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GitHub Repository: Ardupilot/ardupilot
 Path: blob/master/libraries/AP_Filesystem/examples/File_IO/File_IO.cpp
Views: 1799
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//Simple File I/O example

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#include <AP_HAL/AP_HAL.h>

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#include <AP_BoardConfig/AP_BoardConfig.h>

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#include <AP_Filesystem/AP_Filesystem.h>

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#include <stdio.h>

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//set according to the data size in file

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#define BUFFER_SIZE 50

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const AP_HAL::HAL& hal = AP_HAL::get_HAL();

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void setup();

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void loop();

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static AP_BoardConfig board_config;

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int file_count = 0;

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const char *dir_path = nullptr;

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static void write_file(const char *);

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static void read_file(const char *);

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void setup()

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{

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    board_config.init();

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    //creating a test directory to store all files

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    dir_path = "./test_dir";

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    hal.console->printf("Creating directory - %s\n", dir_path);

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    int ret = AP::FS().mkdir(dir_path);

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    if (ret == -1) {

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        if (errno == EEXIST) {

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            hal.console->printf("Directory - %s already exist\n", dir_path);

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        } else {

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            hal.console->printf("Failed to create directory %s - %s\n", dir_path, strerror(errno));

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        }

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    }

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}

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void loop()

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{

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    //creating 10 files in test directory

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    if (file_count == 10) {

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        hal.console->printf("Finished creating files\n\n");

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        hal.scheduler->delay(1000);

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        return;

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    }

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    file_count += 1;

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    char file_path[100];

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    snprintf(file_path, sizeof(file_path), "%s/test_%d.txt", dir_path, file_count);

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    write_file(file_path);

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    hal.scheduler->delay(1000);

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    read_file(file_path);

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    hal.scheduler->delay(1000);

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}

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static void write_file(const char *file_path)

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{

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    char write_buf[BUFFER_SIZE];

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    //creating or opening a file in write mode

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    const int open_fd = AP::FS().open(file_path, O_WRONLY | O_CREAT | O_TRUNC);

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    if (open_fd == -1) {

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        hal.console->printf("Open %s failed - %s\n", file_path, strerror(errno));

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        return;

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    }

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    //writing to file

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    const char *s = "Hello_World";

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    hal.console->printf("Writing to file %s => %s_%d\n", file_path, s, file_count);

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    snprintf(write_buf, sizeof(write_buf), "%s_%d\n", s, file_count);

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    const ssize_t to_write = strlen(write_buf);

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    const ssize_t write_size = AP::FS().write(open_fd, write_buf, to_write);

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    if (write_size == -1 or write_size != to_write) {

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        hal.console->printf("Write failed - %s\n", strerror(errno));

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        return;

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    }

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    //closing file after writing

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    AP::FS().close(open_fd);

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}

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static void read_file(const char *file_path)

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{

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    char read_buf[BUFFER_SIZE];

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    //opening a file in read mode

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    const int open_fd = AP::FS().open(file_path, O_RDONLY);

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    if (open_fd == -1) {

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        hal.console->printf("Open %s failed\n", file_path);

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        return;

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    }

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    //reading from file

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    const ssize_t read_size = AP::FS().read(open_fd, read_buf, sizeof(read_buf));

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    if (read_size == -1) {

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        hal.console->printf("Read failed - %s\n", strerror(errno));

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        return;

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    }

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    hal.console->printf("Reading from file %s => %s\n", file_path, read_buf);

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    //closing file after reading

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    AP::FS().close(open_fd);

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}

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AP_HAL_MAIN();

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