DarkflameServer/dCommon/AMFDeserialize.cpp

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#include "AMFDeserialize.h"
#include "AMFFormat.h"
/**
* AMF3 Reference document https://rtmp.veriskope.com/pdf/amf3-file-format-spec.pdf
* AMF3 Deserializer written by EmosewaMC
*/
AMFValue* AMFDeserialize::Read(RakNet::BitStream* inStream) {
if (!inStream) return nullptr;
AMFValue* returnValue = nullptr;
// Read in the value type from the bitStream
int8_t marker;
inStream->Read(marker);
// Based on the typing, create the value associated with that and return the base value class
switch (marker) {
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case AMFValueType::AMFUndefined: {
returnValue = new AMFUndefinedValue();
break;
}
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case AMFValueType::AMFNull: {
returnValue = new AMFNullValue();
break;
}
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case AMFValueType::AMFFalse: {
returnValue = new AMFFalseValue();
break;
}
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case AMFValueType::AMFTrue: {
returnValue = new AMFTrueValue();
break;
}
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case AMFValueType::AMFInteger: {
returnValue = ReadAmfInteger(inStream);
break;
}
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case AMFValueType::AMFDouble: {
returnValue = ReadAmfDouble(inStream);
break;
}
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case AMFValueType::AMFString: {
returnValue = ReadAmfString(inStream);
break;
}
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case AMFValueType::AMFArray: {
returnValue = ReadAmfArray(inStream);
break;
}
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// TODO We do not need these values, but if someone wants to implement them
// then please do so and add the corresponding unit tests.
case AMFValueType::AMFXMLDoc:
case AMFValueType::AMFDate:
case AMFValueType::AMFObject:
case AMFValueType::AMFXML:
case AMFValueType::AMFByteArray:
case AMFValueType::AMFVectorInt:
case AMFValueType::AMFVectorUInt:
case AMFValueType::AMFVectorDouble:
case AMFValueType::AMFVectorObject:
case AMFValueType::AMFDictionary: {
throw static_cast<AMFValueType>(marker);
break;
}
default:
throw static_cast<AMFValueType>(marker);
break;
}
return returnValue;
}
uint32_t AMFDeserialize::ReadU29(RakNet::BitStream* inStream) {
bool byteFlag = true;
uint32_t actualNumber{};
uint8_t numberOfBytesRead{};
while (byteFlag && numberOfBytesRead < 4) {
uint8_t byte{};
inStream->Read(byte);
// Parse the byte
if (numberOfBytesRead < 3) {
byteFlag = byte & static_cast<uint8_t>(1 << 7);
byte = byte << 1UL;
}
// Combine the read byte with our current read in number
actualNumber <<= 8UL;
actualNumber |= static_cast<uint32_t>(byte);
// If we are not done reading in bytes, shift right 1 bit
if (numberOfBytesRead < 3) actualNumber = actualNumber >> 1UL;
numberOfBytesRead++;
}
return actualNumber;
}
std::string AMFDeserialize::ReadString(RakNet::BitStream* inStream) {
auto length = ReadU29(inStream);
// Check if this is a reference
bool isReference = length % 2 == 1;
// Right shift by 1 bit to get index if reference or size of next string if value
length = length >> 1;
if (isReference) {
std::string value(length, 0);
inStream->Read(&value[0], length);
// Empty strings are never sent by reference
if (!value.empty()) accessedElements.push_back(value);
return value;
} else {
// Length is a reference to a previous index - use that as the read in value
return accessedElements[length];
}
}
AMFValue* AMFDeserialize::ReadAmfDouble(RakNet::BitStream* inStream) {
auto doubleValue = new AMFDoubleValue();
double value;
inStream->Read<double>(value);
doubleValue->SetDoubleValue(value);
return doubleValue;
}
AMFValue* AMFDeserialize::ReadAmfArray(RakNet::BitStream* inStream) {
auto arrayValue = new AMFArrayValue();
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// Read size of dense array
auto sizeOfDenseArray = (ReadU29(inStream) >> 1);
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// Then read Key'd portion
while (true) {
auto key = ReadString(inStream);
// No more values when we encounter an empty string
if (key.size() == 0) break;
arrayValue->InsertValue(key, Read(inStream));
}
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// Finally read dense portion
for (uint32_t i = 0; i < sizeOfDenseArray; i++) {
arrayValue->PushBackValue(Read(inStream));
}
return arrayValue;
}
AMFValue* AMFDeserialize::ReadAmfString(RakNet::BitStream* inStream) {
auto stringValue = new AMFStringValue();
stringValue->SetStringValue(ReadString(inStream));
return stringValue;
}
AMFValue* AMFDeserialize::ReadAmfInteger(RakNet::BitStream* inStream) {
auto integerValue = new AMFIntegerValue();
integerValue->SetIntegerValue(ReadU29(inStream));
return integerValue;
}