123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321 | /* unexpand - convert blanks to tabs Copyright (C) 1989-2025 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 only maximal strings of initial blanks and tabs into tabs. 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); preserve any blanks beyond the tab stops given. --all -a Use tabs wherever they would replace 2 or more blanks, not just at the beginnings of lines. David MacKenzie <djm@gnu.ai.mit.edu> */#include <config.h>#include <ctype.h>#include <stdio.h>#include <getopt.h>#include <sys/types.h>#include"system.h"#include"expand-common.h"/* The official name of this program (e.g., no 'g' prefix). */#define PROGRAM_NAME"unexpand"#define AUTHORS proper_name ("David MacKenzie")/* For long options that have no equivalent short option, use a non-character as a pseudo short option, starting with CHAR_MAX + 1. */enum{ CONVERT_FIRST_ONLY_OPTION = CHAR_MAX +1};static struct option const longopts[] ={{"tabs", required_argument,nullptr,'t'},{"all", no_argument,nullptr,'a'},{"first-only", no_argument,nullptr, CONVERT_FIRST_ONLY_OPTION},{GETOPT_HELP_OPTION_DECL},{GETOPT_VERSION_OPTION_DECL},{nullptr,0,nullptr,0}};voidusage(int status){if(status != EXIT_SUCCESS)emit_try_help();else{printf(_("\Usage: %s [OPTION]... [FILE]...\n\"), program_name);fputs(_("\Convert blanks in each FILE to tabs, writing to standard output.\n\"), stdout);emit_stdin_note();emit_mandatory_arg_note();fputs(_("\ -a, --all convert all blanks, instead of just initial blanks\n\ --first-only convert only leading sequences of blanks (overrides -a)\n\ -t, --tabs=N have tabs N characters apart instead of 8 (enables -a)\n\"), stdout);emit_tab_list_info();fputs(HELP_OPTION_DESCRIPTION, stdout);fputs(VERSION_OPTION_DESCRIPTION, stdout);emit_ancillary_info(PROGRAM_NAME);}exit(status);}/* Change blanks to tabs, writing to stdout. Read each file in 'file_list', in order. */static voidunexpand(void){/* Input stream. */FILE*fp =next_file(nullptr);/* The array of pending blanks. In non-POSIX locales, blanks can include characters other than spaces, so the blanks must be stored, not merely counted. */char*pending_blank;if(!fp)return;/* The worst case is a non-blank character, then one blank, then a tab stop, then MAX_COLUMN_WIDTH - 1 blanks, then a non-blank; so allocate MAX_COLUMN_WIDTH bytes to store the blanks. */ pending_blank =ximalloc(max_column_width);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. */ colno column =0;/* Column the next input tab stop is on. */ colno next_tab_column =0;/* Index in TAB_LIST of next tab stop to examine. */ idx_t tab_index =0;/* If true, the first pending blank came just before a tab stop. */bool one_blank_before_tab_stop =false;/* If true, the previous input character was a blank. This is initially true, since initial strings of blanks are treated as if the line was preceded by a blank. */bool prev_blank =true;/* Number of pending columns of blanks. */ idx_t pending =0;/* Convert a line of text. */do{while((c =getc(fp)) <0&& (fp =next_file(fp)))continue;if(convert){bool blank = !!isblank(c);if(blank){bool last_tab; next_tab_column =get_next_tab_column(column, &tab_index,&last_tab);if(last_tab) convert =false;if(convert){if(c =='\t'){ column = next_tab_column;if(pending) pending_blank[0] ='\t';}else{ column++;if(! (prev_blank && column == next_tab_column)){/* It is not yet known whether the pending blanks will be replaced by tabs. */if(column == next_tab_column) one_blank_before_tab_stop =true; pending_blank[pending++] = c; prev_blank =true;continue;}/* Replace the pending blanks by a tab or two. */ pending_blank[0] = c ='\t';}/* Discard pending blanks, unless it was a single blank just before the previous tab stop. */ pending = one_blank_before_tab_stop;}}else if(c =='\b'){/* Go back one column, and force recalculation of the next tab stop. */ column -= !!column; next_tab_column = column; tab_index -= !!tab_index;}else{ column++;if(!column)error(EXIT_FAILURE,0,_("input line is too long"));}if(pending){if(pending >1&& one_blank_before_tab_stop) pending_blank[0] ='\t';if(fwrite(pending_blank,1, pending, stdout) != pending)write_error(); pending =0; one_blank_before_tab_stop =false;} prev_blank = blank; convert &= convert_entire_line || blank;}if(c <0){free(pending_blank);return;}if(putchar(c) <0)write_error();}while(c !='\n');}}intmain(int argc,char**argv){bool have_tabval =false; colno tabval IF_LINT( =0);int c;/* If true, cancel the effect of any -a (explicit or implicit in -t), so that only leading blanks will be considered. */bool convert_first_only =false;initialize_main(&argc, &argv);set_program_name(argv[0]);setlocale(LC_ALL,"");bindtextdomain(PACKAGE, LOCALEDIR);textdomain(PACKAGE);atexit(close_stdout);while((c =getopt_long(argc, argv,",0123456789at:", longopts,nullptr))!= -1){switch(c){case'?':usage(EXIT_FAILURE);case'a': convert_entire_line =true;break;case't': convert_entire_line =true;parse_tab_stops(optarg);break;case CONVERT_FIRST_ONLY_OPTION: convert_first_only =true;break;case',':if(have_tabval)add_tab_stop(tabval); have_tabval =false;break; case_GETOPT_HELP_CHAR;case_GETOPT_VERSION_CHAR(PROGRAM_NAME, AUTHORS);default:if(!have_tabval){ tabval =0; have_tabval =true;}if(!DECIMAL_DIGIT_ACCUMULATE(tabval, c -'0'))error(EXIT_FAILURE,0,_("tab stop value is too large"));break;}}if(convert_first_only) convert_entire_line =false;if(have_tabval)add_tab_stop(tabval);finalize_tab_stops();set_file_list((optind < argc) ? &argv[optind] :nullptr);unexpand();cleanup_file_list_stdin();return exit_status;}
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