118 lines
3.1 KiB
C++
118 lines
3.1 KiB
C++
#include "master.hpp"
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namespace factor {
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void free_list::clear_free_list() {
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for (cell i = 0; i < free_list_count; i++)
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small_blocks[i].clear();
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large_blocks.clear();
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free_block_count = 0;
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free_space = 0;
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}
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void free_list::initial_free_list(cell start, cell end, cell occupied) {
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clear_free_list();
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if (occupied != end - start) {
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free_heap_block* last_block = (free_heap_block*)(start + occupied);
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last_block->make_free(end - (cell)last_block);
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add_to_free_list(last_block);
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}
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}
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void free_list::add_to_free_list(free_heap_block* block) {
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cell size = block->size();
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free_block_count++;
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free_space += size;
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if (size < free_list_count * data_alignment)
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small_blocks[size / data_alignment].push_back(block);
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else
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large_blocks.insert(block);
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}
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free_heap_block* free_list::find_free_block(cell size) {
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/* Check small free lists */
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if (size / data_alignment < free_list_count) {
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std::vector<free_heap_block*>& blocks = small_blocks[size / data_alignment];
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if (blocks.size() == 0) {
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/* Round up to a multiple of 'size' */
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cell large_block_size = ((allocation_page_size + size - 1) / size) * size;
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/* Allocate a block this big */
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free_heap_block* large_block = find_free_block(large_block_size);
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if (!large_block)
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return NULL;
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large_block = split_free_block(large_block, large_block_size);
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/* Split it up into pieces and add each piece back to the free list */
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for (cell offset = 0; offset < large_block_size; offset += size) {
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free_heap_block* small_block = large_block;
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large_block = (free_heap_block*)((cell)large_block + size);
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small_block->make_free(size);
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add_to_free_list(small_block);
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}
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}
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free_heap_block* block = blocks.back();
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blocks.pop_back();
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free_block_count--;
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free_space -= block->size();
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return block;
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} else {
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/* Check large free list */
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free_heap_block key;
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key.make_free(size);
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large_block_set::iterator iter = large_blocks.lower_bound(&key);
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large_block_set::iterator end = large_blocks.end();
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if (iter != end) {
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free_heap_block* block = *iter;
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large_blocks.erase(iter);
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free_block_count--;
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free_space -= block->size();
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return block;
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}
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return NULL;
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}
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}
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free_heap_block* free_list::split_free_block(free_heap_block* block,
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cell size) {
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if (block->size() != size) {
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/* split the block in two */
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free_heap_block* split = (free_heap_block*)((cell)block + size);
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split->make_free(block->size() - size);
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block->make_free(size);
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add_to_free_list(split);
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}
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return block;
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}
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bool free_list::can_allot_p(cell size) {
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return largest_free_block() >= std::max(size, allocation_page_size);
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}
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cell free_list::largest_free_block() {
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if (large_blocks.size()) {
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large_block_set::reverse_iterator last = large_blocks.rbegin();
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return (*last)->size();
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} else {
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for (int i = free_list_count - 1; i >= 0; i--) {
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if (small_blocks[i].size())
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return small_blocks[i].back()->size();
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}
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return 0;
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}
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}
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}
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