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-rw-r--r--other/ssharp/compress.c156
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diff --git a/other/ssharp/compress.c b/other/ssharp/compress.c
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1/*
2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
5 * Interface to packet compression for ssh.
6 *
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".
12 */
13
14#include "includes.h"
15RCSID("$OpenBSD: compress.c,v 1.14 2001/04/05 10:39:01 markus Exp $");
16
17#include "log.h"
18#include "buffer.h"
19#include "zlib.h"
20#include "compress.h"
21
22static z_stream incoming_stream;
23static z_stream outgoing_stream;
24static int compress_init_send_called = 0;
25static int compress_init_recv_called = 0;
26
27/*
28 * Initializes compression; level is compression level from 1 to 9
29 * (as in gzip).
30 */
31
32void
33buffer_compress_init_send(int level)
34{
35 if (compress_init_send_called == 1)
36 deflateEnd(&incoming_stream);
37 compress_init_send_called = 1;
38 debug("Enabling compression at level %d.", level);
39 if (level < 1 || level > 9)
40 fatal("Bad compression level %d.", level);
41 deflateInit(&outgoing_stream, level);
42}
43void
44buffer_compress_init_recv(void)
45{
46 if (compress_init_recv_called == 1)
47 inflateEnd(&incoming_stream);
48 compress_init_recv_called = 1;
49 inflateInit(&incoming_stream);
50}
51
52/* Frees any data structures allocated for compression. */
53
54void
55buffer_compress_uninit(void)
56{
57 debug("compress outgoing: raw data %lu, compressed %lu, factor %.2f",
58 outgoing_stream.total_in, outgoing_stream.total_out,
59 outgoing_stream.total_in == 0 ? 0.0 :
60 (double) outgoing_stream.total_out / outgoing_stream.total_in);
61 debug("compress incoming: raw data %lu, compressed %lu, factor %.2f",
62 incoming_stream.total_out, incoming_stream.total_in,
63 incoming_stream.total_out == 0 ? 0.0 :
64 (double) incoming_stream.total_in / incoming_stream.total_out);
65 if (compress_init_recv_called == 1)
66 inflateEnd(&incoming_stream);
67 if (compress_init_send_called == 1)
68 deflateEnd(&outgoing_stream);
69}
70
71/*
72 * Compresses the contents of input_buffer into output_buffer. All packets
73 * compressed using this function will form a single compressed data stream;
74 * however, data will be flushed at the end of every call so that each
75 * output_buffer can be decompressed independently (but in the appropriate
76 * order since they together form a single compression stream) by the
77 * receiver. This appends the compressed data to the output buffer.
78 */
79
80void
81buffer_compress(Buffer * input_buffer, Buffer * output_buffer)
82{
83 char buf[4096];
84 int status;
85
86 /* This case is not handled below. */
87 if (buffer_len(input_buffer) == 0)
88 return;
89
90 /* Input is the contents of the input buffer. */
91 outgoing_stream.next_in = (u_char *) buffer_ptr(input_buffer);
92 outgoing_stream.avail_in = buffer_len(input_buffer);
93
94 /* Loop compressing until deflate() returns with avail_out != 0. */
95 do {
96 /* Set up fixed-size output buffer. */
97 outgoing_stream.next_out = (u_char *)buf;
98 outgoing_stream.avail_out = sizeof(buf);
99
100 /* Compress as much data into the buffer as possible. */
101 status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH);
102 switch (status) {
103 case Z_OK:
104 /* Append compressed data to output_buffer. */
105 buffer_append(output_buffer, buf,
106 sizeof(buf) - outgoing_stream.avail_out);
107 break;
108 default:
109 fatal("buffer_compress: deflate returned %d", status);
110 /* NOTREACHED */
111 }
112 } while (outgoing_stream.avail_out == 0);
113}
114
115/*
116 * Uncompresses the contents of input_buffer into output_buffer. All packets
117 * uncompressed using this function will form a single compressed data
118 * stream; however, data will be flushed at the end of every call so that
119 * each output_buffer. This must be called for the same size units that the
120 * buffer_compress was called, and in the same order that buffers compressed
121 * with that. This appends the uncompressed data to the output buffer.
122 */
123
124void
125buffer_uncompress(Buffer * input_buffer, Buffer * output_buffer)
126{
127 char buf[4096];
128 int status;
129
130 incoming_stream.next_in = (u_char *) buffer_ptr(input_buffer);
131 incoming_stream.avail_in = buffer_len(input_buffer);
132
133 for (;;) {
134 /* Set up fixed-size output buffer. */
135 incoming_stream.next_out = (u_char *) buf;
136 incoming_stream.avail_out = sizeof(buf);
137
138 status = inflate(&incoming_stream, Z_PARTIAL_FLUSH);
139 switch (status) {
140 case Z_OK:
141 buffer_append(output_buffer, buf,
142 sizeof(buf) - incoming_stream.avail_out);
143 break;
144 case Z_BUF_ERROR:
145 /*
146 * Comments in zlib.h say that we should keep calling
147 * inflate() until we get an error. This appears to
148 * be the error that we get.
149 */
150 return;
151 default:
152 fatal("buffer_uncompress: inflate returned %d", status);
153 /* NOTREACHED */
154 }
155 }
156}