cut: refactor into set-fields module

Extract the functionality of parsing --field=LIST into a separate
module, to be used by other programs.

* src/cut.c: move field parsing code from here ...
* src/set-fields.{c,h}: ... to here.
  (set_fields): generalize by supporting multiple parsing/reporting
  options.
  (struct range_pair): rename to field_range_pair.
* src/local.mk: link cut with set-field.
* po/POTFILES.in: add set-field.c
* tests/misc/cut.pl: update wording of error messages

1 files changed, 49 insertions, 0 deletions

diff --git a/src/set-fields.h b/src/set-fields.h
new file mode 100644
index 000000000..2c55c2984
--- /dev/null
+++ b/src/set-fields.h
@@ -0,0 +1,49 @@
+/* set-fields.h -- parse field list argument
+
+   Copyright (C) 2015 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/>.  */
+#ifndef SET_FIELDS_H
+# define SET_FIELDS_H
+
+struct field_range_pair
+  {
+    size_t lo;
+    size_t hi;
+  };
+
+/* Array of `struct range_pair' holding all the finite ranges. */
+extern struct field_range_pair *frp;
+
+/* Number of finite ranges specified by the user. */
+extern size_t n_frp;
+
+/* field list parsing options */
+enum
+{
+  SETFLD_ALLOW_DASH = 0x01,     /* allow single dash meaning 'all fields' */
+  SETFLD_COMPLEMENT = 0x02,     /* complement the field list */
+  SETFLD_ERRMSG_USE_POS = 0x04  /* when reporting errors, say 'position' instead
+                                   of 'field' (used with cut -b/-c) */
+};
+
+/* allocates and initializes the FRP array and N_FRP count */
+void
+set_fields (const char *fieldstr, unsigned int options);
+
+/* frees memory allocated by set_fields() */
+void
+reset_fields (void);
+
+#endif