ex_file_copy.c

n_file_copy_verified() and n_file_same_content()

n_file_copy_verified() and n_file_same_content()

Author

Castagnier Mickael

Version

1.0

Date

24/09/2026

Copies a file larger than one block, checks the copy is there and equal, that no ".part" is left, that an existing destination is refused and left as it was, that a missing source fails without leaving anything, and that n_file_same_content() tells equal files from different ones of the same size.

 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
 
#include "nilorea/n_common.h"
#include "nilorea/n_files.h"
#include "nilorea/n_log.h"

static int failures = 0;

static void expect_true(const char* what, int ok) {
    if (!ok) {
        n_log(LOG_ERR, "FAIL: %s", what);
        failures++;
    }
}

static int there(const char* path) {
    FILE* f = fopen(path, "rb");
 
    if (!f) return 0;
    fclose(f);
    return 1;
}
 
int main(void) {
    const char* tmp = getenv("TMPDIR") ? getenv("TMPDIR") : "/tmp";
    char src[512], dst[512], part[520], other[512];
    size_t copied = 0, i = 0;
    FILE* f = NULL;
 
    set_log_level(LOG_NOTICE);
    snprintf(src, sizeof(src), "%s/ex_file_copy_%d.src", tmp, (int)getpid());
    snprintf(dst, sizeof(dst), "%s/ex_file_copy_%d.dst", tmp, (int)getpid());
    snprintf(part, sizeof(part), "%s.part", dst);
    snprintf(other, sizeof(other), "%s/ex_file_copy_%d.other", tmp, (int)getpid());
 
    /* A little over three blocks, so the loop turns and the tail is short. */
    f = fopen(src, "wb");
    if (!f) return 1;
    for (i = 0; i < 800000; i++) fputc((int)((i * 7 + i / 13) & 0xff), f);
    fclose(f);
 
    expect_true("a file is copied", n_file_copy_verified(src, dst, &copied) == TRUE);
    expect_true("every byte of it", copied == 800000);
    expect_true("the copy is equal", n_file_same_content(src, dst) == TRUE);
    expect_true("no part file is left", !there(part));
    expect_true("an existing copy is not replaced", n_file_copy_verified(src, dst, NULL) == FALSE);
    expect_true("and is still equal after the refusal", n_file_same_content(src, dst) == TRUE);
 
    /* Same size, one byte different. */
    f = fopen(other, "wb");
    if (f) {
        for (i = 0; i < 800000; i++) fputc(i == 500000 ? 0 : (int)((i * 7 + i / 13) & 0xff), f); /* 29 there in the original */
        fclose(f);
    }
    expect_true("one byte different is different", n_file_same_content(src, other) == FALSE);
    remove(other);
 
    remove(dst);
    expect_true("a missing source fails", n_file_copy_verified(other, dst, NULL) == FALSE);
    expect_true("and leaves nothing", !there(dst) && !there(part));
    expect_true("a NULL is refused", n_file_copy_verified(NULL, dst, NULL) == FALSE);
 
    remove(src);
    remove(dst);
    n_log(LOG_NOTICE, "ex_file_copy: %s", failures ? "FAILED" : "ok");
    return failures ? 1 : 0;
}