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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" | |
680cee3b | 15 | RCSID("$OpenBSD: buffer.c,v 1.16 2002/06/26 08:54:18 markus 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 | { |
e9a17296 | 72 | void *p; |
73 | ||
680cee3b | 74 | if (len > 0x100000) |
75 | fatal("buffer_append_space: len %u not supported", len); | |
76 | ||
3c0ef626 | 77 | /* If the buffer is empty, start using it from the beginning. */ |
78 | if (buffer->offset == buffer->end) { | |
79 | buffer->offset = 0; | |
80 | buffer->end = 0; | |
81 | } | |
82 | restart: | |
83 | /* If there is enough space to store all data, store it now. */ | |
84 | if (buffer->end + len < buffer->alloc) { | |
e9a17296 | 85 | p = buffer->buf + buffer->end; |
3c0ef626 | 86 | buffer->end += len; |
e9a17296 | 87 | return p; |
3c0ef626 | 88 | } |
89 | /* | |
90 | * If the buffer is quite empty, but all data is at the end, move the | |
91 | * data to the beginning and retry. | |
92 | */ | |
93 | if (buffer->offset > buffer->alloc / 2) { | |
94 | memmove(buffer->buf, buffer->buf + buffer->offset, | |
95 | buffer->end - buffer->offset); | |
96 | buffer->end -= buffer->offset; | |
97 | buffer->offset = 0; | |
98 | goto restart; | |
99 | } | |
100 | /* Increase the size of the buffer and retry. */ | |
101 | buffer->alloc += len + 32768; | |
680cee3b | 102 | if (buffer->alloc > 0xa00000) |
103 | fatal("buffer_append_space: alloc %u not supported", | |
104 | buffer->alloc); | |
3c0ef626 | 105 | buffer->buf = xrealloc(buffer->buf, buffer->alloc); |
106 | goto restart; | |
e9a17296 | 107 | /* NOTREACHED */ |
3c0ef626 | 108 | } |
109 | ||
110 | /* Returns the number of bytes of data in the buffer. */ | |
111 | ||
112 | u_int | |
113 | buffer_len(Buffer *buffer) | |
114 | { | |
115 | return buffer->end - buffer->offset; | |
116 | } | |
117 | ||
118 | /* Gets data from the beginning of the buffer. */ | |
119 | ||
120 | void | |
e9a17296 | 121 | buffer_get(Buffer *buffer, void *buf, u_int len) |
3c0ef626 | 122 | { |
123 | if (len > buffer->end - buffer->offset) | |
124 | fatal("buffer_get: trying to get more bytes %d than in buffer %d", | |
125 | len, buffer->end - buffer->offset); | |
126 | memcpy(buf, buffer->buf + buffer->offset, len); | |
127 | buffer->offset += len; | |
128 | } | |
129 | ||
130 | /* Consumes the given number of bytes from the beginning of the buffer. */ | |
131 | ||
132 | void | |
133 | buffer_consume(Buffer *buffer, u_int bytes) | |
134 | { | |
135 | if (bytes > buffer->end - buffer->offset) | |
136 | fatal("buffer_consume: trying to get more bytes than in buffer"); | |
137 | buffer->offset += bytes; | |
138 | } | |
139 | ||
140 | /* Consumes the given number of bytes from the end of the buffer. */ | |
141 | ||
142 | void | |
143 | buffer_consume_end(Buffer *buffer, u_int bytes) | |
144 | { | |
145 | if (bytes > buffer->end - buffer->offset) | |
146 | fatal("buffer_consume_end: trying to get more bytes than in buffer"); | |
147 | buffer->end -= bytes; | |
148 | } | |
149 | ||
150 | /* Returns a pointer to the first used byte in the buffer. */ | |
151 | ||
e9a17296 | 152 | void * |
3c0ef626 | 153 | buffer_ptr(Buffer *buffer) |
154 | { | |
155 | return buffer->buf + buffer->offset; | |
156 | } | |
157 | ||
158 | /* Dumps the contents of the buffer to stderr. */ | |
159 | ||
160 | void | |
161 | buffer_dump(Buffer *buffer) | |
162 | { | |
163 | int i; | |
e9a17296 | 164 | u_char *ucp = buffer->buf; |
3c0ef626 | 165 | |
166 | for (i = buffer->offset; i < buffer->end; i++) { | |
167 | fprintf(stderr, "%02x", ucp[i]); | |
168 | if ((i-buffer->offset)%16==15) | |
169 | fprintf(stderr, "\r\n"); | |
170 | else if ((i-buffer->offset)%2==1) | |
171 | fprintf(stderr, " "); | |
172 | } | |
173 | fprintf(stderr, "\r\n"); | |
174 | } |