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core(persistence): fix reserveNodeSpace() implementation

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- avoid data copying after buffer block shrink
- resize current block in case of single FileNode
This commit is contained in:
Alexander Alekhin 2019-09-25 14:01:44 +03:00
parent 2fef9bc1d8
commit 6e246ee58c
1 changed files with 24 additions and 2 deletions
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26
modules/core/src/persistence.cpp
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@ -1307,6 +1307,9 @@ public:
// In the case (b) the existing tag and the name are copied automatically.
uchar* reserveNodeSpace(FileNode& node, size_t sz)
{
bool shrinkBlock = false;
size_t shrinkBlockIdx = 0, shrinkSize = 0;
uchar *ptr = 0, *blockEnd = 0;
if( !fs_data_ptrs.empty() )
@ -1315,19 +1318,32 @@ public:
size_t ofs = node.ofs;
CV_Assert( blockIdx == fs_data_ptrs.size()-1 );
CV_Assert( ofs <= fs_data_blksz[blockIdx] );
CV_Assert( freeSpaceOfs <= fs_data_blksz[blockIdx] );
//CV_Assert( freeSpaceOfs <= ofs + sz );
ptr = fs_data_ptrs[blockIdx] + ofs;
blockEnd = fs_data_ptrs[blockIdx] + fs_data_blksz[blockIdx];
CV_Assert(ptr >= fs_data_ptrs[blockIdx] && ptr <= blockEnd);
if( ptr + sz <= blockEnd )
{
freeSpaceOfs = ofs + sz;
return ptr;
}
fs_data[blockIdx]->resize(ofs);
fs_data_blksz[blockIdx] = ofs;
if (ofs == 0) // FileNode is a first component of this block. Resize current block instead of allocation of new one.
{
fs_data[blockIdx]->resize(sz);
ptr = &fs_data[blockIdx]->at(0);
fs_data_ptrs[blockIdx] = ptr;
fs_data_blksz[blockIdx] = sz;
freeSpaceOfs = sz;
return ptr;
}
shrinkBlock = true;
shrinkBlockIdx = blockIdx;
shrinkSize = ofs;
}
size_t blockSize = std::max((size_t)CV_FS_MAX_LEN*4 - 256, sz) + 256;
@ -1352,6 +1368,12 @@ public:
}
}
if (shrinkBlock)
{
fs_data[shrinkBlockIdx]->resize(shrinkSize);
fs_data_blksz[shrinkBlockIdx] = shrinkSize;
}
return new_ptr;
}