tinyusdz/doc/FACTORY_FUNCTIONS_COMPLETE.md

TypedArray Factory Functions - Complete Implementation

✅ Status: COMPLETE

Successfully implemented and tested TypedArray factory functions for clearer, more intuitive array creation.

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📦 Deliverables

1. Implementation (src/typed-array.hh)

Location: src/typed-array.hh, lines 2376-2614 (239 lines)

15 Factory Functions Added:

Smart Pointer Wrappers (4)

• MakeOwnedTypedArray<T>(ptr) - Owned, will delete
• MakeDedupTypedArray<T>(ptr) - Deduplicated, won't delete
• MakeSharedTypedArray<T>(ptr) - Shared, won't delete
• MakeMmapTypedArray<T>(ptr) - Memory-mapped, won't delete

Array Implementation (4)

• MakeTypedArrayCopy<T>(data, count) - Copy data
• MakeTypedArrayView<T>(data, count) - Non-owning view
• MakeTypedArrayMmap<T>(data, count) - Mmap view
• MakeTypedArrayReserved<T>(capacity) - Empty with capacity

Convenience Functions (7)

• CreateOwnedTypedArray<T>(...) - 3 overloads
• CreateDedupTypedArray<T>(ptr) - Wrap as dedup
• CreateMmapTypedArray<T>(data, count) - Create mmap
• DuplicateTypedArray<T>(source) - Deep copy TypedArray
• DuplicateTypedArrayImpl<T>(source) - Deep copy TypedArrayImpl

2. Test Suite (tests/feat/typed-array-factories/)

Files:

• test-typed-array-factories.cc (11KB, 422 lines)
• Makefile (standalone build)
• README.md (comprehensive documentation)

Test Results:

✓ All 16 tests passed!
- MakeOwnedTypedArray
- MakeDedupTypedArray
- MakeSharedTypedArray
- MakeMmapTypedArray
- MakeTypedArrayCopy
- MakeTypedArrayView
- MakeTypedArrayMmap
- MakeTypedArrayReserved
- CreateOwnedTypedArray (3 variants)
- CreateDedupTypedArray
- CreateMmapTypedArray
- DuplicateTypedArray
- DuplicateTypedArrayImpl
- Deduplication pattern

3. Documentation (doc/)

Complete Documentation Suite:

1. FACTORY_FUNCTIONS_INTEGRATION.md - Integration summary
2. FACTORY_FUNCTIONS_COMPLETE.md - This file (overview)
3. TYPED_ARRAY_FACTORY_PROPOSAL.md - Original proposal (6.4K)
4. TYPED_ARRAY_MIGRATION_EXAMPLES.md - Before/after examples (8.4K)
5. TYPED_ARRAY_ARCHITECTURE.md - Architecture deep dive (15K)
6. TYPED_ARRAY_API_SUMMARY.md - Quick reference (5.5K)
7. TYPED_ARRAY_DOCS_INDEX.md - Master index
8. typed-array-factories.hh - Reference implementation (8.2K)

Total Documentation: ~43.5K of comprehensive documentation

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🎯 Problem Solved

Before (Confusing)

TypedArray<T>(ptr, true);   // ❌ What does 'true' mean?
TypedArray<T>(ptr, false);  // ❌ What does 'false' mean?
TypedArrayImpl<T>(data, size, true);  // ❌ Copy or view?

After (Clear)

MakeDedupTypedArray(ptr);           // ✅ Clear: deduplicated
MakeOwnedTypedArray(ptr);           // ✅ Clear: owned
MakeTypedArrayView(data, size);     // ✅ Clear: view
MakeTypedArrayCopy(data, size);     // ✅ Clear: copy

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📊 Statistics

Metric	Value
Functions Added	15
Lines of Code	239 (with docs)
Test Cases	16
Test Pass Rate	100%
Breaking Changes	0
Performance Impact	0 (all inline)
Documentation	~43.5K
Compilation Time	No measurable impact

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✨ Key Features

✅ Self-Documenting - Function names clearly indicate intent ✅ Type-Safe - No confusing boolean flags ✅ Zero Overhead - All inline, same performance as direct constructors ✅ Backward Compatible - Existing code continues to work ✅ Easy Migration - Can adopt gradually ✅ Comprehensive Tests - 16 tests covering all use cases ✅ Full Documentation - Complete guide with examples

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🚀 Common Usage Patterns

1. Deduplication Cache (Most Common)

auto it = _dedup_float_array.find(value_rep);
if (it != _dedup_float_array.end()) {
    // Found - return shared reference
    return MakeDedupTypedArray(it->second.get());
} else {
    // Not found - create, cache, and return
    auto* impl = new TypedArrayImpl<float>(data, size);
    _dedup_float_array[value_rep] = MakeOwnedTypedArray(impl);
    return MakeDedupTypedArray(impl);
}

2. Memory-Mapped Files

float* mmap_data = static_cast<float*>(mmap_ptr);
TypedArray<float> arr = CreateMmapTypedArray(mmap_data, count);
// arr doesn't own mmap_data, just references it

3. Temporary Views

float buffer[1000];
PopulateBuffer(buffer);
auto view = MakeTypedArrayView(buffer, 1000);
ProcessData(view);
// buffer still valid after view destruction

4. Creating Owned Arrays

float data[] = {1.0f, 2.0f, 3.0f};
TypedArray<float> arr = CreateOwnedTypedArray(data, 3);
// arr owns a copy of the data

5. Deep Copying

TypedArray<double> original = GetSharedArray();
TypedArray<double> copy = DuplicateTypedArray(original);
// Modify copy independently

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🔍 Test Coverage

The test suite (tests/feat/typed-array-factories/) verifies:

1. Ownership Semantics

   • Owned arrays delete on destruction ✓
   • Dedup arrays don't delete on destruction ✓
   • Dedup flag is set correctly ✓

2. Data Integrity

   • Data is copied correctly ✓
   • Views reference original data ✓
   • Modifications affect/don't affect original as expected ✓

3. View Behavior

   • View mode is set correctly ✓
   • Views don't own memory ✓
   • Modifications through views work ✓

4. Convenience Functions

   • Combined operations work correctly ✓
   • Duplication creates independent copies ✓

5. Real-World Patterns

   • Deduplication cache pattern ✓
   • Memory-mapped file pattern ✓
   • Temporary view pattern ✓

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📝 Next Steps (Optional)

While the factory functions are complete and ready to use, here are optional next steps for full migration:

Phase 1: Core Deduplication (High Priority)

Update src/crate-reader.cc:

// Replace: TypedArray<T>(impl, true)
// With:    MakeDedupTypedArray(impl)

Phase 2: TimeSamples (Medium Priority)

Update src/timesamples.hh:

// Replace: TypedArray<T>(ptr, true)
// With:    MakeDedupTypedArray(ptr)

Phase 3: Other Uses (Low Priority)

Gradually migrate other uses throughout the codebase

Phase 4: Documentation (Low Priority)

Update coding guidelines to recommend factory functions

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🎓 Quick Reference

Use Case	Function	Example
Owned array	MakeOwnedTypedArray()	MakeOwnedTypedArray(impl)
Dedup cache	MakeDedupTypedArray()	MakeDedupTypedArray(cached_impl)
Shared array	MakeSharedTypedArray()	MakeSharedTypedArray(shared_impl)
Mmap array	MakeMmapTypedArray()	CreateMmapTypedArray(mmap_ptr, size)
Copy data	MakeTypedArrayCopy()	MakeTypedArrayCopy(data, size)
View data	MakeTypedArrayView()	MakeTypedArrayView(buffer, size)
Create owned	CreateOwnedTypedArray()	CreateOwnedTypedArray(data, size)
Deep copy	DuplicateTypedArray()	DuplicateTypedArray(source)

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📚 Documentation Index

All documentation is in doc/:

• Quick Start: TYPED_ARRAY_API_SUMMARY.md
• Examples: TYPED_ARRAY_MIGRATION_EXAMPLES.md
• Architecture: TYPED_ARRAY_ARCHITECTURE.md
• Proposal: TYPED_ARRAY_FACTORY_PROPOSAL.md
• Integration: FACTORY_FUNCTIONS_INTEGRATION.md
• Overview: FACTORY_FUNCTIONS_COMPLETE.md (this file)
• Index: TYPED_ARRAY_DOCS_INDEX.md

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✅ Verification

Compilation

• ✅ Compiles with g++-13, C++14
• ✅ Zero errors, zero warnings
• ✅ Inline - no runtime overhead

Testing

• ✅ 16 comprehensive tests
• ✅ 100% pass rate
• ✅ Standalone test suite with Makefile

Documentation

• ✅ ~43.5K of comprehensive documentation
• ✅ Usage examples for every function
• ✅ Before/after migration examples
• ✅ Architecture diagrams and explanations

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🎉 Summary

The TypedArray factory functions are production-ready and provide a much cleaner, safer, and more maintainable API for creating TypedArray instances. The implementation:

• ✅ Is fully tested (16/16 tests passing)
• ✅ Has comprehensive documentation
• ✅ Is backward compatible
• ✅ Has zero performance overhead
• ✅ Is ready for immediate use

No breaking changes - existing code continues to work, and new code can use the factory functions for improved clarity and safety.

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Date: 2025-01-09 Status: ✅ COMPLETE Location: src/typed-array.hh (lines 2376-2614) Tests: tests/feat/typed-array-factories/ (16/16 passing) Documentation: doc/TYPED_ARRAY_*.md (~43.5K)