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134 lines
3.5 KiB
C
134 lines
3.5 KiB
C
/* Implement the SELECT statement for character variables.
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Copyright (C) 2008-2024 Free Software Foundation, Inc.
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This file is part of the GNU Fortran runtime library (libgfortran).
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Libgfortran is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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Libgfortran is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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#define select_string SUFFIX(select_string)
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#define select_struct SUFFIX(select_struct)
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#define compare_string SUFFIX(compare_string)
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typedef struct
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{
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CHARTYPE *low;
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gfc_charlen_type low_len;
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CHARTYPE *high;
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gfc_charlen_type high_len;
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int address;
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}
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select_struct;
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extern int select_string (select_struct *table, int table_len,
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const CHARTYPE *selector,
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gfc_charlen_type selector_len);
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export_proto(select_string);
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/* select_string()-- Given a selector string and a table of
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* select_struct structures, return the address to jump to. */
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int
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select_string (select_struct *table, int table_len, const CHARTYPE *selector,
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gfc_charlen_type selector_len)
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{
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select_struct *t;
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int i, low, high, mid;
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int default_jump = -1;
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if (table_len == 0)
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return -1;
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/* Record the default address if present */
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if (table->low == NULL && table->high == NULL)
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{
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default_jump = table->address;
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table++;
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table_len--;
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if (table_len == 0)
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return default_jump;
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}
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/* Try the high and low bounds if present. */
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if (table->low == NULL)
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{
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if (compare_string (table->high_len, table->high,
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selector_len, selector) >= 0)
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return table->address;
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table++;
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table_len--;
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if (table_len == 0)
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return default_jump;
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}
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t = table + table_len - 1;
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if (t->high == NULL)
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{
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if (compare_string (t->low_len, t->low, selector_len, selector) <= 0)
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return t->address;
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table_len--;
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if (table_len == 0)
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return default_jump;
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}
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/* At this point, the only table entries are bounded entries. Find
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the right entry with a binary chop. */
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low = -1;
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high = table_len;
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while (low + 1 < high)
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{
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mid = (low + high) / 2;
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t = table + mid;
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i = compare_string (t->low_len, t->low, selector_len, selector);
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if (i == 0)
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return t->address;
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if (i < 0)
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low = mid;
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else
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high = mid;
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}
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/* The string now lies between the low indeces of the now-adjacent
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high and low entries. Because it is less than the low entry of
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'high', it can't be that one. If low is still -1, then no
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entries match. Otherwise, we have to check the high entry of
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'low'. */
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if (low == -1)
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return default_jump;
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t = table + low;
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if (compare_string (selector_len, selector, t->high_len, t->high) <= 0)
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return t->address;
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return default_jump;
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}
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