+/* Implement the SELECT statement for character variables.
+ Copyright 2008 Free Software Foundation, Inc.
+
+This file is part of the GNU Fortran runtime library (libgfortran).
+
+Libgfortran 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.
+
+In addition to the permissions in the GNU General Public License, the
+Free Software Foundation gives you unlimited permission to link the
+compiled version of this file into combinations with other programs,
+and to distribute those combinations without any restriction coming
+from the use of this file. (The General Public License restrictions
+do apply in other respects; for example, they cover modification of
+the file, and distribution when not linked into a combine
+executable.)
+
+Libgfortran 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 libgfortran; see the file COPYING. If not, write to
+the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA. */
+
+
+#define select_string SUFFIX(select_string)
+#define select_struct SUFFIX(select_struct)
+#define compare_string SUFFIX(compare_string)
+
+typedef struct
+{
+ CHARTYPE *low;
+ gfc_charlen_type low_len;
+ CHARTYPE *high;
+ gfc_charlen_type high_len;
+ int address;
+}
+select_struct;
+
+extern int select_string (select_struct *table, int table_len,
+ const CHARTYPE *selector,
+ gfc_charlen_type selector_len);
+export_proto(select_string);
+
+
+/* select_string()-- Given a selector string and a table of
+ * select_struct structures, return the address to jump to. */
+
+int
+select_string (select_struct *table, int table_len, const CHARTYPE *selector,
+ gfc_charlen_type selector_len)
+{
+ select_struct *t;
+ int i, low, high, mid;
+ int default_jump = -1;
+
+ if (table_len == 0)
+ return -1;
+
+ /* Record the default address if present */
+
+ if (table->low == NULL && table->high == NULL)
+ {
+ default_jump = table->address;
+
+ table++;
+ table_len--;
+ if (table_len == 0)
+ return default_jump;
+ }
+
+ /* Try the high and low bounds if present. */
+
+ if (table->low == NULL)
+ {
+ if (compare_string (table->high_len, table->high,
+ selector_len, selector) >= 0)
+ return table->address;
+
+ table++;
+ table_len--;
+ if (table_len == 0)
+ return default_jump;
+ }
+
+ t = table + table_len - 1;
+
+ if (t->high == NULL)
+ {
+ if (compare_string (t->low_len, t->low, selector_len, selector) <= 0)
+ return t->address;
+
+ table_len--;
+ if (table_len == 0)
+ return default_jump;
+ }
+
+ /* At this point, the only table entries are bounded entries. Find
+ the right entry with a binary chop. */
+
+ low = -1;
+ high = table_len;
+
+ while (low + 1 < high)
+ {
+ mid = (low + high) / 2;
+
+ t = table + mid;
+ i = compare_string (t->low_len, t->low, selector_len, selector);
+
+ if (i == 0)
+ return t->address;
+
+ if (i < 0)
+ low = mid;
+ else
+ high = mid;
+ }
+
+ /* The string now lies between the low indeces of the now-adjacent
+ high and low entries. Because it is less than the low entry of
+ 'high', it can't be that one. If low is still -1, then no
+ entries match. Otherwise, we have to check the high entry of
+ 'low'. */
+
+ if (low == -1)
+ return default_jump;
+
+ t = table + low;
+ if (compare_string (selector_len, selector, t->high_len, t->high) <= 0)
+ return t->address;
+
+ return default_jump;
+}
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