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| #include<stdio.h>
#include<malloc.h>
#include<algorithm>
struct buddy
{
unsigned int size;
unsigned int* longest;
unsigned int* offset;
bool* is_exist;
bool* is_alloc;
bool* is_cut;
bool* is_run;
};
inline bool is_power_of_2(unsigned x) {
return !(x & (x - 1));
}
unsigned fixsize(unsigned size) {
size |= size >> 1;
size |= size >> 2;
size |= size >> 4;
size |= size >> 8;
size |= size >> 16;
return size + 1;
}
inline unsigned left_leaf(unsigned index) {
return index * 2 + 1;
}
inline unsigned right_leaf(unsigned index) {
return index * 2 + 2;
}
inline unsigned parent(unsigned index) {
return (index + 1) / 2 - 1;
}
struct buddy* buddy_new(int size) {
struct buddy* self;
unsigned node_size;
int i;
if (size < 1) {
size = 1;
}
if (is_power_of_2(size) == false) {
size = fixsize(size);
}
self = (struct buddy*)malloc(2 * size * sizeof(size_t));
self->size = size;
node_size = size * 2;
self->longest = (unsigned int*)malloc((size * 2 - 1) * sizeof(unsigned int));
self->offset = (unsigned int*)malloc((size * 2 - 1) * sizeof(unsigned int));
self->is_exist = (bool*)malloc((size * 2 - 1) * sizeof(bool));
self->is_alloc = (bool*)malloc((size * 2 - 1) * sizeof(bool));
self->is_cut = (bool*)malloc((size * 2 - 1) * sizeof(bool));
self->is_run = (bool*)malloc((size * 2 - 1) * sizeof(bool));
for (i = 0; i < size * 2 - 1; ++i) {
if (is_power_of_2(i + 1)) {
node_size /= 2;
}
self->longest[i] = node_size;
self->offset[i] = 0;
self->is_exist[i] = false;
self->is_alloc[i] = false;
self->is_cut[i] = false;
self->is_run[i] = true;
}
self->is_exist[0] = true;
return self;
}
void buddy_print(buddy* bd) {
int i, j;
int layers;
int y = 2;
int size = bd->size;
int size_tmp = size;
for (layers = 1; size_tmp != 1; layers++) {
size_tmp /= 2;
}
printf("\nbuddy size: %d (%d layers)\n", size, layers);
for (i = 1; i <= 2 * size - 1; i++)
{
for (j = 0; j < layers; j++)
{
printf(" ");
}
if (bd->is_exist[i - 1] == false)
{
printf("%d", bd->longest[i - 1]);
}
else if (bd->is_cut[i - 1] == true)
{
printf("(%d)", bd->longest[i - 1]);
}
else if (bd->is_alloc[i - 1] == true)
{
printf("<%d>", bd->longest[i - 1]);
}
else if (bd->is_alloc[i - 1] == false)
{
printf("[%d]", bd->longest[i - 1]);
}
if (i == y - 1) {
printf("\n");
y = y * 2;
layers--;
}
}
}
void buddy_alloc(struct buddy* bp, int size) {
unsigned index = 0;
unsigned node_size;
unsigned offset = 0;
int i;
struct buddy* self = bp;
if (size <= 0 || size > self->longest[1]) {
printf("\nSize wrong\n");
}
else if (!is_power_of_2(size)) {
size = fixsize(size);
}
for (i = 0; i < self->size * 2 - 1; ++i) {
self->is_run[i] = true;
}
for (node_size = self->size; node_size != size; node_size /= 2) {
if (self->longest[left_leaf(index)] >= size && self->is_alloc[left_leaf(index)] == false
&& self->is_run[left_leaf(index)] == true) {
if (self->is_exist[left_leaf(index)] == false) {
self->is_cut[index] = true;
self->is_exist[left_leaf(index)] = true;
self->is_exist[right_leaf(index)] = true;
}
if (self->longest[left_leaf(index)] == size && self->is_cut[left_leaf(index)] == true) {
self->is_run[left_leaf(index)] = false;
node_size *= 2;
continue;
}
index = left_leaf(index);
}
else if (self->longest[right_leaf(index)] >= size && self->is_alloc[right_leaf(index)] == false
&& self->is_run[right_leaf(index)] == true) {
index = right_leaf(index);
}
else
{
self->is_run[index] = false;
if (index == 0) {
break;
}
index = parent(index);
node_size *= 4;
}
offset = (index + 1) * node_size - self->size;
}
if (index == 0) {
printf("\nbuffer is full\n");
return;
}
self->is_alloc[index] = true;
self->offset[index] = offset;
printf("your index:%d\n", index);
printf("your offset:%d\n", offset);
}
void buddy_free(struct buddy* self, int bdindex) {
unsigned node_size;
unsigned index = bdindex;
if (self->is_exist[index] == false) {
printf("\nIndex wrong\n");
return;
}
if (self->is_cut[index] == true) {
printf("\nIts children are still being used\n");
return;
}
if (self->is_alloc[index] == false) {
printf("\nDouble free\n");
return;
}
printf("\ntarget buffer index: %d\n", index);
printf(">> size: %d\n", self->longest[index]);
printf(">> offset: %d\n", self->offset[index]);
for (; index != 0;) {
if (self->is_alloc[index] = true) {
self->is_alloc[index] = false;
}
index = parent(index);
if (self->is_alloc[left_leaf(index)] == false && self->is_alloc[right_leaf(index)] == false
&& self->is_cut[left_leaf(index)] == false && self->is_cut[right_leaf(index)] == false) {
self->is_exist[left_leaf(index)] = false;
self->is_exist[right_leaf(index)] = false;
self->is_cut[index] = false;
}
}
}
char Choose() {
char choice[2];
printf("----------------\n");
printf("|Buddy System |\n");
printf("| |\n");
printf("|your choice: |\n");
printf("|1. new |\n");
printf("|2. alloc |\n");
printf("|3. free |\n");
printf("|4. show |\n");
printf("|5. exit |\n");
printf("----------------\n");
printf(">> ");
scanf("%s", choice);
choice[1] = 0;
return choice[0];
}
int main() {
buddy* bd = NULL;
int size;
char choice;
while (true)
{
choice = Choose();
switch (choice)
{
case 0x31:
printf("input size:\n");
printf(">> ");
scanf("%d", &size);
bd = buddy_new(size);
buddy_print(bd);
break;
case 0x32:
if (bd == NULL) {
printf("\nplease create a Buddy System first\n\n");
continue;
}
printf("input size\n");
printf(">> ");
scanf("%d", &size);
buddy_alloc(bd, size);
buddy_print(bd);
break;
case 0x33:
if (bd == NULL) {
printf("\nplease create a Buddy System first\n\n");
continue;
}
printf("input offset\n");
printf(">> ");
scanf("%d", &size);
buddy_free(bd, size);
buddy_print(bd);
break;
case 0x34:
if (bd == NULL) {
printf("\nplease create a Buddy System first\n\n");
continue;
}
buddy_print(bd);
break;
case 0x35:
printf("\nending\n");
exit(0);
default:
printf("Choice wrong\n");
break;
}
}
return 0;
}
|