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