136 lines
4.0 KiB
C
136 lines
4.0 KiB
C
#include "memorymap.h"
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#include <stdbool.h>
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int compare_regions(struct memory_region_t *lhs, struct memory_region_t *rhs)
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{
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if(lhs->location == rhs->location)
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{
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return lhs->size > rhs->size ? 1
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: (lhs->size == rhs->size ? 0
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: -1);
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}
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else
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{
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return lhs->location > rhs->location ? 1 : -1;
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}
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}
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bool region_overlaps(struct memory_region_t *lhs, struct memory_region_t *rhs)
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{
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if(rhs->location < lhs->location)
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{
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return rhs->location + rhs->size > lhs->location;
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}
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return rhs->location < lhs->location + lhs->size;
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}
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bool region_contains(struct memory_region_t *lhs, struct memory_region_t *rhs)
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{
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return (rhs->location >= lhs->location) &&
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(rhs->location + rhs->size <= lhs->location + lhs->size);
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}
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void insert_map_entry(struct memory_map_t *map, physaddr_t location, size_t size, unsigned int type)
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{
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struct memory_region_t new_region = {.location = location, .size = size, .type = type};
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unsigned int i = 0;
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while(i < map->size)
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{
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if(compare_regions(&new_region, &map->array[i]) < 0)
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{
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struct memory_region_t buffer = new_region;
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new_region = map->array[i];
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map->array[i] = buffer;
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}
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i++;
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}
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map->array[i] = new_region;
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map->size++;
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}
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void remove_map_entry(struct memory_map_t *map, int index)
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{
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if(index >= 0 && index < map->size)
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{
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for(int i = index; i < map->size - 1; i++)
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{
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map->array[i] = map->array[i + 1];
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}
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map->size--;
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}
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}
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int trim_map(struct memory_map_t *map, int index)
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{
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if(index + 1 >= map->size)
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{
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return -1;
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}
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struct memory_region_t left = map->array[index];
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struct memory_region_t right = map->array[index + 1];
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if(region_overlaps(&left, &right))
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{
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if(left.type == right.type)
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{
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left.size = (right.location + right.size > left.location + left.size ? right.location + right.size : left.location + left.size) - left.location;
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remove_map_entry(map, index + 1);
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return index;
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}
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else if(left.type < right.type)
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{
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if(region_contains(&right, &left))
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{
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remove_map_entry(map, index);
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return index;
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}
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else if(left.location + left.size <= right.location + right.size)
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{
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left.size = (right.location > left.location) ? right.location - left.location : 0;
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return index + 1;
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}
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else
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{
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struct memory_region_t new_right = {
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.location = right.location + right.size,
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.size = (left.location + left.size) - (right.location + right.size),
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.type = left.type};
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left.size = (right.location > left.location) ? right.location - left.location : 0;
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if(left.size == 0)
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remove_map_entry(map, index);
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insert_map_entry(map, new_right.location, new_right.size, new_right.type);
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return index + 2;
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}
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}
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else
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{
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if(region_contains(&left, &right))
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{
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remove_map_entry(map, index + 1);
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return index;
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}
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else
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{
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right.size = (right.location + right.size) - (left.location + left.size);
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right.location = left.location + left.size;
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return index + 1;
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}
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}
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}
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else if((left.location + left.size == right.location) && left.type == right.type)
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{
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left.size = right.location + right.size - left.location;
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remove_map_entry(map, index + 1);
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return index;
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}
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return index + 1;
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}
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void insert_region(struct memory_map_t *map, physaddr_t location, size_t size, unsigned int type)
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{
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insert_map_entry(map, location, size, type);
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int i = 0;
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while(i >= 0)
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{
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i = trim_map(map, i);
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}
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} |