summaryrefslogtreecommitdiff
path: root/lib/server/ProtocolUncertainStream.cpp
blob: 60c1fa1d07e6936241aa191ebe96563d785ee7d6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
// --------------------------------------------------------------------------
//
// File
//		Name:    ProtocolUncertainStream.h
//		Purpose: Read part of another stream
//		Created: 2003/12/05
//
// --------------------------------------------------------------------------

#include "Box.h"
#include "ProtocolUncertainStream.h"
#include "ServerException.h"
#include "Protocol.h"

#include "MemLeakFindOn.h"

// --------------------------------------------------------------------------
//
// Function
//		Name:    ProtocolUncertainStream::ProtocolUncertainStream(IOStream &, int)
//		Purpose: Constructor, taking another stream.
//		Created: 2003/12/05
//
// --------------------------------------------------------------------------
ProtocolUncertainStream::ProtocolUncertainStream(IOStream &rSource)
	: mrSource(rSource),
	  mBytesLeftInCurrentBlock(0),
	  mFinished(false)
{
}

// --------------------------------------------------------------------------
//
// Function
//		Name:    ProtocolUncertainStream::~ProtocolUncertainStream()
//		Purpose: Destructor. Won't absorb any unread bytes.
//		Created: 2003/12/05
//
// --------------------------------------------------------------------------
ProtocolUncertainStream::~ProtocolUncertainStream()
{
	if(!mFinished)
	{
		TRACE0("ProtocolUncertainStream::~ProtocolUncertainStream() destroyed when stream not complete\n");
	}
}

// --------------------------------------------------------------------------
//
// Function
//		Name:    ProtocolUncertainStream::Read(void *, int, int)
//		Purpose: As interface.
//		Created: 2003/12/05
//
// --------------------------------------------------------------------------
int ProtocolUncertainStream::Read(void *pBuffer, int NBytes, int Timeout)
{
	// Finished?
	if(mFinished)
	{
		return 0;
	}
	
	int read = 0;
	while(read < NBytes)
	{
		// Anything we can get from the current block?
		ASSERT(mBytesLeftInCurrentBlock >= 0);
		if(mBytesLeftInCurrentBlock > 0)
		{
			// Yes, let's use some of these up
			int toRead = (NBytes - read);
			if(toRead > mBytesLeftInCurrentBlock)
			{
				// Adjust downwards to only read stuff out of the current block
				toRead = mBytesLeftInCurrentBlock;
			}
			
			// Read it
			int r = mrSource.Read(((uint8_t*)pBuffer) + read, toRead, Timeout);
			// Give up now if it didn't return anything
			if(r == 0)
			{
				return read;
			}
			
			// Adjust counts of bytes by the bytes recieved
			read += r;
			mBytesLeftInCurrentBlock -= r;
			
			// stop now if the stream returned less than we asked for -- avoid blocking
			if(r != toRead)
			{
				return read;
			}
		}
		else
		{
			// Read the header byte to find out how much there is in the next block
			uint8_t header;
			if(mrSource.Read(&header, 1, Timeout) == 0)
			{
				// Didn't get the byte, return now
				return read;
			}
			
			// Interpret the byte...
			if(header == Protocol::ProtocolStreamHeader_EndOfStream)
			{
				// All done.
				mFinished = true;
				return read;
			}
			else if(header <= Protocol::ProtocolStreamHeader_MaxEncodedSizeValue)
			{
				// get size of the block from the Protocol's lovely list
				mBytesLeftInCurrentBlock = Protocol::sProtocolStreamHeaderLengths[header];
			}
			else if(header == Protocol::ProtocolStreamHeader_SizeIs64k)
			{
				// 64k
				mBytesLeftInCurrentBlock = (64*1024);
			}
			else
			{
				// Bad. It used the reserved values.
				THROW_EXCEPTION(ServerException, ProtocolUncertainStreamBadBlockHeader)	
			}
		}
	}

	// Return the number read
	return read;
}

// --------------------------------------------------------------------------
//
// Function
//		Name:    ProtocolUncertainStream::BytesLeftToRead()
//		Purpose: As interface.
//		Created: 2003/12/05
//
// --------------------------------------------------------------------------
IOStream::pos_type ProtocolUncertainStream::BytesLeftToRead()
{
	// Only know how much is left if everything is finished
	return mFinished?(0):(IOStream::SizeOfStreamUnknown);
}

// --------------------------------------------------------------------------
//
// Function
//		Name:    ProtocolUncertainStream::Write(const void *, int)
//		Purpose: As interface. But will exception.
//		Created: 2003/12/05
//
// --------------------------------------------------------------------------
void ProtocolUncertainStream::Write(const void *pBuffer, int NBytes)
{
	THROW_EXCEPTION(ServerException, CantWriteToProtocolUncertainStream)
}

// --------------------------------------------------------------------------
//
// Function
//		Name:    ProtocolUncertainStream::StreamDataLeft()
//		Purpose: As interface.
//		Created: 2003/12/05
//
// --------------------------------------------------------------------------
bool ProtocolUncertainStream::StreamDataLeft()
{
	return !mFinished;
}

// --------------------------------------------------------------------------
//
// Function
//		Name:    ProtocolUncertainStream::StreamClosed()
//		Purpose: As interface.
//		Created: 2003/12/05
//
// --------------------------------------------------------------------------
bool ProtocolUncertainStream::StreamClosed()
{
	// always closed
	return true;
}