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      1 /*	$NetBSD: buffer.h,v 1.5 2017/10/13 00:11:56 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2005 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christos Zoulas.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <stddef.h>
     33 #include <stdio.h>
     34 #include <stdlib.h>
     35 #include <wchar.h>
     36 #include <err.h>
     37 
     38 #define BUF_SIZE	BUFSIZ
     39 struct buffer {
     40 	wchar_t *ptr;
     41 	wchar_t *bptr;
     42 	wchar_t *eptr;
     43 };
     44 
     45 static void
     46 buf_init(struct buffer *buf)
     47 {
     48 	buf->ptr = buf->bptr = calloc(BUF_SIZE, sizeof(*buf->ptr));
     49 	if (buf->ptr == NULL)
     50 		err(1, "Cannot allocate buffer");
     51 	buf->eptr = buf->ptr + BUF_SIZE;
     52 }
     53 
     54 static void
     55 buf_end(struct buffer *buf)
     56 {
     57 	free(buf->bptr);
     58 }
     59 
     60 static void
     61 buf_grow(struct buffer *buf, size_t minsize)
     62 {
     63 	ptrdiff_t diff;
     64 	size_t len = (buf->eptr - buf->bptr) +
     65 	    (minsize > BUF_SIZE ? minsize : BUF_SIZE);
     66 	wchar_t *nptr = realloc(buf->bptr, len * sizeof(*buf->ptr));
     67 
     68 	if (nptr == NULL)
     69 		err(1, "Cannot grow buffer");
     70 
     71 	if (nptr == buf->bptr) {
     72 		buf->eptr = buf->bptr + len;
     73 		return;
     74 	}
     75 
     76 	diff = nptr - buf->bptr;
     77 	buf->bptr += diff;
     78 	buf->eptr = buf->bptr + len;
     79 	buf->ptr += diff;
     80 }
     81 
     82 static inline void
     83 buf_putc(struct buffer *buf, wchar_t c)
     84 {
     85 	if (buf->ptr >= buf->eptr)
     86 		buf_grow(buf, 1);
     87 	*buf->ptr++ = c;
     88 }
     89 
     90 static inline void
     91 buf_reset(struct buffer *buf)
     92 {
     93 	buf->ptr = buf->bptr;
     94 }
     95 
     96 static inline wchar_t
     97 buf_unputc(struct buffer *buf)
     98 {
     99 	return buf->ptr > buf->bptr ? *--buf->ptr : '\0';
    100 }
    101