uf22bin.c

// libc
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>

// microsoft uf2
#include "uf2.h"

// libuf2
#include "libuf2.h"

void uf22bin(FILE *in, int fd_out, off_t start_address) {
    UF2_Block uf2;

    // read UF2 blocks from input file
    while (uf2_read_block(&uf2, in))
    {
        off_t off;

        // adjust output file offset for the first byte to be at start_address
        if (uf2.targetAddr < start_address)
            uf2_fatal("data from UF2 before the base offset specified on command line");
        off = uf2.targetAddr - start_address;

        // write data out at the specified offset filling gaps with '\0'
        if (pwrite(fd_out, uf2.data, uf2.payloadSize, off) < uf2.payloadSize)
            uf2_fatal("writing binary data out");
    }
}

void usage(char const *arg0) {
    fprintf(stderr, "usage: %s [-a 0x01230000] [-o file.bin] [file.uf2]\n", arg0);
    exit(1);
}

int main(int argc, char **argv) {
    char const *arg0 = *argv;
    FILE *in = stdin;
    int out = STDOUT_FILENO;
    uint32_t start_address = 0x00000000;
    char *p;

    arg0 = *argv;
    for (int c; (c = getopt(argc, argv, "a:o:")) != -1;) {
        switch (c) {
        case 'a':
            start_address = strtoul(optarg, &p, 0);
            if (*p != '\0')
                uf2_fatal("invalid start address number format");
            break;
        case 'o':
            if ((out = open(optarg, O_WRONLY | O_CREAT, 0644)) == -1)
                uf2_fatal(optarg);
            break;
        default:
            usage(arg0);
        }
    }
    argv += optind;
    argc -= optind;

    if (argc > 1)
        usage(arg0);

    if (argc == 1) {
        if ((in = fopen(argv[0], "r")) == NULL)
            uf2_fatal(argv[0]);
    }

    uf22bin(in, out, start_address);
    return 0;
}