a29d9ea9da
to get the prototypes or macros are defined in it Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
135 lines
4.0 KiB
C
135 lines
4.0 KiB
C
/****************************************************************************
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* apps/examples/random/random_main.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <debug.h>
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#include <unistd.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Configuration ************************************************************/
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#ifndef CONFIG_EXAMPLES_MAXSAMPLES
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# define CONFIG_EXAMPLES_MAXSAMPLES 64
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#endif
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#ifndef CONFIG_EXAMPLES_NSAMPLES
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# define CONFIG_EXAMPLES_NSAMPLES 8
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#endif
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#if CONFIG_EXAMPLES_NSAMPLES > CONFIG_EXAMPLES_MAXSAMPLES
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# warning CONFIG_EXAMPLES_NSAMPLES > CONFIG_EXAMPLES_MAXSAMPLES
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# undef CONFIG_EXAMPLES_NSAMPLES
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# define CONFIG_EXAMPLES_NSAMPLES CONFIG_EXAMPLES_MAXSAMPLES
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#endif
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* rand_main
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****************************************************************************/
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int main(int argc, FAR char *argv[])
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{
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uint32_t buffer[CONFIG_EXAMPLES_MAXSAMPLES];
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int nsamples = CONFIG_EXAMPLES_NSAMPLES;
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ssize_t nread;
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int fd;
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/* One argument is possible... the number of samples to collect */
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if (argc > 1)
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{
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nsamples = atoi(argv[1]);
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}
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/* Clip the number of samples to the configured buffer size */
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if (nsamples < 0)
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{
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nsamples = 0;
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}
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else if (nsamples > CONFIG_EXAMPLES_MAXSAMPLES)
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{
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nsamples = CONFIG_EXAMPLES_MAXSAMPLES;
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}
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/* fill buffer to make it super-clear as to what has and has not been
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* written
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*/
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memset(buffer, 0xcc, sizeof(buffer));
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/* Open /dev/random */
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fd = open("/dev/random", O_RDONLY);
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if (fd < 0)
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{
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int errcode = errno;
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fprintf(stderr, "ERROR: Failed to open /dev/random: %d\n", errcode);
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exit(EXIT_FAILURE);
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}
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/* Read the requested number of samples */
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printf("Reading %d random numbers\n", nsamples);
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fflush(stdout);
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nread = read(fd, buffer, nsamples * sizeof(uint32_t));
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if (nread < 0)
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{
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int errcode = errno;
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fprintf(stderr, "ERROR: Read from /dev/random failed: %d\n", errcode);
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close(fd);
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exit(EXIT_FAILURE);
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}
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if (nread != nsamples * sizeof(uint32_t))
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{
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fprintf(stderr, "ERROR: Read from /dev/random only produced %zd "
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"bytes\n", nread);
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close(fd);
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exit(EXIT_FAILURE);
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}
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/* Dump the sample buffer */
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lib_dumpbuffer("Random values", (FAR const uint8_t *)buffer, nread);
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close(fd);
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return EXIT_SUCCESS;
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}
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