned len;
  84                                 *ptr = '\0';
  85 # if ENABLE_UNICODE_SUPPORT
  86                                 len = unicode_strwidth(ptr_strbeg);
  87 # else
  88                                 len = ptr - ptr_strbeg;
  89 # endif
  90                                 len = tab_size - (len % tab_size);
  91                                 /*while (ptr[1] == '\t') { ptr++; len += tab_size; } - can handle many tabs at once */
  92                                 printf("%s%*s", ptr_strbeg, len, "");
  93                                 ptr_strbeg = ptr + 1;
  94                         }
  95                         ptr++;
  96                 }
  97                 fputs(ptr_strbeg, stdout);
  98                 free(line);
  99         }
 100 }
 101 #endif
 102
 103 #if ENABLE_UNEXPAND
 104 static void unexpand(FILE *file, unsigned tab_size, unsigned opt)
 105 {
 106         char *line;
 107
 108         while ((line = xmalloc_fgets(file)) != NULL) {
 109                 char *ptr = line;
 110                 unsigned column = 0;
 111
 112                 while (*ptr) {
 113                         unsigned n;
 114                         unsigned len = 0;
 115
 116                         while (*ptr == ' ') {
 117                                 ptr++;
 118                                 len++;
 119                         }
 120                         column += len;
 121                         if (*ptr == '\t') {
 122                                 column += tab_size - (column % tab_size);
 123                                 ptr++;
 124                                 continue;
 125                         }
 126
 127                         n = column / tab_size;
 128                         if (n) {
 129                                 len = column = column % tab_size;
 130                                 while (n--)
 131                                         putchar('\t');
 132                         }
 133
 134                         if ((opt & OPT_INITIAL) && ptr != line) {
 135                                 printf("%*s%s", len, "", ptr);
 136                                 break;
 137                         }
 138                         n = strcspn(ptr, "\t ");
 139                         printf("%*s%.*s", len, "", n, ptr);
 140 # if ENABLE_UNICODE_SUPPORT
 141                         {
 142                                 char c = ptr[n];
 143                                 ptr[n] = '\0';
 144                                 len = unicode_strwidth(ptr);
 145                                 ptr[n] = c;
 146                         }
 147 # else
 148                         len = n;
 149 # endif
 150                         ptr += n;
 151                         column = (column + len) % tab_size;
 152                 }
 153                 free(line);
 154         }
 155 }
 156 #endif
 157
 158 int expand_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 159 int expand_main(int argc UNUSED_PARAM, char **argv)
 160 {
 161         /* Default 8 spaces for 1 tab */
 162         const char *opt_t = "8";
 163         FILE *file;
 164         unsigned tab_size;
 165         unsigned opt;
 166         int exit_status = EXIT_SUCCESS;
 167
 168         init_unicode();
 169
 170         if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e')) {
 171                 opt = getopt32long(argv, "it:",
 172                                 "initial\0"          No_argument       "i"
 173                                 "tabs\0"             Required_argument "t"
 174                                 , &opt_t
 175                 );
 176         } else {
 177                 opt = getopt32long(argv, "^"
 178                                 "ft:a"
 179                                 "\0"
 180                                 "ta" /* -t NUM sets -a */,
 181                                 "first-only\0"       No_argument       "i"
 182                                 "tabs\0"             Required_argument "t"
 183                                 "all\0"              No_argument       "a"
 184                                 , &opt_t
 185                 );
 186                 /* -f --first-only is the default */
 187                 if (!(opt & OPT_ALL)) opt |= OPT_INITIAL;
 188         }
 189         tab_size = xatou_range(opt_t, 1, UINT_MAX);
 190
 191         argv += optind;
 192
 193         if (!*argv) {
 194                 *--argv = (char*)bb_msg_standard_input;
 195         }
 196         do {
 197                 file = fopen_or_warn_stdin(*argv);
 198                 if (!file) {
 199                         exit_status = EXIT_FAILURE;
 200                         continue;
 201                 }
 202
 203                 if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e'))
 204                         IF_EXPAND(expand(file, tab_size, opt));
 205                 else
 206                         IF_UNEXPAND(unexpand(file, tab_size, opt));
 207
 208                 /* Check and close the file */
 209                 if (fclose_if_not_stdin(file)) {
 210                         bb_simple_perror_msg(*argv);
 211                         exit_status = EXIT_FAILURE;
 212                 }
 213                 /* If stdin also clear EOF */
 214                 if (file == stdin)
 215                         clearerr(file);
 216         } while (*++argv);
 217
 218         /* Now close stdin also */
 219         /* (if we didn't read from it, it's a no-op) */
 220         if (fclose(stdin))
 221                 bb_perror_msg_and_die(bb_msg_standard_input);
 222
 223         fflush_stdout_and_exit(exit_status);
 224 }