+++ /dev/null
-/*
-winnie - an experimental window system
-
-Copyright (C) 2013 Eleni Maria Stea
-
-This program is free software: you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with this program. If not, see <http://www.gnu.org/licenses/>.
-
-Author: Eleni Maria Stea <elene.mst@gmail.com>
-*/
-
-#include <assert.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
-#include <string.h>
-
-#include <errno.h>
-#include <fcntl.h>
-#include <sys/mman.h>
-#include <sys/stat.h>
-#include <unistd.h>
-
-#include <map>
-
-#include "shalloc.h"
-
-#define SHMNAME "/winnie.shm"
-
-#define POOL_SIZE 16777216
-#define BLOCK_SIZE 512
-
-#define NUM_BLOCKS (POOL_SIZE / BLOCK_SIZE)
-#define BITMAP_SIZE (NUM_BLOCKS / 32)
-
-static bool is_allocated(int block_number);
-static int addr_to_block(unsigned char *addr);
-static unsigned char *block_to_addr(int block_number);
-static void alloc_blocks(int block_pos, int num_blocks);
-static void free_blocks(int block_pos, int num_blocks);
-
-static void print_stats();
-static int fd;
-
-static unsigned char *pool;
-static std::map<int, int> alloc_sizes; //starting block -> number of blocks
-
-// 0 means not allocated 1 means allocated
-static uint32_t bitmap[BITMAP_SIZE];
-
-struct Statistics {
- int alloc_num;
- int free_num;
- int alloc_memsize;
- int free_memsize;
-};
-
-static Statistics stats;
-
-bool init_shared_memory()
-{
- if(((fd = shm_open(SHMNAME, O_RDWR | O_CREAT, S_IRWXU)) == -1)) {
- fprintf(stderr, "Failed to open shared memory: %s\n", strerror(errno));
- return false;
- }
- ftruncate(fd, POOL_SIZE);
-
- if((pool = (unsigned char*)mmap(0, POOL_SIZE, PROT_READ | PROT_WRITE,
- MAP_SHARED, fd, 0)) == (void*)-1) {
- fprintf(stderr, "Failed to map shared memory: %s\n", strerror(errno));
- }
-
- shm_unlink(SHMNAME);
-
- for(int i=0; i<BITMAP_SIZE; i++) {
- bitmap[i] = 0;
- }
-
- alloc_sizes.clear();
- memset(&stats, 0, sizeof stats);
-
- return true;
-}
-
-void destroy_shared_memory()
-{
- print_stats();
- if(munmap(pool, POOL_SIZE) == -1) {
- fprintf(stderr, "Failed to unmap shared memory: %s\n", strerror(errno));
- }
-}
-
-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);
- }
-}
-
-void *get_pool()
-{
- return (void*)pool;
-}
-
-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);
-}
-
projects / winnie / blobdiff