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08574987d9
* libguile/ports-internal.h (SCM_PORT): Rename from SCM_PTAB_ENTRY. (scm_t_port_internal, SCM_PORT_GET_INTERNAL): Remove. (SCM_FILENAME, SCM_SET_FILENAME, SCM_LINUM, SCM_COL): Adapt. * libguile/ports.c: * libguile/poll.c: * libguile/ioext.c: * libguile/fports.c: * libguile/filesys.c: * libguile/print.c: * libguile/read.c: * libguile/rw.c: * libguile/strings.c: Adapt.
225 lines
6.5 KiB
C
225 lines
6.5 KiB
C
/* Copyright (C) 2010, 2013 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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#define _GNU_SOURCE
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <poll.h>
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#include "libguile/_scm.h"
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#include "libguile/bytevectors.h"
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#include "libguile/error.h"
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#include "libguile/numbers.h"
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#include "libguile/ports-internal.h"
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#include "libguile/validate.h"
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#include "libguile/poll.h"
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/* {Poll}
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*/
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/* Poll a set of file descriptors, waiting until one or more of them is
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ready to perform input or output.
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This is a low-level interface. See the `(ice-9 poll)' module for a more
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usable wrapper.
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`pollfds' is expected to be a bytevector, laid out in contiguous blocks of 64
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bits. Each block has the format of one `struct pollfd': a 32-bit int file
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descriptor, a 16-bit int events mask, and a 16-bit int revents mask.
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The number of pollfd structures in `pollfds' is specified in
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`nfds'. `pollfds' must be at least long enough to support that number of
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structures. It may be longer, in which case the trailing entries are left
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untouched.
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The pollfds bytevector is modified directly, setting the returned events in
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the final two bytes (the revents member).
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Since Scheme ports can buffer input or output in userspace, a Scheme
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poll interface needs to take that into account as well. The `ports'
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argument, a vector big enough for `nfds' elements, is given for this
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purpose. If a pollfd entry has a corresponding open port, that port
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is scanned for available input or output before dropping into the
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poll. If any port has buffered I/O available, the poll syscall is
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still issued, but with a timeout of 0 milliseconds, and a full port
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scan occurs after the poll returns.
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If timeout is given and is non-negative, the poll will return after that
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number of milliseconds if no fd became active.
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*/
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static SCM
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scm_primitive_poll (SCM pollfds, SCM nfds, SCM ports, SCM timeout)
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#define FUNC_NAME "primitive-poll"
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{
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int rv = 0;
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nfds_t i;
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nfds_t c_nfds;
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int c_timeout;
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int have_buffered_io = 0;
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struct pollfd *fds;
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SCM_VALIDATE_BYTEVECTOR (SCM_ARG1, pollfds);
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c_nfds = scm_to_uint32 (nfds);
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c_timeout = scm_to_int (timeout);
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if (SCM_UNLIKELY (SCM_BYTEVECTOR_LENGTH (pollfds)
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< c_nfds * sizeof(struct pollfd)))
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SCM_OUT_OF_RANGE (SCM_ARG2, nfds);
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SCM_VALIDATE_VECTOR (SCM_ARG3, ports);
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if (SCM_UNLIKELY (SCM_SIMPLE_VECTOR_LENGTH (ports) < c_nfds))
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SCM_OUT_OF_RANGE (SCM_ARG3, ports);
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fds = (struct pollfd*)SCM_BYTEVECTOR_CONTENTS (pollfds);
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for (i = 0; i < c_nfds; i++)
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{
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SCM port = SCM_SIMPLE_VECTOR_REF (ports, i);
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short int revents = 0;
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if (SCM_PORTP (port))
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{
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if (SCM_CLOSEDP (port))
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revents |= POLLERR;
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else
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{
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scm_t_port *pt = SCM_PORT (port);
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if (scm_port_buffer_can_take (pt->read_buf) > 0)
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/* Buffered input waiting to be read. */
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revents |= POLLIN;
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if (SCM_OUTPUT_PORT_P (port)
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&& scm_port_buffer_can_put (pt->write_buf) > 1)
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/* Buffered output possible. The "> 1" is because
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writing the last byte would flush the port. */
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revents |= POLLOUT;
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}
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}
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if (revents & fds[i].events)
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{
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have_buffered_io = 1;
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c_timeout = 0;
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break;
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}
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}
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SCM_SYSCALL (rv = poll (fds, c_nfds, c_timeout));
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if (rv == -1)
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SCM_SYSERROR;
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if (have_buffered_io)
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for (i = 0; i < c_nfds; i++)
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{
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SCM port = SCM_SIMPLE_VECTOR_REF (ports, i);
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short int revents = 0;
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if (SCM_PORTP (port))
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{
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if (SCM_CLOSEDP (port))
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revents |= POLLERR;
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else
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{
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scm_t_port *pt = SCM_PORT (port);
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if (scm_port_buffer_can_take (pt->read_buf) > 0)
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/* Buffered input waiting to be read. */
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revents |= POLLIN;
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if (SCM_OUTPUT_PORT_P (port)
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&& scm_port_buffer_can_put (pt->write_buf) > 1)
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/* Buffered output possible. The "> 1" is because
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writing the last byte would flush the port. */
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revents |= POLLOUT;
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}
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}
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/* Mask in the events we are interested, and test if any are
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interesting. */
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if ((revents &= fds[i].events))
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{
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/* Could be the underlying fd is also ready for reading. */
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if (!fds[i].revents)
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rv++;
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/* In any case, add these events to whatever the syscall
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set. */
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fds[i].revents |= revents;
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}
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}
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return scm_from_int (rv);
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}
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#undef FUNC_NAME
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static void
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scm_init_poll (void)
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{
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scm_c_define_gsubr ("primitive-poll", 4, 0, 0, scm_primitive_poll);
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scm_c_define ("%sizeof-struct-pollfd", scm_from_size_t (sizeof (struct pollfd)));
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#ifdef POLLIN
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scm_c_define ("POLLIN", scm_from_int (POLLIN));
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#endif
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#ifdef POLLPRI
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scm_c_define ("POLLPRI", scm_from_int (POLLPRI));
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#endif
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#ifdef POLLOUT
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scm_c_define ("POLLOUT", scm_from_int (POLLOUT));
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#endif
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#ifdef POLLRDHUP
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scm_c_define ("POLLRDHUP", scm_from_int (POLLRDHUP));
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#endif
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#ifdef POLLERR
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scm_c_define ("POLLERR", scm_from_int (POLLERR));
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#endif
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#ifdef POLLHUP
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scm_c_define ("POLLHUP", scm_from_int (POLLHUP));
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#endif
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#ifdef POLLNVAL
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scm_c_define ("POLLNVAL", scm_from_int (POLLNVAL));
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#endif
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}
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void
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scm_register_poll (void)
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{
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scm_c_register_extension ("libguile-" SCM_EFFECTIVE_VERSION,
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"scm_init_poll",
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(scm_t_extension_init_func) scm_init_poll,
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NULL);
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}
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/*
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Local Variables:
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c-file-style: "gnu"
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End:
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*/
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