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Commit | Line | Data |
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8efc0c15 | 1 | /* |
2 | ||
3 | buffer.c | |
4 | ||
5 | Author: Tatu Ylonen <ylo@cs.hut.fi> | |
6 | ||
7 | Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
8 | All rights reserved | |
9 | ||
10 | Created: Sat Mar 18 04:15:33 1995 ylo | |
11 | ||
12 | Functions for manipulating fifo buffers (that can grow if needed). | |
13 | ||
14 | */ | |
15 | ||
16 | #include "includes.h" | |
17 | RCSID("$Id$"); | |
18 | ||
19 | #include "xmalloc.h" | |
20 | #include "buffer.h" | |
21 | #include "ssh.h" | |
22 | ||
23 | /* Initializes the buffer structure. */ | |
24 | ||
25 | void buffer_init(Buffer *buffer) | |
26 | { | |
27 | buffer->alloc = 4096; | |
28 | buffer->buf = xmalloc(buffer->alloc); | |
29 | buffer->offset = 0; | |
30 | buffer->end = 0; | |
31 | } | |
32 | ||
33 | /* Frees any memory used for the buffer. */ | |
34 | ||
35 | void buffer_free(Buffer *buffer) | |
36 | { | |
37 | memset(buffer->buf, 0, buffer->alloc); | |
38 | xfree(buffer->buf); | |
39 | } | |
40 | ||
41 | /* Clears any data from the buffer, making it empty. This does not actually | |
42 | zero the memory. */ | |
43 | ||
44 | void buffer_clear(Buffer *buffer) | |
45 | { | |
46 | buffer->offset = 0; | |
47 | buffer->end = 0; | |
48 | } | |
49 | ||
50 | /* Appends data to the buffer, expanding it if necessary. */ | |
51 | ||
52 | void buffer_append(Buffer *buffer, const char *data, unsigned int len) | |
53 | { | |
54 | char *cp; | |
55 | buffer_append_space(buffer, &cp, len); | |
56 | memcpy(cp, data, len); | |
57 | } | |
58 | ||
59 | /* Appends space to the buffer, expanding the buffer if necessary. | |
60 | This does not actually copy the data into the buffer, but instead | |
61 | returns a pointer to the allocated region. */ | |
62 | ||
63 | void buffer_append_space(Buffer *buffer, char **datap, unsigned int len) | |
64 | { | |
65 | /* If the buffer is empty, start using it from the beginning. */ | |
66 | if (buffer->offset == buffer->end) | |
67 | { | |
68 | buffer->offset = 0; | |
69 | buffer->end = 0; | |
70 | } | |
71 | ||
72 | restart: | |
73 | /* If there is enough space to store all data, store it now. */ | |
74 | if (buffer->end + len < buffer->alloc) | |
75 | { | |
76 | *datap = buffer->buf + buffer->end; | |
77 | buffer->end += len; | |
78 | return; | |
79 | } | |
80 | ||
81 | /* If the buffer is quite empty, but all data is at the end, move the | |
82 | data to the beginning and retry. */ | |
83 | if (buffer->offset > buffer->alloc / 2) | |
84 | { | |
85 | memmove(buffer->buf, buffer->buf + buffer->offset, | |
86 | buffer->end - buffer->offset); | |
87 | buffer->end -= buffer->offset; | |
88 | buffer->offset = 0; | |
89 | goto restart; | |
90 | } | |
91 | ||
92 | /* Increase the size of the buffer and retry. */ | |
93 | buffer->alloc += len + 32768; | |
94 | buffer->buf = xrealloc(buffer->buf, buffer->alloc); | |
95 | goto restart; | |
96 | } | |
97 | ||
98 | /* Returns the number of bytes of data in the buffer. */ | |
99 | ||
100 | unsigned int buffer_len(Buffer *buffer) | |
101 | { | |
102 | return buffer->end - buffer->offset; | |
103 | } | |
104 | ||
105 | /* Gets data from the beginning of the buffer. */ | |
106 | ||
107 | void buffer_get(Buffer *buffer, char *buf, unsigned int len) | |
108 | { | |
109 | if (len > buffer->end - buffer->offset) | |
110 | fatal("buffer_get trying to get more bytes than in buffer"); | |
111 | memcpy(buf, buffer->buf + buffer->offset, len); | |
112 | buffer->offset += len; | |
113 | } | |
114 | ||
115 | /* Consumes the given number of bytes from the beginning of the buffer. */ | |
116 | ||
117 | void buffer_consume(Buffer *buffer, unsigned int bytes) | |
118 | { | |
119 | if (bytes > buffer->end - buffer->offset) | |
120 | fatal("buffer_get trying to get more bytes than in buffer"); | |
121 | buffer->offset += bytes; | |
122 | } | |
123 | ||
124 | /* Consumes the given number of bytes from the end of the buffer. */ | |
125 | ||
126 | void buffer_consume_end(Buffer *buffer, unsigned int bytes) | |
127 | { | |
128 | if (bytes > buffer->end - buffer->offset) | |
129 | fatal("buffer_get trying to get more bytes than in buffer"); | |
130 | buffer->end -= bytes; | |
131 | } | |
132 | ||
133 | /* Returns a pointer to the first used byte in the buffer. */ | |
134 | ||
135 | char *buffer_ptr(Buffer *buffer) | |
136 | { | |
137 | return buffer->buf + buffer->offset; | |
138 | } | |
139 | ||
140 | /* Dumps the contents of the buffer to stderr. */ | |
141 | ||
142 | void buffer_dump(Buffer *buffer) | |
143 | { | |
144 | int i; | |
145 | unsigned char *ucp = (unsigned char *)buffer->buf; | |
146 | ||
147 | for (i = buffer->offset; i < buffer->end; i++) | |
148 | fprintf(stderr, " %02x", ucp[i]); | |
149 | fprintf(stderr, "\n"); | |
150 | } |