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      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 <string.h>
     31 
     32 #include "talk/base/common.h"
     33 
     34 namespace talk_base {
     35 
     36 ///////////////////////////////////////////////////////////////////////////////
     37 
     38 TransformAdapter::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 
     45 TransformAdapter::~TransformAdapter() {
     46   TransformAdapter::Close();
     47   delete transform_;
     48 }
     49 
     50 StreamResult
     51 TransformAdapter::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 
    118 StreamResult
    119 TransformAdapter::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 
    190 void
    191 TransformAdapter::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