blob: e183d101798e87e9273280e6ad6c6d750fcd4d67 [file] [log] [blame]
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
2
3buffer.c
4
5Author: Tatu Ylonen <ylo@cs.hut.fi>
6
7Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8 All rights reserved
9
10Created: Sat Mar 18 04:15:33 1995 ylo
11
12Functions for manipulating fifo buffers (that can grow if needed).
13
14*/
15
16#include "includes.h"
17RCSID("$Id: buffer.c,v 1.1 1999/10/27 03:42:43 damien Exp $");
18
19#include "xmalloc.h"
20#include "buffer.h"
21#include "ssh.h"
22
23/* Initializes the buffer structure. */
24
25void 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
35void 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
44void 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
52void 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
63void 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
100unsigned int buffer_len(Buffer *buffer)
101{
102 return buffer->end - buffer->offset;
103}
104
105/* Gets data from the beginning of the buffer. */
106
107void 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
117void 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
126void 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
135char *buffer_ptr(Buffer *buffer)
136{
137 return buffer->buf + buffer->offset;
138}
139
140/* Dumps the contents of the buffer to stderr. */
141
142void 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}