NetBSD/usr.bin/fmt/buffer.h

104 lines
3.0 KiB
C

/* $NetBSD: buffer.h,v 1.2 2005/12/24 20:52:20 perry 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* 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 <err.h>
struct buffer {
char *ptr;
char *bptr;
char *eptr;
};
static void
buf_init(struct buffer *buf)
{
buf->ptr = buf->bptr = malloc(BUFSIZ);
if (buf->ptr == NULL)
err(1, "Cannot allocate buffer");
buf->eptr = buf->ptr + BUFSIZ;
}
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 > BUFSIZ ? minsize : BUFSIZ;
char *nptr = realloc(buf->bptr, len);
if (nptr == NULL)
err(1, "Cannot grow buffer");
if (nptr == buf->bptr)
return;
diff = nptr - buf->bptr;
buf->bptr += diff;
buf->eptr = buf->bptr + len;
buf->ptr += diff;
}
static inline void
buf_putc(struct buffer *buf, char 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 char
buf_unputc(struct buffer *buf)
{
return buf->ptr > buf->bptr ? *--buf->ptr : '\0';
}