721 lines
17 KiB
C
721 lines
17 KiB
C
/* Copyright (C) 2002, 2003, 2005, 2007 Free Software Foundation, Inc.
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Contributed by Andy Vaught
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This file is part of the GNU Fortran 95 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 2, or (at your option)
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any later version.
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In addition to the permissions in the GNU General Public License, the
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Free Software Foundation gives you unlimited permission to link the
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compiled version of this file into combinations with other programs,
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and to distribute those combinations without any restriction coming
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from the use of this file. (The General Public License restrictions
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do apply in other respects; for example, they cover modification of
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the file, and distribution when not linked into a combine
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executable.)
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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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You should have received a copy of the GNU General Public License
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along with Libgfortran; see the file COPYING. If not, write to
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the Free Software Foundation, 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, USA. */
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#include "io.h"
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#include <stdlib.h>
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#include <string.h>
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/* IO locking rules:
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UNIT_LOCK is a master lock, protecting UNIT_ROOT tree and UNIT_CACHE.
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Concurrent use of different units should be supported, so
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each unit has its own lock, LOCK.
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Open should be atomic with its reopening of units and list_read.c
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in several places needs find_unit another unit while holding stdin
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unit's lock, so it must be possible to acquire UNIT_LOCK while holding
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some unit's lock. Therefore to avoid deadlocks, it is forbidden
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to acquire unit's private locks while holding UNIT_LOCK, except
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for freshly created units (where no other thread can get at their
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address yet) or when using just trylock rather than lock operation.
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In addition to unit's private lock each unit has a WAITERS counter
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and CLOSED flag. WAITERS counter must be either only
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atomically incremented/decremented in all places (if atomic builtins
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are supported), or protected by UNIT_LOCK in all places (otherwise).
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CLOSED flag must be always protected by unit's LOCK.
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After finding a unit in UNIT_CACHE or UNIT_ROOT with UNIT_LOCK held,
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WAITERS must be incremented to avoid concurrent close from freeing
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the unit between unlocking UNIT_LOCK and acquiring unit's LOCK.
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Unit freeing is always done under UNIT_LOCK. If close_unit sees any
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WAITERS, it doesn't free the unit but instead sets the CLOSED flag
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and the thread that decrements WAITERS to zero while CLOSED flag is
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set is responsible for freeing it (while holding UNIT_LOCK).
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flush_all_units operation is iterating over the unit tree with
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increasing UNIT_NUMBER while holding UNIT_LOCK and attempting to
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flush each unit (and therefore needs the unit's LOCK held as well).
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To avoid deadlocks, it just trylocks the LOCK and if unsuccessful,
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remembers the current unit's UNIT_NUMBER, unlocks UNIT_LOCK, acquires
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unit's LOCK and after flushing reacquires UNIT_LOCK and restarts with
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the smallest UNIT_NUMBER above the last one flushed.
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If find_unit/find_or_create_unit/find_file/get_unit routines return
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non-NULL, the returned unit has its private lock locked and when the
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caller is done with it, it must call either unlock_unit or close_unit
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on it. unlock_unit or close_unit must be always called only with the
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private lock held. */
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/* Subroutines related to units */
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#define CACHE_SIZE 3
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static gfc_unit *unit_cache[CACHE_SIZE];
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gfc_offset max_offset;
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gfc_unit *unit_root;
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#ifdef __GTHREAD_MUTEX_INIT
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__gthread_mutex_t unit_lock = __GTHREAD_MUTEX_INIT;
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#else
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__gthread_mutex_t unit_lock;
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#endif
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/* We use these filenames for error reporting. */
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static char stdin_name[] = "stdin";
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static char stdout_name[] = "stdout";
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static char stderr_name[] = "stderr";
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/* This implementation is based on Stefan Nilsson's article in the
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* July 1997 Doctor Dobb's Journal, "Treaps in Java". */
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/* pseudo_random()-- Simple linear congruential pseudorandom number
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* generator. The period of this generator is 44071, which is plenty
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* for our purposes. */
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static int
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pseudo_random (void)
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{
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static int x0 = 5341;
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x0 = (22611 * x0 + 10) % 44071;
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return x0;
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}
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/* rotate_left()-- Rotate the treap left */
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static gfc_unit *
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rotate_left (gfc_unit * t)
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{
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gfc_unit *temp;
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temp = t->right;
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t->right = t->right->left;
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temp->left = t;
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return temp;
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}
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/* rotate_right()-- Rotate the treap right */
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static gfc_unit *
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rotate_right (gfc_unit * t)
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{
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gfc_unit *temp;
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temp = t->left;
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t->left = t->left->right;
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temp->right = t;
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return temp;
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}
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static int
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compare (int a, int b)
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{
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if (a < b)
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return -1;
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if (a > b)
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return 1;
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return 0;
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}
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/* insert()-- Recursive insertion function. Returns the updated treap. */
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static gfc_unit *
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insert (gfc_unit *new, gfc_unit *t)
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{
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int c;
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if (t == NULL)
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return new;
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c = compare (new->unit_number, t->unit_number);
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if (c < 0)
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{
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t->left = insert (new, t->left);
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if (t->priority < t->left->priority)
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t = rotate_right (t);
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}
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if (c > 0)
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{
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t->right = insert (new, t->right);
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if (t->priority < t->right->priority)
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t = rotate_left (t);
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}
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if (c == 0)
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internal_error (NULL, "insert(): Duplicate key found!");
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return t;
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}
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/* insert_unit()-- Create a new node, insert it into the treap. */
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static gfc_unit *
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insert_unit (int n)
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{
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gfc_unit *u = get_mem (sizeof (gfc_unit));
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memset (u, '\0', sizeof (gfc_unit));
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u->unit_number = n;
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#ifdef __GTHREAD_MUTEX_INIT
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{
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__gthread_mutex_t tmp = __GTHREAD_MUTEX_INIT;
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u->lock = tmp;
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}
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#else
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__GTHREAD_MUTEX_INIT_FUNCTION (&u->lock);
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#endif
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__gthread_mutex_lock (&u->lock);
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u->priority = pseudo_random ();
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unit_root = insert (u, unit_root);
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return u;
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}
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static gfc_unit *
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delete_root (gfc_unit * t)
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{
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gfc_unit *temp;
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if (t->left == NULL)
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return t->right;
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if (t->right == NULL)
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return t->left;
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if (t->left->priority > t->right->priority)
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{
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temp = rotate_right (t);
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temp->right = delete_root (t);
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}
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else
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{
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temp = rotate_left (t);
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temp->left = delete_root (t);
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}
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return temp;
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}
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/* delete_treap()-- Delete an element from a tree. The 'old' value
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* does not necessarily have to point to the element to be deleted, it
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* must just point to a treap structure with the key to be deleted.
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* Returns the new root node of the tree. */
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static gfc_unit *
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delete_treap (gfc_unit * old, gfc_unit * t)
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{
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int c;
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if (t == NULL)
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return NULL;
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c = compare (old->unit_number, t->unit_number);
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if (c < 0)
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t->left = delete_treap (old, t->left);
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if (c > 0)
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t->right = delete_treap (old, t->right);
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if (c == 0)
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t = delete_root (t);
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return t;
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}
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/* delete_unit()-- Delete a unit from a tree */
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static void
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delete_unit (gfc_unit * old)
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{
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unit_root = delete_treap (old, unit_root);
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}
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/* get_external_unit()-- Given an integer, return a pointer to the unit
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* structure. Returns NULL if the unit does not exist,
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* otherwise returns a locked unit. */
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static gfc_unit *
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get_external_unit (int n, int do_create)
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{
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gfc_unit *p;
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int c, created = 0;
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__gthread_mutex_lock (&unit_lock);
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retry:
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for (c = 0; c < CACHE_SIZE; c++)
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if (unit_cache[c] != NULL && unit_cache[c]->unit_number == n)
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{
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p = unit_cache[c];
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goto found;
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}
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p = unit_root;
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while (p != NULL)
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{
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c = compare (n, p->unit_number);
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if (c < 0)
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p = p->left;
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if (c > 0)
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p = p->right;
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if (c == 0)
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break;
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}
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if (p == NULL && do_create)
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{
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p = insert_unit (n);
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created = 1;
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}
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if (p != NULL)
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{
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for (c = 0; c < CACHE_SIZE - 1; c++)
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unit_cache[c] = unit_cache[c + 1];
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unit_cache[CACHE_SIZE - 1] = p;
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}
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if (created)
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{
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/* Newly created units have their lock held already
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from insert_unit. Just unlock UNIT_LOCK and return. */
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__gthread_mutex_unlock (&unit_lock);
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return p;
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}
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found:
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if (p != NULL)
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{
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/* Fast path. */
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if (! __gthread_mutex_trylock (&p->lock))
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{
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/* assert (p->closed == 0); */
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__gthread_mutex_unlock (&unit_lock);
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return p;
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}
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inc_waiting_locked (p);
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}
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__gthread_mutex_unlock (&unit_lock);
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if (p != NULL)
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{
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__gthread_mutex_lock (&p->lock);
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if (p->closed)
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{
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__gthread_mutex_lock (&unit_lock);
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__gthread_mutex_unlock (&p->lock);
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if (predec_waiting_locked (p) == 0)
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free_mem (p);
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goto retry;
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}
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dec_waiting_unlocked (p);
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}
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return p;
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}
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gfc_unit *
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find_unit (int n)
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{
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return get_external_unit (n, 0);
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}
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gfc_unit *
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find_or_create_unit (int n)
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{
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return get_external_unit (n, 1);
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}
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gfc_unit *
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get_internal_unit (st_parameter_dt *dtp)
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{
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gfc_unit * iunit;
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/* Allocate memory for a unit structure. */
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iunit = get_mem (sizeof (gfc_unit));
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if (iunit == NULL)
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{
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generate_error (&dtp->common, ERROR_INTERNAL_UNIT, NULL);
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return NULL;
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}
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memset (iunit, '\0', sizeof (gfc_unit));
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#ifdef __GTHREAD_MUTEX_INIT
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{
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__gthread_mutex_t tmp = __GTHREAD_MUTEX_INIT;
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iunit->lock = tmp;
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}
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#else
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__GTHREAD_MUTEX_INIT_FUNCTION (&iunit->lock);
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#endif
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__gthread_mutex_lock (&iunit->lock);
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iunit->recl = dtp->internal_unit_len;
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/* For internal units we set the unit number to -1.
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Otherwise internal units can be mistaken for a pre-connected unit or
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some other file I/O unit. */
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iunit->unit_number = -1;
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/* Set up the looping specification from the array descriptor, if any. */
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if (is_array_io (dtp))
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{
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iunit->rank = GFC_DESCRIPTOR_RANK (dtp->internal_unit_desc);
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iunit->ls = (array_loop_spec *)
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get_mem (iunit->rank * sizeof (array_loop_spec));
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dtp->internal_unit_len *=
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init_loop_spec (dtp->internal_unit_desc, iunit->ls);
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}
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/* Set initial values for unit parameters. */
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iunit->s = open_internal (dtp->internal_unit, dtp->internal_unit_len);
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iunit->bytes_left = iunit->recl;
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iunit->last_record=0;
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iunit->maxrec=0;
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iunit->current_record=0;
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iunit->read_bad = 0;
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/* Set flags for the internal unit. */
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iunit->flags.access = ACCESS_SEQUENTIAL;
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iunit->flags.action = ACTION_READWRITE;
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iunit->flags.form = FORM_FORMATTED;
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iunit->flags.pad = PAD_YES;
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iunit->flags.status = STATUS_UNSPECIFIED;
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iunit->endfile = NO_ENDFILE;
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/* Initialize the data transfer parameters. */
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dtp->u.p.advance_status = ADVANCE_YES;
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dtp->u.p.blank_status = BLANK_UNSPECIFIED;
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dtp->u.p.seen_dollar = 0;
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dtp->u.p.skips = 0;
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dtp->u.p.pending_spaces = 0;
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dtp->u.p.max_pos = 0;
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dtp->u.p.at_eof = 0;
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/* This flag tells us the unit is assigned to internal I/O. */
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dtp->u.p.unit_is_internal = 1;
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return iunit;
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}
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/* free_internal_unit()-- Free memory allocated for internal units if any. */
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void
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free_internal_unit (st_parameter_dt *dtp)
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{
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if (!is_internal_unit (dtp))
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return;
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if (dtp->u.p.current_unit->ls != NULL)
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free_mem (dtp->u.p.current_unit->ls);
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sclose (dtp->u.p.current_unit->s);
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if (dtp->u.p.current_unit != NULL)
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free_mem (dtp->u.p.current_unit);
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}
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/* get_unit()-- Returns the unit structure associated with the integer
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* unit or the internal file. */
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gfc_unit *
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get_unit (st_parameter_dt *dtp, int do_create)
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{
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if ((dtp->common.flags & IOPARM_DT_HAS_INTERNAL_UNIT) != 0)
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return get_internal_unit(dtp);
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/* Has to be an external unit */
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dtp->u.p.unit_is_internal = 0;
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dtp->internal_unit_desc = NULL;
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return get_external_unit (dtp->common.unit, do_create);
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}
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/*************************/
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/* Initialize everything */
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void
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init_units (void)
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{
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gfc_unit *u;
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unsigned int i;
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#ifndef __GTHREAD_MUTEX_INIT
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__GTHREAD_MUTEX_INIT_FUNCTION (&unit_lock);
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#endif
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if (options.stdin_unit >= 0)
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{ /* STDIN */
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u = insert_unit (options.stdin_unit);
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u->s = input_stream ();
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u->flags.action = ACTION_READ;
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u->flags.access = ACCESS_SEQUENTIAL;
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u->flags.form = FORM_FORMATTED;
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u->flags.status = STATUS_OLD;
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u->flags.blank = BLANK_NULL;
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u->flags.pad = PAD_YES;
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u->flags.position = POSITION_ASIS;
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u->recl = options.default_recl;
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u->endfile = NO_ENDFILE;
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u->file_len = strlen (stdin_name);
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u->file = get_mem (u->file_len);
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memmove (u->file, stdin_name, u->file_len);
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__gthread_mutex_unlock (&u->lock);
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}
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if (options.stdout_unit >= 0)
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{ /* STDOUT */
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u = insert_unit (options.stdout_unit);
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u->s = output_stream ();
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u->flags.action = ACTION_WRITE;
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u->flags.access = ACCESS_SEQUENTIAL;
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u->flags.form = FORM_FORMATTED;
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u->flags.status = STATUS_OLD;
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u->flags.blank = BLANK_NULL;
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u->flags.position = POSITION_ASIS;
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u->recl = options.default_recl;
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u->endfile = AT_ENDFILE;
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u->file_len = strlen (stdout_name);
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u->file = get_mem (u->file_len);
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memmove (u->file, stdout_name, u->file_len);
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__gthread_mutex_unlock (&u->lock);
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}
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if (options.stderr_unit >= 0)
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{ /* STDERR */
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u = insert_unit (options.stderr_unit);
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u->s = error_stream ();
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u->flags.action = ACTION_WRITE;
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u->flags.access = ACCESS_SEQUENTIAL;
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u->flags.form = FORM_FORMATTED;
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u->flags.status = STATUS_OLD;
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u->flags.blank = BLANK_NULL;
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u->flags.position = POSITION_ASIS;
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u->recl = options.default_recl;
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u->endfile = AT_ENDFILE;
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u->file_len = strlen (stderr_name);
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u->file = get_mem (u->file_len);
|
|
memmove (u->file, stderr_name, u->file_len);
|
|
|
|
__gthread_mutex_unlock (&u->lock);
|
|
}
|
|
|
|
/* Calculate the maximum file offset in a portable manner.
|
|
* max will be the largest signed number for the type gfc_offset.
|
|
*
|
|
* set a 1 in the LSB and keep a running sum, stopping at MSB-1 bit. */
|
|
|
|
max_offset = 0;
|
|
for (i = 0; i < sizeof (max_offset) * 8 - 1; i++)
|
|
max_offset = max_offset + ((gfc_offset) 1 << i);
|
|
}
|
|
|
|
|
|
static int
|
|
close_unit_1 (gfc_unit *u, int locked)
|
|
{
|
|
int i, rc;
|
|
|
|
/* If there are previously written bytes from a write with ADVANCE="no"
|
|
Reposition the buffer before closing. */
|
|
if (u->saved_pos > 0)
|
|
{
|
|
char *p;
|
|
|
|
p = salloc_w (u->s, &u->saved_pos);
|
|
|
|
if (!(u->unit_number == options.stdout_unit
|
|
|| u->unit_number == options.stderr_unit))
|
|
{
|
|
size_t len;
|
|
|
|
const char crlf[] = "\r\n";
|
|
#ifdef HAVE_CRLF
|
|
len = 2;
|
|
#else
|
|
len = 1;
|
|
#endif
|
|
if (swrite (u->s, &crlf[2-len], &len) != 0)
|
|
os_error ("Close after ADVANCE_NO failed");
|
|
}
|
|
}
|
|
|
|
rc = (u->s == NULL) ? 0 : sclose (u->s) == FAILURE;
|
|
|
|
u->closed = 1;
|
|
if (!locked)
|
|
__gthread_mutex_lock (&unit_lock);
|
|
|
|
for (i = 0; i < CACHE_SIZE; i++)
|
|
if (unit_cache[i] == u)
|
|
unit_cache[i] = NULL;
|
|
|
|
delete_unit (u);
|
|
|
|
if (u->file)
|
|
free_mem (u->file);
|
|
u->file = NULL;
|
|
u->file_len = 0;
|
|
|
|
if (!locked)
|
|
__gthread_mutex_unlock (&u->lock);
|
|
|
|
/* If there are any threads waiting in find_unit for this unit,
|
|
avoid freeing the memory, the last such thread will free it
|
|
instead. */
|
|
if (u->waiting == 0)
|
|
free_mem (u);
|
|
|
|
if (!locked)
|
|
__gthread_mutex_unlock (&unit_lock);
|
|
|
|
return rc;
|
|
}
|
|
|
|
void
|
|
unlock_unit (gfc_unit *u)
|
|
{
|
|
__gthread_mutex_unlock (&u->lock);
|
|
}
|
|
|
|
/* close_unit()-- Close a unit. The stream is closed, and any memory
|
|
* associated with the stream is freed. Returns nonzero on I/O error.
|
|
* Should be called with the u->lock locked. */
|
|
|
|
int
|
|
close_unit (gfc_unit *u)
|
|
{
|
|
return close_unit_1 (u, 0);
|
|
}
|
|
|
|
|
|
/* close_units()-- Delete units on completion. We just keep deleting
|
|
* the root of the treap until there is nothing left.
|
|
* Not sure what to do with locking here. Some other thread might be
|
|
* holding some unit's lock and perhaps hold it indefinitely
|
|
* (e.g. waiting for input from some pipe) and close_units shouldn't
|
|
* delay the program too much. */
|
|
|
|
void
|
|
close_units (void)
|
|
{
|
|
__gthread_mutex_lock (&unit_lock);
|
|
while (unit_root != NULL)
|
|
close_unit_1 (unit_root, 1);
|
|
__gthread_mutex_unlock (&unit_lock);
|
|
}
|
|
|
|
|
|
/* update_position()-- Update the flags position for later use by inquire. */
|
|
|
|
void
|
|
update_position (gfc_unit *u)
|
|
{
|
|
if (file_position (u->s) == 0)
|
|
u->flags.position = POSITION_REWIND;
|
|
else if (file_length (u->s) == file_position (u->s))
|
|
u->flags.position = POSITION_APPEND;
|
|
else
|
|
u->flags.position = POSITION_ASIS;
|
|
}
|
|
|
|
|
|
/* filename_from_unit()-- If the unit_number exists, return a pointer to the
|
|
name of the associated file, otherwise return the empty string. The caller
|
|
must free memory allocated for the filename string. */
|
|
|
|
char *
|
|
filename_from_unit (int n)
|
|
{
|
|
char *filename;
|
|
gfc_unit *u;
|
|
int c;
|
|
|
|
/* Find the unit. */
|
|
u = unit_root;
|
|
while (u != NULL)
|
|
{
|
|
c = compare (n, u->unit_number);
|
|
if (c < 0)
|
|
u = u->left;
|
|
if (c > 0)
|
|
u = u->right;
|
|
if (c == 0)
|
|
break;
|
|
}
|
|
|
|
/* Get the filename. */
|
|
if (u != NULL)
|
|
{
|
|
filename = (char *) get_mem (u->file_len + 1);
|
|
unpack_filename (filename, u->file, u->file_len);
|
|
return filename;
|
|
}
|
|
else
|
|
return (char *) NULL;
|
|
}
|
|
|