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comparison src/io/rx_inflate.c @ 0:d39e1d0d75b6

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author paulo@hit-nxdomain.opendns.com
date Sat, 20 Feb 2010 21:18:28 -0800
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1 /*
2 * $Id: rx_inflate.c,v 1.10 2004/04/05 07:56:54 hipnod Exp $
3 *
4 * Copyright (C) 2003 giFT project (gift.sourceforge.net)
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2, or (at your option) any
9 * later version.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 */
16
17 #include "gt_gnutella.h"
18
19 #include "rx_stack.h"
20 #include "rx_layer.h"
21
22 #include <zlib.h>
23
24 /*****************************************************************************/
25
26 /* this is small for testing purposes */
27 #define RX_INFLATE_BUFSIZE 256
28
29 #define RX_INFLATE(rx) \
30 ((struct rx_inflate *) (((rx)->udata)))
31
32 struct rx_inflate
33 {
34 z_stream z;
35 BOOL init_done;
36 };
37
38 /*****************************************************************************/
39
40 static BOOL rx_inflate_init (struct rx_layer *rx, void *udata)
41 {
42 struct rx_inflate *rx_inflate;
43
44 if (!(rx_inflate = NEW (struct rx_inflate)))
45 return FALSE;
46
47 /* inflateInit() may touch these variables */
48 rx_inflate->z.zalloc = Z_NULL;
49 rx_inflate->z.zfree = Z_NULL;
50 rx_inflate->z.opaque = Z_NULL;
51 rx_inflate->z.next_in = Z_NULL;
52 rx_inflate->z.avail_in = 0;
53
54 if (inflateInit (&rx_inflate->z) != Z_OK)
55 {
56 gt_rx_stack_abort (rx->stack);
57 return FALSE;
58 }
59
60 rx->udata = rx_inflate;
61
62 rx_inflate->init_done = TRUE;
63
64 return TRUE;
65 }
66
67 static void rx_inflate_destroy (struct rx_layer *rx)
68 {
69 struct rx_inflate *rx_inflate = RX_INFLATE(rx);
70
71 /*
72 * We don't check the error here, there could very well be leftover data
73 * and it would be annoying to print a message every time.
74 */
75 inflateEnd (&rx_inflate->z);
76 rx_inflate->init_done = FALSE;
77
78 FREE (rx_inflate);
79 }
80
81 static void rx_inflate_enable (struct rx_layer *rx)
82 {
83 /* nothing -- we only process data when it comes towards us */
84 }
85
86 static void rx_inflate_disable (struct rx_layer *rx)
87 {
88 /* nothing */
89 }
90
91 /*
92 * Handle the data from the lower layer, decompress it, and pass
93 * it to the upper layer.
94 */
95 static struct io_buf *read_buf (struct rx_layer *rx, struct io_buf *io_buf)
96 {
97 struct rx_inflate *rx_inflate = RX_INFLATE(rx);
98 struct io_buf *out_msg;
99 z_streamp inz;
100 int ret;
101 size_t uncompressed_size;
102 size_t compressed_read;
103 size_t out_size = RX_INFLATE_BUFSIZE;
104 size_t avail;
105 static size_t running_cnt = 0;
106 static int msg_count = 0;
107
108 avail = io_buf_read_avail (io_buf);
109
110 if (avail == 0)
111 return NULL;
112
113 if (!(out_msg = io_buf_new (out_size)))
114 {
115 GT->dbg (GT, "couldn't allocate memory for recv buf");
116 gt_rx_stack_abort (rx->stack);
117 return NULL;
118 }
119
120 assert (rx_inflate->init_done);
121 inz = &rx_inflate->z;
122
123 inz->next_in = io_buf_read_ptr (io_buf);
124 inz->avail_in = avail;
125 inz->next_out = io_buf_write_ptr (out_msg);
126 inz->avail_out = out_size;
127
128 ret = inflate (inz, Z_SYNC_FLUSH);
129
130 if (ret != Z_OK)
131 {
132 if (IO_DEBUG)
133 GT->dbg (GT, "zlib recv error: %d", ret);
134
135 gt_rx_stack_abort (rx->stack);
136 io_buf_free (out_msg);
137 return NULL;
138 }
139
140 uncompressed_size = out_size - inz->avail_out;
141 compressed_read = avail - inz->avail_in;
142
143 running_cnt += uncompressed_size;
144 if (IO_DEBUG && ++msg_count % 50 == 0)
145 {
146 GT->dbg (GT, "uncompressed %u bytes", running_cnt);
147 running_cnt = 0;
148 }
149
150 /* add the bytes we read to the new messge */
151 io_buf_push (out_msg, uncompressed_size);
152
153 /* pop the old bytes we read off the incoming message */
154 io_buf_pop (io_buf, compressed_read);
155
156 return out_msg;
157 }
158
159 /*
160 * Parse the data into buffers, and send it to the upper layers. packets to
161 */
162 static void rx_inflate_recv (struct rx_layer *rx, struct io_buf *io_buf)
163 {
164 struct io_buf *msg;
165
166 while (rx->enabled && (msg = read_buf (rx, io_buf)))
167 {
168 assert (msg != NULL);
169 gt_rx_layer_recv (rx, msg);
170
171 /*
172 * NOTE: gt_rx_layer_recv() may abort the stack here... there's not much
173 * we can do about that, but in practice that doesn't happen and we
174 * won't access freed memory because the stack doesn't get freed until
175 * the lowest rx layer is notified of the abort...pretty hacky.
176 */
177 }
178
179 /* we have to free the buffer */
180 io_buf_free (io_buf);
181 }
182
183 /*****************************************************************************/
184
185 struct rx_layer_ops gt_rx_inflate_ops =
186 {
187 rx_inflate_init,
188 rx_inflate_destroy,
189 rx_inflate_enable,
190 rx_inflate_disable,
191 rx_inflate_recv,
192 };