1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
|
/*
*
* buffer.c
*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
*
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
*
* Created: Sat Mar 18 04:15:33 1995 ylo
*
* Functions for manipulating fifo buffers (that can grow if needed).
*
*/
#include "includes.h"
RCSID("$Id: buffer.c,v 1.4 1999/11/24 19:53:44 markus Exp $");
#include "xmalloc.h"
#include "buffer.h"
#include "ssh.h"
/* Initializes the buffer structure. */
void
buffer_init(Buffer *buffer)
{
buffer->alloc = 4096;
buffer->buf = xmalloc(buffer->alloc);
buffer->offset = 0;
buffer->end = 0;
}
/* Frees any memory used for the buffer. */
void
buffer_free(Buffer *buffer)
{
memset(buffer->buf, 0, buffer->alloc);
xfree(buffer->buf);
}
/*
* Clears any data from the buffer, making it empty. This does not actually
* zero the memory.
*/
void
buffer_clear(Buffer *buffer)
{
buffer->offset = 0;
buffer->end = 0;
}
/* Appends data to the buffer, expanding it if necessary. */
void
buffer_append(Buffer *buffer, const char *data, unsigned int len)
{
char *cp;
buffer_append_space(buffer, &cp, len);
memcpy(cp, data, len);
}
/*
* Appends space to the buffer, expanding the buffer if necessary. This does
* not actually copy the data into the buffer, but instead returns a pointer
* to the allocated region.
*/
void
buffer_append_space(Buffer *buffer, char **datap, unsigned int len)
{
/* If the buffer is empty, start using it from the beginning. */
if (buffer->offset == buffer->end) {
buffer->offset = 0;
buffer->end = 0;
}
restart:
/* If there is enough space to store all data, store it now. */
if (buffer->end + len < buffer->alloc) {
*datap = buffer->buf + buffer->end;
buffer->end += len;
return;
}
/*
* If the buffer is quite empty, but all data is at the end, move the
* data to the beginning and retry.
*/
if (buffer->offset > buffer->alloc / 2) {
memmove(buffer->buf, buffer->buf + buffer->offset,
buffer->end - buffer->offset);
buffer->end -= buffer->offset;
buffer->offset = 0;
goto restart;
}
/* Increase the size of the buffer and retry. */
buffer->alloc += len + 32768;
buffer->buf = xrealloc(buffer->buf, buffer->alloc);
goto restart;
}
/* Returns the number of bytes of data in the buffer. */
unsigned int
buffer_len(Buffer *buffer)
{
return buffer->end - buffer->offset;
}
/* Gets data from the beginning of the buffer. */
void
buffer_get(Buffer *buffer, char *buf, unsigned int len)
{
if (len > buffer->end - buffer->offset)
fatal("buffer_get trying to get more bytes than in buffer");
memcpy(buf, buffer->buf + buffer->offset, len);
buffer->offset += len;
}
/* Consumes the given number of bytes from the beginning of the buffer. */
void
buffer_consume(Buffer *buffer, unsigned int bytes)
{
if (bytes > buffer->end - buffer->offset)
fatal("buffer_get trying to get more bytes than in buffer");
buffer->offset += bytes;
}
/* Consumes the given number of bytes from the end of the buffer. */
void
buffer_consume_end(Buffer *buffer, unsigned int bytes)
{
if (bytes > buffer->end - buffer->offset)
fatal("buffer_get trying to get more bytes than in buffer");
buffer->end -= bytes;
}
/* Returns a pointer to the first used byte in the buffer. */
char *
buffer_ptr(Buffer *buffer)
{
return buffer->buf + buffer->offset;
}
/* Dumps the contents of the buffer to stderr. */
void
buffer_dump(Buffer *buffer)
{
int i;
unsigned char *ucp = (unsigned char *) buffer->buf;
for (i = buffer->offset; i < buffer->end; i++)
fprintf(stderr, " %02x", ucp[i]);
fprintf(stderr, "\n");
}
|
