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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 | 15 | RCSID("$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 | 23 | void |
5260325f | 24 | buffer_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 | 34 | void |
5260325f | 35 | buffer_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 | 46 | void |
5260325f | 47 | buffer_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 | 55 | void |
6c0fa2b1 | 56 | buffer_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 | 69 | void * |
70 | buffer_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 | } | |
79 | restart: | |
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 | 106 | u_int |
5260325f | 107 | buffer_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 | 114 | void |
6c0fa2b1 | 115 | buffer_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 | 126 | void |
1e3b8b07 | 127 | buffer_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 | 136 | void |
1e3b8b07 | 137 | buffer_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 | 146 | void * |
5260325f | 147 | buffer_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 | 154 | void |
5260325f | 155 | buffer_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 | } |