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* libguile/Makefile.am (noinst_HEADERS): Add atomics-internal.h. * libguile/atomics-internal.h: New file. * libguile/ports-internal.h (refcount): New member. * libguile/ports.c (release_port, scm_dynwind_acquire_port): New facility for acquiring a port within a dynwind. (scm_port_poll, scm_i_read_bytes, scm_setvbuf, scm_end_input) (scm_i_write_bytes, scm_char_ready_p, scm_seek) (scm_truncate_file, trampoline_to_c_read) (trampoline_to_c_write): Acquire port. (scm_c_make_port_with_encoding): Init refcount to 1. (scm_close_port): Release port. * doc/ref/api-io.texi (I/O Extensions): Add documentation
85 lines
2.2 KiB
C
85 lines
2.2 KiB
C
#ifndef SCM_ATOMICS_INTERNAL_H
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#define SCM_ATOMICS_INTERNAL_H
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/* Copyright (C) 2016
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* Free Software Foundation, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public License
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* as published by the Free Software Foundation; either version 3 of
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* the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301 USA
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*/
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#include <stdint.h>
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#define HAVE_C11_ATOMICS (__STDC_VERSION__ >= 201112L && !defined(__STDC_NO_ATOMICS__))
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#if HAVE_C11_ATOMICS
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#include <stdatomic.h>
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static inline uint32_t
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scm_atomic_subtract_uint32 (uint32_t *obj, uint32_t arg)
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{
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return atomic_fetch_sub (obj, arg);
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}
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static inline _Bool
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scm_atomic_compare_and_swap_uint32 (uint32_t *obj, uint32_t *expected,
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uint32_t desired)
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{
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return atomic_compare_exchange_weak (obj, expected, desired);
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}
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#else /* HAVE_C11_ATOMICS */
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/* Fallback implementation using locks. */
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#include "libguile/threads.h"
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static scm_i_pthread_mutex_t atomics_lock = SCM_I_PTHREAD_MUTEX_INITIALIZER;
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static inline uint32_t
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scm_atomic_subtract_uint32 (uint32_t *obj, uint32_t arg)
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{
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uint32_t ret;
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scm_i_pthread_mutex_lock (&atomics_lock);
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ret = *obj;
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*obj -= arg;
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scm_i_pthread_mutex_unlock (&atomics_lock);
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return ret;
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}
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static inline int
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scm_atomic_compare_and_swap_uint32 (uint32_t *obj, uint32_t *expected,
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uint32_t desired)
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{
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int ret;
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scm_i_pthread_mutex_lock (&atomics_lock);
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if (*obj == *expected)
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{
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*obj = desired;
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ret = 1;
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}
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else
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{
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*expected = *obj;
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ret = 0;
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}
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scm_i_pthread_mutex_unlock (&atomics_lock);
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return ret;
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}
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#endif /* HAVE_C11_ATOMICS */
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#endif /* SCM_ATOMICS_INTERNAL_H */
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