| /* Implement the SELECT statement for character variables. |
| Contributed by Andy Vaught |
| |
| This file is part of the GNU Fortran 95 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. */ |
| |
| #include "libgfortran.h" |
| |
| typedef struct |
| { |
| char *low; |
| int low_len; |
| char *high; |
| int high_len; |
| void *address; |
| } |
| select_struct; |
| |
| extern void * select_string (select_struct *table, int table_len, |
| void *default_jump, const char *selector, |
| int 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. */ |
| |
| void * |
| select_string (select_struct *table, int table_len, void *default_jump, |
| const char *selector, int selector_len) |
| { |
| select_struct *t; |
| int i, low, high, mid; |
| |
| if (table_len == 0) |
| return default_jump; |
| |
| /* 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; |
| } |