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      1 /*
      2  * libjingle
      3  * Copyright 2013, 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/app/webrtc/mediaconstraintsinterface.h"
     29 
     30 #include "talk/base/stringencode.h"
     31 
     32 namespace webrtc {
     33 
     34 const char MediaConstraintsInterface::kValueTrue[] = "true";
     35 const char MediaConstraintsInterface::kValueFalse[] = "false";
     36 
     37 // Set |value| to the value associated with the first appearance of |key|, or
     38 // return false if |key| is not found.
     39 bool MediaConstraintsInterface::Constraints::FindFirst(
     40     const std::string& key, std::string* value) const {
     41   for (Constraints::const_iterator iter = begin(); iter != end(); ++iter) {
     42     if (iter->key == key) {
     43       *value = iter->value;
     44       return true;
     45     }
     46   }
     47   return false;
     48 }
     49 
     50 // Find the highest-priority instance of the boolean-valued constraint) named by
     51 // |key| and return its value as |value|. |constraints| can be null.
     52 // If |mandatory_constraints| is non-null, it is incremented if the key appears
     53 // among the mandatory constraints.
     54 // Returns true if the key was found and has a valid boolean value.
     55 // If the key appears multiple times as an optional constraint, appearances
     56 // after the first are ignored.
     57 // Note: Because this uses FindFirst, repeated optional constraints whose
     58 // first instance has an unrecognized value are not handled precisely in
     59 // accordance with the specification.
     60 bool FindConstraint(const MediaConstraintsInterface* constraints,
     61                     const std::string& key, bool* value,
     62                     size_t* mandatory_constraints) {
     63   std::string string_value;
     64   if (!constraints) {
     65     return false;
     66   }
     67   if (constraints->GetMandatory().FindFirst(key, &string_value)) {
     68     if (mandatory_constraints)
     69       ++*mandatory_constraints;
     70     return talk_base::FromString(string_value, value);
     71   }
     72   if (constraints->GetOptional().FindFirst(key, &string_value)) {
     73     return talk_base::FromString(string_value, value);
     74   }
     75   return false;
     76 }
     77 
     78 }  // namespace webrtc
     79