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
|
#include "Lwo2Chunk.h"
#include "stream/utils.h"
namespace model
{
Lwo2Chunk::Lwo2Chunk(const std::string& identifier_, Type type) :
_chunkType(type),
identifier(identifier_),
stream(std::ios_base::in | std::ios_base::out | std::ios_base::binary)
{
// FORM sub-chunks are normal chunks and have 4 bytes size info
// whereas subchunks of e.g. CLIP use 2 bytes of size info
_sizeDescriptorByteCount = _chunkType == Type::Chunk ? 4 : 2;
}
unsigned int Lwo2Chunk::getContentSize() const
{
unsigned int totalSize = 0;
// Start with the size of the contents
// (don't use seek as we don't know if the client still wants to write stuff)
totalSize += static_cast<unsigned int>(stream.str().length());
if (!subChunks.empty())
{
// Sum up the size of the subchunks
for (const Lwo2Chunk::Ptr& chunk : subChunks)
{
totalSize += 4; // ID (4 bytes)
totalSize += chunk->_sizeDescriptorByteCount; // Subchunk Size Info (can be 4 or 2 bytes)
// While the child chunk size itself doesn't include padding, we need to respect
// it when calculating the size of this parent chunk
unsigned int childChunkSize = chunk->getContentSize();
totalSize += childChunkSize + (childChunkSize % 2); // add 1 padding byte if odd
}
}
// Chunk size can be odd, padding must be handled by client code
return totalSize;
}
Lwo2Chunk::Ptr Lwo2Chunk::addChunk(const std::string& identifier_, Type type)
{
subChunks.push_back(std::make_shared<Lwo2Chunk>(identifier_, type));
return subChunks.back();
}
Lwo2Chunk::Ptr Lwo2Chunk::addChunk(const std::string& identifier_)
{
return addChunk(identifier_, Type::Chunk);
}
// Adds a Chunk (size type U2) to this one
Lwo2Chunk::Ptr Lwo2Chunk::addSubChunk(const std::string& identifier_)
{
return addChunk(identifier_, Type::SubChunk);
}
void Lwo2Chunk::flushBuffer()
{
stream.flush();
for (const Lwo2Chunk::Ptr& chunk : subChunks)
{
chunk->flushBuffer();
}
}
void Lwo2Chunk::writeToStream(std::ostream& output)
{
// Flush all buffers before writing to the output stream
flushBuffer();
output.write(identifier.c_str(), identifier.length());
if (_chunkType == Type::Chunk)
{
stream::writeBigEndian<uint32_t>(output, getContentSize());
}
else
{
stream::writeBigEndian<uint16_t>(output, static_cast<uint16_t>(getContentSize()));
}
// Write the direct contents of this chunk
std::string str = stream.str();
output.write(str.c_str(), str.length());
// Write all subchunks
for (const Lwo2Chunk::Ptr& chunk : subChunks)
{
chunk->writeToStream(output);
// Add the padding byte after the chunk
if (chunk->getContentSize() % 2 == 1)
{
output.write("\0", 1);
}
}
}
}
|
