1/*
2 * libjingle
3 * Copyright 2004--2005, Google Inc.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 *  1. Redistributions of source code must retain the above copyright notice,
9 *     this list of conditions and the following disclaimer.
10 *  2. Redistributions in binary form must reproduce the above copyright notice,
11 *     this list of conditions and the following disclaimer in the documentation
12 *     and/or other materials provided with the distribution.
13 *  3. The name of the author may not be used to endorse or promote products
14 *     derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#include "talk/base/transformadapter.h"
29
30#include <cstring>
31
32#include "talk/base/common.h"
33
34namespace talk_base {
35
36///////////////////////////////////////////////////////////////////////////////
37
38TransformAdapter::TransformAdapter(StreamInterface * stream,
39                                   TransformInterface * transform,
40                                   bool direction_read)
41    : StreamAdapterInterface(stream), transform_(transform),
42      direction_read_(direction_read), state_(ST_PROCESSING), len_(0) {
43}
44
45TransformAdapter::~TransformAdapter() {
46  TransformAdapter::Close();
47  delete transform_;
48}
49
50StreamResult
51TransformAdapter::Read(void * buffer, size_t buffer_len,
52                       size_t * read, int * error) {
53  if (!direction_read_)
54    return SR_EOS;
55
56  while (state_ != ST_ERROR) {
57    if (state_ == ST_COMPLETE)
58      return SR_EOS;
59
60    // Buffer more data
61    if ((state_ == ST_PROCESSING) && (len_ < sizeof(buffer_))) {
62      size_t subread;
63      StreamResult result = StreamAdapterInterface::Read(
64                              buffer_ + len_,
65                              sizeof(buffer_) - len_,
66                              &subread,
67                              &error_);
68      if (result == SR_BLOCK) {
69        return SR_BLOCK;
70      } else if (result == SR_ERROR) {
71        state_ = ST_ERROR;
72        break;
73      } else if (result == SR_EOS) {
74        state_ = ST_FLUSHING;
75      } else {
76        len_ += subread;
77      }
78    }
79
80    // Process buffered data
81    size_t in_len = len_;
82    size_t out_len = buffer_len;
83    StreamResult result = transform_->Transform(buffer_, &in_len,
84                                                buffer, &out_len,
85                                                (state_ == ST_FLUSHING));
86    ASSERT(result != SR_BLOCK);
87    if (result == SR_EOS) {
88      // Note: Don't signal SR_EOS this iteration, unless out_len is zero
89      state_ = ST_COMPLETE;
90    } else if (result == SR_ERROR) {
91      state_ = ST_ERROR;
92      error_ = -1; // TODO: propagate error
93      break;
94    } else if ((out_len == 0) && (state_ == ST_FLUSHING)) {
95      // If there is no output AND no more input, then something is wrong
96      state_ = ST_ERROR;
97      error_ = -1; // TODO: better error code?
98      break;
99    }
100
101    len_ -= in_len;
102    if (len_ > 0)
103      memmove(buffer_, buffer_ + in_len, len_);
104
105    if (out_len == 0)
106      continue;
107
108    if (read)
109      *read = out_len;
110    return SR_SUCCESS;
111  }
112
113  if (error)
114    *error = error_;
115  return SR_ERROR;
116}
117
118StreamResult
119TransformAdapter::Write(const void * data, size_t data_len,
120                        size_t * written, int * error) {
121  if (direction_read_)
122    return SR_EOS;
123
124  size_t bytes_written = 0;
125  while (state_ != ST_ERROR) {
126    if (state_ == ST_COMPLETE)
127      return SR_EOS;
128
129    if (len_ < sizeof(buffer_)) {
130      // Process buffered data
131      size_t in_len = data_len;
132      size_t out_len = sizeof(buffer_) - len_;
133      StreamResult result = transform_->Transform(data, &in_len,
134                                                  buffer_ + len_, &out_len,
135                                                  (state_ == ST_FLUSHING));
136
137      ASSERT(result != SR_BLOCK);
138      if (result == SR_EOS) {
139        // Note: Don't signal SR_EOS this iteration, unless no data written
140        state_ = ST_COMPLETE;
141      } else if (result == SR_ERROR) {
142        ASSERT(false); // When this happens, think about what should be done
143        state_ = ST_ERROR;
144        error_ = -1; // TODO: propagate error
145        break;
146      }
147
148      len_ = out_len;
149      bytes_written = in_len;
150    }
151
152    size_t pos = 0;
153    while (pos < len_) {
154      size_t subwritten;
155      StreamResult result = StreamAdapterInterface::Write(buffer_ + pos,
156                                                          len_ - pos,
157                                                          &subwritten,
158                                                          &error_);
159      if (result == SR_BLOCK) {
160        ASSERT(false); // TODO: we should handle this
161        return SR_BLOCK;
162      } else if (result == SR_ERROR) {
163        state_ = ST_ERROR;
164        break;
165      } else if (result == SR_EOS) {
166        state_ = ST_COMPLETE;
167        break;
168      }
169
170      pos += subwritten;
171    }
172
173    len_ -= pos;
174    if (len_ > 0)
175      memmove(buffer_, buffer_ + pos, len_);
176
177    if (bytes_written == 0)
178      continue;
179
180    if (written)
181      *written = bytes_written;
182    return SR_SUCCESS;
183  }
184
185  if (error)
186    *error = error_;
187  return SR_ERROR;
188}
189
190void
191TransformAdapter::Close() {
192  if (!direction_read_ && (state_ == ST_PROCESSING)) {
193    state_ = ST_FLUSHING;
194    do {
195      Write(0, 0, NULL, NULL);
196    } while (state_ == ST_FLUSHING);
197  }
198  state_ = ST_COMPLETE;
199  StreamAdapterInterface::Close();
200}
201
202} // namespace talk_base
203