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Diffstat (limited to 'libwinnie/src/shalloc.cc')
| -rw-r--r-- | libwinnie/src/shalloc.cc | 213 |
1 files changed, 0 insertions, 213 deletions
diff --git a/libwinnie/src/shalloc.cc b/libwinnie/src/shalloc.cc deleted file mode 100644 index 1bb7db2..0000000 --- a/libwinnie/src/shalloc.cc +++ /dev/null @@ -1,213 +0,0 @@ -/* -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 <stdint.h> -#include <stdlib.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 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)); - } - - 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)); - } - shm_unlink(SHMNAME); -} - -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); -} - |