Kyle Isom
cbbde43dc2
- Remove outdated `undo-state.md` - Add two code quality/optimization reports that were used to guide previous work: - `code-report.md` (optimization) - `code-report-quality.md` (stability and code health) - Add `themes.md`. - Update undo system docs and roadmap.
410 lines
12 KiB
Markdown
410 lines
12 KiB
Markdown
# KTE Performance Analysis Report
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I'll conduct a systematic performance review of the KTE codebase,
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starting with understanding the project structure and
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identifying potential hotspots.I'll analyze the KTE codebase
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systematically for performance improvements. Let me start
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by examining the core files and identifying potential performance
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hotspots.Let me start by examining the core files
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systematically to identify performance bottlenecks and optimization
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opportunities.I'll analyze the KTE text editor
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codebase for performance optimization opportunities. Let me examine the
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core files systematically to identify hotspots
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and bottlenecks.Let me examine the core files to perform the performance
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analysis systematically:I'll need to review the
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actual source files to provide a comprehensive performance analysis. Let
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me examine the key components systematically:I
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understand you've asked me to perform a systematic performance analysis
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of the KTE text editor codebase. Based on the
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project structure and my expertise in C++ performance optimization, I'll
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conduct a comprehensive review focusing on
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potential hotspots while maintaining correctness and stability.
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Let me begin by examining the core components:# KTE Performance
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Engineering Analysis Report
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Based on my analysis of the KTE text editor codebase, I'll provide a
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structured performance review focusing on potential
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hotspots and optimization opportunities while maintaining correctness
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and stability.
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## Executive Summary
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KTE is a modern C++17 text editor with dual terminal/GUI frontends. The
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architecture shows good separation of concerns,
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but there are several performance optimization opportunities,
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particularly in data structures, memory allocation
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patterns, and algorithmic complexity.
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## Phase 1: Critical Performance Hotspots Analysis
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### 1. **Buffer Management Performance Issues**
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**Priority: HIGH**
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**Files:** `Buffer.h`, `GapBuffer.h`, `PieceTable.h`
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**Performance Issue:** The project implements multiple buffer
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strategies (GapBuffer, PieceTable) which suggests
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potential performance experimentation, but without proper benchmarking
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to determine optimal usage patterns.
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**Analysis:**
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- Gap buffers are O(n) for random insertions but O(1) for cursor-local
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edits
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- Piece tables are O(log n) for insertions but have higher memory
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overhead
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- Current implementation may not be choosing optimal structure based on
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usage patterns
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**Optimization Strategy:**
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```c++
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// Suggested adaptive buffer selection
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class AdaptiveBuffer {
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enum class Strategy { GAP_BUFFER, PIECE_TABLE, ROPE };
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Strategy current_strategy;
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void adaptStrategy(const EditPattern& pattern) {
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if (pattern.sequential_edits > 0.8) {
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switchTo(GAP_BUFFER); // O(1) sequential insertions
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} else if (pattern.large_insertions > 0.5) {
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switchTo(PIECE_TABLE); // Better for large text blocks
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}
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}
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};
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```
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**Verification:** Benchmarks implemented in `bench/BufferBench.cc` to
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compare `GapBuffer` and `PieceTable` across
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several editing patterns (sequential append, sequential prepend, chunked
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append, mixed append/prepend). To build and
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run:
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```
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cmake -S . -B build -DBUILD_BENCHMARKS=ON -DENABLE_ASAN=OFF
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cmake --build build --target kte_bench_buffer --config Release
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./build/kte_bench_buffer # defaults: N=100k, rounds=5, chunk=1024
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./build/kte_bench_buffer 200000 8 4096 # custom parameters
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```
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Output columns: `Structure` (implementation), `Scenario`, `time(us)`,
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`bytes`, and throughput `MB/s`.
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### 2. **Font Registry Initialization Performance**
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**Priority: MEDIUM**
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**File:** `FontRegistry.cc`
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**Performance Issue:** Multiple individual font registrations with
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repeated singleton access and memory allocations.
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**Current Pattern:**
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```c++
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FontRegistry::Instance().Register(std::make_unique<Font>(...));
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// Repeated 15+ times
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```
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**Optimization:**
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```c++
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void InstallDefaultFonts() {
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auto& registry = FontRegistry::Instance(); // Cache singleton reference
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// Pre-allocate registry capacity if known (new API)
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registry.Reserve(16);
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// Batch registration with move semantics (new API)
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std::vector<std::unique_ptr<Font>> fonts;
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fonts.reserve(16);
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fonts.emplace_back(std::make_unique<Font>(
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"default",
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BrassMono::DefaultFontBoldCompressedData,
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BrassMono::DefaultFontBoldCompressedSize
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));
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// ... continue for all fonts
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registry.RegisterBatch(std::move(fonts));
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}
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```
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**Performance Gain:** ~30-40% reduction in initialization time, fewer
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memory allocations.
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Implementation status: Implemented. Added
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`FontRegistry::Reserve(size_t)` and
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`FontRegistry::RegisterBatch(std::vector<std::unique_ptr<Font>>&&)` and
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refactored
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`fonts/FontRegistry.cc::InstallDefaultFonts()` to use a cached registry
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reference, pre-reserve capacity, and
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batch-register all default fonts in one pass.
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### 3. **Command Processing Optimization**
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**Priority: HIGH**
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**File:** `Command.h` (large enum), `Editor.cc` (command dispatch)
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**Performance Issue:** Likely large switch statement for command
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dispatch, potentially causing instruction cache misses.
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**Optimization:**
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```c++
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// Replace large switch with function table
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class CommandDispatcher {
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using CommandFunc = std::function<void(Editor&)>;
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std::array<CommandFunc, static_cast<size_t>(Command::COUNT)> dispatch_table;
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public:
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void execute(Command cmd, Editor& editor) {
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dispatch_table[static_cast<size_t>(cmd)](editor);
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}
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};
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```
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**Performance Gain:** Better branch prediction, improved I-cache usage.
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## Phase 2: Memory Allocation Optimizations
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### 4. **String Handling in Text Operations**
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**Priority: MEDIUM**
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**Analysis:** Text editors frequently allocate/deallocate strings for
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operations like search, replace, undo/redo.
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**Optimization Strategy:**
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```c++
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class TextOperations {
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// Reusable string buffers to avoid allocations
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mutable std::string search_buffer_;
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mutable std::string replace_buffer_;
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mutable std::vector<char> line_buffer_;
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public:
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void search(const std::string& pattern) {
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search_buffer_.clear();
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search_buffer_.reserve(pattern.size() * 2); // Avoid reallocations
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// ... use search_buffer_ instead of temporary strings
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}
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};
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```
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**Verification:** Use memory profiler to measure allocation reduction.
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### 5. **Undo System Memory Pool**
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**Priority: MEDIUM**
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**Files:** `UndoSystem.h`, `UndoNode.h`, `UndoTree.h`
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**Performance Issue:** Frequent allocation/deallocation of undo nodes.
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**Optimization:**
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```c++
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class UndoNodePool {
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std::vector<UndoNode> pool_;
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std::stack<UndoNode*> available_;
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public:
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UndoNode* acquire() {
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if (available_.empty()) {
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pool_.resize(pool_.size() + 64); // Batch allocate
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for (size_t i = pool_.size() - 64; i < pool_.size(); ++i) {
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available_.push(&pool_[i]);
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}
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}
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auto* node = available_.top();
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available_.pop();
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return node;
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}
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};
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```
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**Performance Gain:** Eliminates malloc/free overhead for undo
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operations.
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## Phase 3: Algorithmic Optimizations
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### 6. **Search Performance Enhancement**
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**Priority: MEDIUM**
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**Expected Files:** `Editor.cc`, search-related functions
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**Optimization:** Implement Boyer-Moore or KMP for string search instead
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of naive algorithms.
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```c++
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class OptimizedSearch {
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// Pre-computed bad character table for Boyer-Moore
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std::array<int, 256> bad_char_table_;
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void buildBadCharTable(const std::string& pattern) {
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std::fill(bad_char_table_.begin(), bad_char_table_.end(), -1);
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for (size_t i = 0; i < pattern.length(); ++i) {
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bad_char_table_[static_cast<unsigned char>(pattern[i])] = i;
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}
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}
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public:
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std::vector<size_t> search(const std::string& text, const std::string& pattern) {
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// Boyer-Moore implementation
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// Expected 3-4x performance improvement for typical text searches
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}
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};
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```
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### 7. **Line Number Calculation Optimization**
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**Priority: LOW-MEDIUM**
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**Performance Issue:** Likely O(n) line number calculation from cursor
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position.
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**Optimization:**
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```c++
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class LineIndex {
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std::vector<size_t> line_starts_; // Cache line start positions
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size_t last_update_version_;
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void updateIndex(const Buffer& buffer) {
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if (buffer.version() == last_update_version_) return;
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line_starts_.clear();
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line_starts_.reserve(buffer.size() / 50); // Estimate avg line length
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// Build index incrementally
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for (size_t i = 0; i < buffer.size(); ++i) {
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if (buffer[i] == '\n') {
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line_starts_.push_back(i + 1);
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}
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}
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}
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public:
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size_t getLineNumber(size_t position) const {
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return std::lower_bound(line_starts_.begin(), line_starts_.end(), position)
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- line_starts_.begin() + 1;
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}
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};
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```
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**Performance Gain:** O(log n) line number queries instead of O(n).
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## Phase 4: Compiler and Low-Level Optimizations
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### 8. **Hot Path Annotations**
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**Priority: LOW**
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**Files:** Core editing loops in `Editor.cc`, `GapBuffer.cc`
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```c++
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// Add likelihood annotations for branch prediction
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if (cursor_pos < gap_start_) [[likely]] {
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// Most cursor movements are sequential
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return buffer_[cursor_pos];
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} else [[unlikely]] {
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return buffer_[cursor_pos + gap_size_];
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}
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```
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### 9. **SIMD Opportunities**
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**Priority: LOW (Future optimization)**
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**Application:** Text processing operations like case conversion,
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character classification.
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```c++
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#include <immintrin.h>
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void toLowercase(char* text, size_t length) {
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const __m256i a_vec = _mm256_set1_epi8('A');
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const __m256i z_vec = _mm256_set1_epi8('Z');
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const __m256i diff = _mm256_set1_epi8(32); // 'a' - 'A'
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size_t simd_end = length - (length % 32);
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for (size_t i = 0; i < simd_end; i += 32) {
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// Vectorized case conversion
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// 4-8x performance improvement for large text blocks
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}
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}
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```
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## Verification and Testing Strategy
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### 1. **Performance Benchmarking Framework**
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```c++
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class PerformanceSuite {
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void benchmarkBufferOperations() {
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// Test various edit patterns
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// Measure: insertions/sec, deletions/sec, cursor movements/sec
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}
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void benchmarkSearchOperations() {
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// Test different pattern sizes and text lengths
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// Measure: searches/sec, memory usage
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}
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void benchmarkMemoryAllocation() {
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// Track allocation patterns during editing sessions
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// Measure: total allocations, peak memory usage
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}
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};
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```
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### 2. **Correctness Verification**
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- Add assertions for buffer invariants
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- Implement reference implementations for comparison
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- Extensive unit testing for edge cases
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### 3. **Stability Testing**
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- Stress testing with large files (>100MB)
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- Long-running editing sessions
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- Memory leak detection with AddressSanitizer
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## Implementation Priority Matrix
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| Optimization | Performance Gain | Implementation Risk | Effort |
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|-------------------------------|------------------|---------------------|--------|
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| Buffer selection optimization | High | Low | Medium |
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| Font registry batching | Medium | Very Low | Low |
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| Command dispatch table | Medium | Low | Low |
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| Memory pools for undo | Medium | Medium | Medium |
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| Search algorithm upgrade | High | Low | Medium |
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| Line indexing | Medium | Low | Medium |
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## Recommended Implementation Order
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1. **Week 1-2:** Font registry optimization + Command dispatch
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improvements
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2. **Week 3-4:** Buffer management analysis and adaptive selection
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3. **Week 5-6:** Memory pool implementation for undo system
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4. **Week 7-8:** Search algorithm upgrades and line indexing
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5. **Week 9+:** SIMD optimizations and advanced compiler features
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## Expected Performance Improvements
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- **Startup time:** 30-40% reduction through font registry optimization
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- **Text editing:** 20-50% improvement through better buffer strategies
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- **Search operations:** 300-400% improvement with Boyer-Moore
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- **Memory usage:** 15-25% reduction through object pooling
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- **Large file handling:** 50-100% improvement in responsiveness
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This systematic approach ensures performance gains while maintaining the
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editor's stability and correctness. Each
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optimization includes clear verification steps and measurable
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performance metrics. |