Annotation of src/usr.bin/ssh/buffer.c, Revision 1.4
1.1 deraadt 1: /*
1.3 deraadt 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: */
1.1 deraadt 15:
16: #include "includes.h"
1.4 ! markus 17: RCSID("$Id: buffer.c,v 1.3 1999/11/24 00:26:01 deraadt Exp $");
1.1 deraadt 18:
19: #include "xmalloc.h"
20: #include "buffer.h"
21: #include "ssh.h"
22:
23: /* Initializes the buffer structure. */
24:
1.2 markus 25: void
26: buffer_init(Buffer *buffer)
1.1 deraadt 27: {
1.2 markus 28: buffer->alloc = 4096;
29: buffer->buf = xmalloc(buffer->alloc);
30: buffer->offset = 0;
31: buffer->end = 0;
1.1 deraadt 32: }
33:
34: /* Frees any memory used for the buffer. */
35:
1.2 markus 36: void
37: buffer_free(Buffer *buffer)
1.1 deraadt 38: {
1.2 markus 39: memset(buffer->buf, 0, buffer->alloc);
40: xfree(buffer->buf);
1.1 deraadt 41: }
42:
1.4 ! markus 43: /*
! 44: * Clears any data from the buffer, making it empty. This does not actually
! 45: * zero the memory.
! 46: */
1.1 deraadt 47:
1.2 markus 48: void
49: buffer_clear(Buffer *buffer)
1.1 deraadt 50: {
1.2 markus 51: buffer->offset = 0;
52: buffer->end = 0;
1.1 deraadt 53: }
54:
55: /* Appends data to the buffer, expanding it if necessary. */
56:
1.2 markus 57: void
58: buffer_append(Buffer *buffer, const char *data, unsigned int len)
1.1 deraadt 59: {
1.2 markus 60: char *cp;
61: buffer_append_space(buffer, &cp, len);
62: memcpy(cp, data, len);
1.1 deraadt 63: }
64:
1.4 ! markus 65: /*
! 66: * Appends space to the buffer, expanding the buffer if necessary. This does
! 67: * not actually copy the data into the buffer, but instead returns a pointer
! 68: * to the allocated region.
! 69: */
1.1 deraadt 70:
1.2 markus 71: void
72: buffer_append_space(Buffer *buffer, char **datap, unsigned int len)
1.1 deraadt 73: {
1.2 markus 74: /* If the buffer is empty, start using it from the beginning. */
75: if (buffer->offset == buffer->end) {
76: buffer->offset = 0;
77: buffer->end = 0;
78: }
79: restart:
80: /* If there is enough space to store all data, store it now. */
81: if (buffer->end + len < buffer->alloc) {
82: *datap = buffer->buf + buffer->end;
83: buffer->end += len;
84: return;
85: }
1.4 ! markus 86: /*
! 87: * If the buffer is quite empty, but all data is at the end, move the
! 88: * data to the beginning and retry.
! 89: */
1.2 markus 90: if (buffer->offset > buffer->alloc / 2) {
91: memmove(buffer->buf, buffer->buf + buffer->offset,
92: buffer->end - buffer->offset);
93: buffer->end -= buffer->offset;
94: buffer->offset = 0;
95: goto restart;
96: }
97: /* Increase the size of the buffer and retry. */
98: buffer->alloc += len + 32768;
99: buffer->buf = xrealloc(buffer->buf, buffer->alloc);
100: goto restart;
1.1 deraadt 101: }
102:
103: /* Returns the number of bytes of data in the buffer. */
104:
1.2 markus 105: unsigned int
106: buffer_len(Buffer *buffer)
1.1 deraadt 107: {
1.2 markus 108: return buffer->end - buffer->offset;
1.1 deraadt 109: }
110:
111: /* Gets data from the beginning of the buffer. */
112:
1.2 markus 113: void
114: buffer_get(Buffer *buffer, char *buf, unsigned int len)
1.1 deraadt 115: {
1.2 markus 116: if (len > buffer->end - buffer->offset)
117: fatal("buffer_get trying to get more bytes than in buffer");
118: memcpy(buf, buffer->buf + buffer->offset, len);
119: buffer->offset += len;
1.1 deraadt 120: }
121:
122: /* Consumes the given number of bytes from the beginning of the buffer. */
123:
1.2 markus 124: void
125: buffer_consume(Buffer *buffer, unsigned int bytes)
1.1 deraadt 126: {
1.2 markus 127: if (bytes > buffer->end - buffer->offset)
128: fatal("buffer_get trying to get more bytes than in buffer");
129: buffer->offset += bytes;
130: }
1.1 deraadt 131:
132: /* Consumes the given number of bytes from the end of the buffer. */
133:
1.2 markus 134: void
135: buffer_consume_end(Buffer *buffer, unsigned int bytes)
1.1 deraadt 136: {
1.2 markus 137: if (bytes > buffer->end - buffer->offset)
138: fatal("buffer_get trying to get more bytes than in buffer");
139: buffer->end -= bytes;
140: }
1.1 deraadt 141:
142: /* Returns a pointer to the first used byte in the buffer. */
143:
1.2 markus 144: char *
145: buffer_ptr(Buffer *buffer)
1.1 deraadt 146: {
1.2 markus 147: return buffer->buf + buffer->offset;
1.1 deraadt 148: }
149:
150: /* Dumps the contents of the buffer to stderr. */
151:
1.2 markus 152: void
153: buffer_dump(Buffer *buffer)
1.1 deraadt 154: {
1.2 markus 155: int i;
156: unsigned char *ucp = (unsigned char *) buffer->buf;
157:
158: for (i = buffer->offset; i < buffer->end; i++)
159: fprintf(stderr, " %02x", ucp[i]);
160: fprintf(stderr, "\n");
1.1 deraadt 161: }
![[BACK]](/icons/back.gif){kind=icon}
Return to buffer.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh