c848a60696
Centralize BASE ↔ USER pointer conversions into reusable, zero-cost macros. Previously, pointer arithmetic (base + 1, ptr - 1) was scattered across allocation/deallocation code with hardcoded offsets. Changes: - NEW: core/box/tiny_ptr_convert_box.h - tiny_base_to_user_inline(): BASE → USER (base + TINY_HEADER_OFFSET) - tiny_user_to_base_inline(): USER → BASE (user - TINY_HEADER_OFFSET) - TINY_HEADER_OFFSET: Centralized constant (currently 1) - Function variants: tiny_base_to_user(), tiny_user_to_base() - Modified: core/front/malloc_tiny_fast.h - L181: return (uint8_t*)base + 1 → tiny_base_to_user_inline(base) - L299: void* base = (void*)((char*)ptr - 1) → tiny_user_to_base_inline(ptr) Benefits: - Self-documenting code (semantic intent is clear) - Single source of truth for header offset - Easier to extend (e.g., variable-length headers, alignment changes) - Type-safe conversions (macro validates pointer types) - Zero performance cost (inline macro, same compiled code) Contract: - Header stored at offset -1 from USER pointer - Allocation: base → user (user = base + 1) - Deallocation: user → base (base = user - 1) No semantic changes - identical logic, just centralized. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
33 lines
987 B
C
33 lines
987 B
C
#ifndef HAKMEM_TINY_PTR_CONVERT_BOX_H
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#define HAKMEM_TINY_PTR_CONVERT_BOX_H
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#include <stddef.h>
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// Purpose: Zero-overhead inline conversions between BASE and USER pointers
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// Contract: Header is stored at offset -1 from USER pointer
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//
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// Example:
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// - Allocation: base → user (user = base + 1)
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// - Deallocation: user → base (base = user - 1)
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//
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// Offset definition (centralized for future extension)
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#define TINY_HEADER_OFFSET 1
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// Direct inline macros (zero cost, lvalue compatible in some contexts)
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#define tiny_base_to_user_inline(base) \
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((void*)((char*)(base) + TINY_HEADER_OFFSET))
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#define tiny_user_to_base_inline(user) \
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((void*)((char*)(user) - TINY_HEADER_OFFSET))
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// Verbose variants (for clarity in critical paths)
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static inline void* tiny_base_to_user(void* base) {
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return tiny_base_to_user_inline(base);
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}
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static inline void* tiny_user_to_base(void* user) {
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return tiny_user_to_base_inline(user);
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}
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#endif // HAKMEM_TINY_PTR_CONVERT_BOX_H
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