Factor out all uses of ctime()

include/drat/string/fs.c

@@ -10,7 +10,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <time.h>
 
 #include <drat/asize.h>
 #include <drat/time.h>

include/drat/string/j.c

@@ -11,7 +11,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <time.h>
 
 #if defined(__APPLE__) || defined(__BSD__)
     #include <sys/stat.h>
@@ -173,12 +172,9 @@ void print_j_inode_val(j_inode_val_t* val, uint16_t val_len) {
     printf("Uncompressed size:      %s\n", tmp_string);
     free(tmp_string);
 
-    time_t timestamp = val->create_time / 1000000000;
-    printf("Creation time:          %s",    ctime(&timestamp));
-    timestamp = val->mod_time / 1000000000;
-    printf("Last modification time: %s",    ctime(&timestamp));
-    timestamp = val->change_time / 1000000000;
-    printf("Last access time:       %s",    ctime(&timestamp));
+    printf("Creation time:          %s",    apfs_timestamp_to_string(val->create_time));
+    printf("Last modification time: %s",    apfs_timestamp_to_string(val->mod_time));
+    printf("Last access time:       %s",    apfs_timestamp_to_string(val->change_time));
     printf("\n");
 
     printf("Number of children / hard links:    %u\n", val->nchildren);

include/drat/time.c

@@ -4,8 +4,9 @@
 
 /**
  * Get a human-readable timestamp from an APFS timestamp (Unix timestamp in
- * nanoseconds). The return value is a newline-terminated C-string store in the
- * static buffer provided by the `ctime` API, so it must not be freed.
+ * nanoseconds). The return value is a newline-terminated C-string stored in
+ * the static buffer provided by the `ctime` API, so it must not be freed, and
+ * this function is not thread-safe.
  */
 char* apfs_timestamp_to_string(uint64_t apfs_timestamp) {
     // Dividing timestamps by 10^9 to convert APFS timestamps (Unix timestamps