Add inline, remove unused exception variable name, safe float computation

[mnorris11]

This is a patch to get it to work internally. It would be easier if things are in SVS, so next version upgrade we don't need to apply this patch.

Reason for changes:

1. inlining: This is from -Werror,-Winline-namespace-reopened-noninline.
2. Unused exception parameter: -Werror,-Wunused-exception-parameter.
3. Float change: acccording to AI: the shift 125 - e goes out of range for uint32_t when e is outside [102, 112]. The result is multiplied by zero so it's "dead" at runtime, but the shift itself is still UB. UBSAN catches it and 5 FP16 tests fail: WriteAndReadIndexSVSFP16, VamanaFP16TrainSaveLoadAndAdd, WriteAndReadStaticIVFFP16, WriteAndReadIndexSVSIVFFP16, IVFFP16TrainAndAdd.
4. index.h Thread clamping: per AI: "compute_centroid_distances (in common.h:675) partitions centroids across threads using StaticPartition(num_centroids). If you have more threads than centroids, some threads get an empty partition. The callback then calls batch.start() and batch.size() on those empty ranges, leading to OOB access into centroids.get_datum() and matmul_results[tid]. The fix clamps the thread pool size to at most the number of centroids at construction time, so every thread gets at least one centroid to work on."
5. sorted_buffer.h change: " back() returns candidates_[size_ - 1]. When the buffer is empty (size_ == 0), that underflows to candidates_[SIZE_MAX] — an OOB read. The original code evaluated back() before checking full(), so on an empty buffer it would access garbage memory before full() returned false and short-circuited the &&. Swapping the operands ensures full() is checked first; if the buffer isn't full, back() is never called. Classic short-circuit evaluation fix."

[rfsaliev]

Thank you @mnorris11 , for the contribution.
There are some suggestions, proposals and comments

[rfsaliev]

Suggested change

	} catch (const ThreadCrashedError&) {
	} catch (const ThreadCrashedError& SVS_UNUSED(err)) {

[rfsaliev]

Please, use SVS formatting rules.

[rfsaliev]

IMHO, this change will negatively affect usability and maintainability for further API major versions.
Instead, a macro can be used here which value defined in version.h depending on SVS_RUNTIME_API_VERSION, e.g.:

#if (SVS_RUNTIME_API_VERSION == 0)
...
#define SVS_API_V0 inline namespace v0
...
#endif

With usage aka:

Suggested change

	namespace svs {
	namespace runtime {
	namespace v0 {
	inline namespace v0 {
	namespace svs {
	namespace runtime {
	SVS_API_V0 {
	...
	} // SVS_API_V0

[rfsaliev]

Thank you @mnorris11 for the PR.
Unfortunately, more complicated changes had to be applied for proper fixes.
There are created 3 separate PRs based on your proposal:

• [CPPRuntime] Fix C++ Runtime Clang compilation errors #328
• Refactor thread pool creation to validate thread count against centroids #329
• Refactor float_to_float16_untyped_slow for clarity and optimization #330

[mnorris11]

Thank you @mnorris11 for the PR. Unfortunately, more complicated changes had to be applied for proper fixes. There are created 3 separate PRs based on your proposal:

• [CPPRuntime] Fix C++ Runtime Clang compilation errors #328
• Refactor thread pool creation to validate thread count against centroids #329
• Refactor float_to_float16_untyped_slow for clarity and optimization #330

gotcha, let me know if I should do anything on this PR!

[ethanglaser]

@mnorris11 are you using clang compiler internally? Or can you provide some more details about what circumstances led to these failures? We can try to align our CI with these cases to avoid issues moving forward.