1 /* $NetBSD: buffer.h,v 1.4 2008/04/28 20:24:12 martin 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 <err.h> 36 37 #define BUF_SIZE BUFSIZ 38 struct buffer { 39 char *ptr; 40 char *bptr; 41 char *eptr; 42 }; 43 44 static void 45 buf_init(struct buffer *buf) 46 { 47 buf->ptr = buf->bptr = malloc(BUF_SIZE); 48 if (buf->ptr == NULL) 49 err(1, "Cannot allocate buffer"); 50 buf->eptr = buf->ptr + BUF_SIZE; 51 } 52 53 static void 54 buf_end(struct buffer *buf) 55 { 56 free(buf->bptr); 57 } 58 59 static void 60 buf_grow(struct buffer *buf, size_t minsize) 61 { 62 ptrdiff_t diff; 63 size_t len = (buf->eptr - buf->bptr) + 64 (minsize > BUF_SIZE ? minsize : BUF_SIZE); 65 char *nptr = realloc(buf->bptr, len); 66 67 if (nptr == NULL) 68 err(1, "Cannot grow buffer"); 69 70 if (nptr == buf->bptr) { 71 buf->eptr = buf->bptr + len; 72 return; 73 } 74 75 diff = nptr - buf->bptr; 76 buf->bptr += diff; 77 buf->eptr = buf->bptr + len; 78 buf->ptr += diff; 79 } 80 81 static inline void 82 buf_putc(struct buffer *buf, char c) 83 { 84 if (buf->ptr >= buf->eptr) 85 buf_grow(buf, 1); 86 *buf->ptr++ = c; 87 } 88 89 static inline void 90 buf_reset(struct buffer *buf) 91 { 92 buf->ptr = buf->bptr; 93 } 94 95 static inline char 96 buf_unputc(struct buffer *buf) 97 { 98 return buf->ptr > buf->bptr ? *--buf->ptr : '\0'; 99 } 100