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[netbsd-mini2440.git] / crypto / external / bsd / openssh / dist / buffer.c
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1 /* $NetBSD$ */
2 /* $OpenBSD: buffer.c,v 1.31 2006/08/03 03:34:41 deraadt Exp $ */
3 /*
4 * Author: Tatu Ylonen <ylo@cs.hut.fi>
5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * All rights reserved
7 * Functions for manipulating fifo buffers (that can grow if needed).
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
16 #include "includes.h"
17 __RCSID("$NetBSD: buffer.c,v 1.11 2009/02/16 20:53:54 christos Exp $");
18 #include <sys/param.h>
20 #include <stdio.h>
21 #include <string.h>
22 #include <stdarg.h>
24 #include "xmalloc.h"
25 #include "buffer.h"
26 #include "log.h"
28 #define BUFFER_MAX_CHUNK 0x100000
29 #define BUFFER_MAX_LEN 0xa00000
30 #define BUFFER_ALLOCSZ 0x008000
32 /* Initializes the buffer structure. */
34 void
35 buffer_init(Buffer *buffer)
37 const u_int len = 4096;
39 buffer->alloc = 0;
40 buffer->buf = xmalloc(len);
41 buffer->alloc = len;
42 buffer->offset = 0;
43 buffer->end = 0;
46 /* Frees any memory used for the buffer. */
48 void
49 buffer_free(Buffer *buffer)
51 if (buffer->alloc > 0) {
52 memset(buffer->buf, 0, buffer->alloc);
53 buffer->alloc = 0;
54 xfree(buffer->buf);
59 * Clears any data from the buffer, making it empty. This does not actually
60 * zero the memory.
63 void
64 buffer_clear(Buffer *buffer)
66 buffer->offset = 0;
67 buffer->end = 0;
70 /* Appends data to the buffer, expanding it if necessary. */
72 void
73 buffer_append(Buffer *buffer, const void *data, u_int len)
75 void *p;
76 p = buffer_append_space(buffer, len);
77 memcpy(p, data, len);
80 static int
81 buffer_compact(Buffer *buffer)
84 * If the buffer is quite empty, but all data is at the end, move the
85 * data to the beginning.
87 if (buffer->offset > MIN(buffer->alloc, BUFFER_MAX_CHUNK)) {
88 memmove(buffer->buf, buffer->buf + buffer->offset,
89 buffer->end - buffer->offset);
90 buffer->end -= buffer->offset;
91 buffer->offset = 0;
92 return (1);
94 return (0);
98 * Appends space to the buffer, expanding the buffer if necessary. This does
99 * not actually copy the data into the buffer, but instead returns a pointer
100 * to the allocated region.
103 void *
104 buffer_append_space(Buffer *buffer, u_int len)
106 u_int newlen;
107 void *p;
109 if (len > BUFFER_MAX_CHUNK)
110 fatal("buffer_append_space: len %u not supported", len);
112 /* If the buffer is empty, start using it from the beginning. */
113 if (buffer->offset == buffer->end) {
114 buffer->offset = 0;
115 buffer->end = 0;
117 restart:
118 /* If there is enough space to store all data, store it now. */
119 if (buffer->end + len < buffer->alloc) {
120 p = buffer->buf + buffer->end;
121 buffer->end += len;
122 return p;
125 /* Compact data back to the start of the buffer if necessary */
126 if (buffer_compact(buffer))
127 goto restart;
129 /* Increase the size of the buffer and retry. */
130 newlen = roundup(buffer->alloc + len, BUFFER_ALLOCSZ);
131 if (newlen > BUFFER_MAX_LEN_HPN)
132 fatal("buffer_append_space: alloc %u not supported",
133 newlen);
134 buffer->buf = xrealloc(buffer->buf, 1, newlen);
135 buffer->alloc = newlen;
136 goto restart;
137 /* NOTREACHED */
141 * Check whether an allocation of 'len' will fit in the buffer
142 * This must follow the same math as buffer_append_space
145 buffer_check_alloc(Buffer *buffer, u_int len)
147 if (buffer->offset == buffer->end) {
148 buffer->offset = 0;
149 buffer->end = 0;
151 restart:
152 if (buffer->end + len < buffer->alloc)
153 return (1);
154 if (buffer_compact(buffer))
155 goto restart;
156 if (roundup(buffer->alloc + len, BUFFER_ALLOCSZ) <= BUFFER_MAX_LEN)
157 return (1);
158 return (0);
161 /* Returns the number of bytes of data in the buffer. */
163 u_int
164 buffer_len(Buffer *buffer)
166 return buffer->end - buffer->offset;
169 /* Gets data from the beginning of the buffer. */
172 buffer_get_ret(Buffer *buffer, void *buf, u_int len)
174 if (len > buffer->end - buffer->offset) {
175 error("buffer_get_ret: trying to get more bytes %d than in buffer %d",
176 len, buffer->end - buffer->offset);
177 return (-1);
179 memcpy(buf, buffer->buf + buffer->offset, len);
180 buffer->offset += len;
181 return (0);
184 void
185 buffer_get(Buffer *buffer, void *buf, u_int len)
187 if (buffer_get_ret(buffer, buf, len) == -1)
188 fatal("buffer_get: buffer error");
191 /* Consumes the given number of bytes from the beginning of the buffer. */
194 buffer_consume_ret(Buffer *buffer, u_int bytes)
196 if (bytes > buffer->end - buffer->offset) {
197 error("buffer_consume_ret: trying to get more bytes than in buffer");
198 return (-1);
200 buffer->offset += bytes;
201 return (0);
204 void
205 buffer_consume(Buffer *buffer, u_int bytes)
207 if (buffer_consume_ret(buffer, bytes) == -1)
208 fatal("buffer_consume: buffer error");
211 /* Consumes the given number of bytes from the end of the buffer. */
214 buffer_consume_end_ret(Buffer *buffer, u_int bytes)
216 if (bytes > buffer->end - buffer->offset)
217 return (-1);
218 buffer->end -= bytes;
219 return (0);
222 void
223 buffer_consume_end(Buffer *buffer, u_int bytes)
225 if (buffer_consume_end_ret(buffer, bytes) == -1)
226 fatal("buffer_consume_end: trying to get more bytes than in buffer");
229 /* Returns a pointer to the first used byte in the buffer. */
231 void *
232 buffer_ptr(Buffer *buffer)
234 return buffer->buf + buffer->offset;
237 /* Dumps the contents of the buffer to stderr. */
239 void
240 buffer_dump(Buffer *buffer)
242 u_int i;
243 u_char *ucp = buffer->buf;
245 for (i = buffer->offset; i < buffer->end; i++) {
246 fprintf(stderr, "%02x", ucp[i]);
247 if ((i-buffer->offset)%16==15)
248 fprintf(stderr, "\r\n");
249 else if ((i-buffer->offset)%2==1)
250 fprintf(stderr, " ");
252 fprintf(stderr, "\r\n");