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/* Implement the SELECT statement for character variables.
Copyright (C) 2008-2020 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 3, or (at your option)
any later version.
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.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#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;
}