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Extend internal API docs, part 2

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Picking up from #8111.

Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
This commit is contained in:
John Ericson 2023-03-26 21:12:25 -04:00
parent 8ae9d66940
commit abd5e7dec0
32 changed files with 640 additions and 359 deletions
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20
src/libutil/chunked-vector.hh
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@ -7,20 +7,24 @@
namespace nix {
/* Provides an indexable container like vector<> with memory overhead
guarantees like list<> by allocating storage in chunks of ChunkSize
elements instead of using a contiguous memory allocation like vector<>
does. Not using a single vector that is resized reduces memory overhead
on large data sets by on average (growth factor)/2, mostly
eliminates copies within the vector during resizing, and provides stable
references to its elements. */
/**
* Provides an indexable container like vector<> with memory overhead
* guarantees like list<> by allocating storage in chunks of ChunkSize
* elements instead of using a contiguous memory allocation like vector<>
* does. Not using a single vector that is resized reduces memory overhead
* on large data sets by on average (growth factor)/2, mostly
* eliminates copies within the vector during resizing, and provides stable
* references to its elements.
*/
template<typename T, size_t ChunkSize>
class ChunkedVector {
private:
uint32_t size_ = 0;
std::vector<std::vector<T>> chunks;
/* keep this out of the ::add hot path */
/**
* Keep this out of the ::add hot path
*/
[[gnu::noinline]]
auto & addChunk()
{