/**
* Reads a block of memory and generates a rabin fingerprint list from it.
* Since most of the time we will not end on a border, the function returns
* a block struct, which keeps track of the current blocksum and rolling checksum
*/
struct rab_block_info *read_rabin_block(void *buf, ssize_t size, struct rab_block_info *cur_block) {
struct rab_block_info *block;
if(cur_block == NULL) {
block=init_empty_block();
if(block == NULL)
return NULL;
}
else {
block=cur_block;
}
//We ended on a border, gen a new tail
if(block->current_poly_finished) {
struct rabin_polynomial *new_poly=gen_new_polynomial(NULL,0,0,0);
block->tail->next_polynomial=new_poly;
block->tail=new_poly;
block->current_poly_finished=0;
}
ssize_t i;
for(i=0;i<size;i++) {
char cur_byte=*((char *)(buf+i));
char pushed_out=block->current_window_data[block->window_pos];
block->current_window_data[block->window_pos]=cur_byte;
block->cur_roll_checksum=(block->cur_roll_checksum*rabin_polynomial_prime)+cur_byte;
block->tail->polynomial=(block->tail->polynomial*rabin_polynomial_prime)+cur_byte;
block->cur_roll_checksum-=(pushed_out*polynomial_lookup_buf[rabin_sliding_window_size]);
block->window_pos++;
block->total_bytes_read++;
block->tail->length++;
if(block->window_pos == rabin_sliding_window_size) //Loop back around
block->window_pos=0;
//If we hit our special value or reached the max win size create a new block
if((block->tail->length >= rabin_polynomial_min_block_size && (block->cur_roll_checksum % rabin_polynomial_average_block_size) == rabin_polynomial_prime)|| block->tail->length == rabin_polynomial_max_block_size) {
block->tail->start=block->total_bytes_read-block->tail->length;
struct rabin_polynomial *new_poly=gen_new_polynomial(NULL,0,0,0);
block->tail->next_polynomial=new_poly;
block->tail=new_poly;
if(i==size-1)
block->current_poly_finished=1;
}
}
return block;
}
//given a file extract blocks and check for duplicates
int extract_blocks(char* filename){
//printf("Processing %s \n",filename);
int fd = open(filename,O_RDONLY | O_LARGEFILE);
uint64_t off=0;
if(fd){
struct stat st;
stat(filename, &st);
total_space+=st.st_size;
//declare a block
unsigned char block_read[READSIZE];
bzero(block_read,sizeof(block_read));
//read first block from file
int aux = pread(fd,block_read,READSIZE,off);
off+= READSIZE;
//check if the file still has more blocks and if size <bzise discard
//the last incomplete block
while(aux>0){
//Process fixed size dups all sizes specified
int curr_sizes_proc=0;
while(curr_sizes_proc<nr_sizes_proc){
int size_block=sizes_proc[curr_sizes_proc];
int size_proced=0;
unsigned char *block_proc;
while(aux-size_proced>=size_block){
block_proc=malloc(size_block);
bzero(block_proc,size_block);
memcpy(block_proc,&block_read[size_proced],size_block);
//index the block and find duplicates
check_duplicates(block_proc,size_block,curr_sizes_proc);
free(block_proc);
size_proced+=size_block;
}
if(aux-size_proced > 0){
incomplete_blocks[curr_sizes_proc]++;
incomplete_space[curr_sizes_proc]+=aux-size_proced;
//process the block anyway
block_proc=malloc(aux-size_proced);
bzero(block_proc,aux-size_proced);
memcpy(block_proc,&block_read[size_proced],aux-size_proced);
//index the block and find duplicates
check_duplicates(block_proc,aux-size_proced,curr_sizes_proc);
free(block_proc);
}
curr_sizes_proc++;
}
//process rabin chunks with avg size of 1K,4K,8K,16K
//min size = avg size/2 and max size = avg size*2
//Process fixed size dups for 1K,4K,8K,16K
int curr_sizes_proc_rabin=0;
while(curr_sizes_proc_rabin<nr_sizes_proc_rabin){
rabin_polynomial_min_block_size=sizes_proc_rabin[curr_sizes_proc_rabin]/2;
rabin_polynomial_max_block_size=sizes_proc_rabin[curr_sizes_proc_rabin]*2;
rabin_polynomial_average_block_size=sizes_proc_rabin[curr_sizes_proc_rabin];
rabin_sliding_window_size=30;
struct rab_block_info *block;
if(cur_block[curr_sizes_proc_rabin] == NULL) {
//printf("Initializing rabin block %d\n",curr_sizes_proc_rabin);
cur_block[curr_sizes_proc_rabin]=init_empty_block();
}
block=cur_block[curr_sizes_proc_rabin];
int i;
for(i=0;i<aux;i++) {
char cur_byte=*((char *)(block_read+i));
char pushed_out=block->current_window_data[block->window_pos];
block->current_window_data[block->window_pos]=cur_byte;
block->cur_roll_checksum=(block->cur_roll_checksum*rabin_polynomial_prime)+cur_byte;
block->tail->polynomial=(block->tail->polynomial*rabin_polynomial_prime)+cur_byte;
block->cur_roll_checksum-=(pushed_out*polynomial_lookup_buf[rabin_sliding_window_size]);
block->window_pos++;
block->total_bytes_read++;
block->tail->length++;
if(block->window_pos == rabin_sliding_window_size) //Loop back around
block->window_pos=0;
//If we hit our special value or reached the max win size create a new block
if((block->tail->length >= rabin_polynomial_min_block_size && (block->cur_roll_checksum % rabin_polynomial_average_block_size) == rabin_polynomial_prime)|| block->tail->length == rabin_polynomial_max_block_size) {
block->tail->start=block->total_bytes_read-block->tail->length;
//insert hash in berkDB
//index the block and find duplicates
check_rabin_duplicates(cur_block[curr_sizes_proc_rabin]->tail,nr_sizes_proc+curr_sizes_proc_rabin);
//free oldblock and polinomial
//free(cur_block[curr_sizes_proc]->tail);
cur_block[curr_sizes_proc_rabin]->tail=gen_new_polynomial(NULL,0,0,0);
//if(i==READSIZE-1)
//cur_block[curr_sizes_proc_rabin]->current_poly_finished=1;
}
}
curr_sizes_proc_rabin++;
}
//free this block from memory and process another
//free(block_read);
//block_read=malloc(sizeof(unsigned char)*READSIZE);
aux = pread(fd,block_read,READSIZE,off);
off+=READSIZE;
}
//zero the blocks a new file is being processed
int auxc=0;
for(auxc=0;auxc<nr_sizes_proc_rabin;auxc++){
struct rab_block_info *lastblock;
lastblock = cur_block[auxc];
if( lastblock->tail->length > 0){
if(lastblock->tail->length < sizes_proc_rabin[auxc]/2 ){
incomplete_blocks[nr_sizes_proc+auxc]++;
incomplete_space[nr_sizes_proc+auxc]+=lastblock->tail->length;
}
//insert hash in berkDB
//index the block and find duplicates
check_rabin_duplicates(lastblock->tail,nr_sizes_proc+auxc);
}
cur_block[auxc]=NULL;
}
close(fd);
}
else{
fprintf(stderr,"error opening file %s\n",filename);
exit(1);
}
return 0;
}