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/*
* BSD Zero Clause License
*
* Copyright (c) 2022 Thomas Voss
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
#include <stdio.h>
#include <unistd.h>
#include "common.h"
#include "lux.h"
static int intlen(int);
int
luxset(lux_t *disp, int n)
{
/* The same deal as in luxget() */
if (disp->__bstream == NULL) {
if ((disp->__bstream = getbstream(disp->__dirfd)) == NULL)
return -1;
} else
rewind(disp->__bstream);
/* After writing the new brightness value to the brightness file, we
* need to truncate it so that luxset(disp, 1234); luxset(disp, 9);
* gives us a final brightness of 2 and not 9234.
*/
fprintf(disp->__bstream, "%d", n);
ftruncate(fileno(disp->__bstream), intlen(n));
return n;
}
int
intlen(int n)
{
return n < 10 ? 1
: n < 100 ? 2
: n < 1000 ? 3
: n < 10000 ? 4
: n < 100000 ? 5
: n < 1000000 ? 6
: n < 10000000 ? 7
: n < 100000000 ? 8
: n < 1000000000 ? 9
: 10;
}
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