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Diffstat (limited to 'src/unexpand.c')
-rw-r--r-- | src/unexpand.c | 540 |
1 files changed, 540 insertions, 0 deletions
diff --git a/src/unexpand.c b/src/unexpand.c new file mode 100644 index 0000000..cbceca0 --- /dev/null +++ b/src/unexpand.c @@ -0,0 +1,540 @@ +/* unexpand - convert blanks to tabs + Copyright (C) 89, 91, 1995-2006 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 2, 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, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* 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 <stdio.h> +#include <getopt.h> +#include <sys/types.h> +#include "system.h" +#include "error.h" +#include "quote.h" +#include "xstrndup.h" + +/* The official name of this program (e.g., no `g' prefix). */ +#define PROGRAM_NAME "unexpand" + +#define AUTHORS "David MacKenzie" + +/* The number of bytes added at a time to the amount of memory + allocated for the output line. */ +#define OUTPUT_BLOCK 256 + +/* The name this program was run with. */ +char *program_name; + +/* If true, convert blanks even after nonblank characters have been + read on the line. */ +static bool convert_entire_line; + +/* If nonzero, the size of all tab stops. If zero, use `tab_list' instead. */ +static size_t tab_size; + +/* The maximum distance between tab stops. */ +static size_t max_column_width; + +/* Array of the explicit column numbers of the tab stops; + after `tab_list' is exhausted, the rest of the line is printed + unchanged. The first column is column 0. */ +static uintmax_t *tab_list; + +/* The number of allocated entries in `tab_list'. */ +static size_t n_tabs_allocated; + +/* The index of the first invalid element of `tab_list', + where the next element can be added. */ +static size_t first_free_tab; + +/* Null-terminated array of input filenames. */ +static char **file_list; + +/* Default for `file_list' if no files are given on the command line. */ +static char *stdin_argv[] = +{ + "-", NULL +}; + +/* True if we have ever read standard input. */ +static bool have_read_stdin; + +/* The desired exit status. */ +static int exit_status; + +/* 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, NULL, 't'}, + {"all", no_argument, NULL, 'a'}, + {"first-only", no_argument, NULL, CONVERT_FIRST_ONLY_OPTION}, + {GETOPT_HELP_OPTION_DECL}, + {GETOPT_VERSION_OPTION_DECL}, + {NULL, 0, NULL, 0} +}; + +void +usage (int status) +{ + if (status != EXIT_SUCCESS) + fprintf (stderr, _("Try `%s --help' for more information.\n"), + program_name); + else + { + printf (_("\ +Usage: %s [OPTION]... [FILE]...\n\ +"), + program_name); + fputs (_("\ +Convert blanks in each FILE to tabs, writing to standard output.\n\ +With no FILE, or when FILE is -, read standard input.\n\ +\n\ +"), stdout); + fputs (_("\ +Mandatory arguments to long options are mandatory for short options too.\n\ +"), stdout); + 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\ + -t, --tabs=LIST use comma separated LIST of tab positions (enables -a)\n\ +"), stdout); + fputs (HELP_OPTION_DESCRIPTION, stdout); + fputs (VERSION_OPTION_DESCRIPTION, stdout); + printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT); + } + exit (status); +} + +/* Add tab stop TABVAL to the end of `tab_list'. */ + +static void +add_tab_stop (uintmax_t tabval) +{ + uintmax_t prev_column = first_free_tab ? tab_list[first_free_tab - 1] : 0; + uintmax_t column_width = prev_column <= tabval ? tabval - prev_column : 0; + + if (first_free_tab == n_tabs_allocated) + tab_list = X2NREALLOC (tab_list, &n_tabs_allocated); + tab_list[first_free_tab++] = tabval; + + if (max_column_width < column_width) + { + if (SIZE_MAX < column_width) + error (EXIT_FAILURE, 0, _("tabs are too far apart")); + max_column_width = column_width; + } +} + +/* Add the comma or blank separated list of tab stops STOPS + to the list of tab stops. */ + +static void +parse_tab_stops (char const *stops) +{ + bool have_tabval = false; + uintmax_t tabval IF_LINT (= 0); + char const *num_start IF_LINT (= NULL); + bool ok = true; + + for (; *stops; stops++) + { + if (*stops == ',' || isblank (to_uchar (*stops))) + { + if (have_tabval) + add_tab_stop (tabval); + have_tabval = false; + } + else if (ISDIGIT (*stops)) + { + if (!have_tabval) + { + tabval = 0; + have_tabval = true; + num_start = stops; + } + + /* Detect overflow. */ + if (!DECIMAL_DIGIT_ACCUMULATE (tabval, *stops - '0', uintmax_t)) + { + size_t len = strspn (num_start, "0123456789"); + char *bad_num = xstrndup (num_start, len); + error (0, 0, _("tab stop is too large %s"), quote (bad_num)); + free (bad_num); + ok = false; + stops = num_start + len - 1; + } + } + else + { + error (0, 0, _("tab size contains invalid character(s): %s"), + quote (stops)); + ok = false; + break; + } + } + + if (!ok) + exit (EXIT_FAILURE); + + if (have_tabval) + add_tab_stop (tabval); +} + +/* Check that the list of tab stops TABS, with ENTRIES entries, + contains only nonzero, ascending values. */ + +static void +validate_tab_stops (uintmax_t const *tabs, size_t entries) +{ + uintmax_t prev_tab = 0; + size_t i; + + for (i = 0; i < entries; i++) + { + if (tabs[i] == 0) + error (EXIT_FAILURE, 0, _("tab size cannot be 0")); + if (tabs[i] <= prev_tab) + error (EXIT_FAILURE, 0, _("tab sizes must be ascending")); + prev_tab = tabs[i]; + } +} + +/* Close the old stream pointer FP if it is non-NULL, + and return a new one opened to read the next input file. + Open a filename of `-' as the standard input. + Return NULL if there are no more input files. */ + +static FILE * +next_file (FILE *fp) +{ + static char *prev_file; + char *file; + + if (fp) + { + if (ferror (fp)) + { + error (0, errno, "%s", prev_file); + exit_status = EXIT_FAILURE; + } + if (STREQ (prev_file, "-")) + clearerr (fp); /* Also clear EOF. */ + else if (fclose (fp) != 0) + { + error (0, errno, "%s", prev_file); + exit_status = EXIT_FAILURE; + } + } + + while ((file = *file_list++) != NULL) + { + if (STREQ (file, "-")) + { + have_read_stdin = true; + prev_file = file; + return stdin; + } + fp = fopen (file, "r"); + if (fp) + { + prev_file = file; + return fp; + } + error (0, errno, "%s", file); + exit_status = EXIT_FAILURE; + } + return NULL; +} + +/* Change blanks to tabs, writing to stdout. + Read each file in `file_list', in order. */ + +static void +unexpand (void) +{ + /* Input stream. */ + FILE *fp = next_file (NULL); + + /* 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 = xmalloc (max_column_width); + + for (;;) + { + /* 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; + + /* Column the next input tab stop is on. */ + uintmax_t next_tab_column = 0; + + /* Index in TAB_LIST of next tab stop to examine. */ + size_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. */ + size_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) + { + if (next_tab_column <= column) + { + if (tab_size) + next_tab_column = + column + (tab_size - column % tab_size); + else + for (;;) + if (tab_index == first_free_tab) + { + convert = false; + break; + } + else + { + uintmax_t tab = tab_list[tab_index++]; + if (column < tab) + { + next_tab_column = tab; + break; + } + } + } + + if (convert) + { + if (next_tab_column < column) + error (EXIT_FAILURE, 0, _("input line is too long")); + + if (c == '\t') + { + column = next_tab_column; + + /* Discard pending blanks, unless it was a single + blank just before the previous tab stop. */ + if (! (pending == 1 && one_blank_before_tab_stop)) + { + pending = 0; + one_blank_before_tab_stop = false; + } + } + 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'; + 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 (fwrite (pending_blank, 1, pending, stdout) != pending) + error (EXIT_FAILURE, errno, _("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) + error (EXIT_FAILURE, errno, _("write error")); + } + while (c != '\n'); + } +} + +int +main (int argc, char **argv) +{ + bool have_tabval = false; + uintmax_t 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); + program_name = argv[0]; + setlocale (LC_ALL, ""); + bindtextdomain (PACKAGE, LOCALEDIR); + textdomain (PACKAGE); + + atexit (close_stdout); + + have_read_stdin = false; + exit_status = EXIT_SUCCESS; + convert_entire_line = false; + tab_list = NULL; + first_free_tab = 0; + + while ((c = getopt_long (argc, argv, ",0123456789at:", longopts, NULL)) + != -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', uintmax_t)) + 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); + + validate_tab_stops (tab_list, first_free_tab); + + if (first_free_tab == 0) + tab_size = max_column_width = 8; + else if (first_free_tab == 1) + tab_size = tab_list[0]; + else + tab_size = 0; + + file_list = (optind < argc ? &argv[optind] : stdin_argv); + + unexpand (); + + if (have_read_stdin && fclose (stdin) != 0) + error (EXIT_FAILURE, errno, "-"); + + exit (exit_status); +} |