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3c0ef626 | 1 | /* |
2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
5 | * Functions for manipulating fifo buffers (that can grow if needed). | |
6 | * | |
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". | |
12 | */ | |
13 | ||
14 | #include "includes.h" | |
0fff78ff | 15 | RCSID("$OpenBSD: buffer.c,v 1.17 2003/09/16 03:03:47 deraadt Exp $"); |
3c0ef626 | 16 | |
17 | #include "xmalloc.h" | |
18 | #include "buffer.h" | |
19 | #include "log.h" | |
20 | ||
21 | /* Initializes the buffer structure. */ | |
22 | ||
23 | void | |
24 | buffer_init(Buffer *buffer) | |
25 | { | |
26 | buffer->alloc = 4096; | |
27 | buffer->buf = xmalloc(buffer->alloc); | |
28 | buffer->offset = 0; | |
29 | buffer->end = 0; | |
30 | } | |
31 | ||
32 | /* Frees any memory used for the buffer. */ | |
33 | ||
34 | void | |
35 | buffer_free(Buffer *buffer) | |
36 | { | |
37 | memset(buffer->buf, 0, buffer->alloc); | |
38 | xfree(buffer->buf); | |
39 | } | |
40 | ||
41 | /* | |
42 | * Clears any data from the buffer, making it empty. This does not actually | |
43 | * zero the memory. | |
44 | */ | |
45 | ||
46 | void | |
47 | buffer_clear(Buffer *buffer) | |
48 | { | |
49 | buffer->offset = 0; | |
50 | buffer->end = 0; | |
51 | } | |
52 | ||
53 | /* Appends data to the buffer, expanding it if necessary. */ | |
54 | ||
55 | void | |
e9a17296 | 56 | buffer_append(Buffer *buffer, const void *data, u_int len) |
3c0ef626 | 57 | { |
e9a17296 | 58 | void *p; |
59 | p = buffer_append_space(buffer, len); | |
60 | memcpy(p, data, len); | |
3c0ef626 | 61 | } |
62 | ||
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 | */ | |
68 | ||
e9a17296 | 69 | void * |
70 | buffer_append_space(Buffer *buffer, u_int len) | |
3c0ef626 | 71 | { |
0fff78ff | 72 | u_int newlen; |
e9a17296 | 73 | void *p; |
74 | ||
680cee3b | 75 | if (len > 0x100000) |
76 | fatal("buffer_append_space: len %u not supported", len); | |
77 | ||
3c0ef626 | 78 | /* If the buffer is empty, start using it from the beginning. */ |
79 | if (buffer->offset == buffer->end) { | |
80 | buffer->offset = 0; | |
81 | buffer->end = 0; | |
82 | } | |
83 | restart: | |
84 | /* If there is enough space to store all data, store it now. */ | |
85 | if (buffer->end + len < buffer->alloc) { | |
e9a17296 | 86 | p = buffer->buf + buffer->end; |
3c0ef626 | 87 | buffer->end += len; |
e9a17296 | 88 | return p; |
3c0ef626 | 89 | } |
90 | /* | |
91 | * If the buffer is quite empty, but all data is at the end, move the | |
92 | * data to the beginning and retry. | |
93 | */ | |
94 | if (buffer->offset > buffer->alloc / 2) { | |
95 | memmove(buffer->buf, buffer->buf + buffer->offset, | |
96 | buffer->end - buffer->offset); | |
97 | buffer->end -= buffer->offset; | |
98 | buffer->offset = 0; | |
99 | goto restart; | |
100 | } | |
101 | /* Increase the size of the buffer and retry. */ | |
0fff78ff | 102 | |
103 | newlen = buffer->alloc + len + 32768; | |
104 | if (newlen > 0xa00000) | |
680cee3b | 105 | fatal("buffer_append_space: alloc %u not supported", |
0fff78ff | 106 | newlen); |
107 | buffer->buf = xrealloc(buffer->buf, newlen); | |
108 | buffer->alloc = newlen; | |
3c0ef626 | 109 | goto restart; |
e9a17296 | 110 | /* NOTREACHED */ |
3c0ef626 | 111 | } |
112 | ||
113 | /* Returns the number of bytes of data in the buffer. */ | |
114 | ||
115 | u_int | |
116 | buffer_len(Buffer *buffer) | |
117 | { | |
118 | return buffer->end - buffer->offset; | |
119 | } | |
120 | ||
121 | /* Gets data from the beginning of the buffer. */ | |
122 | ||
123 | void | |
e9a17296 | 124 | buffer_get(Buffer *buffer, void *buf, u_int len) |
3c0ef626 | 125 | { |
126 | if (len > buffer->end - buffer->offset) | |
127 | fatal("buffer_get: trying to get more bytes %d than in buffer %d", | |
128 | len, buffer->end - buffer->offset); | |
129 | memcpy(buf, buffer->buf + buffer->offset, len); | |
130 | buffer->offset += len; | |
131 | } | |
132 | ||
133 | /* Consumes the given number of bytes from the beginning of the buffer. */ | |
134 | ||
135 | void | |
136 | buffer_consume(Buffer *buffer, u_int bytes) | |
137 | { | |
138 | if (bytes > buffer->end - buffer->offset) | |
139 | fatal("buffer_consume: trying to get more bytes than in buffer"); | |
140 | buffer->offset += bytes; | |
141 | } | |
142 | ||
143 | /* Consumes the given number of bytes from the end of the buffer. */ | |
144 | ||
145 | void | |
146 | buffer_consume_end(Buffer *buffer, u_int bytes) | |
147 | { | |
148 | if (bytes > buffer->end - buffer->offset) | |
149 | fatal("buffer_consume_end: trying to get more bytes than in buffer"); | |
150 | buffer->end -= bytes; | |
151 | } | |
152 | ||
153 | /* Returns a pointer to the first used byte in the buffer. */ | |
154 | ||
e9a17296 | 155 | void * |
3c0ef626 | 156 | buffer_ptr(Buffer *buffer) |
157 | { | |
158 | return buffer->buf + buffer->offset; | |
159 | } | |
160 | ||
161 | /* Dumps the contents of the buffer to stderr. */ | |
162 | ||
163 | void | |
164 | buffer_dump(Buffer *buffer) | |
165 | { | |
166 | int i; | |
e9a17296 | 167 | u_char *ucp = buffer->buf; |
3c0ef626 | 168 | |
169 | for (i = buffer->offset; i < buffer->end; i++) { | |
170 | fprintf(stderr, "%02x", ucp[i]); | |
171 | if ((i-buffer->offset)%16==15) | |
172 | fprintf(stderr, "\r\n"); | |
173 | else if ((i-buffer->offset)%2==1) | |
174 | fprintf(stderr, " "); | |
175 | } | |
176 | fprintf(stderr, "\r\n"); | |
177 | } |