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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" | |
42f11eb2 | 15 | RCSID("$OpenBSD: buffer.c,v 1.10 2001/01/21 19:05:45 markus 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 |
1e3b8b07 | 56 | buffer_append(Buffer *buffer, const char *data, u_int len) |
8efc0c15 | 57 | { |
5260325f | 58 | char *cp; |
59 | buffer_append_space(buffer, &cp, len); | |
60 | memcpy(cp, 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 | |
6ae2364d | 69 | void |
1e3b8b07 | 70 | buffer_append_space(Buffer *buffer, char **datap, u_int len) |
8efc0c15 | 71 | { |
5260325f | 72 | /* If the buffer is empty, start using it from the beginning. */ |
73 | if (buffer->offset == buffer->end) { | |
74 | buffer->offset = 0; | |
75 | buffer->end = 0; | |
76 | } | |
77 | restart: | |
78 | /* If there is enough space to store all data, store it now. */ | |
79 | if (buffer->end + len < buffer->alloc) { | |
80 | *datap = buffer->buf + buffer->end; | |
81 | buffer->end += len; | |
82 | return; | |
83 | } | |
aa3378df | 84 | /* |
85 | * If the buffer is quite empty, but all data is at the end, move the | |
86 | * data to the beginning and retry. | |
87 | */ | |
5260325f | 88 | if (buffer->offset > buffer->alloc / 2) { |
89 | memmove(buffer->buf, buffer->buf + buffer->offset, | |
90 | buffer->end - buffer->offset); | |
91 | buffer->end -= buffer->offset; | |
92 | buffer->offset = 0; | |
93 | goto restart; | |
94 | } | |
95 | /* Increase the size of the buffer and retry. */ | |
96 | buffer->alloc += len + 32768; | |
97 | buffer->buf = xrealloc(buffer->buf, buffer->alloc); | |
98 | goto restart; | |
8efc0c15 | 99 | } |
100 | ||
101 | /* Returns the number of bytes of data in the buffer. */ | |
102 | ||
1e3b8b07 | 103 | u_int |
5260325f | 104 | buffer_len(Buffer *buffer) |
8efc0c15 | 105 | { |
5260325f | 106 | return buffer->end - buffer->offset; |
8efc0c15 | 107 | } |
108 | ||
109 | /* Gets data from the beginning of the buffer. */ | |
110 | ||
6ae2364d | 111 | void |
1e3b8b07 | 112 | buffer_get(Buffer *buffer, char *buf, u_int len) |
8efc0c15 | 113 | { |
5260325f | 114 | if (len > buffer->end - buffer->offset) |
f54651ce | 115 | fatal("buffer_get: trying to get more bytes than in buffer"); |
5260325f | 116 | memcpy(buf, buffer->buf + buffer->offset, len); |
117 | buffer->offset += len; | |
8efc0c15 | 118 | } |
119 | ||
120 | /* Consumes the given number of bytes from the beginning of the buffer. */ | |
121 | ||
6ae2364d | 122 | void |
1e3b8b07 | 123 | buffer_consume(Buffer *buffer, u_int bytes) |
8efc0c15 | 124 | { |
5260325f | 125 | if (bytes > buffer->end - buffer->offset) |
f54651ce | 126 | fatal("buffer_consume: trying to get more bytes than in buffer"); |
5260325f | 127 | buffer->offset += bytes; |
128 | } | |
8efc0c15 | 129 | |
130 | /* Consumes the given number of bytes from the end of the buffer. */ | |
131 | ||
6ae2364d | 132 | void |
1e3b8b07 | 133 | buffer_consume_end(Buffer *buffer, u_int bytes) |
8efc0c15 | 134 | { |
5260325f | 135 | if (bytes > buffer->end - buffer->offset) |
f54651ce | 136 | fatal("buffer_consume_end: trying to get more bytes than in buffer"); |
5260325f | 137 | buffer->end -= bytes; |
138 | } | |
8efc0c15 | 139 | |
140 | /* Returns a pointer to the first used byte in the buffer. */ | |
141 | ||
5260325f | 142 | char * |
143 | buffer_ptr(Buffer *buffer) | |
8efc0c15 | 144 | { |
5260325f | 145 | return buffer->buf + buffer->offset; |
8efc0c15 | 146 | } |
147 | ||
148 | /* Dumps the contents of the buffer to stderr. */ | |
149 | ||
6ae2364d | 150 | void |
5260325f | 151 | buffer_dump(Buffer *buffer) |
8efc0c15 | 152 | { |
5260325f | 153 | int i; |
1e3b8b07 | 154 | u_char *ucp = (u_char *) buffer->buf; |
5260325f | 155 | |
156 | for (i = buffer->offset; i < buffer->end; i++) | |
157 | fprintf(stderr, " %02x", ucp[i]); | |
158 | fprintf(stderr, "\n"); | |
8efc0c15 | 159 | } |