bootloader/snprintf.c at master · tsiry-sandratraina.com/rockbox-zig

A modern Music Player Daemon based on Rockbox open source high quality audio player

libadwaita audio rust zig deno mpris rockbox mpd

rockbox-zig / bootloader / snprintf.c

at master 80 lines 2.2 kB view raw

 1/***************************************************************************
 2 *             __________               __   ___.
 3 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 4 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 5 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 6 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 7 *                     \/            \/     \/    \/            \/
 8 * $Id$
 9 *
10 * Copyright (C) 2002 by Gary Czvitkovicz
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version 2
15 * of the License, or (at your option) any later version.
16 *
17 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
18 * KIND, either express or implied.
19 *
20 ****************************************************************************/
21
22/*
23 * Minimal printf and snprintf formatting functions
24 *
25 * These support %c %s %l %d %u and %x(%p)
26 * Field width and zero-padding flag only
27 */
28
29#include <stdio.h>
30#include <stdarg.h>
31#include <stdbool.h>
32#include <limits.h>
33#include "format.h"
34
35struct for_snprintf {
36    unsigned char *ptr; /* where to store it */
37    size_t bytes; /* amount already stored */
38    size_t max;   /* max amount to store */
39};
40
41static int sprfunc(void *ptr, unsigned char letter)
42{
43    struct for_snprintf *pr = (struct for_snprintf *)ptr;
44    if(pr->bytes < pr->max) {
45        *pr->ptr = letter;
46        pr->ptr++;
47        pr->bytes++;
48        return true;
49    }
50    return false; /* filled buffer */
51}
52
53
54int snprintf(char *buf, size_t size, const char *fmt, ...)
55{
56    int len;
57    va_list ap;
58
59    va_start(ap, fmt);
60    len = vsnprintf(buf, size, fmt, ap);
61    va_end(ap);
62
63    return len;
64}
65
66int vsnprintf(char *buf, size_t size, const char *fmt, va_list ap)
67{
68    struct for_snprintf pr;
69
70    pr.ptr = (unsigned char *)buf;
71    pr.bytes = 0;
72    pr.max = size;
73
74    format(sprfunc, &pr, fmt, ap);
75
76    /* make sure it ends with a trailing zero */
77    pr.ptr[(pr.bytes < pr.max) ? 0 : -1] = '\0';
78
79    return pr.bytes;
80}