src/files.c

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * Copyright 2023 Mike Becker. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "ascension/files.h"
#include "ascension/error.h"

#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

asc_file asc_file_mmap_rdonly(char const *filename) {
    int fd = open(filename, O_RDONLY);
    if (fd < 0) {
        asc_dprintf("Failed to open file %s", filename);
        return (cxstring) {NULL, 0};
    }

    struct stat statbuf;
    int err = fstat(fd, &statbuf);
    if (err < 0) {
        close(fd);
        asc_dprintf("Failed to stat file %s", filename);
        return (cxstring) {NULL, 0};
    }

    char const *data = mmap(NULL, statbuf.st_size, PROT_READ, MAP_SHARED, fd, 0);
    if (data == MAP_FAILED) {
        close(fd);
        asc_dprintf("Failed to map file %s into memory", filename);
        return (cxstring) {NULL, 0};
    }
    close(fd);

    return cx_strn(data, statbuf.st_size);
}

void asc_file_unmap(asc_file file) {
    munmap((void *) file.ptr, file.length);
}