rockbox/bootloader/snprintf.c

81 lines
2.1 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Gary Czvitkovicz
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
/*
* Minimal printf and snprintf formatting functions
*
* These support %c %s %l %d %u and %x(%p)
* Field width and zero-padding flag only
*/
#include <stdio.h>
#include <stdarg.h>
#include <stdbool.h>
#include <limits.h>
#include "format.h"
struct for_snprintf {
unsigned char *ptr; /* where to store it */
size_t bytes; /* amount already stored */
size_t max; /* max amount to store */
};
static int sprfunc(void *ptr, unsigned char letter)
{
struct for_snprintf *pr = (struct for_snprintf *)ptr;
if(pr->bytes < pr->max) {
*pr->ptr = letter;
pr->ptr++;
pr->bytes++;
return true;
}
return false; /* filled buffer */
}
int snprintf(char *buf, size_t size, const char *fmt, ...)
{
int len;
va_list ap;
va_start(ap, fmt);
len = vsnprintf(buf, size, fmt, ap);
va_end(ap);
return len;
}
int vsnprintf(char *buf, size_t size, const char *fmt, va_list ap)
{
struct for_snprintf pr;
pr.ptr = (unsigned char *)buf;
pr.bytes = 0;
pr.max = size;
format(sprfunc, &pr, fmt, ap);
/* make sure it ends with a trailing zero */
pr.ptr[(pr.bytes < pr.max) ? 0 : -1] = '\0';
return pr.bytes;
}