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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" | |
e9a17296 | 15 | RCSID("$OpenBSD: buffer.c,v 1.15 2002/01/18 18:14:17 stevesk 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 | ||
3c0ef626 | 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) { | |
e9a17296 | 82 | p = buffer->buf + buffer->end; |
3c0ef626 | 83 | buffer->end += len; |
e9a17296 | 84 | return p; |
3c0ef626 | 85 | } |
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 | */ | |
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; | |
e9a17296 | 101 | /* NOTREACHED */ |
3c0ef626 | 102 | } |
103 | ||
104 | /* Returns the number of bytes of data in the buffer. */ | |
105 | ||
106 | u_int | |
107 | buffer_len(Buffer *buffer) | |
108 | { | |
109 | return buffer->end - buffer->offset; | |
110 | } | |
111 | ||
112 | /* Gets data from the beginning of the buffer. */ | |
113 | ||
114 | void | |
e9a17296 | 115 | buffer_get(Buffer *buffer, void *buf, u_int len) |
3c0ef626 | 116 | { |
117 | if (len > buffer->end - buffer->offset) | |
118 | fatal("buffer_get: trying to get more bytes %d than in buffer %d", | |
119 | len, buffer->end - buffer->offset); | |
120 | memcpy(buf, buffer->buf + buffer->offset, len); | |
121 | buffer->offset += len; | |
122 | } | |
123 | ||
124 | /* Consumes the given number of bytes from the beginning of the buffer. */ | |
125 | ||
126 | void | |
127 | buffer_consume(Buffer *buffer, u_int bytes) | |
128 | { | |
129 | if (bytes > buffer->end - buffer->offset) | |
130 | fatal("buffer_consume: trying to get more bytes than in buffer"); | |
131 | buffer->offset += bytes; | |
132 | } | |
133 | ||
134 | /* Consumes the given number of bytes from the end of the buffer. */ | |
135 | ||
136 | void | |
137 | buffer_consume_end(Buffer *buffer, u_int bytes) | |
138 | { | |
139 | if (bytes > buffer->end - buffer->offset) | |
140 | fatal("buffer_consume_end: trying to get more bytes than in buffer"); | |
141 | buffer->end -= bytes; | |
142 | } | |
143 | ||
144 | /* Returns a pointer to the first used byte in the buffer. */ | |
145 | ||
e9a17296 | 146 | void * |
3c0ef626 | 147 | buffer_ptr(Buffer *buffer) |
148 | { | |
149 | return buffer->buf + buffer->offset; | |
150 | } | |
151 | ||
152 | /* Dumps the contents of the buffer to stderr. */ | |
153 | ||
154 | void | |
155 | buffer_dump(Buffer *buffer) | |
156 | { | |
157 | int i; | |
e9a17296 | 158 | u_char *ucp = buffer->buf; |
3c0ef626 | 159 | |
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 | } | |
167 | fprintf(stderr, "\r\n"); | |
168 | } |