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8efc0c15 1/*
5260325f 2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
5260325f 3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
5260325f 5 * Functions for manipulating fifo buffers (that can grow if needed).
6ae2364d 6 *
bcbf86ec 7 * As far as I am concerned, the code I have written for this software
8 * can be used freely for any purpose. Any derived versions of this
9 * software must be clearly marked as such, and if the derived work is
10 * incompatible with the protocol description in the RFC file, it must be
11 * called by a name other than "ssh" or "Secure Shell".
5260325f 12 */
8efc0c15 13
14#include "includes.h"
e6207598 15RCSID("$OpenBSD: buffer.c,v 1.15 2002/01/18 18:14:17 stevesk Exp $");
8efc0c15 16
17#include "xmalloc.h"
18#include "buffer.h"
42f11eb2 19#include "log.h"
8efc0c15 20
21/* Initializes the buffer structure. */
22
6ae2364d 23void
5260325f 24buffer_init(Buffer *buffer)
8efc0c15 25{
5260325f 26 buffer->alloc = 4096;
27 buffer->buf = xmalloc(buffer->alloc);
28 buffer->offset = 0;
29 buffer->end = 0;
8efc0c15 30}
31
32/* Frees any memory used for the buffer. */
33
6ae2364d 34void
5260325f 35buffer_free(Buffer *buffer)
8efc0c15 36{
5260325f 37 memset(buffer->buf, 0, buffer->alloc);
38 xfree(buffer->buf);
8efc0c15 39}
40
aa3378df 41/*
42 * Clears any data from the buffer, making it empty. This does not actually
43 * zero the memory.
44 */
8efc0c15 45
6ae2364d 46void
5260325f 47buffer_clear(Buffer *buffer)
8efc0c15 48{
5260325f 49 buffer->offset = 0;
50 buffer->end = 0;
8efc0c15 51}
52
53/* Appends data to the buffer, expanding it if necessary. */
54
6ae2364d 55void
6c0fa2b1 56buffer_append(Buffer *buffer, const void *data, u_int len)
8efc0c15 57{
6c0fa2b1 58 void *p;
59 p = buffer_append_space(buffer, len);
60 memcpy(p, data, len);
8efc0c15 61}
62
aa3378df 63/*
64 * Appends space to the buffer, expanding the buffer if necessary. This does
65 * not actually copy the data into the buffer, but instead returns a pointer
66 * to the allocated region.
67 */
8efc0c15 68
6c0fa2b1 69void *
70buffer_append_space(Buffer *buffer, u_int len)
8efc0c15 71{
6c0fa2b1 72 void *p;
73
5260325f 74 /* If the buffer is empty, start using it from the beginning. */
75 if (buffer->offset == buffer->end) {
76 buffer->offset = 0;
77 buffer->end = 0;
78 }
79restart:
80 /* If there is enough space to store all data, store it now. */
81 if (buffer->end + len < buffer->alloc) {
6c0fa2b1 82 p = buffer->buf + buffer->end;
5260325f 83 buffer->end += len;
6c0fa2b1 84 return p;
5260325f 85 }
aa3378df 86 /*
87 * If the buffer is quite empty, but all data is at the end, move the
88 * data to the beginning and retry.
89 */
5260325f 90 if (buffer->offset > buffer->alloc / 2) {
91 memmove(buffer->buf, buffer->buf + buffer->offset,
92 buffer->end - buffer->offset);
93 buffer->end -= buffer->offset;
94 buffer->offset = 0;
95 goto restart;
96 }
97 /* Increase the size of the buffer and retry. */
98 buffer->alloc += len + 32768;
99 buffer->buf = xrealloc(buffer->buf, buffer->alloc);
100 goto restart;
6c0fa2b1 101 /* NOTREACHED */
8efc0c15 102}
103
104/* Returns the number of bytes of data in the buffer. */
105
1e3b8b07 106u_int
5260325f 107buffer_len(Buffer *buffer)
8efc0c15 108{
5260325f 109 return buffer->end - buffer->offset;
8efc0c15 110}
111
112/* Gets data from the beginning of the buffer. */
113
6ae2364d 114void
6c0fa2b1 115buffer_get(Buffer *buffer, void *buf, u_int len)
8efc0c15 116{
5260325f 117 if (len > buffer->end - buffer->offset)
b37caf1a 118 fatal("buffer_get: trying to get more bytes %d than in buffer %d",
119 len, buffer->end - buffer->offset);
5260325f 120 memcpy(buf, buffer->buf + buffer->offset, len);
121 buffer->offset += len;
8efc0c15 122}
123
124/* Consumes the given number of bytes from the beginning of the buffer. */
125
6ae2364d 126void
1e3b8b07 127buffer_consume(Buffer *buffer, u_int bytes)
8efc0c15 128{
5260325f 129 if (bytes > buffer->end - buffer->offset)
f54651ce 130 fatal("buffer_consume: trying to get more bytes than in buffer");
5260325f 131 buffer->offset += bytes;
132}
8efc0c15 133
134/* Consumes the given number of bytes from the end of the buffer. */
135
6ae2364d 136void
1e3b8b07 137buffer_consume_end(Buffer *buffer, u_int bytes)
8efc0c15 138{
5260325f 139 if (bytes > buffer->end - buffer->offset)
f54651ce 140 fatal("buffer_consume_end: trying to get more bytes than in buffer");
5260325f 141 buffer->end -= bytes;
142}
8efc0c15 143
144/* Returns a pointer to the first used byte in the buffer. */
145
6c0fa2b1 146void *
5260325f 147buffer_ptr(Buffer *buffer)
8efc0c15 148{
5260325f 149 return buffer->buf + buffer->offset;
8efc0c15 150}
151
152/* Dumps the contents of the buffer to stderr. */
153
6ae2364d 154void
5260325f 155buffer_dump(Buffer *buffer)
8efc0c15 156{
5260325f 157 int i;
e6207598 158 u_char *ucp = buffer->buf;
5260325f 159
8002af61 160 for (i = buffer->offset; i < buffer->end; i++) {
161 fprintf(stderr, "%02x", ucp[i]);
162 if ((i-buffer->offset)%16==15)
163 fprintf(stderr, "\r\n");
164 else if ((i-buffer->offset)%2==1)
165 fprintf(stderr, " ");
166 }
0490e609 167 fprintf(stderr, "\r\n");
8efc0c15 168}
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