Cytoplasm/include/Cytoplasm/Util.h
Jordan Bancino 461357b526 Move headers from src/include to include/Cytoplasm.
This makes it easier to build Cytoplasm as a component of another
program (for example, Telodendria), or as a standalone system library.
2024-01-13 18:40:31 -05:00

116 lines
4 KiB
C

/*
* Copyright (C) 2022-2024 Jordan Bancino <@jordan:bancino.net>
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge,
* publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef CYTOPLASM_UTIL_H
#define CYTOPLASM_UTIL_H
/***
* @Nm Util
* @Nd Some misc. helper functions that don't need their own headers.
* @Dd February 15 2023
*
* This header holds a number of random functions related to strings,
* time, the filesystem, and other simple tasks that don't require a
* full separate API. For the most part, the functions here are
* entirely standalone, depending only on POSIX functions, however
* there are a few that depend explicitly on a few other APIs. Those
* are noted.
*/
#include <stdio.h>
#include <stddef.h>
#include <sys/types.h>
#include "Stream.h"
/**
* Get the current timestamp in milliseconds since the Unix epoch. This
* uses
* .Xr gettimeofday 2
* and time_t, and converts it to a single number, which is then
* returned to the caller.
* .Pp
* A note on the 2038 problem: as long as sizeof(time_t) >= 8, that is,
* as long as the time_t type is 64 bits or more, then everything
* should be fine. On most, if not, all, 64-bit systems, time_t is 64
* bits. time_t is promoted to a 64-bit integer before it is converted
* to milliseconds, so there is no risk of overflue due to the
* multiplication by 1000. However, if time_t is only 32 bits, it will
* overflow before it even gets to this function, which will cause this
* function to produce unexpected results.
*/
extern uint64_t UtilTsMillis(void);
/**
* Use
* .Xr stat 2
* to get the last modified time of the given file, or zero if there
* was an error getting the last modified time of a file. This is
* primarily useful for caching file data.
*/
extern uint64_t UtilLastModified(char *);
/**
* This function behaves just like the system call
* .Xr mkdir 2 ,
* but it creates any intermediate directories as necessary, unlike
* .Xr mkdir 2 .
*/
extern int UtilMkdir(const char *, const mode_t);
/**
* Sleep the calling thread for the given number of milliseconds.
* POSIX does not have a very friendly way to sleep, so this wraps
* .Xr nanosleep 2
* to make its usage much, much simpler.
*/
extern int UtilSleepMillis(uint64_t);
/**
* This function works identically to the POSIX
* .Xr getdelim 3 ,
* except that it assumes pointers were allocated with the Memory API
* and it reads from a Stream instead of a file pointer.
*/
extern ssize_t UtilGetDelim(char **, size_t *, int, Stream *);
/**
* This function is just a special case of
* .Fn UtilGetDelim
* that sets the delimiter to the newline character.
*/
extern ssize_t UtilGetLine(char **, size_t *, Stream *);
/**
* Get a unique number associated with the current thread.
* Numbers are assigned in the order that threads call this
* function, but are guaranteed to be unique in identifying
* the thread in a more human-readable way than just casting
* the return value of
* .Fn pthread_self
* to a number.
*/
extern uint32_t UtilThreadNo(void);
#endif /* CYTOPLASM_UTIL_H */