refactor: Refactor CompileParseRules.cc for type safety, modern C++, and documentation

[grahamsedman]

📌 Summary

This PR refactors src/tscore/CompileParseRules.cc to address compilation errors, type safety issues, modern C++ best practices, and documentation gaps. The changes ensure compatibility across 32-bit and 64-bit targets, fix narrowing conversion warnings, and improve code clarity and maintainability.

---

✅ Problems Addressed

Problem	Root Cause	Solution
Narrowing conversion errors	char is signed on x86, causing negative values (e.g., -128) for ASCII >127, which cannot be narrowed to unsigned char on 32-bit targets.	Use uint8_t for character arrays and explicitly cast to unsigned when writing to files.
Unused header	#include "tscore/ink_string.h" is included but never used.	Removed the unused header.
Poor header organization	Headers were split into two sections, reducing readability.	Consolidated all headers at the top of the file.
Missing documentation	No Doxygen comments for the file, functions, or variables.	Added comprehensive Doxygen documentation.
Non-thread-safe uint_to_binary	The function used a static char buf[33], making it unsafe for concurrent use.	Refactored to return std::string (RAII-managed, thread-safe).
C-style I/O	Used FILE* and fprintf, which are less type-safe and require manual resource management.	Replaced with std::ofstream (RAII-based, type-safe).
Poor Doxygen practice	@section license causes warnings due to duplicate labels across files.	Removed @section and kept the license text directly in the file header.
Unused macro	#define COMPILE_PARSE_RULES is defined but never used.	Removed the macro.
Outdated data types	Used unsigned int and char instead of fixed-width types (uint8_t, uint32_t).	Replaced with <cstdint> types for portability and clarity.

---

🔧 Key Changes

1. File Header & Includes

• Removed: #define COMPILE_PARSE_RULES, #include "tscore/ink_string.h".
• Added: <cstdint>, <fstream>, <iomanip>, <string>.
• Refactored: Consolidated all includes at the top of the file.
• Documentation: Added a detailed Doxygen file header explaining the purpose, generated files, and modern C++ features used.

2. Data Types

• Bitmask arrays: Changed from unsigned int to uint32_t for explicit size and future-proofing.
• Character arrays: Changed from char to uint8_t to guarantee an unsigned range (0-255) and avoid sign-extension issues.
• Loop variables: Changed from int to uint16_t or uint8_t for semantic clarity.

3. uint_to_binary Function

• Before: Used a static char buf[33] (non-thread-safe).
• After: Returns std::string (thread-safe, RAII-managed).
• Parameter: Changed from unsigned int to uint32_t for explicit size.

4. File I/O

• Before: Used FILE* and fprintf (C-style, manual resource management).
• After: Uses std::ofstream (RAII-based, type-safe, modern C++).
• Format specifiers: Replaced %d with static_cast<unsigned> to avoid sign-extension issues when printing uint8_t values.

5. Doxygen Documentation

• Added detailed comments for:
  • File purpose and generated outputs.
  • Each global array (parseRulesCType, tparseRulesCType, etc.).
  • The uint_to_binary function.
  • The main function (including its steps and classification functions).

---

🧪 Testing

• Compilation: Verified on x86 (signed char) and ARM (unsigned char) targets.
• Output: Confirmed that generated files (ParseRulesCType, ParseRulesCTypeToUpper, ParseRulesCTypeToLower) contain correct values (no negative numbers for ASCII >127).
• Thread Safety: The refactored uint_to_binary is now thread-safe.