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Diffstat (limited to 'src/expand.c')
| -rw-r--r-- | src/expand.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/src/expand.c b/src/expand.c new file mode 100644 index 0000000..ed78ca8 --- /dev/null +++ b/src/expand.c @@ -0,0 +1,237 @@ +/* expand - convert tabs to spaces + Copyright (C) 1989-2022 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* By default, convert all tabs to spaces. + Preserves backspace characters in the output; they decrement the + column count for tab calculations. + The default action is equivalent to -8. + + Options: + --tabs=tab1[,tab2[,...]] + -t tab1[,tab2[,...]] + -tab1[,tab2[,...]] If only one tab stop is given, set the tabs tab1 + columns apart instead of the default 8. Otherwise, + set the tabs at columns tab1, tab2, etc. (numbered from + 0); replace any tabs beyond the tab stops given with + single spaces. + --initial + -i Only convert initial tabs on each line to spaces. + + David MacKenzie <djm@gnu.ai.mit.edu> */ + +#include <config.h> + +#include <stdio.h> +#include <getopt.h> +#include <sys/types.h> +#include "system.h" +#include "die.h" + +#include "expand-common.h" + +/* The official name of this program (e.g., no 'g' prefix). */ +#define PROGRAM_NAME "expand" + +#define AUTHORS proper_name ("David MacKenzie") + +static char const shortopts[] = "it:0::1::2::3::4::5::6::7::8::9::"; + +static struct option const longopts[] = +{ + {"tabs", required_argument, NULL, 't'}, + {"initial", no_argument, NULL, 'i'}, + {GETOPT_HELP_OPTION_DECL}, + {GETOPT_VERSION_OPTION_DECL}, + {NULL, 0, NULL, 0} +}; + +void +usage (int status) +{ + if (status != EXIT_SUCCESS) + emit_try_help (); + else + { + printf (_("\ +Usage: %s [OPTION]... [FILE]...\n\ +"), + program_name); + fputs (_("\ +Convert tabs in each FILE to spaces, writing to standard output.\n\ +"), stdout); + + emit_stdin_note (); + emit_mandatory_arg_note (); + + fputs (_("\ + -i, --initial do not convert tabs after non blanks\n\ + -t, --tabs=N have tabs N characters apart, not 8\n\ +"), stdout); + emit_tab_list_info (); + fputs (HELP_OPTION_DESCRIPTION, stdout); + fputs (VERSION_OPTION_DESCRIPTION, stdout); + emit_ancillary_info (PROGRAM_NAME); + } + exit (status); +} + + +/* Change tabs to spaces, writing to stdout. + Read each file in 'file_list', in order. */ + +static void +expand (void) +{ + /* Input stream. */ + FILE *fp = next_file (NULL); + + if (!fp) + return; + + while (true) + { + /* Input character, or EOF. */ + int c; + + /* If true, perform translations. */ + bool convert = true; + + + /* The following variables have valid values only when CONVERT + is true: */ + + /* Column of next input character. */ + uintmax_t column = 0; + + /* Index in TAB_LIST of next tab stop to examine. */ + size_t tab_index = 0; + + + /* Convert a line of text. */ + + do + { + while ((c = getc (fp)) < 0 && (fp = next_file (fp))) + continue; + + if (convert) + { + if (c == '\t') + { + /* Column the next input tab stop is on. */ + uintmax_t next_tab_column; + bool last_tab; + + next_tab_column = get_next_tab_column (column, &tab_index, + &last_tab); + + if (last_tab) + next_tab_column = column + 1; + + if (next_tab_column < column) + die (EXIT_FAILURE, 0, _("input line is too long")); + + while (++column < next_tab_column) + if (putchar (' ') < 0) + die (EXIT_FAILURE, errno, _("write error")); + + c = ' '; + } + else if (c == '\b') + { + /* Go back one column, and force recalculation of the + next tab stop. */ + column -= !!column; + tab_index -= !!tab_index; + } + else + { + column++; + if (!column) + die (EXIT_FAILURE, 0, _("input line is too long")); + } + + convert &= convert_entire_line || !! isblank (c); + } + + if (c < 0) + return; + + if (putchar (c) < 0) + die (EXIT_FAILURE, errno, _("write error")); + } + while (c != '\n'); + } +} + +int +main (int argc, char **argv) +{ + int c; + + initialize_main (&argc, &argv); + set_program_name (argv[0]); + setlocale (LC_ALL, ""); + bindtextdomain (PACKAGE, LOCALEDIR); + textdomain (PACKAGE); + + atexit (close_stdout); + convert_entire_line = true; + + while ((c = getopt_long (argc, argv, shortopts, longopts, NULL)) != -1) + { + switch (c) + { + case 'i': + convert_entire_line = false; + break; + + case 't': + parse_tab_stops (optarg); + break; + + case '0': case '1': case '2': case '3': case '4': + case '5': case '6': case '7': case '8': case '9': + if (optarg) + parse_tab_stops (optarg - 1); + else + { + char tab_stop[2]; + tab_stop[0] = c; + tab_stop[1] = '\0'; + parse_tab_stops (tab_stop); + } + break; + + case_GETOPT_HELP_CHAR; + + case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS); + + default: + usage (EXIT_FAILURE); + } + } + + finalize_tab_stops (); + + set_file_list ((optind < argc) ? &argv[optind] : NULL); + + expand (); + + cleanup_file_list_stdin (); + + return exit_status; +} |