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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" | |
ff2d7a98 | 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 | { | |
13a4a46b | 26 | const u_int len = 4096; |
27 | ||
28 | buffer->alloc = 0; | |
29 | buffer->buf = xmalloc(len); | |
30 | buffer->alloc = len; | |
3c0ef626 | 31 | buffer->offset = 0; |
32 | buffer->end = 0; | |
33 | } | |
34 | ||
35 | /* Frees any memory used for the buffer. */ | |
36 | ||
37 | void | |
38 | buffer_free(Buffer *buffer) | |
39 | { | |
13a4a46b | 40 | if (buffer->alloc > 0) { |
41 | memset(buffer->buf, 0, buffer->alloc); | |
42 | xfree(buffer->buf); | |
43 | } | |
3c0ef626 | 44 | } |
45 | ||
46 | /* | |
47 | * Clears any data from the buffer, making it empty. This does not actually | |
48 | * zero the memory. | |
49 | */ | |
50 | ||
51 | void | |
52 | buffer_clear(Buffer *buffer) | |
53 | { | |
54 | buffer->offset = 0; | |
55 | buffer->end = 0; | |
56 | } | |
57 | ||
58 | /* Appends data to the buffer, expanding it if necessary. */ | |
59 | ||
60 | void | |
e9a17296 | 61 | buffer_append(Buffer *buffer, const void *data, u_int len) |
3c0ef626 | 62 | { |
e9a17296 | 63 | void *p; |
64 | p = buffer_append_space(buffer, len); | |
65 | memcpy(p, data, len); | |
3c0ef626 | 66 | } |
67 | ||
68 | /* | |
69 | * Appends space to the buffer, expanding the buffer if necessary. This does | |
70 | * not actually copy the data into the buffer, but instead returns a pointer | |
71 | * to the allocated region. | |
72 | */ | |
73 | ||
e9a17296 | 74 | void * |
75 | buffer_append_space(Buffer *buffer, u_int len) | |
3c0ef626 | 76 | { |
2eff4de8 | 77 | u_int newlen; |
e9a17296 | 78 | void *p; |
79 | ||
ff2d7a98 | 80 | if (len > 0x100000) |
81 | fatal("buffer_append_space: len %u not supported", len); | |
82 | ||
3c0ef626 | 83 | /* If the buffer is empty, start using it from the beginning. */ |
84 | if (buffer->offset == buffer->end) { | |
85 | buffer->offset = 0; | |
86 | buffer->end = 0; | |
87 | } | |
88 | restart: | |
89 | /* If there is enough space to store all data, store it now. */ | |
90 | if (buffer->end + len < buffer->alloc) { | |
e9a17296 | 91 | p = buffer->buf + buffer->end; |
3c0ef626 | 92 | buffer->end += len; |
e9a17296 | 93 | return p; |
3c0ef626 | 94 | } |
95 | /* | |
96 | * If the buffer is quite empty, but all data is at the end, move the | |
97 | * data to the beginning and retry. | |
98 | */ | |
99 | if (buffer->offset > buffer->alloc / 2) { | |
100 | memmove(buffer->buf, buffer->buf + buffer->offset, | |
101 | buffer->end - buffer->offset); | |
102 | buffer->end -= buffer->offset; | |
103 | buffer->offset = 0; | |
104 | goto restart; | |
105 | } | |
106 | /* Increase the size of the buffer and retry. */ | |
2eff4de8 | 107 | |
108 | newlen = buffer->alloc + len + 32768; | |
109 | if (newlen > 0xa00000) | |
ff2d7a98 | 110 | fatal("buffer_append_space: alloc %u not supported", |
2eff4de8 | 111 | newlen); |
112 | buffer->buf = xrealloc(buffer->buf, newlen); | |
113 | buffer->alloc = newlen; | |
3c0ef626 | 114 | goto restart; |
e9a17296 | 115 | /* NOTREACHED */ |
3c0ef626 | 116 | } |
117 | ||
118 | /* Returns the number of bytes of data in the buffer. */ | |
119 | ||
120 | u_int | |
121 | buffer_len(Buffer *buffer) | |
122 | { | |
123 | return buffer->end - buffer->offset; | |
124 | } | |
125 | ||
126 | /* Gets data from the beginning of the buffer. */ | |
127 | ||
128 | void | |
e9a17296 | 129 | buffer_get(Buffer *buffer, void *buf, u_int len) |
3c0ef626 | 130 | { |
131 | if (len > buffer->end - buffer->offset) | |
132 | fatal("buffer_get: trying to get more bytes %d than in buffer %d", | |
133 | len, buffer->end - buffer->offset); | |
134 | memcpy(buf, buffer->buf + buffer->offset, len); | |
135 | buffer->offset += len; | |
136 | } | |
137 | ||
138 | /* Consumes the given number of bytes from the beginning of the buffer. */ | |
139 | ||
140 | void | |
141 | buffer_consume(Buffer *buffer, u_int bytes) | |
142 | { | |
143 | if (bytes > buffer->end - buffer->offset) | |
144 | fatal("buffer_consume: trying to get more bytes than in buffer"); | |
145 | buffer->offset += bytes; | |
146 | } | |
147 | ||
148 | /* Consumes the given number of bytes from the end of the buffer. */ | |
149 | ||
150 | void | |
151 | buffer_consume_end(Buffer *buffer, u_int bytes) | |
152 | { | |
153 | if (bytes > buffer->end - buffer->offset) | |
154 | fatal("buffer_consume_end: trying to get more bytes than in buffer"); | |
155 | buffer->end -= bytes; | |
156 | } | |
157 | ||
158 | /* Returns a pointer to the first used byte in the buffer. */ | |
159 | ||
e9a17296 | 160 | void * |
3c0ef626 | 161 | buffer_ptr(Buffer *buffer) |
162 | { | |
163 | return buffer->buf + buffer->offset; | |
164 | } | |
165 | ||
166 | /* Dumps the contents of the buffer to stderr. */ | |
167 | ||
168 | void | |
169 | buffer_dump(Buffer *buffer) | |
170 | { | |
171 | int i; | |
e9a17296 | 172 | u_char *ucp = buffer->buf; |
3c0ef626 | 173 | |
174 | for (i = buffer->offset; i < buffer->end; i++) { | |
175 | fprintf(stderr, "%02x", ucp[i]); | |
176 | if ((i-buffer->offset)%16==15) | |
177 | fprintf(stderr, "\r\n"); | |
178 | else if ((i-buffer->offset)%2==1) | |
179 | fprintf(stderr, " "); | |
180 | } | |
181 | fprintf(stderr, "\r\n"); | |
182 | } |