/*      $NetBSD: buffer.h,v 1.5 2017/10/13 00:11:56 christos Exp $      */

/*-
* Copyright (c) 2005 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Christos Zoulas.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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 <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <wchar.h>
#include <err.h>

#define BUF_SIZE        BUFSIZ
struct buffer {
       wchar_t *ptr;
       wchar_t *bptr;
       wchar_t *eptr;
};

static void
buf_init(struct buffer *buf)
{
       buf->ptr = buf->bptr = calloc(BUF_SIZE, sizeof(*buf->ptr));
       if (buf->ptr == NULL)
               err(1, "Cannot allocate buffer");
       buf->eptr = buf->ptr + BUF_SIZE;
}

static void
buf_end(struct buffer *buf)
{
       free(buf->bptr);
}

static void
buf_grow(struct buffer *buf, size_t minsize)
{
       ptrdiff_t diff;
       size_t len = (buf->eptr - buf->bptr) +
           (minsize > BUF_SIZE ? minsize : BUF_SIZE);
       wchar_t *nptr = realloc(buf->bptr, len * sizeof(*buf->ptr));

       if (nptr == NULL)
               err(1, "Cannot grow buffer");

       if (nptr == buf->bptr) {
               buf->eptr = buf->bptr + len;
               return;
       }

       diff = nptr - buf->bptr;
       buf->bptr += diff;
       buf->eptr = buf->bptr + len;
       buf->ptr += diff;
}

static inline void
buf_putc(struct buffer *buf, wchar_t c)
{
       if (buf->ptr >= buf->eptr)
               buf_grow(buf, 1);
       *buf->ptr++ = c;
}

static inline void
buf_reset(struct buffer *buf)
{
       buf->ptr = buf->bptr;
}

static inline wchar_t
buf_unputc(struct buffer *buf)
{
       return buf->ptr > buf->bptr ? *--buf->ptr : '\0';
}