kopia lustrzana https://gitlab.com/sane-project/backends
199 wiersze
6.0 KiB
C
199 wiersze
6.0 KiB
C
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/* sane - Scanner Access Now Easy.
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Copyright (C) 1997 David Mosberger-Tang
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This file is part of the SANE package.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program 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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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 this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA.
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As a special exception, the authors of SANE give permission for
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additional uses of the libraries contained in this release of SANE.
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The exception is that, if you link a SANE library with other files
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to produce an executable, this does not by itself cause the
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resulting executable to be covered by the GNU General Public
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License. Your use of that executable is in no way restricted on
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account of linking the SANE library code into it.
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This exception does not, however, invalidate any other reasons why
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the executable file might be covered by the GNU General Public
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License.
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If you submit changes to SANE to the maintainers to be included in
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a subsequent release, you agree by submitting the changes that
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those changes may be distributed with this exception intact.
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If you write modifications of your own for SANE, it is your choice
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whether to permit this exception to apply to your modifications.
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If you do not wish that, delete this exception notice.
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This file implements a routine to restore option values saved to a
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file (using sanei_save_values()). This is a bit tricky since
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setting an option may change the availability of other options.
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The problem is that we don't know the order of the set-value calls
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that resulted in the saved set of option values. One solution
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might be to simply keep setting all option values until we no
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longer get any changes to the option value set. However, that has
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the potential for live-lock. Instead, we keep track of what
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options caused a SANE_INFO_RELOAD_OPTIONS. For such options, their
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value is set exactly once. This guarantees convergence after a
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bounded (and usually small) number of iterations. The resulting
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value set is guaranteed to be the desired (saved) one as long as
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setting an option that affects availability of other options does
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not "lose" its value by setting another option. I don't think any
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sane backend would do this and since this is SANE, we just proved
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that this algorithm works perfectly. */
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#ifdef _AIX
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# include <lalloca.h> /* MUST come first for AIX! */
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#endif
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#include <sane/config.h>
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#include <lalloca.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#ifdef HAVE_LIBC_H
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# include <libc.h> /* NeXTStep/OpenStep */
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#endif
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#include <sane/sane.h>
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#include <sane/sanei_wire.h>
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#include <sane/sanei_codec_ascii.h>
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#define BITS_PER_LONG (8*sizeof (u_long))
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#define SET(set, bit) \
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((set)[(bit)/BITS_PER_LONG] |= (1UL << (bit)%BITS_PER_LONG))
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#define IS_SET(set, bit) \
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(((set)[(bit)/BITS_PER_LONG] & (1UL << (bit)%BITS_PER_LONG)) != 0)
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int
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sanei_load_values (int fd, SANE_Handle device)
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{
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const SANE_Option_Descriptor *opt;
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SANE_Word *word_array;
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SANE_String name, str;
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u_long *caused_reload;
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SANE_Int num_options;
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SANE_Status status;
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int i, keep_going;
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SANE_Word word;
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SANE_Int info;
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off_t offset;
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size_t size;
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char *buf;
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Wire w;
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offset = lseek (fd, 0, SEEK_CUR);
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w.io.fd = fd;
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w.io.read = read;
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w.io.write = write;
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sanei_w_init (&w, sanei_codec_ascii_init);
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sanei_w_set_dir (&w, WIRE_DECODE);
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keep_going = 0;
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sane_control_option (device, 0, SANE_ACTION_GET_VALUE, &num_options, 0);
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size = (num_options + BITS_PER_LONG - 1) / BITS_PER_LONG * sizeof (long);
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caused_reload = alloca (size);
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memset (caused_reload, 0, size);
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while (1)
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{
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sanei_w_space (&w, 3);
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if (!w.status)
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sanei_w_string (&w, &name);
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if (w.status)
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{
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if (keep_going)
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{
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lseek (fd, offset, SEEK_SET);
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sanei_w_set_dir (&w, WIRE_DECODE);
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keep_going = 0;
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continue;
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}
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return 0;
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}
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status = SANE_STATUS_GOOD;
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info = 0;
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for (i = 1; (opt = sane_get_option_descriptor (device, i)); ++i)
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{
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if (!opt->name || strcmp (opt->name, name) != 0)
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continue;
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if (IS_SET(caused_reload, i))
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continue;
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switch (opt->type)
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{
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case SANE_TYPE_BOOL:
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case SANE_TYPE_INT:
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case SANE_TYPE_FIXED:
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if (opt->size == sizeof (SANE_Word))
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{
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sanei_w_word (&w, &word);
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status = sane_control_option (device, i,
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SANE_ACTION_SET_VALUE,
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&word, &info);
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}
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else
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{
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SANE_Int len;
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sanei_w_array (&w, &len, (void **) &word_array,
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(WireCodecFunc) sanei_w_word,
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sizeof (SANE_Word));
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status = sane_control_option (device, i,
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SANE_ACTION_SET_VALUE,
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word_array, &info);
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w.direction = WIRE_FREE;
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sanei_w_array (&w, &len, (void **) &word_array,
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(WireCodecFunc) sanei_w_word,
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sizeof (SANE_Word));
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w.direction = WIRE_DECODE;
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}
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break;
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case SANE_TYPE_STRING:
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sanei_w_string (&w, &str);
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buf = malloc (opt->size);
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strncpy (buf, str, opt->size);
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buf[opt->size - 1] = '\0';
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sanei_w_free (&w, (WireCodecFunc) sanei_w_string, &str);
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status = sane_control_option (device, i, SANE_ACTION_SET_VALUE,
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buf, &info);
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break;
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case SANE_TYPE_BUTTON:
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case SANE_TYPE_GROUP:
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break;
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}
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break;
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}
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sanei_w_free (&w, (WireCodecFunc) sanei_w_string, &name);
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if (status == SANE_STATUS_GOOD && (info & SANE_INFO_RELOAD_OPTIONS))
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{
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SET (caused_reload, i);
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keep_going = 1;
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}
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}
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return 0;
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}
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