2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * Functions for manipulating fifo buffers (that can grow if needed).
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".
15 RCSID("$OpenBSD: buffer.c,v 1.16 2002/06/26 08:54:18 markus Exp $");
21 /* Initializes the buffer structure. */
24 buffer_init(Buffer *buffer)
27 buffer->buf = xmalloc(buffer->alloc);
32 /* Frees any memory used for the buffer. */
35 buffer_free(Buffer *buffer)
37 memset(buffer->buf, 0, buffer->alloc);
42 * Clears any data from the buffer, making it empty. This does not actually
47 buffer_clear(Buffer *buffer)
53 /* Appends data to the buffer, expanding it if necessary. */
56 buffer_append(Buffer *buffer, const void *data, u_int len)
59 p = buffer_append_space(buffer, len);
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.
70 buffer_append_space(Buffer *buffer, u_int len)
76 fatal("buffer_append_space: len %u not supported", len);
78 /* If the buffer is empty, start using it from the beginning. */
79 if (buffer->offset == buffer->end) {
84 /* If there is enough space to store all data, store it now. */
85 if (buffer->end + len < buffer->alloc) {
86 p = buffer->buf + buffer->end;
91 * If the buffer is quite empty, but all data is at the end, move the
92 * data to the beginning and retry.
94 if (buffer->offset > buffer->alloc / 2) {
95 memmove(buffer->buf, buffer->buf + buffer->offset,
96 buffer->end - buffer->offset);
97 buffer->end -= buffer->offset;
101 /* Increase the size of the buffer and retry. */
103 newlen = buffer->alloc + len + 32768;
104 if (newlen > 0xa00000)
105 fatal("buffer_append_space: alloc %u not supported",
107 buffer->buf = xrealloc(buffer->buf, newlen);
108 buffer->alloc = newlen;
113 /* Returns the number of bytes of data in the buffer. */
116 buffer_len(Buffer *buffer)
118 return buffer->end - buffer->offset;
121 /* Gets data from the beginning of the buffer. */
124 buffer_get(Buffer *buffer, void *buf, u_int len)
126 if (len > buffer->end - buffer->offset)
127 fatal("buffer_get: trying to get more bytes %d than in buffer %d",
128 len, buffer->end - buffer->offset);
129 memcpy(buf, buffer->buf + buffer->offset, len);
130 buffer->offset += len;
133 /* Consumes the given number of bytes from the beginning of the buffer. */
136 buffer_consume(Buffer *buffer, u_int bytes)
138 if (bytes > buffer->end - buffer->offset)
139 fatal("buffer_consume: trying to get more bytes than in buffer");
140 buffer->offset += bytes;
143 /* Consumes the given number of bytes from the end of the buffer. */
146 buffer_consume_end(Buffer *buffer, u_int bytes)
148 if (bytes > buffer->end - buffer->offset)
149 fatal("buffer_consume_end: trying to get more bytes than in buffer");
150 buffer->end -= bytes;
153 /* Returns a pointer to the first used byte in the buffer. */
156 buffer_ptr(Buffer *buffer)
158 return buffer->buf + buffer->offset;
161 /* Dumps the contents of the buffer to stderr. */
164 buffer_dump(Buffer *buffer)
167 u_char *ucp = buffer->buf;
169 for (i = buffer->offset; i < buffer->end; i++) {
170 fprintf(stderr, "%02x", ucp[i]);
171 if ((i-buffer->offset)%16==15)
172 fprintf(stderr, "\r\n");
173 else if ((i-buffer->offset)%2==1)
174 fprintf(stderr, " ");
176 fprintf(stderr, "\r\n");