godot/core/object/callable_method_pointer.cpp

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/*  callable_method_pointer.cpp                                           */
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#include "callable_method_pointer.h"

bool CallableCustomMethodPointerBase::compare_equal(const CallableCustom *p_a, const CallableCustom *p_b) {
	const CallableCustomMethodPointerBase *a = static_cast<const CallableCustomMethodPointerBase *>(p_a);
	const CallableCustomMethodPointerBase *b = static_cast<const CallableCustomMethodPointerBase *>(p_b);

	if (a->comp_size != b->comp_size) {
		return false;
	}

	// Avoid sorting by memory address proximity, which leads to unpredictable performance over time
	// due to the reuse of old addresses for newer objects. Use byte-wise comparison to leverage the
	// backwards encoding of little-endian systems as a way to decouple spatiality and time.
	return memcmp(a->comp_ptr, b->comp_ptr, a->comp_size * 4) == 0;
}

bool CallableCustomMethodPointerBase::compare_less(const CallableCustom *p_a, const CallableCustom *p_b) {
	const CallableCustomMethodPointerBase *a = static_cast<const CallableCustomMethodPointerBase *>(p_a);
	const CallableCustomMethodPointerBase *b = static_cast<const CallableCustomMethodPointerBase *>(p_b);

	if (a->comp_size != b->comp_size) {
		return a->comp_size < b->comp_size;
	}

	// See note in compare_equal().
	return memcmp(a->comp_ptr, b->comp_ptr, a->comp_size * 4) < 0;
}

CallableCustom::CompareEqualFunc CallableCustomMethodPointerBase::get_compare_equal_func() const {
	return compare_equal;
}

CallableCustom::CompareLessFunc CallableCustomMethodPointerBase::get_compare_less_func() const {
	return compare_less;
}

uint32_t CallableCustomMethodPointerBase::hash() const {
	return h;
}

void CallableCustomMethodPointerBase::_setup(uint32_t *p_base_ptr, uint32_t p_ptr_size) {
	comp_ptr = p_base_ptr;
	comp_size = p_ptr_size / 4;

	// Precompute hash.
	for (uint32_t i = 0; i < comp_size; i++) {
		if (i == 0) {
			h = hash_murmur3_one_32(comp_ptr[i]);
		} else {
			h = hash_murmur3_one_32(comp_ptr[i], h);
		}
	}
}