maint: refactor common expand(1) and unexpand(1) code

* src/expand.c, src/unexpand.c: Move global variables from here...
* src/expand-common.h, src/expand-common.c: ... to here.
* src/expand.c, src/unexpand.c: (parse_tab_stops, validate_tab_stops,
next_file): Move identical functions to new module.
(add_tab_stop): Move to new module, including additional code from
'unexpand' (keeping max_column_width) which will have no effect in when
used in 'expand'. Refactor common next-column calculation code
into a new function 'get_next_tab_column'.
* src/local.mk: (src_expand_SOURCES, src_unexpand_SOURCES): Add
'expand-common.c'; (noinst_HEADERS): Add 'expand-common.h'.
* po/POTFILES.in: Add 'expand-common.c'.
* tests/misc/expand.pl: Add more tests.
* tests/misc/unexpand.pl: Likewise.
* TODO: Move conclusions to above test after investigation.

1 files changed, 72 insertions, 0 deletions

diff --git a/src/expand-common.h b/src/expand-common.h
new file mode 100644
index 000000000..8cb207997
--- /dev/null
+++ b/src/expand-common.h
@@ -0,0 +1,72 @@
+/* expand-common - common functionality for expand/unexapnd
+
+   Copyright (C) 1989-2016 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 <http://www.gnu.org/licenses/>.  */
+
+/* If true, convert blanks even after nonblank characters have been
+   read on the line.  */
+extern bool convert_entire_line;
+
+/* The maximum distance between tab stops.  */
+extern size_t max_column_width;
+
+/* Null-terminated array of input filenames.  */
+//extern char **file_list;
+
+/* Default for 'file_list' if no files are given on the command line.  */
+//extern char *stdin_argv[];
+
+/* True if we have ever read standard input.  */
+//extern bool have_read_stdin;
+
+/* The desired exit status.  */
+extern int exit_status;
+
+/* Add tab stop TABVAL to the end of 'tab_list'.  */
+extern void
+add_tab_stop (uintmax_t tabval);
+
+/* Add the comma or blank separated list of tab stops STOPS
+   to the list of tab stops.  */
+extern void
+parse_tab_stops (char const *stops);
+
+/* TODO: Document */
+extern uintmax_t
+get_next_tab_column (const uintmax_t column, size_t* tab_index,
+                     bool* last_tab);
+
+/* Called after all command-line options have been parsed,
+   sets the final tab-stops values */
+extern void
+finalize_tab_stops (void);
+
+
+
+
+/* Sets new file-list */
+extern void
+set_file_list (char **file_list);
+
+/* 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.  */
+extern FILE *
+next_file (FILE *fp);
+
+/* */
+extern void
+cleanup_file_list_stdin (void);