libc/sprintf.c

/*
 * Copyright (C) 2008 The Android Open Source Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the 
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <stdarg.h>

#include <boot/boot.h>
#include "libc_private.h"

struct snprintf_ctxt 
{
    char *next;
    int avail;
};

static void snprintf_putc(unsigned n, void *cookie)
{
    struct snprintf_ctxt *ctxt = cookie;
    
    if(ctxt->avail > 0) {
        *ctxt->next++ = n;
        ctxt->avail--;
    }
}

int snprintf(char *str, int sz, const char *fmt, ...)
{
    va_list ap;
    struct snprintf_ctxt ctxt;
    
    if(sz < 1) return 0;
    
    ctxt.avail = sz - 1;
    ctxt.next = str;
    
    va_start(ap, fmt);
    __xprintf(fmt, ap, snprintf_putc, &ctxt);
    va_end(ap);

    *ctxt.next = 0;
    return ctxt.next - str;
}