+void *sh_malloc(size_t bytes)
+{
+ if(!bytes) {
+ return 0;
+ }
+
+ int num_blocks = (bytes + BLOCK_SIZE - 1) / BLOCK_SIZE;
+
+ int free_block;
+ int ctr = 0;
+ for(int i=0; i<NUM_BLOCKS; i++) {
+ if(!is_allocated(i)) {
+ if(!ctr) {
+ free_block = i;
+ }
+ ctr++;
+ }
+ else {
+ ctr = 0;
+ }
+
+ if(ctr == num_blocks) {
+ alloc_blocks(free_block, num_blocks);
+ return block_to_addr(free_block);
+ }
+ }
+
+ return 0;
+}
+
+void sh_free(void *ptr)
+{
+ int block = addr_to_block((unsigned char*)ptr);
+ std::map<int, int>::iterator it;
+ if((it = alloc_sizes.find(block)) != alloc_sizes.end()) {
+ int num_blocks = it->second;
+ free_blocks(block, num_blocks);
+ alloc_sizes.erase(it);
+ }
+ else {
+ fprintf(stderr, "Attempt to free non-existent blocks from: %d\n", block);
+ }
+}
+
+static bool is_allocated(int block_number)
+{
+ int idx = block_number / 32;
+ int bit_num = block_number % 32;
+
+ if((bitmap[idx] >> bit_num) & 1) {
+ return true;
+ }
+
+ return false;
+}
+
+static int addr_to_block(unsigned char *addr)
+{
+ assert(addr >= pool);
+ assert(addr < pool + POOL_SIZE);
+
+ return (addr - pool) / BLOCK_SIZE;
+}
+
+static unsigned char *block_to_addr(int block_number)
+{
+ assert(block_number >= 0);
+ assert(block_number < NUM_BLOCKS);
+
+ return pool + block_number * BLOCK_SIZE;
+}
+
+static void alloc_blocks(int block_pos, int num_blocks)
+{
+ for(int i=0; i<num_blocks; i++) {
+ int block_number = i + block_pos;
+ int idx = block_number / 32;
+ int bit_num = block_number % 32;
+
+ bitmap[idx] |= ((uint32_t)1 << bit_num); // or pow(2, i)
+ }
+
+ alloc_sizes[block_pos] = num_blocks;
+
+ stats.alloc_num++;
+ stats.alloc_memsize += BLOCK_SIZE * num_blocks;
+}
+
+static void free_blocks(int block_pos, int num_blocks)
+{
+ for(int i=0; i<num_blocks; i++) {
+ int block_number = i + block_pos;
+ int idx = block_number / 32;
+ int bit_num = block_number % 32;
+
+ bitmap[idx] &= ~((uint32_t)1 << bit_num);
+ }
+
+ stats.free_num++;
+ stats.free_memsize += BLOCK_SIZE * num_blocks;
+}
+
+static void print_stats()
+{
+ printf("Total allocated memory: %d\n", stats.alloc_memsize);
+ printf("Total deallocated memory: %d\n", stats.free_memsize);
+ printf("Number of allocations: %d\n", stats.alloc_num);
+ printf("Number of deallocations: %d\n", stats.free_num);
+}
+